chapter 7 section 3 notes
TRANSCRIPT
Chapter 7 Section 3Chapter 7 Section 3
Soil ErosionSoil Erosion
• Soil EROSION or loss is important because plants do not grow as well when topsoil is lost
• Causes and effects of soil erosion – many humans activities disturb the natural BALANCE between soil production and soil erosion.
– AGRICULTURAL CULTIVATION – increased farming removes the plant cover, leaving soils open to wind and water erosion.
– FOREST HARVESTING – removes forest which increases erosion and particularly damages tropical rain forest soil.
– OVERGRAZING results when animals graze until almost all ground cover disappears.
– EXCESS SEDIMENT can damage the environment when soil erosion is severe
• Preventing soil erosion – soil must be PROTECTED
– Manage crops
• Farmers plant SHELTER BEDS of trees to break the force of the wind.
• Bare soil can be COVERED with decaying plants to hold soil in place
• Farmers can GRAZE ANIMALS on vegetation instead of plowing it under.
• With NO-TILL farming, plant stalks are left in the field to provide cover for soil.
– Reduce erosion on slopes
• CONTOUR farming reduces soil erosion by planting along the contours of slopes
• TERRACING creates steep-sided flat areas for crops on the sides of hills and mountains.
– Reduce erosion of exposed soil
• WATER is sprayed onto bare soil to reduce wind erosion
• Topsoil is replaced and TREES are planted
• WATER flow can be controlled in strip mines
• After mining, the land can be RECLAIMED