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Transcript of Soil Conservation
THE VALUE OF SOIL The value of soil is reduced when: soil loses its fertility and when topsoil is lost due to erosion.
SOIL DAMAGE AND LOSS Contour plowing - farmers plow their fields along the curves of a slope.
SOIL CONSERVATION Dust Bowl
“Dirty Thirties” For 8 years, dust blew on the southern plains.
“The simplest acts of life — breathing, eating a meal, taking a walk — were no longer simple.” “Farmers watched helplessly as their crops blew away.”
“Children wore dust masks to and from school.” “Poor agricultural practices and years of sustained drought caused the Dust Bowl.” Fertile soil is valuable b/c: There is a limited supply and it takes a long time to form.
Less than 1/8 of the land on Earth has soils that are well suited for farming. Loss of fertility can occur when: soil has been exhausted or damaged. Loss of topsoil can occur when: soil is exposed and eroded quickly by water and wind Soil Loss in the Dust Bowl: drought and poor agricultural practices caused the Dust Bowl Conservation plowing - farmers disturb the soil and its plant cover as little as possible; dead weeds and stalks are left in the ground to help return soil nutrients, retain moisture, and hold soil in place. Crop rotation - farmers plant different crops in a field each year b/c different types of plants absorb different amounts of nutrients from the soil. Wind breaks - barriers used to reduce and redirect wind; usually consists of trees and shrubs, but can include crops and fences Terracing - a leveled section of a hill cultivated area, designed to slow or prevent the rapid surface runoff of irrigation water. Silt Fencing - a temporary barrier designed to retain sediment