the landscape through a soil scientist’s eyes... Advance slide
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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
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OVERVIEW
• Presentation
Overview of major rating
systems
Comparison of systems
What approach?
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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
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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
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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
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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)
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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
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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
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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
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ALISH
DOA/USDA,
UH/CTAHR
1977-78
• Acreage in Agricultural
District
ALISH statewide:
846,363 acres (estimate)
Percent ALISH:
45.8% of ag district
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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
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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)
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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
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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
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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
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LESA
LESA
Commission
1983-86
• Acreage in Agricultural
District
LESA IAL statewide:
759,534 acres (estimate)
Percent LESA IAL:
41.1% of ag district
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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
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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
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Comparison
of Systems
• Amount of land rated
suitable for agriculture
LEAST
LCC
LSB
LESA
ALISH
21% of ag district
24%
41%
46%
MOST
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• 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
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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
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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
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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
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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
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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
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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
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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...
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Closing
Thoughts
Example of how one factor-irrigation--changes ratings
Under LCC system, good ag lands WITHOUT irrigation
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Closing
Thoughts
Example of how one factor-irrigation--changes ratings
... good ag lands WITH irrigation
... without irrigation
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Closing
Thoughts
Two views of Lanai pineapple
under different rating systems-LSB “D” vs. ALISH “Unique”
ALISH
LSB
“C”
“Unique”
“D”
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Closing
Thoughts
LSB
Two views of Hanalei Valley taro
under different rating systems-LSB “E” vs. ALISH “Unique”
ALISH “unique”
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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
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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
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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