1. Intro to Soils

2. Objectives Define terms relating to soil. Describe factors affecting soil formation. Describe soil weathering factors. Describe the procedure for classifying different portions of land for agricultural uses.

3. Soil Terminology Soil – layer of natural materials on earth’s surface containing both organic and inorganic materials and capable of supporting plant life Organic matter – dead plant and animal material in varying stages of decay

4. Soil Formation Parent materials – materials underlying the soil and from which the soil was formed 5 categories: –Minerals and rocks –Glacial deposits –Loess deposits –Alluvial and marine deposits –Organic deposits

5. Minerals Solid, inorganic, chemically uniform substances naturally occurring in the earth Common minerals for soil formation include micas, iron oxides, and silica

6. Rocks Three types –Igneous – formed by the cooling of molten materials pushed up to the earth’s surface –Sedimentary – formed by the solidification of sediment Includes rocks that form in layers (river rocks) –Metamorphic – igneous or sedimentary rocks that have been reformed because of heat or pressure

7. Glacial Deposits Formed from glaciers scooping up massive amounts of surface material Mostly found in midwestern United States

8. Loess Deposits Wind-blown silt Located in eastern Mississippi Valley

9. Alluvial and Marine Deposits Alluvial – Left by moving fresh water Marine – Left by ancient ocean floors

10. Organic Deposits In swampy and marshy areas where plant life are abundant Organic substances form in which plants can grow in

11. Weathering The breaking of rocks or soil into smaller and smaller pieces Examples include: – Temperature changes – Water action – Plant roots – Ice expansion – Mechanical grinding

12. Physical Properties of Soil Slope – most important factor in determining the productivity of soil –Why? Texture – proportions of sand, silt, and clay in the soil Soil drainage – natural ability of soil to allow water to flow through it Flood hazard – likelihood that a given field will receive flood damage

13. Physical Properties of Soil Erosion – degree to which soil has already been damaged Topsoil / subsoil thickness – depth of those layers available for plant root production

14. Land Capability Classes 8 classes that tell how productive the land is for agricultural purposes They are as follows: –Class I – best land for ag production, safely cultivated with minimal erosion-control measures, nearly level, well drained

15. Land Capability Classes –Class II – good land for all types of farming, but may have some limitation –Class III – moderately good land Can be cultivated and farmed regularly, but it has some important limitations –Class IV – has severe limitations, but can be cultivated with careful soil management

16. Land Capability Classes –Class V – nearly level land, but has some soil property making it unsuitable for cultivation –Class VI – serious limitations, may be very rocky or very shallow usable surface soil –Class VII – severely limiting properties –Class VIII – one or more extreme limitations

17. Objectives Define terms relating to soil. Describe factors affecting soil formation. Describe soil weathering factors. Describe the procedure for classifying different portions of land for agricultural uses.

20. Intro to ____________

21. Soil Terminology _____________ – layer of ____________ materials on earth’s surface containing both _____________ and inorganic materials and capable of supporting ________________ life Organic matter – __________ plant and animal material in varying stages of _________________

22. Soil Formation _________________ materials – materials underlying the soil and from which the soil was ________________ 5 categories: –__________________ and rocks –________________ deposits –______________ deposits –________________ and marine deposits –Organic _______________

23. Minerals Solid, ______________, chemically uniform substances ________________ occurring in the earth Common minerals for soil formation include ___________________, _________________ oxides, and ____________

24. ______________________ Three types –________________ – formed by the cooling of _________________________ materials pushed up to the earth’s surface –_________________ – formed by the solidification of sediment Includes rocks that form in ______________________ (river rocks) –Metamorphic – igneous or sedimentary rocks that have been reformed because of ______________ or _____________________

25. Glacial Deposits Formed from _______________ scooping up massive amounts of ______________________ material Mostly found in ___________________ United States

26. _________________ Deposits Wind-blown ___________________ Located in _____________________ _____________________ Valley

27. _________________________ and Marine Deposits Alluvial – Left by ______________ fresh water Marine – Left by ancient ____________ floors

28. Organic Deposits In ______________ and marshy areas where _______________ life are abundant Organic substances form in which ___________________ can grow in

29. ___________________________ The ________________ of rocks or soil into smaller and smaller ____________ Examples include: – _______________________ changes – ___________________ action – Plant ___________________ – Ice expansion – Mechanical ________________________

30. _________________ Properties of Soil ______________ – most important factor in determining the productivity of soil –Why? _______________ – proportions of sand, silt, and clay in the soil Soil ___________________ – natural ability of soil to allow water to flow through it _____________ hazard – likelihood that a given field will receive flood damage

31. Physical Properties of Soil Erosion – degree to which soil has already been ___________________ ______________ / subsoil thickness – depth of those layers available for plant root production

32. Land Capability Classes ________ classes that tell how productive the land is for ________________________ purposes They are as follows: –Class I – ________ land for ag production, safely cultivated with _________________ erosion-control measures, nearly level, well drained

33. Land Capability Classes –Class II – good land for all types of farming, but _______ have some limitation –Class III – _________________ good land Can be cultivated and farmed regularly, but it has some important _____________________ –Class IV – has _____________ limitations, but can be cultivated with careful soil management

34. Land Capability Classes –Class V – nearly level land, but has some soil property making it ________________ for cultivation –Class VI – _____________ limitations, may be very rocky or very shallow usable surface soil –Class VII – severely limiting properties –Class VIII – one or more ______________ limitations