EVSC 220 Lecture Notes - Lecture 5: Soil Ph, Tillage, Siltation
Document Summary
Outline the relationship between ph, speciation, bioavailability, and toxicity. If you have vegetation cover over 70% erosion is almost non existent. Longer the slope the faster water moves, if you can slow water down by vegetation it will have an interrupted ow and slow it down. At 40% plant cover there is almost no wind erosion but still water erosion. Tree canopy and understory both removed, increasing erosion risk. Severe, slow moving res can also contribute to hydrophobicity of near surface soil. Soil repels water, increasing run-o and reducing potential for seed germination. Hydrophobicity - chemical change to the soil organic matter that repels water and reduced in ltration rates, water hits and beads up instead of soaking into the soil. High clay soils very cohesive, therefore resistant to water erosion. Sandy soils have high in ltration rates, therefore resistant to water erosion, but because they tend to be dry, they are susceptible to wind erosion.