Transcript the landscape through a soil scientist’s eyes...  Advance slide

the landscape through a soil scientist’s eyes...
Advance slide
Agricultural Land Rating
Systems...
for the Non-Soil Scientist
Earl Yamamoto, State Department of Agriculture
February 5, 2000
Advance slide
OVERVIEW
• Presentation
 Overview of major rating
systems
 Comparison of systems
 What approach?
Advance slide
OVERVIEW
• Four major systems
 Land Capability
Classification,
USDA
 Overall Productivity Rating,
Land Study Bureau, UH
 Agricultural Lands of
Importance to the State of
Hawaii (ALISH),
DOA/USDA/CTAHR
 Land Evaluation & Site
Assessment (LESA) System,
LESA Commission
Advance slide
Land
Capability
Classification
USDA
1972
• Description
 Statewide USDA & UH soil
surveys
• Soil data used by all systems
 Agricultural suitability as limited
by soil & climatic conditions
• System favors mainland field crop
& mechanization
 8 Classes I-VIII, best to worse
• Effective cutoff=LCC Class IV
 Productivity estimated only for
limited crops
• Sugar, pine, pasture, woodland
 Soils mapped statewide
Advance slide
Land
Capability
Classification
USDA
1972
• Acreage in Agricultural
District
 LCC I, II & III statewide:
381,609 acres (estimate)
 Percent LCC I, II & III:
20.6% of ag district
Advance slide
Overall
Productivity
Ratings,
Detailed
Land
Classification
LSB, UH
1965-1972
• Description
 Developed concurrent with
USDA soil survey
 Soils grouped into land types
based on soil & productive
capabilities
 Two sets of productivity ratings:
• Overall Productivity Rating-
“A”, very good to “E”, not suitable
• Crop Productivity ratings for
Pine, sugar, vegetables, forage,
grazing, orchard, timber
 Soil types drawn over aerial
photos (variable scales)
Advance slide
Overall
Productivity
Ratings,
Detailed
Land
Classification
LSB, UH
1965-1972
• Acreage in Agricultural
District
 LSB A-C statewide:
447,250 acres (estimate)
 Percent LSB A-C:
24% of ag district
Advance slide
ALISH
DOA/USDA,
UH/CTAHR
1977-78
• Description
 Part of national effort (USDA)
to inventory important
farmlands
 National criteria applied,
adapted by USDA, CTAHR &
DOA
 Adopted by State Board of
Agriculture, 1977
 Broad range of factors
considered
• Soils, climate, moisture supply, input
use, etc.,
• Production-related factors
generalized
Advance slide
ALISH
DOA/USDA,
UH/CTAHR
1977-78
• Description
 3 classes of
important agricultural lands
• Prime
– Soils with best physical, chemical, &
climatic properties for mechanized
field crops
– Excludes built-up land/urban, water
bodies
• Unique
– Land other than prime for unique
high-value crops--coffee, taro,
watercress, etc.
• Other important agricultural
lands
– State or local important lands for
production, not prime or unique;
needing irrigation or requiring
commercial production
management
Advance slide
ALISH
DOA/USDA,
UH/CTAHR
1977-78
• Acreage in Agricultural
District
 ALISH statewide:
846,363 acres (estimate)
 Percent ALISH:
45.8% of ag district
Advance slide
LESA
LESA
Commission
1983-86
• Description
 1983 State Land Evaluation &
Site Assessment Commission
(Act 273, Session Laws, 1983)
• Standards & criteria for
identifying important agricultural
lands
• Inventory of important
agricultural land
 LESA system
• Numeric scoring system
• USDA system to determine
impact of federal activity on
farmland
• Used to identify lands or
evaluate individual sites
Advance slide
LESA
LESA
Commission
1983-86
• Description
 Three components
• Agricultural production goals
• Land evaluation (LE)
– Soils, topography, climate
• Site assessment (SA)
– Non-physical properties (location,
land use)
Advance slide
LESA
LESA
Commission
1983-86
• Description
 Ag production goals
for crop acreage
requirements
• Amount of land required to attain
ag production objectives
• Estimates based on current &
expected levels of production,
population & per capita
consumption
• Typical crops profiled:
– Sugar, pine, mac nuts, coffee, local
dairy, eggs/poultry
• Crop acreage used to set cutoff
score for LESA IAL lands
Advance slide
LESA
LESA
Commission
1983-86
• Description
 Land Evaluation (LE)
• Combines 5 soil ratings into
single score for land capability
–
–
–
–
–
LCC
ALISH
LSB
Modified Storie Index
Soil Potential Index
• LE score is weighted average
Advance slide
LESA
LESA
Commission
1983-86
• Description
 Site Assessment (SA)
• Based on USDA LESA manual,
selected locational,
environmental, operational
factors
• 10 site factors;
categories of factors:
– Farm productivity/profitability
– Land use potential/conflicting uses
– Conformance with government
programs/policies
• Soils rated for each criterion,
weighted, summed
 Final LESA rating=
(LE rating+SA score) divided by 2
 Threshold score for LESA IAL
based on projected acreage
 Mapping & GIS coverage limited
Advance slide
LESA
LESA
Commission
1983-86
• Acreage in Agricultural
District
 LESA IAL statewide:
759,534 acres (estimate)
 Percent LESA IAL:
41.1% of ag district
Advance slide
Comparison
of Systems
• Common features
 Soils-based with factors for
topography, climate
• Vary in consideration of other
attributes like crop yield
 Limitations to agricultural
productivity considered in
some form
• Mostly physical and climatic
limitations
 All are available on State GIS
in some form
Advance slide
Comparison
of Systems
• Major differences
 Soils-based systems exclude
other factors related to ag
profitability
 Determination of ag land
requirements
• LESA system unique in its use of
agricultural production goals
• Other systems do not
predetermine land requirements
 Incorporation of land use
policy considerations
• LESA includes policy criteria
• Land use policy dealt with in
other systems only by the
exclusion of urbanized, built-up,
subdivided land
Advance slide
Comparison
of Systems
• Amount of land rated
suitable for agriculture
LEAST
LCC
LSB
LESA
ALISH
21% of ag district
24%
41%
46%
MOST
Advance slide
• Comparison of systems
LCC -- Lands better than Class IV
ALISH 8
LCC & “Other Important Ag”
ALISH
“Prime”
LSB -- “A”-“C” lands
LESA 8
LSB above threshold IAL score
LESA
Lands
Advance slide
Comparison
of Systems
• Evaluation criteria
(based on CTAHR, 1990)
 Ease of use
• Low cost, clear explanations,
factors well-defined
 Objectivity
• Measurable factors with
quantifiable data
 Consistency
• Scores would be same across
individuals, clear definitions,
interpretations consistent, no
incentive for score manipulation
 Adaptability
• Can be readily updated to
reflect change
 GIS-readiness
Advance slide
Comparison
of Systems
• Ease of Use
 Easiest
• LCC
Straightforward use of soils data
• ALISH
• LSB
Crop indices & inputs would
need to be reassessed; more
cost to State
 Difficult
• LESA
Most complex, scoring system is
opaque, mapping problems;
most costly to define & use
Advance slide
Comparison
of Systems
• Objectivity
 Most objective
• LCC
• LSB
Criteria clear/quantifiable for
both
 Less objective
• ALISH
No standardized way to define
“unique”
 Least
• LESA
Factors not clear, difficult to
quantify & map
Advance slide
Comparison
of Systems
• Consistency
 Most consistent
• LCC
• LSB
Properties, criteria clear
 Less so
• ALISH
Both “unique” & “other”
introduce variability
 Least
• LESA
Variability in interpreting,
assigning values/weights to
factors
Advance slide
Comparison
of Systems
• Adaptability
 Most adaptable
• ALISH
Criteria can be reapplied,
accommodates unique crops
 Less so
• LCC
Criteria constant, least sensitive
to local crop potential
• LSB
Dated, system indexed to sugar
& pine & farm practices at time
 Least
• LESA
Components outdated; indexed
to sugar & pine; productivity
goals rigid; most difficult to
update
Advance slide
Comparison
of Systems
• GIS-readiness
 Most GIS-ready
• LCC
USDA NRCS maintains GIS soils
data, source of State GIS data
• ALISH
On State GIS, USDA soils data for
update available
 Less so
• LSB
On State GIS, data old
 Least GIS-ready
• LESA
Data on State GIS of
questionable value/need to
redigitize; problems encountered
in mapping factors
Advance slide
Closing
Thoughts
• Summary
1. Each of the systems has
limitations in application-none ideal
2. Ratings change with change
in conditions or opportunities
Some examples...
Advance slide
Closing
Thoughts
 Example of how one factor-irrigation--changes ratings
Under LCC system, good ag lands WITHOUT irrigation
Advance slide
Closing
Thoughts
Example of how one factor-irrigation--changes ratings
... good ag lands WITH irrigation
... without irrigation
Advance slide
Closing
Thoughts
Two views of Lanai pineapple
under different rating systems-LSB “D” vs. ALISH “Unique”
ALISH
LSB
“C”
“Unique”
“D”
Advance slide
Closing
Thoughts
LSB
Two views of Hanalei Valley taro
under different rating systems-LSB “E” vs. ALISH “Unique”
ALISH “unique”
Advance slide
Closing
Thoughts
• Summary
1. Each of the systems has
limitations in application-none ideal
2. Ratings change with change
in conditions or opportunities
3. All need to be updated to
reflect present conditions-some more than others
4. In general, system is more
robust if:
• Emphasis is on resource
suitability
• System criteria are well-defined
Advance slide
Closing
Thoughts
• In considering a
system...
 Purpose of ratings:
identify resource,
system will be soils-based
 Factors of land use policy
more appropriate for public
decision making process,
creates problems if built into rating
system
 Must weigh value of
additional time/money spent
on development &
maintenance of system
Advance slide
Credits
Department of Agriculture
James Nakatani, Director
Earl Yamamoto
State Office of Planning, DBEDT
David Blane, Director
Ruby Edwards
Chris Chung
Dennis Kim, State GIS Program