The Destruction of Soils

By Samad Aslam Khan
Soil is destructed in many ways. Erosion is one of the forces that tend to war down the earth's surface. During natural erosion some soil is carried away, but the process goes on so slowly that new soils are formed about fast as the older soils disappear. Thus natural erosion is not very harmful.

Another type of erosion, known as soil erosion or sheet erosion, is different from natural erosion in that it goes on very rapidly. Large amounts of rich topsoil are carried away by the erosion each year due to largely to the poor management of land areas. A few examples will make this clear.

When forest areas are carelessly cut away, the deep humus covering of the forest floor is easily washed away. Soon the slopes are cut deep with gullies.

In western part of America, great numbers of animals graze in mountains. If the animals are permitted to overgraze, the grass is eaten down more rapidly than it can grow. When it is close-cropped in this way, the roots are often exposed and the grass dies. Also, the constant tramping of the animals tends to cut the roots and cause the grass to die. The roots of grass tend to hold the soil in place. When these roots are destroyed, the loose soil can be more easily washed away by running water.

In some of prairie states the land once had a natural cover of grass. When these grasslands were plowed for the production of crops, the soil was exposed to sheet erosion. In this way much valuable topsoil has been carried away by running water.

In some areas where the natural cover has been broken, large amounts of topsoil have been blown away by the winds. Rainfall varies from year to year. If a period of prolonged drought happens to come when the natural grass soil covering has been broken, the soil may blow away in dust storms.

Some of the areas in the so-called "dust bowl" have been turned into barren deserts. The land became covered with sand which drifted almost like snow over farms, building, and highways. These farms had to be abandoned.