soil science- ppt土壤学ppt.PPT

Desalination Desalination is used to remove ions from water. The Middle East has the least amount of freshwater than any other area on the planet and desalination is used to provide freshwater for agricultural and household purposes. This prevents salinization of the soil through agriculture. Contaminated Soil Cleanup Site cleanup depends upon the pollutant Acid = neutralization Heavy metals = chelation, de-toxification Organic solvents = incineration Other = secure landfill Electrokinetic separation removes metals and organic contaminants from low permeability soil, mud, sludge, and marine dredging Remediation Biological organisms can be used to clean up Phytoremediation uses plants to remove pollutants from the soil; as the soil takes up water through the root systems, it takes up the pollution and incorporates it into the plant tissue. Bioventing introduces air into the soil which promotes biodegradation Conservation What is soil conservation? The protection of soil against erosion or deterioration How can we do that? The Laws The U.S. Soil Conservation Act of 1935 established the Soil Conservation Service.? This agency deals with soil erosion problems and was enacted following the Dust Bowl. Soil Water Resources Conservation Act of 1977 This Act provides for a continuing appraisal of U.S. soil, water and related resources, including fish and wildlife habitats, and a soil and water conservation program to assist landowners and land users in furthering soil and water conservation Agricultural Methods No-till or minimum tillage methods protect the top soil Shaping of the land decreases runoff Windbreaks prevent erosion from wind Crop rotation prevents nutrient depletion Aquatic Protection Protection along riparian zone Riprap Lake zones with emergent plants protect sediment (littoral zone) Wetlands are characterized by the type of soil present, the hydrology and the species of flora and fauna Alternative Irrigation Drip irrigation methods deliver water direc