Agricultural Land Rating Systems

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the landscape through a soil scientists eyes...
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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 ClassificationUSDA1972

• 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 cutoffLCC Class IV
• Productivity estimated only for limited crops
• Sugar, pine, pasture, woodland
• Soils mapped statewide

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Land Capability ClassificationUSDA1972

• 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
ClassificationLSB, 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)

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Overall Productivity Ratings,Detailed Land
ClassificationLSB, UH1965-1972

• Acreage in Agricultural District
• LSB A-C statewide
• 447,250 acres (estimate)
• Percent LSB A-C
• 24 of ag district

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ALISHDOA/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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ALISHDOA/USDA, UH/CTAHR 1977-78

• Description
• 3 classes ofimportant 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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ALISHDOA/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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LESALESA 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

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LESALESA Commission1983-86

• 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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LESALESA Commission1983-86

• Description
• Ag production goalsfor 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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LESALESA Commission1983-86

• 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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• Description
• Site Assessment (SA)
• Based on USDA LESA manual, selected locational,
  environmental, operational factors
• 10 site factorscategories 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 ratingSA score) divided
  by 2
• Threshold score for LESA IAL based on projected
  acreage
• Mapping GIS coverage limited

LESALESA Commission1983-86
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LESALESA Commission1983-86

• 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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Comparisonof Systems

• Amount of land rated suitable for agriculture
• LEAST
• LCC 21 of ag district
• LSB 24
• LESA 41
• ALISH 46
• MOST

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• Comparison of systems

• LCC -- Lands better than Class IV

ALISH 8 Prime Other Important Ag
LCC
ALISH

• LSB -- A-C lands

LESA 8 Lands above threshold IAL score
LESA
LSB
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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
• LCCStraightforward use of soils data
• ALISH
• LSBCrop indices inputs would need to be
  reassessed more cost to State
• Difficult
• LESAMost complex, scoring system is opaque,
  mapping problems most costly to define use

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Comparison of Systems

• Objectivity
• Most objective
• LCC
• LSBCriteria clear/quantifiable for both
• Less objective
• ALISHNo standardized way to define unique
• Least
• LESAFactors not clear, difficult to quantify
  map

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Comparison of Systems

• Consistency
• Most consistent
• LCC
• LSBProperties, criteria clear
• Less so
• ALISHBoth unique other introduce
  variability
• Least
• LESAVariability 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
• LCCCriteria constant, least sensitive to local
  crop potential
• LSBDated, system indexed to sugar pine farm
  practices at time
• Least
• LESAComponents outdated indexed to sugar
  pine productivity goals rigid most difficult to
  update

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Comparison of Systems

• 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
• LSBOn State GIS, data old
• Least GIS-ready
• LESAData 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

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Closing Thoughts

• Example of how one factor--irrigation--changes
  ratings

... good ag lands WITH irrigation
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• Two views of Lanai pineapple under different
  rating systems--LSB D vs. ALISH Unique

Closing Thoughts
C
Unique
D
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• Two views of Hanalei Valley taro under different
  rating systems--LSB E vs. ALISH Unique

Closing Thoughts
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 ratingsidentify 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
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