1. Soil Surveys & Land Use
Planning
©Vivek Srivastava

2. Objectives
 Knowledge of purposes & uses for soil
surveys
 Identify tasks for soil survey & the reports
involved
 Methods of soil evaluation & interpretation
 Use of electronic databases

3. Introduction
 Soil survey – fact-finding mission, following
by a report on the findings
 Description of the characteristics of the soils
in a given area
 Classification of the soils
 Delineate boundaries of soils on a map
 Predictions of behaviors of the soils

4. Introduction
 Contain
 Data for many users
 Farmers, forecasters agronomists: evaluate potential
production of the soil, management needs to
maximize that potential
 Planners, community officials, engineers, developers,
home buyers: evaluate the site for building
construction purposes, strengths, limitations

5. Conducting a Soil Survey
 Before any surveying begins, a plan is made
& information is collected
 Conferences
 Collect aerial photographs
 Satellite images
 Initial field reviews

6. Soil Survey Reports
 Contents of a Soil Survey

7. Conducting a Soil Survey
 Preparation of a legend
 Initial field reviews conducted in soil pits in the
most extensive landforms
 Soil-mapping unit: area of soil that is
delineated from adjacent areas on a map
 Differences may be:
 Slope
 Erosion
 Soil profile

8. Soil Survey Reports
 Physical & chemical properties of the soils
 Soil & water features
 Chemical analysis
 Clay mineralogy
 Engineering index data
 Soil classification

9. Soil Survey Reports
 Natural fertility
 Soil depth
 Tendency to accumulate soluble salts
 Soil structure
 Soil engineering properties
 Climate
 Natural vegetation
 Adapted crops & their expected productivity

10. Soil Survey Reports
 Recreational development potential
 Wildlife habitat
 Building site development
 Sanitary facility needs
 Construction materials
 Water management
 Engineering index

11. Soil Survey Reports
 Value of Detailed Soil Survey Reports
 Most soil properties recorded in a soil survey
change very slowly
 Typically semiperminent properties:
 Land relief (topography)
 Soil texture
 Organic matter content
 Geologic origin

12. Soil Survey Reports
 Reasons why a resurvey may be done:
 Some information was not gathered in a previous
survey
 New management practices
 Changes in crops grown
 Yield prediction changes
 http://soils.usda.gov

13. Land Evaluation
 Land-use planning done for: urban areas,
rural areas
 Major issues:
 Quality of environment
 Environmental sustainability of ag production
systems
 Pollution of nitrate, phosphate, pesticides
 Erosion of land
 Declining soil fertility

14. Land Evaluation
 Problems caused by these issues may have
various/multiple facets
 Agronomic
 Economic
 Political
 Social

15. Land Evaluation
 LESA system – Land Evaluation and Site
Assessment
 Guide the conversion of farmland to urban uses
 Attempts to preserve the best farmland
 Three procedures:
 Land capability classification
 Current category of land is documented
 Soil rated according to capability

16. Land Evaluation
 Land Capability Classification
 Classification & sub classification for all soil-
mapping units
 Class I Soils
 Can be used continuously for intensive crop
production w/ good farming practices
 No restrictions
 Class II Soils
 More limitations than Class I land for crop production
 2-5% slope is main difference

17. Land Evaluation
 Class III Soils
 Severe limitations
 Requires more special conservation practices than
Class II to keep it continually productive
 Can have shallow soil
 Slopes 6-10%
 Shallow water tables

18. Land Evaluation
 Class IV
 Severe limitations for cropping use
 Greater intensity of conservation practices for
cultivated crops that Class III
 Recommend permanent crops (e.g. pastures)
 Slope 12-18%
 Class V
 Boulders, wetness, problems impractical to correct
 Not necessarily erosion risk
 Can’t be cultivated
 Use for pasture, range, woodland, wildlife habitat

19. Land Evaluation
 Class VI
 Slope 18-30%
 Same limitations as Class V soils, except more need
for sustainable management practices
 Class VII
 Severe limitations
 Extreme care to protect the soil
 Even using grazing, wildlife, timber
 Slope >30%

20. Land Evaluation
 Class VIII
 Very severe limitations
 Steep slopes, rock lands, swamps, etc.
 Can only be used for wildlife, recreation, watersheds,
aesthetic appreciation
 Land capability subclasses – soil groups w/in
the 8 classes that explain the reasons for
limitations of intensive crop production
 e – erosion hazard
 w - wetness

21. Land Evaluation
 s – shallow, droughty, stony, permafrost
 c – climate too cold or dry

23. Land Evaluation
 Ratings for Soil Potential
 Indicates the relative quality of a soil for a
particular use compared with other soils in a
given area
 Developed for planning purposes
 Supplement land capability classes, woodland
suitability groups, range sites, soil limitation
ratings

24. Data Interpretation for Soil Uses
 Can be rated to have slight, moderate, severe
limitations
 Severe
 Soil will require major soil reclamation, special
design, high costs, or intensive soil maintenance
to use for the item listed
 Very Severe
 Great difficulty in the soil’s use, high costs, or
both

25. Data Interpretation for Soil Uses
 Slight & Moderate
 May indicate problems w/:
 Shallow
 Low permeability
 Strong acidity
 High salt concentration
 Various other problems