Envirothon

1. Envirothon Soil

2. Topics • Soil • Soil Formation • Soil Texture • Soil Color • Organic Matter • pH • Salinity • Soil Air • Compaction/Shrink-Swell • Drainage • Erosion • Soil Surveys-How to Use Them • References

3. Typical Loamy Soil

4. Typical Clayey Soil

5. Typical Sandy Soil

6. Forming Factors • Climate • Living Organisms • Parent Material • Topography • Time

7. Climate • Most influential factor • Temperature and precipitation in particular • Determines the nature and speed of formation • High Heat, High humidity, abundant rain=a lot of power

8. Living Organisms • Plants and animals • Grasses vs trees • Microorganisms

9. Parent Material • Geology • Gulf Coast was a fluvial deltaic system • Soils are derived from loamy and clayey sediments • About 14,000 years old

10. Topography • Nearly level • Slope occurs along drainage

11. Time • Soils on flood plains and coast line are youngest • Stable landscapes have older soils • Takes about 500 years to form an inch of soil from hard parent material

12. Texture • USDA • % of Sand, Silt and Clay • Key factor chemically and physically

13. Clayey Soils • High Shrink-Swell • High Organic Content • High Water Holding Capacity • Agriculturally productive • Difficult to work with

14. Sandy Soil • High pore space • Low organic matter • Low fertility • Low water holding capacity • Easy to work with

15. Loamy Soil • Wide array of soils • Low to High Fertility • Low to High Organic content • Low to High Water Holding Content • Moderate to work with

16. Soil Color • Dark=high organic content • Light=low organic content • Red, yellow, brown is well drained • Gray could mean excessive wetness

17. Dark= High Organic • Most clayey soils in our area are dark and have high organic content

18. Light=Low organic content • <1 percent • Most loamy and sandy soils in our area are low in organic content

19. Well Drained • High on the landscape • Ridges and sloping areas • Yellow, red or brown • Black is usually well drained

20. Gray Could be Wet • Gray surface • Contains mottles (oxidized or reduced iron) • Concave landscape • Wet soils could be associated with wetlands!

21. Organic Matter • Accumulation of partially decomposed plant and animal residues • Loosens soil • Nutrient source for plants • Increases water holding capacity • Food for microbes

22. Soil Organic Matter • Highest in the surface where the majority of biotic activity occurs • Important to stockpile surface layer • Easily destroyed when disturbed

23. Increasing Organic Content • Warm and humid conditions are ideal for microorganisms • Constant struggle • Leave grass clippings, leaves, and twigs • Add mulch

24. Organic Matter Considerations • Carbon to Nitrogen ratio • Microbes use nitrogen to eat carbon • Could cause nitrogen difficiency in plants • Add nitrogen fertilizer • Will correct over time • Use good compost

25. Soil pH • Ideal pH range is 5.5 to 7.5 • pH >8.5 could mean high salt content • pH<4 Aluminum and Iron toxicity • pH meters • Add lime for soils less than 5.5 and sulfur for soils above 7.5 • Local soils are in good pH range • Best to not get too worried about changing pH

26. Salinity • A localized problem on Gulf Coast • Almost all soils have some salinity • Causes soil to become hard • Damages roots and stunts plants • Damages steel

27. Soil Air • Well aerated soils support better plant growth • Mechanical aerator • Incorporate organic matter into the soil for a long term solution

28. Soil Compaction • Occurs in high traffic areas • Occurs when soils are manipulated when wet • Plowing or incorporating organic matter decreases compaction • Minimize hazard of compaction by having a good thick layer of mulch on surface

29. Shrink and Swell • All clayey soils do it • swell when wet and shrink when dry • $$$$$ to fix damage

30. Soil Drainage Classes • Very poorly Drained-Water is at or near the surface during much of the growing season • Poorly drained-The soil is wet at shallow depths periodically during the growing season or remains wet for long periods. • Somewhat Poorly drained-The soil is wet at a shallow depth for significant periods during the growing season. • Moderately Well drained-Water is removed from the soil somewhat slowly during some periods of the year • Well drained-Water is removed from the soil readily, but not rapidly. • Somewhat Excessively Drained-Water is removed from the soil rapidly. • Excessively Drained-Water is removed from the soil very rapidly.

31. Drainage • Poorly drained soils are gray with oxidized iron zones • Concave landscapes • Usually have water loving plants

32. Drainage • Well drained are brown, yellow or red and most black soils • Convex landscapes • Avoid making depressions if you want the soil to stay well drained

33. Erosion • Soil moved by wind or water • Occurs in high traffic areas where surface vegetation is gone • Areas with more than 3 percent slope are susceptible • Mulch and terraces (anything to slow wind and water down)

34. Soil Surveys • An inventory of soils that includes maps, interpretative tables, and soil descriptions for use in general land use planning

35. Using a Soil Survey • Locate your area of interest in the soil map section • Identify all of the soil map unit symbols at your area of interest

36. How to Use Soil Surveys • Go to the table that contain the information you seek • Find your map unit symbol and then find the land use practice • Table provides information on suitability for that soil for that particular land practice

37. References • The Nature and Properties of Soils, by Nyle C. Brady • http://soils.usda.gov/ • http://www.tx.nrcs.usda.gov/ • http://soildatamart.nrcs.usda.gov/ • http://soilcrop.tamu.edu/

38. Contacts • USDA-Natural Resources Conservation Service • Rosenberg=281-232-6898 ext 3 • Angleton=979-849-6820 • Temple State Soils Staff=254-742-9850 • Rosenberg Soil Survey Office=281-232-4668 ext 5