1. Soils Soils are the result of weathering F Mechanical F Chemical l Critical resources for food, timber, textiles... l Waste filters l Understanding soils is important for land-use planning, and engineering

2. Idealized soil profile from a humid climate at middle latitudes Zone of Leaching

3. Horizon Development and Climate

4. Soil textural classes

5. Topsoil ecosystem in a temperate climate

6. Porosity and Permeability Water saturation and air space Nutrients to plant roots

7. The Water Table The level below which the soil is saturated with water (no air space)

8. Soil water Representative water budgets Deficiencies can be remedied by storage and irrigation

9. Effect of climate on soil development

10. The Principal Soil Types

11. Effect of climate on soil types tundra soils Precipitation Temperature cold hot cool lowhigh50 cm/yr pedalferspedocals laterites tundra soils

12. Principal soil types in the USA

13. Effect of climate on soil types A typical pedocal with white caliche (CaCO 3 ) deposits in a shallow B horizon

14. Effect of climate on soils Making laterite bricks Temple at Angkor Wat Cambodia (700 yrs old) Laterite Tundra soil

15. A Newer Classification of Soil Types Pf Pc Pf Pf, Pc L Pf, L

16. Rates of soil formation: Central USA: ~ 1 cm/100 years in very porous and permeable rock Humid N. Carolina: ~ 1 cm/5 years“ Granite may require over 1000 years for a cm

18. Universal Soil Loss Equation A = RKLSCP l A = long-term average annual soil loss for site l R = long-term rainfall runoff erosion factor l K = soil erodibility index l L = hill slope/length factor l S = hill slope gradient (slope) factor l C = soil cover factor P = erosion-control practice factor

19. Both Ends of the Erosion Problem Serious soil erosion and gully formation related to diversion of water runoff over a few months in central California Sediment pollution following heavy rains in North Carolina

20. Soil Degradation l Erosion l Deforestation l Agricultural depletion l Contamination - Pollution F Salinization F Pesticides F Chemical additions and spills l Urbanization l Desertification l Overgrazing

21. Raindrop impact: millions in a single shower hit at ~ 30 mph Soil Erosion

22. Rill-wash and gullying in loose and poorly-consolidated soils Soil Erosion

27. Number of dust storms during the month of March, 1936 Soil Erosion

28. Effects of logging in Madagasgar

29. Soil Erosion Figure 3.12:(a) a natural forested slope (b) the same slope following a clearcut

30. Soil Erosion Figure 3.12:(c) the same slope after conversion to farmland (b) the same slope following urbanization

31. Soil Erosion

32. 1968 motorcycles first come to Deer Creek near Bakersfield, CA 1972 after only 4 years of ORV use little vegetation or topsoil remains

33. Soil Erosion ORV users increased from 21 to 38 million between 1982 and 1992 ATVs rip through a marsh in West Virginia Great Grizzly Hike, Montana

34. Soil Erosion 1985 photo of bulldozer and jeep tracks in Alaskan tundra made in 1946

35. Soil Erosion

36. Salt accumulation due to irrigation in an arid climate: San Fernando Valley

37. Worldwide Distribution of Salt-affected Soils

39. Chemical Contamination of Soils

40. Grain production levels off while population continues to grow

41. Cleaning Up Chemical Contamination

42. Combating Soil Degradation

44. Strip-croppingand Contour plowing Combating Soil Degradation

45. Rice terraces in Asia Combating Soil Degradation

46. No-tillFarming

47. Soil Surveys and Adequate Planning