John Lindholm, age 14, of Scottsdale, Ariz
What causes soil erosion?
Our planet is rich in air and water, We need have no worry about running out of these vital supplies. The layers of soil are equally vital to our survival, for they feed the plants which provide our food and oxygen and our supply of soil is limited. Whatts more, it is being constantly lost and worn away by erosion and it behooves us to learn all we can about this extravagant waste and how to stop it.
At one time, certain barren areas of Italy and Israeli were fertile farmlands, The rich soil was eroded or worn away by careless and backward methods of agriculture. The settlers of North America found many soil.‑rich areas and left them barren for the same reasons. In Nature, the process ‑of erosion works steadily on the hills and plains, in the valleys and waterways. This slow wearing away of the surface rocks and soils produces many changes, but seldom sudden disaster.
In Nature, strange to say, erosion is part of the patient process of building new soil, for one of its basic ingredients is powdered rock. Pockets of water freeze and expand, cracking the porous rocks. Some rocks are weakened by air and moisture which dissolves certain of their chemicals. Rain and running water wash away the chipped and broken fragments. Soil begins to form when plants and animals mingle their living and dying with layers of this rocky debris. Larger plants arrive, matting the crumby soil with their roots. Winds and floods can no longer tear it away and the rain tends to sink below.
When a farmer clears new land, he may remove the plant life which protected it from natural erosion. The precious crumbs of soil are washed away by the rain and after a drought, the powdery dust is blown far away by the winds.
After 20 years of neglect, a layer of soil five to ten inches deep can be eroded by wind and water ‑ and Nature must work 10,000 years to replace it.
Trees should be planted along rivers and waterways to protect the soil during flood times. Grasses and rooty crops protect the fields from wind and water erosion. And a wise farmer studies the shape of his land to find where the natural run‑off will gush down the slopes, carrying with it his precious topsoil. He may plant his crops in terraces, where the rainfall is coaxed to sink down instead of running over the ground. He may guide and save his rainfall by contour plowing with horizontal furrow which prevent the run‑.off from gushing down his slopes.
In Nature, the slow process of erosion reshapes the face of the earth and builds new soil. It may take 1,000 years to build one inch of topsoil. Man, who needs this soil to survive, can work with Nature to protect and enrich it ‑ he can work against Nature and allow the patient work of ages to be destroyed by erosion in a few years.