1. Human Impacts on Soil “The Dirt on Dirt”

2. Degradation Light - about 700 million ha Moderate - about 900 million ha (size of China) Severe - about 300 million ha Extreme - about 10 million ha (no restoration possible)

3. Degradation: Causes 1.Nutrient depletion 2.Chemical & physical degradation 3.Erosion - Soil loss 1.Nutrients “mined” out of the soil by agriculture 2.“Slash & Burn” agriculture 3.Replaced with fertilizer

4. Degradation: Causes 1.Nutrient depletion 2.Chemical & physical degradation 3.Erosion - Soil loss Chemical 1.Over use of fertilizer 2.Over use of pesticides 3.Spills - oils, etc. 4.Salination Australian salination

5. Degradation: Causes 1.Nutrient depletion 2.Chemical & physical degradation 3.Erosion - Soil loss Physical 1.Compaction 2.Waterlogging

6. Degradation: Causes 1.Nutrient depletion 2.Chemical & physical degradation 3.Erosion - Soil loss 80% of all degradation  “Fast” soil formation - 1 mm/yr  Require about > 15 cm soil for healthy crops  Many places erosion > 1mm/yr Main Culprits: Water & Wind

7. Regions of Soil Erosion

8. Get Involved! We all eat… Vote with your Food! Source:USDA Population