agricultural land rating systems... for the non-soil scientist earl yamamoto, state department of...
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Agricultural Land Rating Systems...
for the Non-Soil Scientist
Earl Yamamoto, State Department of AgricultureFebruary 5, 2000 Advance slide
• Presentation Overview of major rating
systems Comparison of systems What approach?
OVERVIEW
Advance slide
• 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
OVERVIEW
Advance slide
Land Capability Classification
USDA1972
• 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 statewideAdvance slide
Land Capability Classification
USDA1972
• 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, UH1965-1972
• 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 forPine, sugar, vegetables, forage, grazing, orchard, timber
Soil types drawn over aerial photos (variable scales)
Advance slide
Overall Productivity Ratings,Detailed Land Classification
LSB, UH1965-1972
• 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 Commission1983-86
• 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
• Description Three components
• Agricultural production goals
• Land evaluation (LE)– Soils, topography, climate
• Site assessment (SA) – Non-physical properties
(location, land use)
LESA
LESA Commission1983-86
Advance slide
• 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
LESA
LESA Commission1983-86
Advance slide
• 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
LESA
LESA Commission1983-86
Advance slide
• 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
LESA
LESA Commission1983-86
Advance slide
LESA
LESA Commission1983-86
• 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
• Amount of land rated suitable for agriculture
LEAST
LCC 21% of ag district LSB 24%
LESA 41% ALISH 46%
MOST
Comparisonof Systems
Advance slide
• Comparison of systems
LSB -- “A”-“C” lands
LCC -- Lands better than Class IV
LCC
LESA
LSB
ALISH
Advance slide
ALISH “Prime” & “Other Important Ag”
LESA Lands above threshold IAL score
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-readinessAdvance slide
Comparison of Systems
• Ease of Use Easiest
•LCCStraightforward 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
• 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
Comparison of Systems
Advance slide
• Adaptability Most adaptable
•ALISH Criteria can be reapplied, accommodates unique crops
Less so•LCC
Criteria constant, least sensitive to local crop potential
•LSBDated, system indexed to sugar & pine & farm practices at time
Least•LESA
Components outdated; indexed to sugar & pine; productivity goals rigid; most difficult to update
Comparison of Systems
Advance slide
• GIS-readiness Most GIS-ready
•LCCUSDA NRCS maintains GIS soils data, source of State GIS data
•ALISHOn 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
Comparison of Systems
Advance slide
Closing Thoughts
• Summary1.Each of the systems has
limitations in application--none ideal2.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
... good ag lands WITH irrigation
... without irrigation
Example of how one factor--irrigation--changes ratings
Advance slide
LSB
“C”“D”
ALISH
“Unique”
Closing Thoughts
Two views of Lanai pineapple under different rating systems--LSB “D” vs. ALISH “Unique”
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
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
• Summary1.Each of the systems has
limitations in application--none ideal
2.Ratings change with change in conditions or opportunities
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 AgricultureJames Nakatani, Director
Earl Yamamoto
State Office of Planning, DBEDTDavid Blane, Director
Ruby EdwardsChris Chung
Dennis Kim, State GIS Program