Soil Degradation and Conservation Action movie

Soil Degradation Land degradation is a huge problem today, especially for the world’s poor An area equal to the size of China and India combined is now classified as having impaired biological function Most the result of poor land management MEDCs Tradition of agriculture has lead to soil conserving practices However…sometimes climate and intensive agriculture lead to devastating levels of erosion still What about LEDCs?

Processes Leading to Soil Degradation Two Types of Processes lead to soil degradation Processes that take away soil Mainly due to removal of vegetation Wind and water then remove the soil Processes that make the soil less suitable for use Various chemicals end up in the soil and make it useless in the long run Over fertilizing (salinization), various pollutants/pesticides

Human Activities Leading to Soil Degradation Overgrazing Too many animals graze in the same area or animals stay in the same area too long Deforestation Selective cutting: careful choosing each tree Strip cutting: Cutting in rows Clear cutting: Removing large areas of trees Ex: In tropical regions leaves deflect and slow down rain

Human Activities Leading to Soil Degradation Unsustainable agriculture Total removal of crop after harvest Having uncovered soil between rows Plowing in the direction of the slope Excessive Pesticides Excessive irrigation (leads to salinization and erosion) Monocultures (deplete specific nutrients)

Soil erosion by water Types Sheet Wash Gullying Wind erosion Uniform loss of soil, usually when water crosses a flat field or mountainous region in a land slide Gullying Rivulets join to become larger, channel becomes wider and deeper, usually on steeper slopes or where water moves fast Wind erosion On drier exposed soils the wind continually removes topsoil

Soil Conservation Soil Conditioners Wind Reduction Most common are organic materials and lime Lime: Increases pH to counter soil acidification Also helps clay particles stick together and act more like sand Organics improves texture and acts as a nutrient source as well Wind Reduction Alley cropping/strip cropping Soil Conserving Cultivation Strip cropping with cover crops between rows Terracing (create horizontal levels on slope) Contour farming (Plow perpendicular to hillside)

Soil Conservation Improved Irrigation Marginal Land Crop Rotation Limiting evaporation reduces salinization Limiting run-off reduces erosion Marginal Land Accept the fact that some land is NOT suitable for farming Crop Rotation Some crops are hungrier than others Rotate with a nitrogen fixer