Erosion is the process by which soil is lost from the land, requiring farmers and gardeners to replace the soil or further fertilize the soil still there. Soil erosion can be caused by water splash or by wind and weeds leeching nutrients out of the soil. Many plants can help prevent soil erosion, and many man-made barriers can be effective as well.
Mulching involves covering the soil between plants with organic matter such as grass, straw, rice husks, leaves or bark. This action keeps nutrients from leaving a given area, reduces the number of weeds that sap the soil of its nutrients and continually adds more organic matter to the soil through the decomposition of the mulch.
Legumes are often grown on the top of soil in order to reduce the number of weeds that appear, preventing weeds from leeching nutrients from the soil. In some cases, these legumes also serve a double purpose of being crops that are harvested and consumed. These legumes, when they perish, return much of the nutrients back to the soil. Legume are often used to keep a plot of land occupied between the growing and harvesting of other crops.
Mixing up the crops by planting alternating rows of crops can reduce the amount of water splash that washes away nutrients from the soil. Sowing these plants early can also prevent soil erosion by preventing much of the water splash that occurs when the soil is bare of crops. When the crops are harvested, any parts that are not part of the harvest should be left in the soil because these parts not only fertilize the soil, but also prevent the growth of weeds. Cultivation should be done as little as possible because cultivation exposes the soil to water splash.
Sometimes man-made barriers are created in order to slow or stop the process of water carrying away nutrient-rich soil. Man-made techniques for preventing soil erosion include terraces, contour plowing and grass strips. Farmers and gardeners commonly try to design their farms so that slopes guide eroding water away from the growing plot.
Many trees and other objects act as effective windbreakers. Wind is another force of nature that can cause soil erosion by blowing away important, nutrient-rich soil. Evergreen trees and shrubs are usually the best windbreakers because they do not lose their leaves in the winter, serving as a windbreaker year-round.