Transcript KOMPENDIUM VALUASI EKOLOGI EKONOMI SUMBERDAYA LAHAN

VALUASI
EKONOMI
SUMBERDAYA
LAHAN
Diabstraksikan : Soemarno
PSL-PPSUB NOPEMBER 2012
LAHAN KUBIS
TIDAK SEMUA LAHAN DAPAT
MENDUKUNG PRODUKSI KUBIS
LAHAN = SUMBERDAYA EKONOMI
Land is the economic resource encompassing natural resources found
within a nation economy. This resource includes timber, land,
fisheries, farms and other similar natural resources. Land is usually a
limited resource for many economies. Although some natural
resources, such as timber, food and animals, are renewable, the
physical land is usually a fixed resource. Nations must carefully use
their land resource by creating a mix of natural and industrial uses.
Using land for industrial purposes allows nations to improve the
production processes for turning natural resources into consumer
goods.
Gross Margin: The simplest economic measure is the gross margin,
which is the cash flow out less the cash flow in, on a per unit area
(normalized or standardized) or aggregate (per-field or per-farm)
basis, in one accounting period (usually a year).
The gross margin can be expressed in terms of the return to labor
or the return to land.
Return to labor: the farm family’s labor is not included as an
expense, and the gross margin must be sufficient to allow the farm
family an adequate income. This makes most sense if the gross
margin is non-normalized, i.e., the actual amount received for the
whole farm.
Return to land: the farm family’s labor is included in the expenses,
as if the labor had been contracted. If the ‘wage’ is at a reasonable
level, the gross margin only has to be positive for the land use to
be feasible. This makes most sense if the gross margin is
normalized, i.e., the amount received per unit land area.
Diunduh dari Sumber: http://smallbusiness.chron.com/economic-definition-fourfactors-production-3941.html .................... 3/11/2012 .
LAHAN …..
Land, In economics, the resource that encompasses the natural
resources used in production. In classical economics, the three factors
of production are land, labour, and capital.
Land was considered to be the “original and inexhaustible gift of
nature.” In modern economics, it is broadly defined to include all that
nature provides, including minerals, forest products, and water and
land resources. While many of these are renewable resources, no one
considers them “inexhaustible.”
The payment to land is called rent.
Like land, its definition has been broadened over time to include
payment to any productive resource with a relatively fixed supply.
Automated Land Evaluation System ‘ALES’.
How ALES links land characteristics with economic values
Starting from the physical inventory of the characteristics of a land
area, how do we arrive at an economic value of a land use if
implemented on that land area?
By means of severity levels of Land Qualities, which can either limit
yield (and thus reduce income) or increase costs.
Land Qualities, and their diagnostic Land Characteristics, can be
divided into two type for this analysis:
1. Location-independent (in-situ) and
2. Location dependent.
E.g. (1) soil and climate qualities and characteristics, (2) distance,
Adjacency.
Diunduh dari Sumber: http://www.britannica.com/EBchecked/topic/329078/land
.................... 3/11/2012 .
LAND QUALITY INDICATOR (LQI)
Some generic indicators of land units that must be monitored,
especially for:
1. Condition of land resources, both positive and negative;
2. Areas arising from different land uses;
3. Rates of adaptation and adoption of recommended/suggested practices;
4. Farm management practices;
5. Yields and other outputs resulting from project interventions or other
development;
6. Rural development issues such as land tenure, population density;
7. Water resources;
8. Fisheries and aquaculture;
9. Forest management;
10. Land-soil nutrients.
Lahan pertanian produktif –mixed cropping
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
The holistic concept of Land (FAO ,1976;
FAO, 1995) :
"Land is a delineable area of the earth's terrestrial
surface, encompassing all attributes of the biosphere
immediately above or below this surface, including those
of the near-surface climate, the soil and terrain forms, the
surface hydrology (including shallow lakes, rivers,
marshes and swamps), the near-surface sedimentary
layers and associated groundwater reserve, the plant and
animal populations, the human settlement pattern and
physical results of past and present human activity
(terracing, water storage or drainage structures, roads,
buildings, etc.).“
The functions of Land:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Production function
Biotic environmental function
Climate-regulative function
Hydrologic function
Storage function
Waste and pollution control function
Living space function
Archive or heritage function
Connective space function.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
Land attributes, characteristics,
properties and qualities (or
limitations/ conditions):
1. ATTRIBUTE, or variable, is a neutral, overarching term for a single or compound aspect
of the land;
2. CHARACTERISTIC is an attribute which is
easily noticed and which serves as a
distinguishing element for different types of
land; it may or may not have a practical
meaning (e.g., soil colour or texture, or height
of forest cover are characteristics without
giving direct information on land quality);
3. PROPERTY is an attribute that already gives a
degree of information on the value of the land
type;
4. LAND QUALITY (or limitation) is a complex
attribute of land which acts in a manner
distinct from the actions of other land
qualities in its influence on the suitability of
land for a specified kind of use.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
KERANGKA-KERJA EVALUASI LAHAN DARI
FAO 1976
LAND QUALITIES RELATED TO PRODUCTIVITY FROM
CROPS OR OTHER PLANT GROWTH
1. Crop yields (a resultant of many qualities listed
below).
2. Moisture availability.
3. Nutrient availability.
4. Oxygen availability in the root zone.
5. Adequacy of foothold for roots.
6. Conditions for germination.
7. Workability of the land (ease of cultivation).
8. Salinity or sodicity.
9. Soil toxicity.
10. Resistance to soil erosion.
11. Pests and diseases related to the land.
12. Flooding hazard (including frequency, periods of
inundation).
13. Temperature regime.
14. Radiation energy and photoperiod.
15. Climatic hazards affecting plant growth (including
wind, hail, frost).
16. Air humidity as affecting plant growth.
17. Drying periods for ripening of crops.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
FRAMEWORK FOR LAND EVALUATION OF 1976
LAND QUALITIES RELATED TO DOMESTIC ANIMAL PRODUCTIVITY
1.
2.
3.
4.
5.
6.
7.
8.
Productivity of grazing land.
Climatic hardships affecting animals.
Endemic pests and diseases.
Nutritive value of grazing land.
Toxicity of grazing land.
Resistance to degradation of vegetation.
Resistance to soil erosion under grazing conditions.
Availability of drinking water.
Lahan pertanian pada saat “bera” mernjadi sumber
rumput pakan ternak
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
FRAMEWORK FOR LAND
EVALUATION OF 1976
LAND QUALITIES RELATED TO FOREST PRODUCTIVITY
1.
2.
3.
4.
5.
6.
The qualities listed may refer to natural forests, forestry
plantations, or both.
Mean annual increments of timber species
Types and quantities of indigenous timber species.
Site factors affecting establishment of young trees.
Pests and diseases.
Fire hazard.
Kawasan hutan tanaman jati
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
FRAMEWORK FOR LAND
EVALUATION OF 1976
LAND QUALITIES RELATED TO
MANAGEMENT AND INPUTS
1. The qualities listed may refer to arable use,
animal production or forestry.
2. Terrain factors affecting mechanization
(trafficability).
3. Terrain factors affecting construction and
maintenance of access-roads (accessibility).
4. Size of potential management units (e.g. forest
blocks, farms, fields).
5. Location in relation to markets and to supplies of
inputs.
1.
2.
FAO. 1976. A framework for land evaluation. Soils Bulletin 32,
FAO, Rome. 72 p. Also, Publication 22, (R. Brinkman and A.
Young (eds.), ILRI, Wageningen, The Netherlands.
FAO. 1995. Planning for sustainable use of land resources:
towards a new approach, W.G. Sombroek and D. Sims. Land
and Water Bulletin 2, FAO, Rome.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
Land qualities related to vertical
components of a natural land unit
ATMOSPHERIC QUALITIES
1.
Atmospheric moisture supply: rainfall, length of growing
season, evaporation, dew formation.
Atmospheric energy for photosynthesis: temperature,
daylength, sunshine conditions.
Atmospheric conditions for crop ripening, harvesting and land
preparation: occurrence of dry spells.
2.
3.
LAND COVER QUALITIES
1.
2.
3.
4.
5.
6.
7.
8.
Value of the standing vegetation as "crop", such as timber.
Value of the standing vegetation as germ plasm:
biodiversity value.
Value of the standing vegetation as protection against
degradation of soils and catchment.
Value of the standing vegetation as regulator of local and
regional climatic conditions.
Regeneration capacity of the vegetation after complete
removal.
Value of the standing vegetation as shelter for crops and
cattle against adverse atmospheric influences.
Hindrance of vegetation at introduction of crops and
pastures: the land "development" costs.
Incidence of above-ground pests and vectors of diseases:
health risks of humans and animals.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
Land qualities related to vertical
components of a natural land unit
LAND SURFACE AND TERRAIN QUALITIES
1. Surface receptivity as seedbed: the tilth condition.
2. Surface treatability: the bearing capacity for cattle,
machinery, etc.
3. Surface limitations for the use of implements
(stoniness, stickiness, etc.): the arability.
4. Spatial regularity of soil and terrain pattern,
determining size and shape of fields with a capacity
for uniform management.
5. Surface liability to deformation: the occurrence or
hazard of wind and water erosion.
6. Accessibility of the land: the degree of remoteness
from means of transport.
7. The presence of open freshwater bodies for use by
humans, animals or fisheries.
8. Surface water storage capacity of the terrain: the
presence or potential of ponds, on-farm reservoirs,
bunds, etc.
9. Surface propensity to yield run-off water, for local
water harvesting or downstream water supply.
10. Accumulation position of the land: degree of fertility
renewal or crop damaging by overflow or overblow.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
Land qualities related to vertical
components of a natural land unit
SOIL QUALITIES
1. Physical soil fertility: the net moisture storage capacity
in the rootable zone.
2. Physical soil toxicity: the presence or hazard of
waterlogging in the rootable zone (i.e. the absence of
oxygen).
3. Chemical soil fertility: the availability of plant
nutrients.
4. Chemical soil toxicity: salinity or salinization hazard;
excess of exchangeable sodium.
5. Biological soil fertility: the N-fixation capacity of the
soil biomass; and its capacity for soil organic matter
turnover.
6. Biological soil toxicity: the presence or hazard of soilborne pests and diseases.
7. Substratum (and soil profile) as source of construction
materials.
8. Substratum (and soil profile) as source of minerals.
9. Biological soil toxicity: the presence or hazard of soilborne pests and diseases.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
Land qualities related to vertical
components of a natural land unit
SUBSTRATUM OR UNDERGROUND QUALITIES
1.
2.
3.
4.
Groundwater level and quality in relation to (irrigated) land use.
Substratum potential for water storage (local use) and conductance
(downstream use).
Presence of unconfined freshwater aquifers.
Substratum (and soil profile) suitability for foundation works
(buildings, roads, canals, etc.)
Deskripsi profil
tanah
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
LAND EVALUATION….
EVALUASI LAHAN
Land evaluation is the
process of assessment of
land performance when used
for specific purposes,
involving the execution and
interpretation of surveys and
LUT
studies of land forms, soils,
vegetation, climate and other
A land utilization type
aspects of land in order to
(FAO, 1976) is a kind of
identify and make a
land use described or
comparison of promising
defined in a higher degree
kinds of land use in terms
of detail than that of a
applicable to the objectives
major kind of land use
of the evaluation.
(such as rainfed
agriculture or forestry), as
an abstraction of actual
land-use systems (which
may be single, compound
or multiple).
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
KETAHANAN LAHAN
Some concepts of resilience of land and its productivity, comparing the
situation in someindustrialized countries (A) with that of most
developing countries (B). (Sombroek, 1993)
Ketahanan suatu Lahan :
The capacity of the land to recover quickly to former levels of
productivity - or to resume the trend to increased productivity - after
an adverse influence such as drought, floods, or human
abandonment or mismanagement.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
MAJOR ISSUES OF LAND MANAGEMENT….
1.
2.
3.
4.
Decline in quality of soils as rooting environments;
Erosion and loss of topsoil by wind and water;
Loss of vegetation cover, including woody perennials;
Acidification, soil fertility decline and plant nutrient
depletion;
5. Salinity and salinization, particularly in irrigated
systems.
Pengelolaan lahan sawah : Palawija musim kemarau
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
INDICATOR : Land condition change
(Change in land qualities).
The type OF INDICATORS:
1.
2.
3.
4.
5.
6.
Physical soil condition;
Diversity or density of vegetation cover;
Thickness of topsoil (by erosion or, conversely, by good
management);
Salinity or sodicity (alkaline conditions);
Terracing;
Establishment of contour vegetation strips.
Unit in which the indicator is measured: areal extent and magnitude of
change of the indicator types , with improvement and deterioration
reported separately.
Mulsa sisa-panen tanaman sebelumnya untuk
mengendalikan evaporasi
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
LAND QUALITY INDICATOR (LQI)
I. Above the soil surface, as related with yields:
1. Cover close to the ground: its density, distribution,
duration, timing.
2. Stress in plants: growth rates; timing and frequency of
wilting; visible nutrient deficiencies or imbalances.
II. On the soil surface, as affecting particularly soil
moisture and runoff+erosion:
Porosity of at least topsoil layers, in millimetric bands:
proportions of incident
rainfall becoming infiltrated;
III. Below the soil surface:
Organic matter content and biological activity, as affecting multiple
features:
Soil architecture:
. structural stability;
. gas exchange
. water movement and retention/release;
Cation exchange capacity:
. nutrient capture and retention;
. pH buffering;
. nutrient availability;
. source of small amounts of recycled nutrients.
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
LIMA MACAM LQI UNTUK PERTANIAN
DAN KEHUTANAN
1. NUTRIENT BALANCE: describes nutrient stocks and flows
as related to different land management systems used by
farmers in specific AEZs and specific countries.
2. YIELD TRENDS AND YIELD GAPS: describes current
yields, yield trends and actual:potential farm-level yields
for the major food crops in different countries.
3. LAND USE INTENSITY: describes the impacts of
agricultural intensification on land quality. Intensification
may involve increased cropping, more value-added
production, and increased amounts and frequency of
inputs; emphasis is on the management practices adopted
by farmers in the transition to intensification.
4. LAND USE DIVERSITY (agrodiversity): describes the
degree of diversification of production systems over the
landscape, including livestock and agroforestry systems;
it reflects the degree of flexibility (and resilience) of
regional farming systems, and their capacity to absorb
shocks and respond to opportunities.
5. LAND COVER: describes the extent, duration and timing
of vegetative cover on the land during major erosive
periods of the year. It is a surrogate for erosion and, along
with land use intensity and diversity, it will increase
understanding on the issues of desertification.
Diunduh dari Sumber:
http://wgbis.ces.iisc.ernet.in/energy/HC270799/LM/SUSLUP/KeySpeakers/ADumanski.
pdf .................... 3/11/2012 .
PRODUKTIVITAS TANAH
SOIL Fertility is the inherent capacity of a soil to supply nutrients in adequate
amounts and suitable proportions, whereas soil productivity is a wider term
referring to the ability of a soil to yield crops (Brady, 1974).
The chief factors in soil productivity are soil organic matter (including microbial
biomass), soil texture, structure, depth, nutrient content, water-storage
capacity, reaction and absence of toxic elements.
The soil productivity depends on physical, hydric, chemical and biologic
characteristics and their interaction.
Brady, N.C. 1974. The Nature and properties of soils. 8th Edition.
Macmillan, New York.
SAWAH IRIGASI TEKNIS
Diunduh dari Sumber:
http://www.fao.org/docrep/006/y4690e/y4690e08.htm.................... 3/11/2012 .
PRODUKTIVITAS LAHAN
Land productivity measures the wealth generated on a
piece of land.
High land productivity translates into :
1. Lower resource wastage,
2. Improved production processes,
3. Shorter turn-around time and,
4. Greater cost-savings.
Mulsa plastik – ciri usahatani intensif
Diunduh dari Sumber: http://www.mpl.ird.fr/crea/tallercolombia/FAO/AGLL/pdfdocs/landqual.pdf .................... 3/11/2012 .
KUALITAS & SIFAT-CIRI,
KARAKTERISTIK TANAH
Soil quality is generally defined in terms of the capacity of a soil to
perform specific functions in relation to human needs or purposes,
including maintaining environmental quality and sustaining plant
and animal production (Lal, 1998a).
Soil quality, in turn, derives from a variety of particular physical,
chemical, and biological properties that support these functions,
including topsoil depth, texture, bulk density, and water-holding
capacity; organic matter, pH level, and extractable nitrogen,
phosphorus, and potassium; and microbial biomass (Mausbach and
Seybold, 1998).
Some of these properties (e.g., pH, N, P, and K) are characterized by
optimum levels; departures from these optima (in either direction)
are associated with reduced soil quality. Other properties (e.g.,
topsoil depth and microbial biomass) contribute positively to soil
quality at all levels, while some (e.g., bulk density) are inversely
related to soil quality.
In addition to soil properties, other characteristics also play a critical
role in determining land quality, including aspects of terrain (such as
slope) and climate (such as temperature and precipitation, and thus
the length of growing period).
1.
2.
Lal, R. 1998a. “Soil Erosion Impact on Agronomic Productivity and
Environment Quality.” Critical Reviews in Plant Sciences 17(4): 319-464.
Mausbach, M. J., and C. A. Seybold . 1998. “Assessment of Soil Quality.”
In Soil Quality and Agricultural Sustainability, edited by Rattan Lal.
Chelsea, MI: Ann Arbor Press.
Diunduh dari Sumber:
http://www.ers.usda.gov/media/521837/aer823c_1_.pdf.................... 3/11/2012 .
STORIE INDEX
The Storie index is a method of soil rating based on soil
characteristics that govern the land's potential utilization and
productivity capacity. It is independent of other physical or
economic factors that might determine the desirability of growing
certain plants in a given location.
The evaluation is easy to be realized, being this an advantage of
this method.
A variety of categories are comprised in few categories.
Four or five parameters are evaluated:
1. A: Soil depth and texture;
2. B: Soil permeability;
3. C: Soil chemical characteristics;
4. D: Drainage, Surface runoff;
5. E: Climate (only if it is not homogeneous, if so than it should
not be included in the formula);
The index is calculated from the multiplication of these
parameters, that is:
Sindex = A x B x C x D x E
The disadvantage of this method is that if we have a value of zero
in any category, than the result will be zero and won't be suitable
for using.
Diunduh dari Sumber:
http://en.wikipedia.org/wiki/Storie_index....................
3/11/2012 .
STORIE INDEX RATING SYSTEM
The Storie Index Rating system ranks soil characteristics according to their
suitability for agriculture from Grade 1 soils (80 to 100 rating), which have few
or no limitations for agricultural production to Grade 6 soils (less than 10),
which are not suitable for agriculture.
Under this system, soils deemed less than prime can function as prime soils
when limitations such as poor drainage, slopes, or soil nutrient deficiencies are
partially or entirely removed.
The six grades, ranges in index rating, and definition of the grades, as defined by
the NRCS, are provided below in Table Storie Index Rating System.
Tanah yang mempunyai rating tinggi cocok untuk multiple cropping
Diunduh dari Sumber:
http://www.ci.oakley.ca.us/UserFiles/File/planning/RiverOaksCrossing%20Revised/3.9
_Agricultural%20Resources_final.pdf.................... 5/11/2012 .
Storie Index Rating System …
Diunduh dari Sumber: .................... 5/11/2012 .
Journal Transactions 4th Int. Cong. Soil Sci. 1950 Vol. 1 pp. 336-339
…
. The Storie Index, a general soil-rating system of particular use in
evaluating soils from an agricultural standpoint for tax
assessment, land appraisal and general land-use planning
purposes, is obtained by the multiplication of the per cent ratings
given to FACTORS:
1. A, the soil-profile depth and permeability;
2. B, texture;
3. C, slope and
4. X, factors modifiable by management, namely drainage,
salinity or alkalinity, nutrient level, acidity, erosion and microrelief.
The crop-productivity rating of a soil type is based on its yield as
compared with that of the soil types giving the highest yield
under stated management practices and climatic conditions, and
is expressed in ratios from 10 to 1 (that is 100% to 10% of highest
yields).
A given soil type may have one rating when undrained, another
when drained and a third when d "a ned and fertilized and so on.
Timber soil ratings are similarly handled but where production is
unknown, they are worked out by multiplying the ratings for
factors A, depth and texture; B, permeability; C, chemical
properties such as salinity; D, drainage and runoff and E, climate,
including rainfall, temperature, aspect.
Diunduh dari Sumber:
http://www.cabdirect.org/abstracts/19511900206.html;jsessionid=C0E71A3FA5EEDD62
EF48270B1D7C59AA .................... 5/11/2012 .
STORIE INDEX RATING SYSTEM…
Gradre
Index
Rating
Definition
1–
Excellent
80 through Soils are well suited to intensive use for growing irrigated crops that
100
are climatically suited to the region.
2 – Good
60 through Soils are good agricultural soils, although they may not be so
79
desirable as Grade 1 because of moderately coarse, coarse, or
gravelly surface soil texture; somewhat less permeable subsoil;
lower plant available water holding capacity, fair fertility; less well
drained conditions, or slight to moderate flood hazards, all acting
separately or in combination.
3 – Fair
40 through Soils are only fairly well suited to general agricultural use and are
59
limited in their use because of moderate slopes; moderate soil
depths; less permeable subsoil; fine, moderately fine, or gravelly
surface soil textures; poor drainage; moderate flood hazards; or fair
to poor fertility levels, all acting alone or in combination.
4 - Poor
20 - 39
Soils are poorly suited. They are severely limited in their agricultural
potential because of shallow soil depths; less permeable subsoil;
steeper slope; or more clayey or gravelly surface soil textures than
Grade 3 soils, as well as poor drainage; greater flood hazards;
hummocky micro-relief; salinity; or fair to poor fertility levels, all
acting alone or in combination.
5- Very
Poor
10 - 19
Soils are very poorly suited for agriculture, are seldom cultivated
and are
more commonly used for range, pasture, or woodland.
6 – Nonagricultur
al
less than
10
Soils are not suited for agriculture at all due to very severe to
extreme physical
limitations, or because of urbanization.
Source: USDA-NRCS 2010
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X
Faktor A : Rating karakter fisik profil tanah
Tanah-tanah aluvial muda yang profilnya belum
berkembang
100 %
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 2 feet
50-60
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 3 feet
70
I
g Subsoil sangat berkerikil
80-95
s Subsoil liat terstrata
80-95
II
Tanah-tanah aluvial muda yang profilnya baru-sedikit
berkembang
95-100
%
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 2 feet
50-60
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 3 feet
70
g Subsoil sangat berkerikil
80-95
s Subsoil liat terstrata
80-95
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
Faktor A : Rating karakter fisik profil tanah
III Tanah-tanah aluvial yang PERKEMBANGAN
profilnya moderat (subsoilnya agak padat)
80-95
%
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 2 feet
40-60
x Fase dangkal (pada material bahan induk yang
konsolidated) --- kedalaman 3 feet
60-70
g Subsoil sangat berkerikil
60-90
IV Tanah-tanah yang profilnya sudah berkembang
(Subsoiolnya liat rapat /padat)
V
Tanah-tanah yang profilnya mempunyai subsoil cadas
(hardpan) pd kedalaman kurang dari 1 foot
40-80
%
5-20 %
Pada kedalaman 1-2 feet
20-30
Pada kedalaman 2-3 feet
30-40
Pada kedalaman 3-4 feet
40-50
Pada kedalaman 4-6 feet
50-80
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
Faktor A : Rating karakter fisik profil tanah
VI Tanah-tanah yang subsoilhya liat rapat terletak pada
bahan induk yang konsolidated (moderat
konsolidated)
VII Tanah-tanah pada dataran upland yang batuan induknya
40-80
%
10-30 %
berupa batuan beku yang keras pada kedalaman kurang
dari 1 foot
Pada kedalaman 1-2 feet
30-50
Pada kedalaman 2-3 feet
50-70
Pada kedalaman 3-4 feet
70-80
Pada kedalaman 4-6 feet
80-100
Pada kedalaman lebih dari 6 feet
100
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station
Berkeley, Univ oc California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
VIII
Tanah-tanah pada dataran upland yang bahan induknya
berupa batuan sedimen yang konsolidated pada
kedalaman kurang dari 1 foot
10-30 %
Pada kedalaman 1-2 feet
30-50
Pada kedalaman 2-3 feet
50-70
Pada kedalaman 3-4 feet
70-80
Pada kedalaman 4-6 feet
80-100
Pada kedalaman lebih dari 6 feet
IX Tanah-tanah pada dataran upland yang bahan induknya
100
20-40 %
berupa material lunak yang konsolidated pada kedalaman
kurang dari 1 foot
Pada kedalaman 1-2 feet
40-60
Pada kedalaman 2-3 feet
60-80
Pada kedalaman 3-4 feet
80-90
Pada kedalaman 4-6 feet
90-100
Pada kedalaman lebih dari 6 feet
100
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X
FAKTOR B. RATING BERDASARKAN TEKSTUR TANAH LAPISAN ATAS
Tekstur Medium:
Lempung berpasir
halus
100%
Lempung
100
Lempung debu
100
Lempung berpasir
95
Lempung liat
berdebu, berkapur
95
Lemp. Liat berdebu,
non kapur
Lemp. Liat berkapur
Lemp. Liat tidak
berkapur
90
Tekstur halus atau
berat
Liat berdebu, sangat
berkapur
70-90
Liat berdebu, tidak
berkapur
60-70
Liat, sangat berkapur
70-80
Liat tidak berkapur
50-70
Tekstur Kasar atau
ringan:
Lempung berpasir kasar
90
Pasir berlempung
80
Pasir snagat halus
80
Pasir halus
65
Pasir
60
95
85-90
Pasir kasar
30-60
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x Faktor X
FAKTOR B. RATING BERDASARKAN TEKSTUR TANAH LAPISAN ATAS
Berkerikil
Lempung berpasir
halus berkerikil
70-80
Berbatu
Lempung berkerikil
60-80
Lempung berpasir
halus berbatu
Lempung debu
berkerikil
60-80
Lempung berbatu
60-80
Lempung perbasir
berkerikil
50-70
Lempung debu
berbatu
60-80
Lempung perbasir
berbatu
50-70
Lemp. Liat berbatu
50-80
Liat berbatu
40-70
Pasir berbatu
10-40
Lemp. Liat berkerikil
Liat berkerikil
Pasir berkerikil
70-80
60-80
40-70
20-30
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
FAKTOR C. RATING BERDASARKAN KEMIRINGAN
A
Hampir datar (kemiringan 0-2%)
100%
AA
Agak berombak (kemiringan 0-2%)
95-100
B
Agak miring (kemiringan 3-8%)
95-100
BB
Berombak (kemiringan 3-8%)
85-100
C
Miring (kemiringan 9-15%)
80-95
CC
Bergelombang (kemiringan 9-15%)
80-95
D
Sangat miring (kemiringan 16-30%)
70-80
DD
Berbukit (kemiringan 16-30%)
70-80
E
Curam (kemiringan 30-45%)
30-50
F
Sangat curam (kemiringan lebih dari 45%)
5-80
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
FAKTOR X. RATING BERDASARKAN FAKTOR LAINNYA, SELAIN
FAKTOR A, B, DAN C.
Alkali
Drainage
Baik
100%
Bebas alkali
100%
Cukup baik
80-90
Sedikit terpengaruh
alkali
60-95
Tergenang moderat
40-80
Pengaruh moderat
30-60
Tergenang parah
10-40
Pengaruh agak parah
15-30
Pengaruh parah
5-15
Subyek banjir
variabel
Unsur Hara
(kesuburan)
Tinggi (subur)
100%
Cukup
95-100
Kemasaman
Sesuai dnegan pH
Miskin
80-95
Sangat miskin
60-80
80-95%
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
FAKTOR X. RATING BERDASARKAN FAKTOR LAINNYA,
SELAIN FAKTOR A, B, DAN C.
Erosi tanah: Tidak ada – Ringan
100%
Deposisi berbahaya
75-95
Erosi permukaan moderat
80-95
Alur dangkal jarang
70-90
Erosi permukaan moderat dg alur
dangkal
60-80
Alur dalam
10-70
Erosi permukana moderat dg alur
dalam
10-60
Erosi permukaan parah
50-80
Erosi permukaan parah dg alur
dangkal
40-50
Erosi permukaan parah dg alur
dalam
10-40
Erosi sangat parah
10-40
Erosi angin moderat
80-95
Erosi angin parah
30-80
Relief mikro:
Smooth
100%
Channel
60-95
Hogwallow
60-95
Low hummock
80-95
High hummock
20-60
Dunes
10-40
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
SOIL RATING CHART
.Storie soil index rating = Faktor A x Faktor B x Faktor C x
Faktor X
SOIL GRADING
GRADE 1
(Excelent)
Tanah-tanah yang mempunyai rate 80-100% dan cocok
untuk berbagai jenis tanaman, tanaman pangan,
perkebunan dan hutan
GRADE 2
(Good)
Tanah-tanah yang mempunyai rate 60-79% dan cocok
untuk banyak jenis tanaman. Hasil tanaman umumnya
baik hingga sangat baik
GRADE 3
(Fair)
Tanah-tanah yang mempunyai rate 40-59% dan
kualitasnya cukup baik, cocok bagi cukup banyak jenis
tanaman, Hasil jenis tanaman tertentu cukup baik
GRADE 4
(Poor)
Tanah-tanah yang mempunyai rate 20-39% dan
mempunyai peluang terbatas bagi pertanian, misalnya
beberapa tanah cocok untuk sawah
GRADE 5
(Very Poor)
Tanah-tanah yang mempunyai rate 10-19% dan
penggunaan pertanian snagat terbatas, kendala serius
seperti solum dangkal, berbatu, atau alkalis
GRADE 6
(Nonagriculture)
Tanah-tanah yang mempunyai rate kurang dari 10%
dan faktor pembatasnya snagat serius, seperti sangat
curam, pasang-surut, lembah banjir.
Sumber: Storie Index Soil Rating. R.E. Storie. Experiment Station Berkeley, Univ oc
California. 1978
KUALITAS & KARAKTERISTIK
LAHAN
"Karakterisik lahan" merupakan atribut lahan yang
dapat diukur atau diestimasi. Misalnya: kemiringan,
curah hujan, tekstur tanah, kapasitas air tersedia,
biomasa vegetasi, dll.
"Kualitas lahan" adalah kompleks atribut lahan yang
mempunyai peranan spesifik dalam menentukan tingkat
kesesuaian lahan untuk suatu penggunaan tertentu.
Misalnya: ketersediaan air, resistensi erosi, bahaya
banjir, dan aksesibilitas.
"Kriteria diagnostik" adalah suatu peubah yang
mempunyai pengaruh tertentu terhadap hasil (atau
input yang diperlukan ) pada penggunaan tertentu, dan
peubah ini juga berfungsi sebagai dasar untuk menilai
kesesuaian suatu bidang lahan bagi penggunaan
tertentu.
“Kriteria diagnostik” ini dapat berupa kualitas lahan,
karakteristik lahan, atau beberapa karakteristik lahan.
Diunduh dari sumber: http://pinterdw.blogspot.com/2012/01/kualiatas-dankarakteristik-lahan.html…… 5/11/2012
KUALITAS LAHAN
Hubungan antara kualitas dan karakteristik lahan yang
dipakai pada metode evaluasi lahan (Djaenudin et al.
2003)..
Kualitas Lahan
Temperatur (tc)
Ketersediaan
Karakteristik Lahan
Temperatur rata -rata (oC)
air
Curah hujan (mm), Kelembaban (%), Lamanya bulan
(wa)
kering (bln)
Ketersediaan
Drainase
oksigen (oa)
Keadaan
media
Tekstur, Bahan kasar (%), Kedalaman tanah (cm)
perakaran (rc)
Gambut
Ketebalan (cm), Ketebalan (cm) jika ada sisipan
bahan mineral/pengkayaan, Kematangan
Retensi hara (nr)
KTK liat (cmol/kg), Kejenuhan basa (%), pH , Corganik (%)
Toksisitas (xc)
Salinitas (dS/m)
Sodisitas (xn)
Alkalinitas/ESP (%)
Bahaya sulfidik (xs)
Bahaya sulfidik (xs) Kedalaman sulfidik (cm)
Bahaya erosi (eh)
Lereng (%), Bahaya erosi
Bahaya banjir (fh)
Genangan
Penyiapan lahan (lp)
Batuan di permukaan (%), Singkapan batuan (%)
Diunduh dari sumber: http://pinterdw.blogspot.com/2012/01/kualiatas-dan-karakteristiklahan.html…… 5/11/2012
LAND USE
Land comprises the physical environment, including climate, relief,
soils, hydrology and vegetation, to the extent that these influence
potential for land use. It includes the results of past and present
human activity, e.g. reclamation from the sea, vegetation
clearance, and also adverse results, e.g. soil salinization. Purely
economic and social characteristics, however, are not included in
the concept of land; these form part of the economic and social
context.
(sumber: http://www.fao.org/docrep/X5310E/x5310e03.htm)
Land use is the human use of land.
Land use involves the management and modification of
natural environment or wilderness into built
environment such as fields, pastures, and settlements.
“LAND USE” has also been defined as "the
arrangements, activities and inputs people undertake in
a certain land cover type to produce, change or
maintain it" (FAO, 1997; FAO/UNEP, 1999)..
Diunduh dari sumber: en.wikipedia.org/wiki/Land_use …… 5/11/2012
LAND UTILIZATION
A land utilization type consists of a set of technical specifications
in a given physical, economic and social setting. This may be the
current environment or a future Betting modified by major land
improvement e, e.g. an irrigation and drainage scheme. Attributes
of land utilization types include data or assumptions on:
1. Produce, including goods (e.g. crops, livestock timber),
cervices (e.g. recreational facilities) or other benefits (e.g.
wildlife conservation)
2. Market orientation, including whether towards subsistence or
commercial production
3. Capital intensity
4. Labour intensity
5. Power sources (e.g. man's labour, draught animals machinery
using fuels)
6. Technical knowledge and attitudes of land users
7. Technology employed (e.g. implements and machinery,
fertilizers, livestock breeds, farm transport, methods of timber
felling)
8. Infrastructure requirements (e.g. sawmills, tat factories,
agricultural advisory services)
9. Size and configuration of land holdings, including whether
consolidated or fragmented
10. Land tenure, the legal or customary manner in which rights to
land are held, by individuals or groups
11. Income levels, expressed per capita, per unit of production
(e.g. farm) or per unit area.
Diunduh dari sumber:
http://www.fao.org/docrep/X5310E/x5310e03.htm
Neoclassical Production Theory
The neoclassical production function for a single output
and two variable inputs can be written:
y = f(x1,x2)
where y is the quantity of output and xi is the quantity
of the ith variable input.
The properties of this production function are specified
by assumptions:
1. Xi ≥ 0 and finite (non-negative, real inputs);
2. f(X1,X2) is finite, nonnegative, real valued, and
single valued for all possible combinations of X1 and
X2;
3. f(X1,X2) is everywhere continuous and everywhere
twice continuously differentiable;
4. f(X1,X2) is subject to the "law" of diminishing
returns.
Diunduh dari
INPUT / FAKTOR PRODUKSI
Of the three factors of production in classical economics, land, labor,
and capital, land may be the most difficult to define. Does it refer to
just the land itself?
Or is land a generic term referring to all natural resources? Air,
sunshine, and water, necessary to make land productive, are all part
of the surrounding ecosystems. While ownership of land itself can
easily be demarcated, ownership of mobile, associated resources is
trickier.
Diunduh dari Sumber:
http://www.csa.com/discoveryguides/envecon/review.php#v2.................... 2/10/2012 .
PROSES PRODUKSI TANAMAN
Many processes affect crop performance : the conservative efficiency of the
use of radiation, water and nutrient on crop growth, those contributing to the
soil water balance and those affecting soil fertility.
Crop growth has been modelled successfully as a function of environmental
factors using the concept of these conservative efficiencies.
Crop production will be described for these levels in terms of potential and
water- or nutrient limited production .
The most suitable cereal crop (depending on the agro-ecological conditions
wheat, rice, maize, millet or sorghum) is taken as a proxy for a wide range of
crops that could be grown, with yields expressed in 'grain equivalents'.
In practice actual production levels may differ from these calculated levels
due to deviant agricultural management. Actual yield is a function of
biophysical as well as the socio-economic conditions
Levels of production and required data for its assessment. (Modified from Rabbinge, 1993).
Rabbinge, R., 1993. The ecological background in food production . In: Crop protection and
sustainable agriculture. John Wiley and Sons, Chichester (Ciba Foundation Symposium 177), pp.
2-29.
Diunduh dari Sumber: http://www.ciesin.org/lw-kmn/yldgap/yldgap.html....................
5/11/2012 .
INPUT-OUTPUT PROCESS
RELATIONSHIPS
Stylized Production Functions or Input-Output Relationships for a Single
Variable Input
Figure illustrates some differently shaped production functions for the case of a
single-variable input production process.
Each graph shows the physical input-output relationship or total physical
product curve as the level of the single variable input is increased with all other
input factors held constant.
In graphs A and B, the law of diminishing returns (sometimes called the law of
variable proportions) prevails - beyond some point, as the level of the variable
input increases with no change in the level of other input factors, increases in
output occur at a diminishing rate (the marginal product is decreasing) and
eventually, beyond the point of maximum output, output declines in absolute
terms (the marginal product becomes negative).
Diunduh dari Sumber: http://www.fao.org/docrep/w7365e/w7365e08.htm....................
5/11/2012 .
Keterkaitan Faktor Produksi
Kaitan Faktor Manajemen Dengan Faktor Produksi Lain
Ada empat faktor produksi pertanian yaitu:
Alam (lahan, iklim, radiasi matahari, air, udara, dll), Tenaga kerja,
Modal, dan Pengelolaan (manajemen).
Faktor produksi alam dan tenaga kerja sering disebut sebagai faktor
produksi primer,
faktor produksi modal dan pengolaan disebut faktor produksi sekunder.
Diunduh dari Sumber: ocw.usu.ac.id/...PERTANIAN/sep_203_handout_faktorfaktor_prod....................... 5/11/2012 .
EKSTERNALITAS
Dalam proses produksi pertanian, masukan-masukan yang
berupa material, tekno¬logi, menejemen dan unsur-unsur agro
ekologi akan diproses untuk menghasilkan keluaran-keluaran
yang berupa hasil-hasil tanaman dan ternak.
Hasil-hasil sampingan dan limbah dari proses produksi tersebut
dapat berupa hasil sedimen, hasil air, dan bahan-bahan kimia
yang dapat menjadi pencemar lingkungan. Limbah ini biasanya
diangkut ke luar dari sistem produksi dan menimbulkan biaya
eksternal dan efek eksternalitas.
Biasanya sistem produksi pertanian di daerah hulu sungai
mempunyai efek eksternal yang cukup luas dan akan diderita
oleh masyarakat di daerah bawah.
Dalam suatu daerah aliran sungai yang mempunyai bangunan
pengairan seperti bendungan, waduk dan jaringan irigasi, efek
eksternalitas tersebut menjadi semakin serius, karena dapat
mengancam kelestarian bangunan-bangunan tersebut.
Diunduh dari Sumber: http://lecture.ub.ac.id/anggota/marno/activity/16054/ ....................
5/11/2012 .
EKSTERNALITAS
“Eksternalitas” timbul kalau kegiatan produksi (dan
konsumsi) memiliki pengaruh yang tidak diharapkan
(tidak langsung) terhadap produsen dan /atau
konsumen lain.
“Eksternalitas positif” terjadi kalau kegiatan yang
dilakukan oleh seseorang memberikan manfaat pada
pihak lain tanpa melalui mekanisme pasar.
“Eksternalitas negatif” terjadi kalau kegiatan oleh
individu menghasilkan dampak yang merugikan pihak
lain.
Pencemaran air sungai atau air sumur dapat
ditimbulkan oleh proses produksi pertanian yang
berasal dari penggunaan pestisida dan pupuk.
Adanya eksternalitas menyebabkan terjadinya
perbedaan antara manfaat (biaya ) sosial dengan
manfaat (biaya) privat. Perbedaan manfaat (biaya ) ini
berkaitan dnegan alokasi sumberdaya yang tidak
efisien. Pihak yang menyebabkan eksternalitas tidak
memiliki dorongan untuk menanggung dampak dari
kegiatannya yang diderita oleh pihak lain.
Diunduh dari Sumber: http://dickyhendramulyadi.blog.com/2012/02/04/eksternalitaslingkungan/.................... 5/11/2012 .
EKSTERNALITAS EROSI TANAH.
“Erosi tanah” merupakan proses terangkutnya material
tanah atau sedimen oleh aliran air yang terjadi di
permukaan tanah.
Kerusakan yang dialami oleh tanah di tempat yang ada
erosi a.l.:
1. Kehilangan unsur hara dan bahan organik.
2. Menurunnya kapasitas infiltrasi (kemampuan tanah
untuk meresapkan air) dan kemampuan tanah
menyimpan air.
3. Meningkatnya kepadatan dan ketahanan penetrasi
tanah.
4. Berkurangnya kemantapan struktur tanah yang pada
akhirnya menyebabkan memburuknya pertumbuhan
tanaman dan menurunnya produktifitas.
Eksternalitas lingkungan akibat erosi tanah a.l.:
1. Sedimentasi dan pendangkalan waduk
2. Tertimbunnya (sedimentasi) jaringan irigasi.
3. Memburuknya kualitas air sungai , air sumur, air
permukaan lainnya,
4. Kerugian ekosistem perairan.
Diunduh dari Sumber: http://ryniforfun.blogspot.com/2010/03/erosi-tanah-dampaknyabagi-kehidupan.html.................... 5/11/2012 .
EKSTERNALITAS
The problem is that the way owners use their land may affect others.
If they dump garbage on their neighbors' land, clearly they are infringing upon
others' rights. But how about if they burn garbage and the resulting smoke
blows onto nearby properties?
What if they pollute a stream and it ends up affecting everyone's water source,
or flush sewage away and it ends up in an ecologically stressed bay?
Although the field of economics traditionally likes to deal with items that can be
easily demarcated, quantified, and tagged with ownership, this becomes
difficult when dealing with our shared ecosystems.
Economics has dealt with this largely by labeling such items externalities, costs
for which the responsible party does not pay.
It then becomes up to the community, and usually the government, to decide
how to deal with externalities.
Diunduh dari Sumber: http://www.tutor2u.net/economics/revision-notes/a2-microexternalities-overview.html.................... 16/11/2012 .
EXTERNALITY
Until now we have assumed that market price includes or 'internalizes'
all relevant costs and benefits. This means the consumer captures all
benefits and the producer pays all the costs.
An externality refers to costs and benefits that are not captured by
market price for whatever reasons, i.e., they are external to market
price.
In effect, the market demand curve reflects only marginal
private benefits (MPB) of consumers but not the external
benefits accruing to society. When such external benefits
are added, vertically, we derive the marginal social benefit
curve (MSB) inclusive of both private and public benefits.
Similarly, the market supply curve reflects only marginal
private costs (MPC) but not costs external to the firm’s
accounting, e.g., pollution that society must pay.
When social costs are added, vertically, to the supply curve
we derive the marginal social cost (MSC) curve inclusive of
both private and public costs.
Diunduh dari Sumber:
http://www.compilerpress.ca/ElementalEconomics/271%20Environmental/Econ%20271
%202.0%20Environmental%20Economics%20b.htm .................... 5/11/2012 .
EXTERNAL BENEFIT
EXTERNAL COST
MSC = marginal social cost; MC =
marginal cost
MSC = MC + MEC
MEC = marginal external cost
MPC = marginal private cost
MC = MPC
Diunduh dari Sumber:
.................... 5/11/2012 .
EKSTERNAL COST - INEFISIENSI
Adanya biaya eksternal mengakibatkan inefisiensi dalam proses produksi
NEGATIVE EXTERNALITIES
A negative externality is a cost associated with an action
that is not borne by the person who chooses to take that
action.
Inefficiency from Negative Externality
When there is a negative externality, the market
equilibrates where the total social marginal cost exceeds
the marginal benefit of the last unit of a good and society
is not as well off as it could be if less were produced.
Diunduh dari Sumber: http://cnx.org/content/m38612/latest/.................... 5/11/2012 .
Over-production with a negative externality
Ps
Pp
Qs
Qp
The failure to internalize the negative externality results in diminished
social well-being.
The over-production occurs when the external costs of waste disposal
in the community are ignored (not internalized).
In this figure, the private profit- maximizing quantity of landfill deposits
produced (Qp ) are greater than the socially optimal production that
occurs when the external costs are included (Q s ).
The amount of overproduction is equal to the distance from Qp to Qs .
In order to account for the external costs imposed on the community
from producing additional (aggregates) deposits into the landfill, it is
important to increase the costs of these deposits from Pp to Ps .
Diunduh dari Sumber: http://www.grin.com/en/doc/230776/a-computable-generalequilibrium-analysis-of-aggregates-materials-recycling.................... 5/11/2012 .
Pigouvian tax applied to a negative externality
What happens when one form of government intervention (a
Pigouvian tax on the disposal of aggregates) is implemented.
With a Pigouvian tax, the tax is set equal to the marginal external
costs at the socially optimal point of production.
In this case, the tax on deposits elevates the price of disposal,
leading to a reduction in the amount of deposits.
A reduction of deposits into the local landfill would most likely
result from corresponding reductions in the amount of
aggregates waste created in the production process or from
finding alternative means of disposal of the waste.
Diunduh dari Sumber:
.................... 5/11/2012 .
. Adverse environmental impacts as negative
externalities
Some adverse environmental impacts may be internalised into a
farmer's decision-making process, e.g. soil erosion, as this may
impact on the revenue-generating potential of the farm in the future.
However, the problem with many environmental impacts is that the
costs are not borne by the producer because there is no mechanism
to price the damage being done and require the producer to pay.
These environmental costs
are externalised, and there
is thus divergence between
the marginal private cost of
production (to which the
producer responds) and the
marginal social cost of
production (which
determines the socially
optimal level of production).
Over-production of farm
output which causes
environmental damage is
shown in the following
diagram.
The farmer would produce
at Q1 where his marginal
private cost equals marginal
revenue, although the
socially efficient level of
output is Qo which takes
into account the additional
social costs of agricultural
production.
Diunduh dari Sumber:
http://www.tcd.ie/Economics/staff/amtthews/FoodPolicy/LectureTopics/Environment/L
ecture20.htm .................... 5/11/2012 .
Divergence between private and social costs
of upland production.
The paper defines the concept of land degradation and costs and
effects of soil erosion. Through the concept of optimal levels of soil
erosion, a conceptual model of the social costs of soil degradation is
elaborated.
The discussion focuses on the measurement aspects of the economic
scarcity of soil in the agriculture sector. Reliable estimates of the true
impacts of soil degradation can only be made if data on marginal
damage costs and marginal conservation costs are available.
The different scarcity indicators are evaluated and competitive land
rental prices are considered as appropriate in indicating soil scarcity in
agriculture.
Diunduh dari Sumber:
http://www.sciencedirect.com/science/article/pii/S0301420704000340 ....................
Optimal level of soil quality and soil costs.
Diunduh dari Sumber: http://www.sciencedirect.com/science/article/pii/S0301420704000340
.................... 5/11/2012 .
EKONOMI LAHAN
There has been a paper recently published by Andrew Leigh,
Economics Professor at ANU, which empirically estimates the impact
of stamp duties on the housing market.
His main finding is that if stamp duties are raised, house prices will
fall by more than in the increase in the tax.
Did you get that? If you increase stamp duty, the total price of
housing (price plus stamp duty) will fall. Sellers suffer, buyers
benefit. It’s a classic land tax - there is no deadweight loss, as
shown in the figure.
Diunduh dari Sumber: http://ckmurray.blogspot.com/2009/11/some-empirical-support-forland.html.................... 31/10/2012 .
PASAR LAHAN
How can such a thing occur? For any other product,
assuming a competitive market, if you add costs to
production, prices will have to go up (even if quantity sold
goes down), or margins will go down (temporarily at
least).
Land, however, has some characteristics that make it quite
different to other goods
1. There is a fixed supply (vertical supply curve), and
2. It is costless to produce (the producer surplus starts at
a price of zero)
Some would argue that land available to be developed is
not in fixed supply, and that town planning regulations can
change that supply. I agree. But these are regulations,
they are not market players, and that does not make
supply of land price elastic (although I would suggest the
supply curve for serviced residential lots above the
intersection with demand is quite elastic as land parcels
are brought to market).
I think both sides would agree that from a theoretical
standpoint, the supply curve is vertical below the
intersection with the demand curve.
Diunduh dari Sumber: .................... 31/10/2012 .
PASAR LAHAN
It is the second point that is far more important to understanding the
land market. Land itself is costless to produce. That means that the
level of demand determines the price of land at any point in time. Not
supply, demand. So when you increase a tax on land the total land
and tax price stays constant, but the underlying value of the land
declines (as shown by the reduced producer surplus in the figure
above).
I have been quite baffled by the success of Christopher Joye’s
argument that the supply of housing is a major factor determining
prices. He maintains two contradictory positions. The first is that we
have a land price boom, not a house price boom. The second is that
we should elastify the supply of housing to avoid further unnecessary
price increases. Hang on chap. We don’t have a problem supplying
housing. Our problem is that we all decided to pay ridiculously high
prices for land.
There are two more characteristics to the land market that make
analysis difficult. There is competitive behaviour in the market for
buying land, both development sites and serviced land parcels, but
not a competitive market for the sale of land.
Diunduh dari Sumber: .................... 31/10/2012 .
RATIONALITAS
Land resources support life, underpin the
economies of nations and the livelihoods of people
across the world
In many places these resources are being
degraded by a series of pressures, and climate
change will only make things worse
Unsustainable land uses and practices take
place for many different reasons, and may
produce irreversible losses in fragile ecosystems
The value of land resources to national
development and poverty reduction is often not
understood properly
Investments in land, sectors or technologies driven
by short-term gains may generate huge negative
externalities, leading to serious depreciation of
natural capital
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
APAKAH SUMBERDAYA ALAM ?
"Value" has multiple meanings, and we must get
a clear understanding about what we mean.
Monetary or "market" value is determined by
exchange of money. If I have a tree and you want
a tree, how much money will I accept and give
you my tree in exchange?
The market value, therefore, depends on a
tension between one person wanting to retain
what they have, and another person wanting to
have what the first person has.
The resolution of the tension is achieved when
ownership changes simultaneously with a flow of
money from the buyer to the seller, and a flow of
ownership from the first owner to the second
owner.
Market value refers only to what we can obtain
from other humans. What can people have? What
can people exchange for money?
Are natural resources always exchangeable for
money? Can humans "make" a tree? Who or what
makes it "ownable," or makes it "property"?
Diunduh dari Sumber:
http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
APAKAH SUMBERDAYA ALAM ?
Humans make artifacts (production) and can give
their time and labor (services).
Humans do not make natural resources, which
are unrelated to either human time or human
production. Humans may only modify natural
resources.
Natural resources are made by Nature and the
energy to make them comes from geochemical,
geophysical and solar energy.
Humans cannot make petroleum, which once was living
plants that have been processed for millions of years
before humans existed, slowly becoming petroleum.
Petroleum is a natural resource that we consider to be
"nonrenewable" because it takes too long to make by the
time scale that we can experience. But we can change
where petroleum is located, and we can process it into
components parts.
Diunduh dari Sumber:
http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
APAKAH SUMBERDAYA ALAM ?
So, when we say that petroleum is valuable, we refer only to what we do with
it. Humans may own the use of petroleum and control the ways that other
people can use it.
Ownership is a concept of humans, who invented laws to formalize the concept.
Groups of humans then agreed to abide by the rules spelled out in the laws.
Laws are also artifacts and laws make money "legal tender." If we "own the
right to modify a right to modify a natural resource" then we may exchange our
right of modification with other people who give us money.
Money is another human artifact and its value is defined by laws, and
ultimately, by many people's opinion about its value. Money cannot be used to
make natural resources, but money and laws are used to influence what other
humans do with natural resources.
Diunduh dari Sumber: http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
31/10/2012 .
The effects of soil productivity on food quality, health and environmental
quality.
Sumber: http://www.naturewatch.ca/english/wormwatch/about/ecology.html
APAKAH SUMBERDAYA ALAM ?
So, the monetary value of
natural resources is what
people believe the value to
be. Our ignorance can cause
the resources to be greatly
undervalued, which is a
major problem. We may not
consider the "replacement
cost" of a limited natural
resource when we establish a
monetary value. Humans are
inherently ignorant; we
simplify complex things and
processes because we do not
understand the "whole"!
Natural resources and the
ecosystem processes
producing them are the most
complex systems we can
imagine -- if, in fact, we
actually can imagine them
accurately. Why are natural
resources valuable to us?
What do we assume about
natural resources and their
"value" when we equate
their existence and use with
money?
Ecosystem services keep our
habitat comfortable and
livable without the outlay of
money. Nature's processes
work for free, powered totally
by solar energy. Some
examples are:
Pest control
Flood control
Water filtration
Soil fertilization
Food production
Oxygen
production
Climate
stabilization
Recreation
opportunities
Diunduh dari Sumber: http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
31/10/2012 .
APAKAH SUMBERDAYA ALAM ?
These services to some extent also can be achieved by technological
means, but at significant monetary investment. Furthermore,
continuing costs are necessary to maintain the services.
The ecosystem, however, will maintain these services without cost,
unless we interfere with these processes. In certain instances there is a
"loss of opportunity value," such as avoiding building highways or
buildings in such a way that they destroy or damage the ecosystem
processes.
The loss of opportunity value is offset by the ecosystem services value
they supply.
We may choose one form value over another form of value, such as
short term use value for long term service value.
Such a choice resembles a decision to save or invest money in order to
allow the investment to grow (increase in monetary value) or to
preserve future options and benefits that may not be fully recognized.
Such long range value requires imagination of future needs and
recognition of the benefits of preserving options for those that may be
valuable in ways we cannot imagine today.
Such projected values require understanding of management of
systems, and possibilities regarding the "replacement value" of a
resource. Making good decisions implies an awareness of many factors
and consequences not easily understood today, or a belief that present
people have an obligation to future generations of people to have
options, opportunities, similar to those we have today.
Diunduh dari Sumber:
http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
31/10/2012 .
APAKAH SUMBERDAYA ALAM ?
Sedimentation in the aquifer cannot be removed, and
chemicals flush very slowly through the aquifer. Those
people who "develop" the areas that damage the aquifer
do not pay the costs of cleaning the water and keeping it
clean. Nor do they pay the cost of sedimentation filling in
the aquifer.
This cost is "externalized" by the perpetrators of the
damage since it is paid with tax funds (the public pays) or
by the individuals who acquire their water from the aquifer
directly. The permanent loss of the capacity of the aquifer
by sedimentation filling it instead of water is paid by all
who eventually lose its "free" services or "use potential" of
unknown possibilities in the future.
Externalizing costs while retaining the right to have an
income from the development seems unfair, but it has been
declared legal. The developers thereby are subsidized by
others who receive no benefits from the ecologically
damaging development.
This is a "market failure" for monetized value whereby the
human(s) who benefit do not pay the cost of their benefits.
Diunduh dari Sumber:
http://www.sbs.utexas.edu/resource/onlinetext/definitions/resources.htm ....................
31/10/2012 .
NRDA : Natural Resources Damage
ASSESSMENT
The NRDA valuation techniques considers five general classes of valuation
techniques:
1. Market-based techniques, which rely on historical information on market
prices and transactions to determine resource values;
2. Nonmarket techniques that rely on indirect estimates of resource values;
3. Nonmarket techniques that are based on direct estimates of resource
values;
4. Cross-cutting valuation techniques, which combine elements of one or
more of these methods; and
5. Ecological valuation techniques used in the emerging field of ecological
economics.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf.................... 31/10/2012 .
Calculating productivity loss due to land degradation
New method to assess the loss of productivity due to soil
degradation.
There is compelling evidence that soils are degrading because of
problems such as erosion and soil depletion. However, nobody
knows how serious the problem really is.
Estimates of the rate of global soil degradation, the economic
losses, and the impact on food security are extremely variable.
This variability is due to various reasons such as lack of an objective
definition of soil degradation and uncertainties in underlying
information.
Consequently, soil degradation appears to be underemphasized on
policy agendas and the investments required to safeguard future
food security are unknown.
Diunduh dari Sumber: . http://www.isric.org/projects/calculating-productivity-loss-due-landdegradation................... 16/11/2012 .
TEKNIK-TEKNIK VALUASI
SUMBERDAYA ALAM
Valuation Techniques, Benefit Types, and Selected Case
Studies
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
TEKNIK-TEKNIK BERBASIS PASAR
The pioneers of natural and environmental resource
valuation relied on
the “law of demand” as a way to measure the market
values for natural
resources and environmental amenities.
While the same is true today, the
degree of sophistication in the measurement of these
values has increased
considerably.
Three market-based techniques that have recorded a
significant history of natural and environmental resource
valuations are described here:
1. The market price approach,
2. The appraisal method, and
3. The resource replacement
costing.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
PENDEKATAN HARGA PASAR
Demand, Supply, and Market Valuation
Demand for natural resources is measured on the assumption that
many factors that might influence demand, such as personal income,
the prices of related goods and services, and individual tastes and
preferences, remain unchanged during the study period.
Under these assumptions, the estimated demand curve is a
systematic measure of how people value the resource.
To illustrate, the figure shows that 20,000 acres of land were sold at a
market price of $1500 per acre. In the course of these land
transactions, $30.0 million exchanged hands in the land market, i.e.,
20,000 x $1500. Had land become increasingly scarce, this scarcity
would ultimately be reflected in higher land prices.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf.................... 31/10/2012 .
CONCUMER SURPLUS…
Economic surplus
Diunduh dari Sumber: http://en.wikipedia.org/wiki/Economic_surplus....................
3/10/2012 .
Now, consider the total area beneath the demand curve up to 20,000 acres, as
defined by A+B. This area measures the value of the resource in terms of the
maximum willingness to pay for the 20,000 acres of land.
The total willingness to pay for 20,000 acres is calculated by adding up what
was actually spent in buying the land, A = $30 million, plus the additional
triangular area B, which defines consumer surplus.
Consumer surplus is the difference between people’s maximum willingness to
pay for 20,000 acres of land (A+B) and what they actually paid (A).
In essence, the area gives a dollar measure of satisfaction that people
received from the land, less what they actually pay for it.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
PRODUCER SURPLUS …
Producer surplus and economic rent are two other
measures of the
benefits (or damages) associated with natural resources
and resource
services.
Producer surplus measures monetary gains from the
production of natural resources, which is the difference
between revenues (C+D) and the economic costs of
producing these resources (D). Similarly, economic rent
measures monetary gains from using natural resources as
factors of production, which is the difference between the
actual payments made in using resources and the lowest
payment that their owners would have been willing to
accept in supplying these resources or resource services.
Thus, producer surplus refers to the sellers’ gains from
trade in the product market, while economic rent measures
the sellers’ gains from trade in the input market.
Accordingly, the use of producer surplus or economic rent
in resource valuation problems depends on whether the
natural resource is considered as a final product or as an
input in the production of a final product.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
PRODUCER SURPLUS …
Referring again to Figure 1, producer surplus is shown by
the area C, which is bordered by the resource supply
curve and the market price of the resource, P = $1500.
This measure reflects changes in the availability of the
natural resource. For example, if the natural resource
were damaged, its supply curve would shift leftward and
producer surplus would diminish.
A similar description could be given to natural resource
damages that result in a reduction in economic rent.
Here, the damages would be incurred by the owners of
the resources. As in the case of measuring the consumer
surplus, both producer surplus and economic rent
require historical information on the market prices and
quantities of natural resources. In addition, the
measures of producer surplus and economic rent require
information relating to the economic costs of producing
and/or supplying the resource to the market.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
APPRAISAL METHOD…
Appraisal methods are particularly well suited to cases involving
natural resources that have been damaged. In the case of land,
for example, the appraiser identifies the fair market value for
comparable properties in both the uninjured and injured
conditions.
The fair market value of the resource (land) is roughly defined as
the amount a knowledgeable buyer would pay a knowledgeable
seller for the resources. This value should reflect, as closely as
possible, the price at which the resource would actually sell in the
market place at the time of the injury.
The application of appraisal methods would seem to hold
particular promise in DOE natural and environmental resource
planning and guidance. However, the point to keep in mind is that
the method is, in fact, quite dependent on the appraiser’s
judgment.
It may be very difficult to identify comparable sales, particularly
for properties that are “comparably” injured. In addition, the types
of natural resources to which this method can be applied are
limited since many natural and environmental resources are not
traded in markets.
Nevertheless, appraisal methods are applicable to soil and water
treatment at federal facilities. Therefore, it is instructive to
consider a notable protocol in applying appraisal methods.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Scott, M.J., et al. 1997. “The Valuation of
Ecological Resources and Functions.”
Environmental Management (forthcoming). …
Scott et al. (1997) estimated the “fair market value”
associated with shrub-steppe conversions based on
sample data from Benton-Franklin Counties of eastern
Washington State. The data were obtained from the Benton
County Assessor’s Office and represent sales transactions
in Benton County involving 7700 acres during the 19931994 calendar year.
The sample was selected to ensure the identification of
recent patterns in the regional development of shrubsteppe land. Consequently, the sample contained 17
transactions of property for residential and/or commercial
development (urban use) and 31 transactions involving
property destined for agricultural development (agricultural
use).
The authors categorized the sales of predisposed
agricultural land according to whether it was irrigated, or
whether it would be used as dry pasture land or dry farm
land.
The sampling of real estate transactions found that shrub
steppe for urban development had the highest average
value, $9208 per acre. Dry pasture land had the lowest
average value, $67 per acre. Meanwhile, irrigated farm land
sold for $1484 per acre.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
RESOURCE REPLACEMENT COST
METHOD…
The costs of replacing natural and environmental
resources are sometimes a useful way of approximating
resource values under specific conditions. The resource
replacement cost method determines damages for
natural resources based on the cost to restore,
rehabilitate, or replace the resource or resource services
without injury to the level of the resource stock or
service flow. In instances where the underlying resource
is not unique and substitutes are readily available, the
application of the replacement cost method is relatively
straightforward.
The investigator proceeds by gathering a sample of
values for the substitutes from primary or secondary
source information. Based on this sample of cost
information, the analyst then prepares an estimate of the
most likely range of expected replacement costs for the
underlying resource or service.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Shechter, M. 1985. “Economic Aspects in the Investigation of
Groundwater
Contamination Episodes,”
in Ground Water, Volume 23, Number 2, U.S. Environmental Protection Agency.
Guidance Manual for Minimizing Pollution from Waste Disposal Sites, EPA
600/2-78-142, Washington, D.C. Environmental Science and Technology. 1980.
Groundwater Strategies, Vol. 14, pp. 1030-35.…
Shechter (1985) applied the replacement cost method at the Price
Landfill in New Jersey to obtain cost estimates of alternatives to deal
with groundwater contamination.
Estimates were based on information obtained from the U.S.
Environmental Protection Agency (1978) and Environmental Science
and Technology (1980). Excluding excavation and reburials, the
estimated costs ranged from $5 million to $8 million (in 1980 dollars)
and included containment and management of the plume, along with
the performance of water treatment until the aquifer had been purged
of noxious substances.
If excavation and reburial were undertaken as part of the restoration
process, the researchers suggest that the period of plume management
and groundwater flow control could be shortened, but that total cost
would rise by about $15 million to $18 million.
Other site restoration activities included in their estimation focused on
securing alternative sources of water to meet Atlantic City’s water
demand for the foreseeable future. These included cost estimates for
the development of a well field to replace four threatened wells,
varying between $6.5 million and $9.3 million. The researchers omitted
other administrative costs from consideration in applying the method,
such as the costs of undertaking various federal, state, and local studies
on the landfill problem, and the attendant litigation costs that might be
involved. It was believed that these administrative costs had the
potential to raise the total cost by another $1.5 million.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Nonmarket Valuation: Indirect
Techniques…
Using market-based techniques to measure the monetary
value of natural resources is feasible provided there is
sufficient market data. In many cases, however, market
information relating to prices and quantities is not
available to estimate the value of the resource or
resource service. In these cases, researchers must
employ what are referred to as nonmarket valuation
methods.
These methods include indirect techniques that rely on
observable behavior in order to deduce how much
something is worth to individuals. Value estimates
obtained using indirect nonmarket valuation techniques
are conceptually identical to the otherwise unobservable
market value.
The indirect nonmarket valuation techniques considered
in this section include the travel cost method, the
random utility method, the hedonic pricing method, and
the factor income method.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
TRAVEL COST METHOD..
The travel cost method is popular for describing the
demand for the natural resource service(s) and
environmental attributes of specific recreational sites.
Designated wilderness areas, ecological parks, fishing
and hunting sites, and scenic sites are examples. People
visit such sites from diverse distances or points of origin.
This observed “travel behavior” is then used to evaluate
the willingness to pay to visit the site; essentially, the
different travel costs from these diverse points of origin
serve as proxies for willingness to pay to visit the site.
Intuitively, one would expect that the environmental
attributes of sites influence the use of these sites.
As such, changes in visitation rates may reflect changes in
the quality of natural resources particular to the site,
thereby providing an estimate of the value of changes in
natural resource and environmental quality.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
TRAVEL COST METHOD..
The greatest disadvantage of travel cost and other
indirect techniques is that they cannot be used unless
there is some easily observable behavior that can be
used to reveal values. In addition, travel cost models
can be technically and statistically complicated.
Data must be employed to statistically estimate
increasingly sophisticated econometric models that
take into account sample selection problems and
nonlinear consumer surplus estimates.
In addition, the resulting estimates sometimes have
been found to be rather sensitive to arbitrary choices
of the functional form of the estimating equation, the
treatment of the value of an individual’s time, the
existence of multiple stops during the travel period,
and the recognition of substitute sites.
Finally, the travel cost approach requires that the
analyst be in a position to correlate environmental
changes with the behavior of visitors.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
. Hedonic Price Method - Amenity Value.
Hedonic pricing is a useful tool in the assessment of amenity value. Early
analysis related residential property values to neighborhood amenities.
These models provided an inferential measure of people’s willingness to pay for
the amenity under study.
The method is used mostly to estimate the willingness to pay for variations in
property values due to the presence or absence of specific environmental
attributes, such as air quality, noise, and panoramic vistas. By comparing the
market value of two properties having different degrees of a specific attribute,
analysts extract the implicit value of the attribute to property buyers and
sellers.
A variation on the approach is to compare the price of a single piece of property
over successive sales. By correcting for other factors that might have influenced
the value of the property, the analyst can isolate the implicit price of an
amenity or bundle of amenities that have changed over time.
The relationship between house price and the presence of trees, in
order to gain an awareness of the value of trees in the urban
environment.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
.. HEDONIC PRICE FUNCTION
However, the reader should be made aware of caveats
pertaining to the values obtained from hedonic price functions.
In particular, the resource values that are obtained directly from
the estimated hedonic price function are subject to fairly
restrictive assumptions.
It may be necessary to employ additional information from
multiple commodity markets relating to the resource under
consideration. Overall, the resulting hedonic price will depend
on the availability of market information pertaining to the
resource, and the revelation of buyer and seller preferences
through market behavior.
Market data on property sales and characteristics are available
through real estate services and municipal sources and can be
readily linked with other secondary data sources.
Despite these positives, a guarded interpretation of the
estimated welfare changes is recommended. Estimation and
interpretation of these measures can be complex and the data
requirements demanding, and there is a need to control for
many important socio-demographic characteristics.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Hedonic Price Method - Value of Life..
Hedonic pricing methods have also been applied in the estimation
of
economic damages associated with occupational health and
safety risks and are becoming more widely accepted in the
determination of personal injury awards in liability cases.
Application in this branch of the hedonic valuation literature often
refers to the “value of life” or the “hedonic value of life.” Clearly,
there is no such thing as a unique value of life. Consequently,
meaningful estimates of the hedonic value of life vary according
to the specific context under consideration.
For one, it must be made clear whose value is under
consideration: Is it a worker who understands and accepts a
health/safety risk, or is it a passer-by who is unaware of the risk
but nevertheless is predisposed to some adverse health impacts?
Moreover, does the hedonic value under consideration concern
the prevention of adverse health consequences from a potential
accident, or does it concern an after-the-fact compensation to be
given to survivors of an accident?
To better understand the significance of these questions, it is
instructive to clarify the concepts that are involved by
distinguishing between two basic hedonic damage values:
the insurance value and the deterrence value.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf.................... 31/10/2012 .
. Adapted from W. Kip Viscusi. 1990. “The Value of Life:
Has Voodoo
Economics Come to the Courts?” Journal of Forensic
Economics 3(3): 1-15..
Consider a situation in which an ER worker faces a relatively small risk
of losing his life, one that is equal to the average hazard posed by a
typical job - an annual risk of death of 1 in 10,000 accidents. Assume
that a hedonic wage study of risk preferences across ER workers is
undertaken thereby revealing that such workers are willing to accept an
annual wage premium (or income compensation) of $500 in order to
face this risk of death. Together, the presence of the health risk and the
hedonic value estimate of the required wage offset establish the “riskdollar tradeoff” for the typical worker. In other words, they establish a
price for bearing human health risk. In this example, $500
compensation for each risk of 1/10,000 of death implies a total
compensation level per statistical death of $5 million.
Assume next that risk mitigation measures are taken that effectively
reduce the chances of an accident by one-half, consistent with an
ALARA-calibrated risk involving the potential death of 1 in 20,000
accidents (or what is equivalent to 0.5 in 10,000). Assuming that
workers risk preferences remain unchanged as reflected by the $500
wage offset, the compensation level per statistical death would also be
reduced by one-half: from $5 million to $2.5 million.
As a measure of deterrence value, this $2.5 million reflects the workers’
valuation of riskmitigating measures. In this way, hedonic value
estimates concerning human health and safety would appear to have
particular relevance in measuring the benefits of achieving ALARA-type
standards.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf.................... 31/10/2012 .
FACTOR INCOME METHOD…
The factor income method is used as a means of valuation in
applications where natural resources are used as inputs in the
production of other goods and services.
Accordingly, the resulting economic costs of production are an
important source of information in applying the factor income
approach. While the method of factor income is not as
welldefined or widely referenced as the hedonic price or travel
cost methodologies, it is recognized by the U.S. Department of
Interior’s natural resource damage assessment regulations.
There are several types of resources for which the factor income
approach is potentially well-suited, including surface water and
groundwater resources, forests, and commercial fisheries.
Surface and groundwater resources may be inputs to irrigated
agriculture, to manufacturing, or to privately owned municipal
water systems.
The products in these cases (agricultural crops, sawlogs,
manufactured goods, and municipal water) may all have market
prices. Similarly, commercial fishery resources (fish populations
or stocks) are inputs to the production of a catch of saleable
fish. A variation on this theme may be useful for valuing
damages to water resources.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
…FACTOR INCOME APPROACH
There are, however, potential problems in applying the factor income
approach.
First, a particular treatment option might not be the least-cost or optimal
response on the part of the water-using entity.
For example, it might be cheaper to change the production process, buy
municipal water or otherwise obtain a different source of water, or make
other changes to the equipment or materials used. In this case, changes in
water treatment costs may overstate damages.
Second, it is possible that other things may change, particularly price and
output levels.
These potential problems can complicate the analysis and require the
researcher to obtain additional technical information concerning the supply
and demand of the underlying resource or resource service.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Nonmarket Valuation: Contingent
Valuation…
Contingent market analysis has estimated a wide variety of use
and nonuse values.
The most obvious way to measure nonmarket values is to ask
people how much they would be willing to pay for the resource
or avoid any damages that might be sustained by the resource.
Alternatively, one could ask how much people would be willing
to accept as compensation for damages to the resource.
Measures obtained using this technique rely on people’s
hypothetical willingness to pay rather than actual marketinformation on their behavior: hence, the term contingent
valuation (CV).
The contingent valuation method is a survey-based approach to
the valuation of nonmarket goods and services. It uses
questionnaires to elicit information about the preference-related
value of the natural resource in question.
The value is said to be contingent upon the existence of a
hypothetical market as described in the survey put to
respondents. In principle, contingent valuation could be used to
estimate the economic value of almost anything.
By default, it is the only method that holds the promise of
measuring nonuse values since all other methods depend on
observing actual behavior associated with the natural resource.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Contingent valuation surveys …
Contingent valuation surveys may be conducted as face-to-face
interviews, telephone interviews, or mail surveys based on a
randomly selected sample or stratified sample of individuals. Faceto-face interviews are the most expensive survey administration
format, but they are generally considered the best, especially if visual
material needs to be presented.
The central goal of the survey is to generate data on respondents’
willingness to pay for (or willingness to accept) some program or
plan that will impact their well-being.
Each respondent is given information about a particular problem.
Each is then presented with a hypothetical occurrence (e.g., specie
endangerment) or a policy action that ensures against the disaster
(e.g., species protection). Each respondent is asked how much
he/she would be willing to pay either to avoid the negative
occurrence or bring about the positive occurrence.
The means of payment (i.e., the payment vehicle) can take on any
number of different forms, including a direct tax, an income tax, or an
access fee. The actual format may take the form of a direct question
(“how much?”), a bidding procedure (a ranking of alternatives), or
referenda votes. Using a referendum to elicit values is preferred
because it is the one that people are most familiar with.
Resulting data are then analyzed statistically and extrapolated to the
population that the sample represents. These responses are gathered
along with socio-demographic information and test statistics
required to determine the consistency of responses and the
sensitivity to scope.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Kopp, R. J., and V. K. Smith. 1992. “Eagle Mine and
Idarado.” In Natural
Resource Damage: Law and Economics, K. M. Ward and J.
W. Duffield (ed.), John
Wiley and Sons, Inc. New York, pp. 365-388.…
The Eagle Mine case study (Kopp and Smith 1992) exemplifies how contingent
valuation methods can be applied in resource damage assessments. Contingent
valuation questions were presented in both an Eagle County and a statewide
survey, to elicit respondents’ willingness to pay for the Eagle River cleanup. The
Eagle County survey asked respondents about their willingness to make annual
payments over 10 years to clean up 200 waste sites involving current legal
action.
Respondents were given brief descriptions of each site. The survey requested
each respondent to perform two allocations: 1) specify from a schedule of
percentages the percent of their total bid for all sites that they would like to
assign to the seven sites, and 2) identify a most important site among these
seven and the percentage of their bid they would like to have allocated to this
one particular site. In addition, respondents were asked to allocate the
percentages of their total bid (for cleanup of all 200 sites) that they associated
with use and nonuse values.
The table below details the results of the analysis. In the Eagle County survey,
questions were designed so that the willingness to pay estimates included both
use and nonuse values, but allowed for the disaggregation of water and
nonwater-based values. In the survey of Colorado residents, no differentiation
between water-based and nonwater-based values was possible, but an
allocation between use and nonuse values was made. The table displays the
mean estimates of annual willingness to pay derived from each survey. In the
case of Eagle County residents, the analysts multiplied the annual mean
willingness-to-pay estimates by growth of 6063 households, carried forward for
10 years, assuming a population growth of 2 percent, and then discounted back
to 1985 at 10 percent. The analysts employed a similar aggregation procedure
for the statewide estimates.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
… CONTINGENT VALUATION SURVEY
QUESTIONNAIRE
The quality of a contingent valuation survey questionnaire is sensitive to the
amount of information that is known beforehand about the way people think
about the underlying natural resource. Certainly, prior information on the
ecological attributes or environmental qualities of a particular resource are
critical factors in conducting a successful contingent valuation survey.
The key point is that, while all the information necessary for assessing an
individual’s value of the resource is collected in the survey, the analyst must
also be able to identify a truly representative sample of well-informed
respondents in order to allow extrapolation to the general subject population.
Thus, information on who uses the resource and who knows about it is critical.
An individuals total value curve for increments and decrements in the level of provision of an
environmental good (after Bradford, 1972).
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
CROSS-CUTTING METHODS …
At the present time, there is considerable professional interest in natural
resource valuations that are based on cross-cutting methods. These valuation
techniques combine elements from market-based methods with pre-existing
estimates of natural resource values based on either direct or indirect
nonmarket valuation techniques.
The interest in applying crosscutting techniques is motivated by the relative
simplicity of using a preexisting study based on an accepted method, as well as
the cost considerations in undertaking a fresh natural resource valuation study.
Two cross-cutting resource valuation techniques that have gained increased
professional attention due to their simplicity and economy of application are
discussed here: benefit
transfer and unit day value.
Conceptual model of winegrowing impacts on ecosystem services.
Diunduh dari Sumber:
http://www.sciencedirect.com/science/article/pii/S0921800910000339 .... 16/11/2012 .
Benefit Transfer …
Benefit transfer is the use of the estimated values or demand
relationship in existing studies to evaluate a site or event for
which no site-specific study is available. Given the expense and
time associated with the estimation of values of nonmarket
natural resources and services, benefit transfer may be a
reasonable method by which to determine such values under
well-defined conditions.
The analyst should consider all available estimates at the onset
of the study. Each estimate should be evaluated by comparing
the methodology and results of the original studies that may have
been undertaken in selecting one that best matches the policy
study under consideration.
1.
2.
3.
4.
5.
6.
7.
8.
9.
The following criteria have proved to be potentially useful in
making this determination:
Purpose of original value estimates
User group(s) considered
Nature of substitutes in the initial study area
Geographic area
Demographic and socio-economic characteristics
Baseline conditions
Specific or unique problem that may be influenced by the
magnitude of the estimates
General attitudes, perceptions, or levels of knowledge
Omitted variables described above.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Ulibarri, C. A. and S. Ghosh. 1995. “Benefit-Transfer Valuation of
Ecological Resources.” Pacific Northwest National Laboratory, Richland,
Washington; and Rowe et al. 1980. “An Experiment on the Economic
Value of
Visibility.” Journal of Environmental Economics and Management, 1-19.
…
Ulibarri and Ghosh (1995) provide a willingness-to-pay estimate to reduce
high particulate matter (PM ) levels using the benefit-transfer method.
Their application focuses on willingness-to-pay estimates for improved
visibility in Benton-Franklin Counties in eastern Washington state. The
authors’ estimates are based on key parameter values derived by Rowe et
al. (1980) using a CV survey instrument.
In using the Rowe et al. parameter estimates, the authors note that their
commodity specification (quality of visibility) is similar to the one
evaluated by Rowe et al. However, to capture the aesthetic realities of the
study site, the authors obtained daily observations of PM levels over the
period 1990-1994 from the Benton-Franklin County Clean Air Authority.
In addition, the authors adjusted the various independent variables
identified in Rowe et al. using county-level census data on the urban/rural
population, age distribution, ethnicity and gender, and the levels of
household income.
Upon making these adjustments, the authors found a measure of the
collective willingness to pay across 54,000 household in the BentonFranklin area of approximately $364,395 per exceedance day, i.e., a day on
which PM levels equal or exceed 150 micrograms per meter, the safe
minimum standards under the Environmental Protection Agency’s National
Ambient Air Quality Standards.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Unit Day Value Method …
The unit day value method is similar to the benefit
transfer method, except that an average value is derived
based on multiple value estimates from existing studies.
Consequently, the unit day value of the underlying
resource reflects a resource having average preferencerelated attributes, amenities, or qualities.
Any of the valuation approaches described above can
potentially serve as underlying studies from which unit
day values are drawn. The application of the unit day
value method may also involve groups of experts
attempting to interpret from the existing set of estimates
(regardless of method used in the original study) a best
estimate for each of a set of generic types of
environmental resources or activities.
The unit day value approach then combines and converts
these estimates into a standardized unit of measure that
reflects the average value of one unit of the resource on
a per-day basis.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
ECOLOGICAL VALUATION …
The conventional natural resource valuation techniques described above have
made little progress in providing a framework to assess the monetary value
derived from ecological functions.
One reason is that ecological functions are often overlooked in terms of
providing preferencerelated value to humans. Thus, the state of the art in
natural resource valuation is in search of a framework for addressing natural
resource values derived from ecological functions.
The emerging field of ecological economics.
It then considers gross primary energy valuation and non-glamorous resource
valuation, which are two approaches to measure ecological values in the
emerging field of ecological economics.
Valuing Ecosystem Goods and Services
The importance (or ‘value’) of ecosystems is roughly divided into three types:
ecological, socio-cultural and economic value. It is reasoned here that the concept
of ecosystem goods and services is inherently anthropocentric: it is the presence
of human beings as valuing agents that enables the translation of basic ecological
structures and processes into value-laden entities.
Diunduh dari Sumber: http://www.fsd.nl/naturevaluation/71609/5/0/30 ........ 16/11/2012 .
ECOLOGICAL ECONOMICS…
Although controversial, some resource valuation professionals believe that
changes in the service flows from ecological systems to human society can
be valued in monetary terms, given existing knowledge, scientific data, and
estimation techniques.
They believe that this would bring such services into management
discussions in terms symmetric with marketed goods and services. As a
general matter, this could improve the efficiency with which society uses
resources.
One reason for this view is the belief that such pricing would encourage
preservation by making explicit the opportunity cost of development and
other economic activities.
These people support the continued refinement and extensions of economic
valuation techniques based on people’s preferences over ecological
resources.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
VALUASI ENERGI PRIMER (PRODUKSI
PRIMER) BRUTO
Gross Primary Energy Valuation
This procedure has been
applied to the valuation of
different wetland types
(Constanza et al. 1989). It is
argued that estimates of
gross primary production
have merit since the entire
food chain depends upon
this primary production.
PRODUKSI PRIMER
Plants produce plant matter from soil
nutrients, water and carbon dioxide, using
the energy of light. It is called primary
production. The diagram shows the carbon
flows (is equal to energy flows).
The methodology is not
without its problems,
however. For instance, it is
not well understood
whether those species
supported by a particular
food chain have equal
social values. In general, the
embodied energy approach
measures only ecologically
based values.
Unlike an economic
valuation approach, values
for such functions and
services as storm
protection, aesthetics, and
water treatment are
completely ignored.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/enviro
nment/guidance/cercla/valuation.pdf.....
............... 31/10/2012 .
Diunduh dari Sumber:
http://www.seafriends.org.nz/enviro/soil/ecology.ht
m.................... 3/10/2012 .
VALUASI SUMBERDAYA
EKOLOGI
The need for a framework addressing the value of
ecological functions is particularly acute in assessing
policy choices that affect the integrity of ecological
systems.
Using the example of wind-blown dust, Ulibarri and
Ghosh (1995) suggest that these policy decisions require
a weighting of ecological values based on two related
subsets of information: what is valued by humans as an
eco-good (i.e., cleaner air) and what has intrinsic value to
the natural eco-system (i.e., vegetative cover).
Using the term ecological resources, the authors focused
attention on resource services that are functionally
important to ecosystems but frequently overlooked in
terms of providing value to humans.
Such resources have received very little attention relative
to their more glamorous cousins, such as endangered
salmon runs or old-growth timber stands.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
VALUASI SUMBERDAYA
EKOLOGI
The preliminary work undertaken by Scott et al. (1997) considered
social values associated with undeveloped shrub-steppe sites; these are
arid environs which are traditionally overlooked in land-use decisions.
Relative to the perceived values, the authors attempted applications of
the benefit transfer method, the travel cost method, and the method of
hedonic damage-pricing. In order to estimate the intrinsic values of
natural ecosystems, they applied a replacement cost methodology
based on the idea of replacing the functions performed by the natural
ecosystem through a human engineered analog.
Using these cross-cutting resource valuation techniques, the authors
maintained that the economic value of shrub-steppe sites reflects both
their ecological services and recreational uses.
Given the uncertainty that exists as to the social benefits from
preserving undeveloped shrub-steppe, they suggest the need for
further analysis in order to establish credibility in ecological site
valuations.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
UNRESOLVED ISSUES…
The following discussion focuses on a series of distinct and
challenging
issues in the valuation of natural resources and the
environment:
1. The choice of a discount rate in assessing the present
and future values of benefits and costs;
2. The individual’s time-preference in deriving benefits
over the near term as opposed to later on;
3. The role of equity and fairness in resource valuations
involving present and future generations;
4. The conceptual understanding of risk and uncertainty in
the valuation of natural resources and the environment;
and e) qualification of the measurement errors in the
application of the natural resource valuation techniques
discussed in this handbook.
Without identifying the potential importance of these
factors in the valuation process, the analysis of natural
resource values will remain incomplete.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
Discounting and Time Preference
Discount rates enable one to determine the present value
of the benefits and costs associated with the future use
and enjoyment of natural resources. If the analyst of
future benefits and costs sets a high discount rate, say 10
percent, the present value of benefits in the distant
future becomes insignificant when compared with the
present value of benefits in the near-term future.
For example, using continuous discounting at the rate of
10 percent, the present value of $1000 of benefits
obtained 2 years in the future is $818.73, and in 10 years
becomes $367.88, less than half as much. By choosing a
lower discount rate, say 2 percent, the analyst reduces
this temporal bias: $1000 of benefits 10 years hence
becomes $818.73.
Given the implications of this basic arithmetic on natural
resource valuations, it is no wonder there is so much
controversy among economists, scientists, and policy
makers over the applications of appropriate discount
rates.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
EQUITY AND FAIRNESS
The valuation of natural and environmental resources
under ethical
criteria diverges sharply from that of the conventional
utilitarian
approach. Land or water values provide some perspective
on this.
Assume, for example, that a tract of land is privately
owned. Its market price reflects the private benefits that it
can provide. If we assume there exists a well-specified
system of property rights over the parcel of land, individual
self-interest would lead to a negotiated settlement over the
rights to buy or lease the land according to the marginal
values of the land in its various alternative uses. It would
be in the owner’s self-interest to ensure that the land would
be allocated to those uses which command highest value
before considering other uses which have lower marginal
values.
This typifies economically efficient resource allocations,
whereby relatively lower-valued uses are effectively
excluded from consideration. It makes no difference if the
land were under public stewardship, because a similar
means of allocation could be achieved by administering an
auction for land-use rights, thereby ensuring that the land
was used where it commanded highest value.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
RISIKO & KETIDAK-PASTIAN…
Natural resource and environmental valuation is difficult, even
when there is relative certainty over prevailing economic and
environmental conditions. In the “real world,” analysts must
confront risky outcomes in proposing environmental decisions
or taking regulatory actions under conditions of uncertainty
about the benefits and costs of these actions.
Consequently, the notions of risk and uncertainty are related: risk
relates to recurring events whose relative frequencies are known
from past experience, while uncertainty relates to unique events
whose probabilities can only be subjectively estimated.
Uncertainty over the outcomes of environmental actions and
policies can influence the valuation of natural and environmental
resources. For instance, can we say with certainty that the
decontamination of DOE land will increase property values? If
not, the analyst may need to introduce probability beliefs into the
valuation process.
The presence of risk and uncertainty affects both willingness to
pay or willingness to accept compensation, with the extent of
each depending on the degree of economic and environmental
uncertainty confronting individuals and on their attitudes towards
risk and uncertainty.
Together, risk and uncertainty affect the valuation of natural and
environmental resources and are commonly examined by the
analyst based on extensions of the uncertainty affect the
valuation of natural and environmental resources.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
MARGIN OF ERROR: AN ORDER OF
MAGNITUDE?
The foregoing discussion points out that monetary valuations involving
natural resources, human health, and the environment are fraught with
many difficulties.
These difficulties are not in the economic theory, but
rather the application of relatively new valuation techniques.
Many
practitioners would agree that considerable progress has been made in
the application of the techniques described in this handbook — an
empirical claim that can only be validated through further applications
and comparative analyses. However, in view of the uniqueness of
circumstances surrounding each application and study site, it may be
inappropriate to compare the estimated values from one study to
another.
For this reason, researchers have attempted to differentiate between
the systematic biases in estimated values — ones which can be
explained by site or sample characteristics — and their “purely
random” counterparts.
To illustrate, we consider the “margin of error” in value of life
estimations investigated by Miller (1990).
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................
31/10/2012 .
NILAI EKONOMI TOTAL
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
LAYANAN (JASA-JASA) EKOSISTEM
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
Regulating services
Sum of all services
TEV
Total
0.3
2.2 0.8 3.3 2.4
2.2
3.3
0.3
0.3
3.3
38.2 5.4 3.5 4.1
1.6
2.4 1.6
0.3
38.5 5.4 3.5 4.1
Total
TEV
4.1 1.4 41.7
13.6
24.4
4.6
3.3
11.4
3.5
5.4 0.3
14.1
8.4 26.3 1.6
91.6
0.5
2.4 1.6
Benefit transfer
Contingent Valuation
Travel Cost
Mitigation & restoration Cost
Replacement cost
Avoided Cost
32.8 1.4 0.3 1.4
Supporting services
Cultural services
Factor Income
Ecosystem services
Provisioning services
Direct market pricing
JASA-JASA PEMBEKALAN
(provisioning services)
4.9 2.7
8.4
8.9 31.2 4.3 100.0
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Methodologies for Economic
Valuation of Drylands (J. Schild, Global
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
KISARAN NILAI YG SANGAT BESAR
Monetary value range
No. of
data
entries
Average
monetary
value
Provisioning
137
Regulating
Minimum
Maximum
3 711
129
31 653
85
7 991
66
38 776
Supporting
42
1 356
160
7 890
Cultural
53
1 505
0.32
10 209
All services
317
14 563
355
88 527
TEV
29
4 155
63
33 195
Total (TEV + all
346
18 718
418
121 722
Ecosystem
services
services)
•
•
Price per hectare per year (USD 2007)
Based on 346 data entries
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Methodologies for Economic
Valuation of Drylands (J. Schild, Global
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
NILAI EKONOMI TOTAL
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
ADAKAH HARGA KESETIMBANGAN
UNTUK ASET-ASET ALAMI?
Harga
Kurva Suplai
KESETIMBANGAN
Kurva
Permintaan
Kuantitas Keseimbangan
Kuantitas
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
Land ecosystem services
1.
2.
3.
4.
5.
6.
7.
8.
Ecosystem services should be compensated
More transparency on opportunities and trade-offs
Better estimation of values
Charge/benefit transfer mechanisms
Incentives to cooperate
Enabling conditions
Advocacy
Political will
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
Sustainable land management : SLM
What drives decisions to use/manage natural
resources responsibly and sustainably?
Why are the economic benefits of SLM not
recognised?
 Benefits of SLM are often difficult to specify
 Several of these benefits have a public goods
character and/or are not traded in a market
 Often a mismatch between the stakeholders
that pay the (opportunity) costs of maintaining
an environmental benefit (e.g. by not
converting a forest to cropland) and the
beneficiaries of that benefit (e.g. downstream
water users benefiting from the regulation of
water flows).
identification of incentives for SLM
mobilization of financial mechanisms
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
MEMAHAMI HAL YANG TIDAK
DIHARAPKAN
Some of the costs of land degradation and benefits
of SLM can be unexpected but of great significance
For example, agricultural lands are the source of
30% of GHG emissions, whilst conversely soils
have the potential to be a major ‘sink’ for carbon
sequestration
Even remote impoverished drylands and fragile
ecosystems may be endowed with substantial
natural wealth (e.g. Salar de Uyuni in Bolivia: the
10,000 sq km high-altitude salt flat stores more
than half of the world’s supply of lithium, but is also
a tourist attraction and a natural habitat for many
species)
difficult choices and tradeoffs
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
EVL: supporting decision making
1.
Reveal the economic costs and benefits of
land use conversion, or of different types
of land management
2.
Show the interests of different groups of
stakeholders in land and ecosystem
management, thereby providing a basis
for conflict resolution and integrated,
participatory planning of resource
management
3.
Calculation of economic efficient land
management options
4.
Provide the basis for setting up Payment
for Ecosystem Services type of schemes,
for allocating funds from the beneficiaries
of ecosystem services to the providers of
these services
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
. Land Quality Indicators for Sustainable Land
Management:
Yield Gap
P.S. Bindraban, D.M. Jansen, J. Vlaming, J.J.R. Groot
Actual yield is a function of biophysical as well as the socio-economic
conditions.
Levels of production and required data for its assessment. (Modified
from Rabbinge, 1993)
Sumber: http://www.ciesin.org/lw-kmn/yldgap/yldgap.html .... 3/11/2012 .
TEEB
The Economics of Ecosystems and Biodiversity (TEEB)
• Quantification of global economic benefits of biodiversity
• Costs of biodiversity loss, ecosystem degradation and declines
in ecosystem services
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
INISIATIF LAINNYA YANG RELEVAN
Natural Capital Project (WWF, Stanford)
•
•
Integrated Valuation of Ecosystem Services and Tradeoffs
(InVEST)
Development of natural capital database
Land Degradation Assessment in Drylands (LADA)
•
•
•
Development of global indicators for land degradation
Use of Sustainable Livelihoods Framework
Global baseline for future monitoring
Hein & de Groot
•
Partial valuation concept focussing on a small number of
ecosystem services
providing the bulk of benefits
Global Methodology for Mapping Human Impacts on the
Biosphere (GLOBIO)
•
Analysis of changes in land use and its impact on ecosystem
services
Dynamic Integrated Model of Climate and the Economy
(DICE)
•
Estimated value on the negative effects of global warming in
a number of crucial areas
such as agriculture
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
INISIATIF LAINNYA YANG RELEVAN
OECD Driver-Pressure-State-Impact-Response (DPSIR)
Framework
•
Development of DPSIR Framework for land degradation
Other relevant models:
•
•
Landscape Ecological Decision & Evaluation Support
System (LEDESS)
Conversion of Land Use and its Effects (CLUE)
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
KAJIAN-KAJIAN SEBELUMNYA
Studies on the costs of land degradation (GM,
Berry et al., 2003)
•
•
7 country case studies showed 3 – 7 % loss of
agricultural GDP due to land degradation
Investment required in remedial action an order of
magnitude smaller than
the estimated costs to the national economy
Studies on ‘costs of inaction’ (WB, Rydén, 2005)
•
25% increase in number of hungry people in Africa
south of the Sahara
due to land degradation and agricultural yield changes
between 2000 – 2010
Economic returns in success stories (GM, Reij &
Steeds, 2003)
•
•
•
•
•
30 % in irrigation, Mali
20 % in soil and water conservation, Niger
More than 20% in forestry, Ethiopia
12 % in forestry, Tanzania
Over 40% small-scale irrigation in northern Nigeria &
Komadougou valley, Niger
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
TERPADU DAN DINAMIK
Multidimensional - modular approach integrating
different methodologies
Multilevel approach
• Top-down aggregated economic analysis
• National-level sectoral economic impact
assessment
• Sub-national local case studies
• Assessment of aspects of the relation between
land resources and economic development
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
KOMPREHENSIF & TER-SEKALA
Applicable to:
• Different spatial scales (local, national,
regional, global)
• Specific study objectives
Total Economic Value:
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
IMPLEMENTASI BERTAHAP
1) Scoping:
Identification of scope, location, spatial scale
and strategic focus based on stakeholder
consultation
Preparation of background information on
socio-economic and environmental context
2) Assessment of land cover type:
Assessment of quantity, spatial distribution
& ecological characteristics of land cover
Method (national level): GIS analysis with
categorization by agro-ecological zones
(governments, FAO)
Method (local level): participatory GIS,
supplemented with CLUE or LEDESS model
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
IMPLEMENTASI BERTAHAP
3) Analysis of ecosystem services:
Analysis of stocks and flows for each land cover
category based on 4-fold categories of ecosystem
services (MA)
Expert judgement and stakeholder consultation on
suitable methodology
Method: Choice from common valuation techniques,
including list of indicators
for ecosystem services and their calculation
ecosystem valuation techniques
Revealed Preference Methods
Market
Prices
Market
Prices
Production Function Surrogate Market
Approaches
Approaches
Change in
Production
Cost-Based
Approaches
Stated
Preference
Methods
Travel Cost
Methods
Replacement
Costs
Contingent
Valuation
Hedonic
Pricing
Mitigative or
Avertive
Expenditures
Conjoint
Analysis
Damage Costs
Avoided
Choice
Experiments
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
IMPLEMENTASI BERTAHAP
4.) Economic significance of study area:
Analysis of role of ecosystem services in community
livelihoods (local) and overall economic development
(national)
Method (local): Secondary statistics & field research
Method (macro-economic): National accounting
frameworks
5.) Assessment of land degradation:
Identification of patterns, pressures, spatial distribution,
causes, driving forces
Analysis of future risks & vulnerabilities
Assessment of ‘costs of inaction’
Method: GIS analysis including defined set of
degradation drivers
6.) Sustainable Land Management:
Analysis of options for reducing/removing degradation
pressures, including their economic viability and
suitable locations
Method: GIS analysis, perhaps supplemented by
models as LEDESS or CLUE
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
EKONOMI SUMBERDAYA LAHAN
Nilai lahan
Rationale – why shall we care about the value of land
Methodologies – which models are currently available
Approach – is there a cost-effective integrated approach
Country case studies – where is being applied
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
KAJIAN-KAJIAN NEGARA :
Cambodia
Ministry of Agriculture, Forestry and Fisheries (MAFF)
Economic Valuation Study (EVS) of land resources in
Cardamom Mountains
Capacity building at national level to undertake future
valuations
Integration of study results into national development
planning processes
Identification of specific financial opportunities for scaling up
SLM investments
Economic valuation approach:
1.
2.
3.
4.
5.
6.
Assessment of the inherent value of Cambodia’s
land resources
Assessment of the costs of land degradation
Analysis of future risks and vulnerabilities
Assessment of the costs of inaction
Identification and assessment of SLM options
Policy dialogue with key stakeholders
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October
KAJIAN-KAJIAN DI NEGARA :
Tanzania
The Relationships among Sustainable Development, Sustainable
Land Management, Sustainable Agriculture, and Sustainable Soil
Management. (Redrawn from Dumanski 1997)
1.
2.
3.
4.
Vice President Office
Economic Valuation Study (EVS) of land resources
Capacity building at national level to undertake future valuations
Integration of study results into national development planning
processes
5. Identification of specific financial opportunities for scaling up SLM
investments
6. Economic valuation approach
Sumber: Economic Valuation of Land
(EVL): Rationale and Objectives. Simone
Quatrini.
Master’s Course on Integrated Drylands
Management, CAREERI, Lanzhou, China. 4-6
October 2010 .
Sumber:
http://www.agnet.org/library.php?func=
view&style=&type_id=4&id=2012080817
2707&print=1.... . 2/11/2012
KAJIAN-KAJIAN DI NEGARA : Zambia
Ministry of Tourism, Environment and Natural
Resources (MTENR)
Zambia Development Agency (ZDA) – Environmental
Council of Zambia (ECZ)
Macro-economic valuation of land in most affected
regions
Capacity building at national level to undertake future
valuations
Integration of economic valuation programme into 6th
National Development Plan
Identification of mechanisms and incentives for
scaling up SLM investments
Approach (same as above)
Sumber: Economic Valuation of Land (EVL): Rationale and Objectives. Simone Quatrini.
Master’s Course on Integrated Drylands Management, CAREERI, Lanzhou, China. 4-6 October 2010 .
The Land Market
and
Natural Resources
Fixed supply of land (to all
uses)
The supply of land to all uses is fixed
Owners receive economic rent
Land supply to a given use
The supply of land to a given use is upward sloping
Land is shifted to its most valuable use (subject to
restrictions in zoning laws, etc.)
The economic suitability of a land area for a land use
( Barlowe, 1986, land use capacity) is the predicted
net economic benefit to a specified party (e.g.,
landowner, land user, society) to be expected if the
land area is dedicated to the use.
The economic value of a land use system
implemented on a given land area is not
synonymous with the market value of the land area
(land evaluation) although the predicted return to a
land unit of various land uses obviously influences
its price.
(In fact, the price should be at least the greatest Net
Present Value of the possible land uses).
Renewable and Non-renewable
resources
Nonrenewable resources (also known as
exhaustible resources) have a finite supply that is
depleted as the resource is consumed
Renewable resources – can be replenished by
producers
Economic suitability of land depends on three types of
factors:
1. The in-situ resource quality, i.e. the response of the
land to the use without regard to its location
(Ricardo). Example: predicted crop yield.
2. The accessibility, and by extension, all costs and
benefits associated with the specific location as
opposed to the resource quality (von Thünen).
Classic example: transportation costs for inputs and
products.
3. Other spatial attributes of the site, not including
accessibility, for example, size, shape, adjacency, and
contiguity. Example: more efficient field work if the
parcel is the correct shape and size.
Price of a nonrenewable resource over time
Price changes over time for nonrenewable resource:
1. Owner may sell a unit today or sell it later at a higher price
2. Owner supplies more today if the expected rate of price
increase is less than the interest rate:
1. leads to lower price today and higher price later
3. Owner supplies less today if the expected rate of price
increase exceeds the interest rate:
1. leads to higher price today and lower price later
4. In equilibrium – rate of price change = interest rate
BASIC
CONCEPTS
OF
ECONOMIC
VALUE
NILAI EKONOMI LAHAN
Economic value is one of many possible ways to define and measure value.
Although other types of value are often important, economic values are useful
to consider when making economic choices – choices that involve tradeoffs in
allocating resources.
\Measures of economic value are based on what people want – their
preferences. Economists generally assume that individuals, not the
government, are the best judges of what they want. Thus, the theory of
economic valuation is based on individual preferences and choices. People
express their preferences through the choices and tradeoffs that they make,
given certain constraints, such as those on income or available time.
The economic value of a particular item, or good, for example a loaf of bread, is
measured by the maximum amount of other things that a person is willing to
give up to have that loaf of bread. If we simplify our example “economy” so
that the person only has two goods to choose from, bread and pasta, the value
of a loaf of bread would be measured by the most pasta that the person is
willing to give up to have one more loaf of bread.
Thus, economic value is measured by the most someone is willing to give up in
other goods and services in order to obtain a good, service, or state of the
world. In a market economy, dollars (or some other currency) are a universally
accepted measure of economic value, because the number of dollars that a
person is willing to pay for something tells how much of all other goods and
services they are willing to give up to get that item.
This is often referred to as “willingness to pay.”
Diunduh dari Sumber: http://www.ecosystemvaluation.org/1-01.htm.................... 31/10/2012 .
NILAI EKONOMI LAHAN
In general, when the price of a good increases, people will purchase less of that
good. This is referred to as the law of demand—people demand less of
something when it is more expensive (assuming prices of other goods and
peoples’ incomes have not changed). By relating the quantity demanded and
the price of a good, we can estimate the demand function for that good. From
this, we can draw the demand curve, the graphical representation of the
demand function.
It is often incorrectly assumed that a good’s market price measures its economic
value. However, the market price only tells us the minimum amount that
people who buy the good are willing to pay for it. When people purchase a
marketed good, they compare the amount they would be willing to pay for that
good with its market price. They will only purchase the good if their willingness
to pay is equal to or greater than the price. Many people are actually willing to
pay more than the market price for a good, and thus their values exceed the
market price.
In order to make resource allocation decisions based on economic values, what
we really want to measure is the net economic benefit from a good or
service. For individuals, this is measured by the amount that people are willing
to pay, beyond what they actually pay. Thus, two goods that sell for the same
price may have different net benefits. For example, I may have a choice
between wheat and multi-grain bread, which both sell for $2.00 per
loaf. Because I prefer multi-grain, I am willing to pay up to $3.00 for a
loaf. However, I would only pay $2.50 at the most for the wheat
bread. Therefore, the net economic benefit I receive for the multi-grain bread is
$1.00, and for the wheat bread is only $.50.
The economic benefit to individuals is often measured by consumer surplus.
This is graphically represented by the area under the demand curve for a good,
above its price.
Diunduh dari Sumber: http://www.ecosystemvaluation.org/1-01.htm.................... 31/10/2012 .
SURPLUS KONSUMEN LAHAN
The economic benefit to individuals, or consumer surplus,
received from a good will change if its price or quality
changes.
For example, if the price of a good increases, but people’s
willingness to pay remains the same, the benefit received
(maximum willingness to pay minus price) will be less than
before. If the quality of a good increases, but price remains
the same, people’s willingness to pay may increase and
thus the benefit received will also increase.
KURVA PERMINTAAN
Harga
SURPLUS KONSUMEN
Harga Pasar
Kuantitas
Diunduh dari Sumber: http://www.ecosystemvaluation.org/1-01.htm ....................
31/10/2012 .
NILAI EKONOMI – HARGA LAHAN
Economic values are also affected by the changes in price or quality of
substitute goods or complementary goods . If the price of a substitute
good changes, the economic value for the good in question will change in
the same direction. For example, wheat bread is a close substitute for
multi-grain bread. So, if the price of multi-grain bread goes up, while the
price of wheat bread remains the same, some people will switch, or
substitute, from multi-grain to wheat bread. Therefore, more wheat
bread is demanded and its demand function shifts upward, making the
area under it, the consumer surplus, greater.
Similarly, if the price of a complementary good, one that is purchased in
conjunction with the good in question, changes, the economic benefit
from the good will change in the opposite direction. For example, if the
price of butter increases, people may buy less of both bread and butter. If
less bread is demanded, then the demand function shifts downward, and
the area under it, the consumer surplus, decreases.
Producers of goods also receive economic benefits, based on the profits
they make when selling the good. Economic benefits to producers are
measured by producer surplus, the area above the supply curve and
below the market price. The supply function tells how many units of a
good producers are willing to produce and sell at a given price. The
supply curve is the graphical representation of the supply
function. Because producers would like to sell more at higher prices, the
supply curve slopes upward.
If producers receive a higher price than the minimum price they would
sell their output for, they receive a benefit from the sale—the producer
surplus. Thus, benefits to producers are similar to benefits to consumers,
because they measure the gains to the producer from receiving a price
higher than the price they would have been willing to sell the good for.
Diunduh dari Sumber: http://www.ecosystemvaluation.org/1-01.htm ....................
31/10/2012 .
MANFAAT EKONOMI DARI LAHAN
When measuring economic benefits of a policy or
initiative that affects an ecosystem, economists
measure the total net economic benefit.
This is the sum of consumer surplus plus producer
surplus, less any costs associated with the policy or
initiative.
Harga
Kurva Suplai dan
Surplus Produsen
Surplus Produsen
Harga Pasar
Kuantitas
Diunduh dari Sumber: http://www.ecosystemvaluation.org/1-01.htm ....................
31/10/2012 .
EKONOMI MLAHAN
Land Economics In a market economy, most of the urban land can be freely sold or
purchased. Thus land economics are concerned about how the price of urban land is
established and how this price will influence the nature, pattern and distribution of land
uses. The above figure provides some basic relationships between the quantity of land
and its price and assumes that there is a free land market. This market mechanism follows
the standard relationship between supply and demand, where an equilibrium price is
reached. A quantity of land Q1 would be available at a price of P1. However, what is
particular to cities is that the supply is fixed since there is a limited amount of available
land. When land is reasonably available (Q1), the price (P1) will be moderate.
Moving towards the downtown the demand rises, land becomes scarcer (Q2) and its price
goes up (P2).
Moving towards the periphery, more land is available, demand drops (Q3), and so does
the price (P3).
Not every type of activities is willing to pay a price P1. Some may even need a price lower
than P3. High land values impose a more intensive usage of space so a higher number of
activities can benefit from a central location. The logic behind the construction of
skyscrapers is therefore obvious and takes place at optimal locations of competition for
land. Different type of activities, each having their own land use, are willing to pay
different rents.
Diunduh dari Sumber: http://people.hofstra.edu/geotrans/eng/ch6en/conc6en/landeconomics.html....................
31/10/2012 .
SOIL EVALUATION THE ROLE OF SOIL
SCIENCE IN LAND EVALUATION…
A review has been made on the concepts and the methodology of
land evaluation.
The results of several evaluation methods have been compared,
applying them to a selection of diverse soils. Although the studies
on land evaluation have been conducted on a broad diversity of
characteristics—not only physical but also social, economic and
political—in practice, it is frequent to limit such studies to the
physical medium, given the heterogeneity of these projects.
Land evaluation requires a team of multidisciplinary evaluators.
The difficulty of forming these teams makes it common for such
studies on land evaluation to be reduced to the analysis of the
physical medium of the soil, creating a certain confusion.
Therefore, we propose using the term “soil evaluation” for the
assessment of the soil properties as a phase prior to land
evaluation, considering soil properties in their broader sense, both
the intrinsic ones (those of the soil itself: depth, texture, etc.) as
well as the extrinsic ones (the soil surface: topography, climate,
hydrology, vegetation, use, etc.).
Soil evaluation would be similar to what today is understood as
land evaluation, but excluding all the social, economic and political
characteristics which would be covered under the concept of “land
evaluation.”
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
Environmental indicators of the degree of suitability of
soils for agricultural use.…
Very favourable
Favourable
Unfavourable
Very
unfavourable
Intrinsic properties
Effective depth, cm
>120
120-70
70-30
<30
balanced
moderate heavy
heavy
light
<10
10-30
30-60
>60
f, md, 3, 2
c, 1
sg, 0
ms, 0
Compact, cemen, gr,
cm
Absent
md, >60
md, >20 or st,
>60
st, < 30
Available water, mm
>100
100-60
60-20
<20
Without hydro
Hydro > 80 cm
Hydro > 40 cm
Hydro a 0 cm
Permeability, cm/hour
>2
2-0.5
0.5-0.1
<0.1
Organic matter, %
>5
5-2
2-1
<1
CEC, cmol(+)kg-1
>40
40-20
20-10
<10
Saturation degree, %
>75
75-50
50-25
<25
7.3-6.7
6.7-5.5 or 7.3-8.0
5.5-4.5 or 8.09.0
<4.5 or >9.0
Carbonates, %
<7
7-15
15-25
>25
Salinity, dSm-1
<2
2-6
6-12
>12
Texture
Course fragments, %
Structure
Internal drainage
pH
Extrinsic properties
Slope, %
<4
4-10
10-25
>25
Surface stoniness,%
<2
2-20
2-20
>50
Surface rockiness, %
<2
2-20
2-20
>50
Flooding, months
0
<1
1-3
>3
<10
10-20
20-60
>60
no problems
limited
severe
very severe
>1000
1000-600
600-300
<300
<1
1-3
3-6
>6
Erosion, Tm/ha/year
Ploughing
Precipitation, mm
Frost, Tª<0º, months
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm.................... 31/10/2012 .
Comparisons between the classes defined by the
soil-evaluation systems.
LCC, Land Capability Classification; Si, Storie Index; RPI, Riquier
Productivity Index; FK, FAO Framework.
LCC
SI
RPI
FK
Intensive soil cultivation
I
1
P1
S1
Moderate soil cultivation
II
2
P2
S2
Limited soil cultivation
III
3
P3
Occasional soil cultivation
IV
4
Grazing
V, VI
5
P4
Forestry
VII
6
P5
Natural reserves
VIII
S3
N
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
… Storie Index (1933).
This represents the first parametric approach that was developed. It is an
index that uses the multiplicative scheme. In addition, it uses intrinsic
properties of the soils (genetic profile, parent material, profile depth,
texture, drainage, nutrients, acidity an alkalinity), characteristics of the soil
surface (slope and microrelief) and aspects of soil conservation (degree of
erosion). The evaluation properties are grouped into four factors that are
quantified in the corresponding tables. The factors are weighed a priori, the
more important being related on a scale from 5 to 100 and the less
important factors from 80 to 100.
With this index, general agricultural soil uses can be evaluated (hence it is a
soil-capability evaluation method). To formulate the index, the four factors
are multiplied together and the index is expressed as a percentage. Six
classes are defined at the degree level, with decreasing values from 1 to 6.
The degrees 1 to 3 are for agricultural use, degree 4 for very limited
agricultural use, 5 for pasture and 6 without use. Subdegrees are
established according to limiting factors: “s” for depth, “p” for
permeability, “x” for texture, “t “ slope, “d” for drainage and “a” for salts.
It is important to emphasize that this system does not consider climatic
characteristics. Thus the evaluation is of the soil itself, valid for comparing
the soils of a certain region with the same type of climate.
This evaluation index was developed for California, and thus application to
other regions of the world has involved numerous modifications (in Canada
by Bowser, 1940; in India by Shome and Raychaudhuri, 1960; in tropical
countries by Sys and Frankart, 1972; in arid regions by Sys and Verheye,
1974).
Diunduh dari Sumber: .................... 31/10/2012 .
Land Capability Classification. …
This method was established by the Soil Conservation Service de
USA according to the system proposed by Klingebiel and
Montgomery (1961) and has been widely used throughout the
world with numerous adaptations. It is a categorical system that
uses qualitative criteria.
The inclusion of a soil within a class is made in the inverse
manner—that is, without directly analysing its capacity, but
rather its degree of limitation with respect to a parameter
according to a concrete use. Some factors that restrict soil use can
be used to define the productive capacity (intrinsic: soil depth,
texture, structure, permeability, rockiness, salinity, soil
management; extrinsic: temperature and rainfall) and yield loss
(slope of the terrain and degree of erosion). Five systems of
permanent agricultural exploitation are considered: permanent
soil cultivation, occasional soil cultivation, pasture, woods and
natural reserves. This system seeks maximum production with
minimum losses in potential.
Depending on the type of limitation, various subclasses of
capacity are established: e, for erosion risks; w, for wetness and
drainage; s, for rooting and tillage limitations resulting from
shallowness, drought risk, stoniness, or salinity; c, for climatic
limitations. The capability units represent similar proposals of use
and management.
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
Productivity index of Riquier et al. (FAO,
1970).
The basic concept of this method is that agricultural-soil productivity,
under optimal management conditions, depends on the intrinsic
characteristics. This is a multiplicative parametric method to evaluate
soil productivity, from a scheme similar to the Storie index. The concept
of productivity is defined as the capacity to produce a certain quantity
of harvest per hectare per year, expressed as a percentage of optimal
productivity, which would provide a suitable soil in its first year of
cultivation. The introduction of improvement practices leads to a
potential productivity or potentiality. The quotient between the
productivity and the potentiality is called the improvement coefficient.
The evaluation is made for three general types of use: agricultural
crops, cultivation of shallow-rooted plants (pastures), and deep-rooted
plants (fruit trees and forestation).
The determining factors of soil depth are: wetness, drainage,
effective depth, texture/structure, base saturation of the adsorbent
complex, soluble-salt concentration, organic matter, cation-exchange
capacity/nature of the clay and mineral reserves. The parameters of the
soil surface (e.g., slope, erosion, flood tendency, or climate) are not
considered
The different parameters are evaluated in tables and, as also
occurs in the Storie index, the evaluation factors present different
weights.
Productivity is expressed as the product of all these factors expressed in
percentages. Five productivity classes are defined: class P1 = excellent;
class P2 = good, valid for all types of agricultural crops; class P3 =
medium, for marginal agricultural use, suitable for non-fruiting trees;
class P4 = poor, for pasture or forestation or recreation; class P5 = very
poor or null, soils not adequate for any type of exploitation.
Diunduh dari Sumber: .................... 31/10/2012 .
Soil Fertility Capability Classification
(FCC). …
This was proposed by Buol et al., (1975) and modified by Sanchez
et al. (1982) to evaluate soil fertility. In this system, three levels
or categories were established.
The first, the type, was determined by the texture of the arable
layer, or of the first 20 cm, if this is thinner. Its denomination and
range are: S, sandy (sandy and sandy loam); L, loams <35% clay
(excluding sandy and sandy loam); C, clayey > 35% clay; O,
organic > 30% organic matter to 50 cm or more.
The type of substrate is the second level and is used when there
is a significant textural change in the first 50 cm of the soil. It is
expressed with the same letters, adding “R” when a rock or a
hard layer is found within this depth.
The third level is comprised of the modifiers, which are the
chemical and physical parameters that negatively influence soil
fertility. These are numerous and are represented by lower-case
letters.
In the denomination of the soil class, the principle limitations for
use are directly represented. For example, for an Orthic
Solonchak, the FCC class that represents it is LCds, which signifies
that it is a soil susceptible to severe erosion (L), limited drainage
(C), dry soil moisture regime (d) and with salinity (s).
Diunduh dari Sumber: .................... 31/10/2012 .
KERANGKA EVALUASI LAHAN
The FAO Framework for Land Evaluation (1976). The FAO
Framework for Land Evaluation (FAO 1976 and subsequent
guidelines: for rainfed agriculture, 1983; forestry, 1984; irrigated
agriculture, 1985; extensive grazing, 1991) is considered to be a
standard reference system in land evaluation throughout the
world (Dent and Young, 1981; van Diepen el al., 1991), and has
been applied both in developed as well as developing countries.
This framework is an approach, not a method. It is
designed primarily to provide tools for the formulation of each
concrete evaluation. The system is based on the following
concepts:
1. The land is qualified, not only the soil.
2. Land suitability must be defined for a specific soil use (crop and
management).
3. Land evaluation was to take into account both the physical conditions
as well as economic ones;
4. The concept of land evaluation is essentially economic, social and
political.
5. The evaluation requires a comparison between two or more
alternative kinds of use.
6. The evaluation must propose a use that is sustainable.
7. A multidisciplinary approach is required (Purnell, 1979; van Diepen et
al., 1991).
These limiting factors are used to define the third category of the
system, which is the subclass. In the symbol of each subclass, the
number of limitations involved should be kept to the minimum
one letter, or, rarely, two. The limitations proposed include: t,
slope; e, erosion risk; p, depth; s, salinity; d, drainage; c,
bioclimatic deficiency; r, rockiness; i, flood risk.
Diunduh dari Sumber: .................... 31/10/2012 .
Evaluation of 30 soils by four methods of soilcapability evaluation. …
Soil type
Parent
material
LCC
SI
RPI
FK
1 Typic Cryosaprist
micaschist
IVsp
4ps
P5fp->(P3)
S3sp
2 Typic Xerofluvent
alluvial
II
2
P2
S2
3 Typic Xerofluvent
alluvial
I
1
P1
S1
4 Typic Xeropsamment
dolomite
VIIr
3g-->(6)
P5g
S3r-->(N)
5 Lithic Xerorthent
micaschist
VIIs
6dg
P5dg
Ns
6 Lithic Xerorthent
dolomite
VIgr
5dgr
P5dg->(P4)
S3d-->(N)
7 Typic Chromoxeret
marl
II
3p-->(2)
P2p
S3-->(S2)
8 Calcixerollic
Xerochrept
marl
IVd
4d
P3d
S3d
9 Calcixerollic
Xerochrept
sandstone
VIg
4gd->(5)
10 Calcixerollic
Xerochrept
conglomerate
III
3d
P5g-->(P4) S2-->(N)
P2-->(P3)
S2
LCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO
Framework.
Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability
or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold,
the results that do not coincide with the evaluations of the other methods; in parenthesis the
results that would correspond with the other methods. In bold and cursive, results that strongly
differ from those of the other methods.
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
Evaluation of 30 soils by four methods of soilcapability evaluation. …
11 Lithic Xerochrept
slate
P3d
S3d
12 Lithic Xerochrept
granite
IId
3d-->(2)
P2dt
S2
13 Typic Humaquept
micaschist
Vp
5p
P5p-->(P4)
S3pf->(N)
14 Typic Cryumbrept
micaschist
IIIs-->(IV)
4s
5fg-->(P3)
S3sf
15 Typic Haplumbert
micaschist
VIIs
5sg-->(6)
P5gf
Ns
andesite
Vm
2-->(5)
P5m->(P4)
Nm
17 Petrogypsic
Gypsiorthid
silts, gypsum
IVdg
5dg->(4)
P4dg->(P3)
S3d
18 Lhitic Haploxeroll
conglomerate
VIIrd
6d
P5dg
Nd
19 Calcic Haploxeroll
micaschist
VIIs
4dg->(6)
P2-->(P5)
Ns
20 Typic Haploxeroll
sandstone
VIIs
5sg-->(6) P2-->(P5)
Ns
16 Vertic Haplargid
IIId-->(4) 5dr-->(4)
LCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO
Framework.
Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability
or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold,
the results that do not coincide with the evaluations of the other methods; in parenthesis the
results that would correspond with the other methods. In bold and cursive, results that strongly
differ from those of the other methods.
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
Evaluation of 30 soils by four methods of soilcapability evaluation. …
21 Typic Haploxeroll
micaschists
VIIs
6s
P5gf
Ns
22 Udic Haplustoll
serpentine
IIId
3dt
P3d
S2
23 Mollic Haploxeralf
limestone
IVd
4d
P3d
S3d
24 Typic Haploxeralf
slate
IIIe
3e
P2-->(P3)
S3e
25 Xerochreptic
Haploxeralf
slate
IIIs
3se
P1-->(P3)
S3se
26 Typic Rhodoxeralf
conglomerate
I
1
P1
S1
27 Calcic Rhodoxeralf
conglomerate
IIg
1-->(2)
P1-->(P2)
S2m
28 Mollic Palexeralf
limestone
IIIr
3t
P2t-->(P3)
S2
29 Typic Palexerult
slate
IIIs
3r
P2-->(P3)
S2
30 Typic Palexerult
clays
IIes->(III)
3t
P3t
S2
LCC, Land Capability Classification; SI, Storie Index; RPI, Riquier Productivity Index; FK, FAO
Framework.
Limiting characteristics: e, erosion; d, depth; g, gravels; f, frozen; m, moisture; p, permeability
or drainage or flooding; r, rocks or pebbles or stones; s, slope; t, texture or structure. In bold,
the results that do not coincide with the evaluations of the other methods; in parenthesis the
results that would correspond with the other methods. In bold and cursive, results that strongly
differ from those of the other methods.
Diunduh dari Sumber: http://edafologia.ugr.es/comun/congres/cartart.htm....................
31/10/2012 .
NILAI
SEWA-EKONOMI
LAHAN
LAND ECONOMIC RENT = Sewa-ekonomi
Lahan
Definition of 'Economic Rent'
The amount of money an owner of a factor of production must receive
in order for that owner to rent out that factor of production. Factors of
production include labor, capital and land.
Sewa-ekonomi “lahan” adalah bagian pembayaran atas “lahan” yang
melebihi dari pendapatan yang diterima dari pilihan terbaik
penggunaan lahan yang mungkin dilakukan; dalam hal ini “lahan”
dipandang mempunyai beberapa macam kegunaan.
DETERMINATION OF LAND RENT
Changes in the demand for land...
S
Land Rent (dollars)
If demand decreases...
rent decreases.
R1
R2
D1
D2
Acres of Land
0
Diunduh dari Sumber: .................... 5/11/2012 .
. SEWA-EKONOMI LAHAN - David Ricardo
Economic rent on land is the value of the difference in productivity
between a given piece of land and the poorest [and/or most
distant], most costly piece of land producing the same goods (e.g.
bushels of wheat) under the same conditions (of labour, capital,
technology, etc.).
Productivity is defined here in terms of both:
1.
2.
The natural fertility of the soil; and the productivity of the
existing technology in utilizing currently available labour and
capital;
The relative distance from the same market:
1. We are discussing this in terms of regional economics with
one market.
2. This part of theorem, on the ‘distance from the market’, did
not originate with Ricardo, but rather with a German
economist: Johann Heinrich von Thünen (1783- 1850), who
noted , some years after the publication of Ricardo’s
Principles, that the closer a piece of land was to the urban
core the higher was its market rent (reflecting economic
rent).
3. You can readily appreciate the significance of this by noting
that Toronto rents in the heart of the financial district on
Bay or University are higher than those in, say, Orangeville
or Bolton to the north of Toronto.
3. Thus productivity differences reflect the cost differences in
supplying grain to that one market from that piece of land.
Diunduh dari Sumber: .................... 5/11/2012 .
SEWA-EKONOMI LAHAN - VON THUNEN
Von Thünen mengembangkan teori dasar konsep
marginal produktivitas secara matematis, dan menyusun
rumus sewa lahan:
R = Y(p − c) − YFm,
dimana R=sewa LAHAN; Y=hasil per unit tanah; c=pengeluaran
produksi per unit komoditas; p=harga pasar per unit komoditas;
F=harga pengangkutan; m=jarak ke pasar.
Model Von Thünen untuk lahan pertanian diciptakan
dengan asumsi:
1. Kota terletak terpusat di dalam keadaan terisolir
2. Keadaan terisolir dikelilingi oleh alam liar.
3. Lahan benar-benar datar dan tidak memiliki sungai
atau pegunungan.
4. Kualitas tanah (kesuburan tanah) dan iklim yang
konsisten.
5. Petani di keadaan terisolir mengangkut barang
mereka sendiri ke pasar melalui gerobak melewati
tanah langsung ke pusat kota, tidak ada jalan.
6. Petani bersikap rasional untuk memaksimalkan
keuntungan.
Diunduh dari Sumber:
http://id.wikipedia.org/wiki/Johann_Heinrich_von_Th%C3%BCnen....................
KESUBURAN TANAH - PRODUKTIVITAS…
Ksuburan tanah merupakan “kualitas tanah”
dalam hal kemampuannya untuk menyediakan
unsur hara yang sesuai, dalam jumlah yang cukup
, dalam keseimbangan yang tepat dan lingkungan
yang sesuai untuk pertumbuhan dan produksi
spesies tanaman.
Kesuburan tanah merupakan manifestasi dari
sifat dan kemampuan tanah.
Produktivitas Tanah merupakan “kemampuan
tanah” untuk memproduksi sesuatu spesies
tanaman dengan sistem pengelolaan tertentu.
Aspek pengelolaan yang dimaksud misalnya
pengaturan jarak tanaman, pemupukan,
pengairan, pemberantasan hama dan penyakit,
dll.
Diunduh dari Sumber: http://ielmasblog.blogspot.com/2012/02/kesuburan-tanah-danproduktivitasnya.html .................... 5/11/2012 .
PRODUKTIVITAS TANAH
Produktivitas tanah pada dasarnya adalah konsep ekonomi
dan bukan sifat tanah, ada tiga hal yang terlibat:
1. Masukan (sistem pengeloalaan khusus),
2. Keluaran (hasil tanaman tertentu),
3. Tipe tanah.
Dengan menetukan biaya dan haraga, keuntungan bersih
dapat dihitung dan digunakan sebagai dasar untuk
menentukan nilai lahan, yang penting dalam penaksiran
NILAI SEWA-EKONOMI LAHAN.
Ada dua segi penting produktivitas tanah, yaitu:
1. Tanah yang berbeda mempunyai kapasitas yang
berbeda untuk menyerap masukan (INPUT) PRODUKSI
untuk menghasilkan keuntungan tertinggi.
2. Tanaman yang berbeda mempunyai kapasitas yang
berbeda untuk meyerap masukan (input) produksi
untuk menghasilkan keuntungan tertinggi pada tipe
tanah tertentu.
Diunduh dari Sumber: http://ielmasblog.blogspot.com/2012/02/kesuburan-tanah-danproduktivitasnya.html .................... 5/11/2012 .
INDEKS PRODUKTIVITAS TANAH
Neill’s (1979) productivity index was modified by
Pierce et al. (1983).
The productivity index was based on the use of
simple easily measurable soil properties to
predict the effect of soil environment on root
growth. This is expressed as follows:
r
PI ∑ = S (Ai x Bi x Ci x Di x Ei x Wfi)
i=1
where: PI = productivity index; Ai = Sufficiency for
available water capacity for the ith soil layer; Bi =
Sufficiency for aeration for the ith soil layer; Ci =
Sufficiency for pH for the ith soil layer; Di = Sufficiency
for bulk density for the ith soil layer; Ei = Sufficiency for
electrical conductivity for the ith soil layer; Wfi = Root
weighting factor; r = Number of horizons in the rooting
zone.
Other parameters like nutrients, management, climate
and genetic factors are presumed to be constant.
Diunduh dari Sumber: http://www.agrosciencejournal.com/public/agro7o31.pdf.................... 5/11/2012 .
INDEKS PRODUKTIVITAS TANAH
. Neill’s model (1979) did not take care of some soil parameters
such as organic carbon, available phosphorus and
exchangeable aluminium that exert key influence on the
productivity of tropical soils. Consequently, a modifixation
was carried out to include these three sufficiencies. The
modified expressions are as follows:
r
P1Mi = ∑ (Ai x Ci x Di x Wfi).
Where: P1Mi = Modified productivity index that involves the
exclusion of sufficiencies for aeration and electrical conductivity.
P1M2 = ∑ (Ai x Ci x Di x Ji x Ki x Li x Wfi).
Where: P1M2 = Modified productivity index that involves the
inclusion of sufficiencies for organic carbon, available phosphorus
and exchangeable aluminium with simultaneous exclusion of
sufficiencies for aeration and electrical conductivity; Ji = Sufficiency
for organic carbon for the ith soil layer; Ki = Sufficiency for available
phosphorus for the ith soil layer; Li = Sufficiency for exchangeable
aluminium for the ith soil layer.
The sufficiencies for available water capacity, bulk density, pH
and root weighting factor for this modification were as
established by Pierce et al. (1983), while other sufficiencies
were established in this research.
Diunduh dari Sumber: .................... 5/11/2012 .
. KECUKUPAN KADAR C-ORGANIK
The rating of organic carbon (Source: Enwezor et al.( 1981 )
Organic carbon content (%)
0.50
0.65
0.80
0.95
1.10
1.25
1.40
1.55
1.70
1.85
2.0 and above
Source: Enwezor et al.( 1981 )
Sufficiency
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
A sufficiency of 1.0 was assigned for
organic carbon content of 2.0 percent in the study area.
It is presumed that soil productivity approaches zero at
organic carbon content of 0.5 or less (Enwexor et al.,
1981).
Enwezor, W.O. Udo, E.J. and Sobulo, R.A. (1981). Fertility Status and Productivity
of acid sands. In: Acid of Southeastern Nigeria. Monograph No. 1 Soil Sci. Soc. of
Nigeria 56-73pp.
Diunduh dari Sumber: http://www.agrosciencejournal.com/public/agro7o3-1.pdf
.................... 5/11/2012 .
. KECUKUPAN P-TERSEDIA
Sufficiency rating of available
phosphorus
In this study, a
sufficiency of 1.0
was assigned for
the highest
available
phosphorus
content of 50 Cmol
kg-1 and it is
assumed that soil
productivity
declines at
available
phosphorus of 15
cmol kg-1 or less
(Landon, 1991).
Available Sufficiency
phosphorus
5
0.1
10
0.2
15
0.3
20
0.14
25
0.5
30
0.6
35
0.7
40
0.8
45
0.9
1. Landon, J.R. (eds). (1991). Booker tropical Soil Manuel: A Handbook for Soil
Survey and Agricultural land Evaluation in the Tropics and Sub-tropics. John
Wiley and Sons Inc. Third Avenue, New York, U.S.A. 474pp.
50
1.0
Diunduh dari Sumber: http://www.agrosciencejournal.com/public/agro7o3-1.pdf
.................... 5/11/2012 .
. KECUKUPAN Al.dd
The highest
sufficiency of 1.0
was assigned for
exchangeable
aluminium
concentration of
2.8 cmol kg-1.
Soil productivity
approaches zero
at exchangeable
aluminium
concentration of
14.0 cmol kg-1 and
above
(Pratt, 1966;
Mclean and
Gilbert, 1927).
1.
2.
Sufficiency rating of exchangeable
aluminium
Exchangeable
aluminium
concentration
(cmol kg-1)
Sufficiency
2.8
1.0
5.6
0.8
8.4
0.6
11.2
0.4
14.0 and above
0.2
Mclean, F.T. and Gilbert, B.E. (1927). The relative aluminium
tolerance of crop plants. Soil Sci. 24: 163-175.
Pratt, F.P. (1966) Aluminium. Department of Soil and Plant
nutrition, University of California Div. Agric, Sci. 12pp..
Diunduh dari Sumber: http://www.agrosciencejournal.com/public/agro7o3-1.pdf
.................... 5/11/2012 .
…
1. Bergstrom, J. C., B. L. Dillman, and J. R. Stoll. 1985. “Public Environmental
Amenity Benefits of Private Land: The Case of Prime Agricultural Land.” Southern
Journal of Agricultural Economics 17(1):139-149.
2. Bergstrom, J. C., J. R. Stoll, J. P. Titre, and V. L. Wright. 1990. “Economic Value of
Wetlands-Based Recreation.” Ecological Economics 2(2):129-147.
3. Crocker, T. D. 1985. “On the Value of the Condition of a Forest Stock.” Land
Economics 61(3):244-254.
4. Diamond, D. B., Jr., 1980. “The Relationship Between Amenities and Urban Land
Prices.” Land Economics 56(1):21-32.
5. Loomis, J., and Anderson, P. 1992. “Idaho v. Southern Refrigerator.” In Natural
Resource Damages: Law and Economics, Ward, K. M. and
6. Duffield, W. J. (ed.), Wiley Law Publications, New York, pp. 389-414.
7. Palmquist, R. B., and L. E. Danielson. 1989. “A Hedonic Study of the Effects of
Erosion Control and Drainage on Farmland Values.” American Journal of
Agricultural Economics 71:55-62.
Diunduh dari Sumber:
http://www.hss.energy.gov/sesa/environment/guidance/cercla/valuation.pdf....................