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Let’s Get Down and Dirty! I APES. Soil is a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and living organisms.

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Presentation on theme: "Let’s Get Down and Dirty! I APES. Soil is a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and living organisms."— Presentation transcript:

1 Let’s Get Down and Dirty! I 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 Channels coalesce into larger channels; water increases velocity and volume; erodes into larger gully Gully Erosion

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

32 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?


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