1. Let’s Get Down and Dirty!
APES

2. Soil is a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and living organisms

3. Mature soils are arranged in a series of zones called soil horizons
Most mature soils have at least three of the possible horizons

4. In forests you will find the O Horizon (surface litter layer)
Topsoil layer (humus)
Subsoil layer (inorganic matter)
Parent material (inorganic matter)

5. The A and O Horizons is where the interaction with bacteria, fungi, earthworms, and small worms take place

6. Fertile soil that produces high crop yields has a thick topsoil layer with lots of humus

7. Dark brown or black topsoil is nitrogen rich and high in organic matter

8. Gray, bright yellow, or red topsoil is low in organic matter and needs Nitrogen enrichment

9. It can take 200 to 1000 years to develop an inch of topsoil

10. Soil Problems Acidic soil – decrease uptake of nutrients
add lime and organic fertilizer
Alkaline soil -western and southwestern United States
Add sulfur – converted by bacteria to sulfuric acid
Soil erosion
Sheet erosion
Rill erosion
Gully erosion

11. Soil removed in uniform layer; slowest moving water at top of hill

12. Flowing water coalesces into small channels; tiny gullies form

13. Gully Erosion
Channels coalesce into larger channels; water increases velocity and volume; erodes into larger gully

14. Harmful Effects of Soil Erosion
Loss of soil fertility
Loss of ability to hold water
Pollutes water, kills fish and shellfish
Clogs irrigation ditches, boat channels
Fills lakes and reservoirs with silt

15. Providence Canyon resulted from poor farming practices – Lumpkin, GA

16. Global Soil Erosion
Topsoil is eroding faster than it forms on about one third of the world’s croplands
15% of land scattered across the globe are too eroded to grow crops because
Overgrazing (35%)
Deforestation (30%)
Unsustainable farming (28%)

17. Global Soil Erosion
About 40% of world’s land used for agriculture is seriously degraded by
Erosion
Salinization
Waterlogging
Soil degradation has reduced food production on about 16% of world’s cropland

18. Practices That Leave Soil Vulnerable to Desertification
Overgrazing on fragile arid and semi-arid land
Deforestation without reforestation
Surface mining without reclamation
Irrigation techniques that lead to increase erosion
Salt buildup from irrigation
Farming on land with unsuitable terrain or soils
Soil compaction by farm machinery and cattle

19. Symptoms of Desertification
Loss of native habitat
Increased erosion
Salinization
Lowering of water table
Reduced surface water supply

20. Consequences of Desertification
Worsening drought
Famine
Declining health standards
Environmental refugees

21. Soil Conservation Conservation tillage farming (no till) Terracing
Contour farming
Strip cropping
Alley cropping
Gully reclamation
Windbreaks or shelterbreaks
Land classification

22. No till farming or Minimum tillage farming

23. Terrace Farming

24. Strip Cropping – a row of crop such as corn alternates in strips with another crop, such as grass-legume mixture, that completely covers the soil

25. Alley cropping or agroforestry – several crops are planted together in strip or alleys between shrubs and trees

26. Windbreaks or shelterbreaks – reduce wind erosion (retain soil moisture, fuelwood, and provide a habitat

27. Gully Reclamation

28. Land Classification
Identify land that should not be cleared of vegetation or planted in crops

29. Restoring Soil Fertility
Organic Fertilizers

30. Restoring Soil Fertility Commercial Inorganic Fertilizer

31. Restoring Soil Fertility
Green Manure – plowing into soil plants currently growing
Composting
Restoring Soil Fertility

32. Restoring Soil Fertility
Crop Rotation – plant areas or strips with nutrient-depleting crops (tobacco, corn, and cotton deplete soil of nitrogen) one year and the next year they plant the same areas with legumes

33. Not crop rotation – center pivot irrigation

34. Questions?