This document discusses soil surveys and their use in land use planning. It describes how soil surveys are conducted by classifying soils, mapping boundaries, and predicting soil behaviors. Soil survey reports contain data on physical and chemical properties to help farmers, planners, and engineers evaluate land uses. The document also explains how soil surveys are used in land evaluation processes to guide development and preserve farmland by rating soil capabilities and limitations for different land uses.

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