Soil Erosion
Soil erosion
Soil erosion occurs when soil is removed through the action of wind and water at a greater rate than it is formed
SOIL
The soil covering the surface of the earth has taken millions of years to form and we must learn to respect it. Soil is formed at a rate of only 1 cm every 100 to 400 years and it takes 3 000 to 12 000 years to build enough soil to form productive land. This means that soil is a nonrenewable resource and once destroyed it is gone forever. If we disregard this, a time will come when there would not be enough soil left to sustain life on earth, because the soil is a necessary growth medium for plants, a home for certain insects and animals, as well as a medium from which we get minerals, such as gold. It is important therefore to treat soil, especially topsoil, as a living entity.
WHAT IS SOIL EROSION?
When a raindrop hits soil that is not protected by a cover of vegetation and where there are no roots to bind the soil, it has the impact of a bullet. Soil particles are loosened, washed down the slope of the land and either end up in the valley or are washed away out to sea by streams and rivers. Erosion removes the topsoil first. Once this nutrient-rich layer is gone, few plants will grow in the soil again. Without soil and plants the land becomes desertlike and unable to support life.
CAUSES OF SOIL EROSION
Erosion occurs when farming practices are not compatible with the fact that soil can be washed away or blown away. These practices are: Overstocking and overgrazing Inappropriate farming techniques such as deep ploughing land 2 or 3 times a year to produce annual crops Lack of crop rotation Planting crops down the contour instead of along it.
Water erosion
Water erosion causes two sets of problems: An on-site loss of agricultural potential An off-site effect of downstream movement of sediment, causing flooding and the silting up of reservoirs.
Sheet erosion
Soil erosion is
Soil erosion occurs when soil is removed through the action of wind and water at a greater rate than it is formed
SOIL
The soil covering the surface of the earth has taken millions of years to form and we must learn to respect it. Soil is formed at a rate of only 1 cm every 100 to 400 years and it takes 3 000 to 12 000 years to build enough soil to form productive land. This means that soil is a nonrenewable resource and once destroyed it is gone forever. If we disregard this, a time will come when there would not be enough soil left to sustain life on earth, because the soil is a necessary growth medium for plants, a home for certain insects and animals, as well as a medium from which we get minerals, such as gold. It is important therefore to treat soil, especially topsoil, as a living entity.
WHAT IS SOIL EROSION?
When a raindrop hits soil that is not protected by a cover of vegetation and where there are no roots to bind the soil, it has the impact of a bullet. Soil particles are loosened, washed down the slope of the land and either end up in the valley or are washed away out to sea by streams and rivers. Erosion removes the topsoil first. Once this nutrient-rich layer is gone, few plants will grow in the soil again. Without soil and plants the land becomes desertlike and unable to support life.
CAUSES OF SOIL EROSION
Erosion occurs when farming practices are not compatible with the fact that soil can be washed away or blown away. These practices are: Overstocking and overgrazing Inappropriate farming techniques such as deep ploughing land 2 or 3 times a year to produce annual crops Lack of crop rotation Planting crops down the contour instead of along it.
Water erosion
Water erosion causes two sets of problems: An on-site loss of agricultural potential An off-site effect of downstream movement of sediment, causing flooding and the silting up of reservoirs.
Sheet erosion
Soil erosion is