Chapter 7 section 4 (land use and soil loss)Presentation Transcript
How Land Use Causes Soil Loss Chapter 7 Section 4
I. Agriculture and Soil Loss Soil is a very important resource for the agricultural business. Many resources are directly tied to the soil. Food, paper products, natural fibers. Vegetables, grains, cotton plants. Cattle, sheep, and pigs feed off the land. When farmers harvest crops the soil is directly exposed to the weather. Erosion occurs. Soil loses nutrients when topsoil is eroded.
II. Historic Tragedy: The Dust Bowl Great Plains: 1800’s People moved to the Great Plains. Plowed under the native drought resistant crops. Began to farm large areas. Corn and wheat were planted; Cattle and sheep grazed on land. As farming continued the natural drought resistant grasses with their extensive root system became increasingly scarce and erosion increased dramatically.
The Great Plains Drought of 1931 Drought started in 1931 and lasted several years. Soil became totally unprotected, wind began blowing the soil away. (erosion) Dust storms raged. More than 8cm of topsoil was lost!
The Great Plains Drought of 1931 Soil was blown to the ocean or piled up against houses. Many farmers went bankrupt and moved elsewhere. 1935: Federal Government began regulating agriculture. Crop rotation, terracing, and contour plowing was required. (Section 3 notes)
The Great Plains Drought of 1931 In areas able to support trees, wind breaks were planted. Over time, the fertility of the Great Plains was restored.