Problems Of Conservation: Soil (1969)

To the farmer, soil has always meant the precious inches of top soil in which he grows his crops. Early in the history of this continent, the growing national economy depended heavily on the farmer and the productivity of his soil. Most people in America lived on the land. Relatively few were city dwellers. But beginning in the 19th century, the face of the land began to change. Industrialization created an age of urban growth. The rise of the cities began. In little more than a century, the land became as much a place for building as for farming. And today, almost 3/4 of our population lives in urban areas where life is mechanized and the earth is paved. Although the basis of our economy has changed from agriculture to industry, and city dwellers seldom see the farmer's fields, the soil is more important to the nation than ever before, for it must help feed and clothe and house a population that has doubled in just 50 years. [Applause] Much of the abundance, many of the necessities and luxuries on which people depend still come from the soil. How are we as a nation caring for this life-supporting surface of the land? How are we conserving this precious resource? To answer these questions, we must first understand the nature of soil and how it is formed. Good productive soil is a relatively thin layer on the very top surface of the land. But top soil is not the same all over the world. This black soil is rich. This light sandy soil may be equally rich. Even though soils may look the same, they can be different, varying sharply in fertility and composition. Each kind of soil is capable of supporting differing types of plant life because of its particular characteristics. But those soils differ widely. Nearly all soils have one common characteristic. They were formed from materials that were originally rock. Rock which has been broken down into tiny particles by natural processes. No matter how fine the parent rock material may become, it will not be soil until organic material is added. Decaying plants and animal remains furnish this organic matter. Bacteria decompose the plant and animal remains. Other earth dwelling organisms airate the soil and help to fertilize it with their castings. It takes nature 500 to a,000 years to build 1 in of top soil. But in minutes, man can disrupt the natural balance that created it with a simple turn of a plow. The key to natural soil conservation is vegetation, plant life, ranging from thick grasses of prairie areas to the dense forests of mountain regions. Plants and their underground root systems form a natural ground cover which holds soil in place and helps prevent its erosion by the forces of rain and wind. When rain falls on soil that has good plant cover, the explosive force of the raindrops is cushioned and lessened before the water reaches the soil. Most of the water is absorbed. What runs off moves slowly. Roots hold the soil together. Every spring, when farmers plow under the natural ground cover as they prepare for planting, they expose their top soil to water erosion. With a natural cover removed, each raindrop hits the soil directly with explosive force. Now the water may tear into the soil easily and wash it off in small reals and gullies. A jar of water taken from the runoff of freshly plowed fields into this river illustrates the loss of soil. If we allow the sediment to settle, you can see that about 1/4 in of top soil lies above the bottom of the jar. From what we saw in the 1/2 gallon jar, imagine how much soil is carried by the entire river. On this soil, it is easy to see the beginning effects of water erosion. If this situation remains unchecked, it can lead to gullies so deep the fields can no longer be plowed. Each rain will cut this gully back farther and farther into the good soil. The erosion of soil by water can create problems which extend beyond a local situation like this. Much top soil is carried in streams to the mouths of rivers where it interferes with navigation and requires constant costly dredging operations. In some places, sediment builds up behind dams and reduces the water storage capacity of reservoirs. What was valuable to a local farmer has become a problem hundreds of miles away. But water is only one of two major forces which make top soil vulnerable to erosion. A field stripped of its natural cover can also be eroded by wind. Even under normal conditions with good rainfall to help hold soil together, the wind can remove a considerable amount of top soil from exposed fields. Some of it accumulates in hollows and roadways, much like drifting snow in winter. Much more than this is carried away and lost forever to the farmer. In the great plain states, where woods and hills do not break the sweep of wind, the plowed fields are particularly vulnerable to this type of erosion. Together, wind and water carry away millions of tons of top soil a year from farmlands throughout the world. Over the years, as man has used the soil to produce his food and fibers, he has frequently disrupted another natural balance within the soil itself. Many years ago, this land was capable of producing a high yield of fine quality corn. The soil was rich in well-balanced nutrient minerals. Slowly, they were used up. The soil was no longer fertile. Here in the same type of soil, man replaced the nutrients used by the plants and the fields still yield abundantly. It is not easy to see the loss of soil through depletion of its nutrients. It's not as dramatic as erosion, but it is an important cause of the shrinking volume of our high yield top soil. Through a combination of wind and water erosion and depletion of soil nutrients, thousands and thousands of acres have been temporarily lost to production. Long ago, when a farmer's soil became poor, he moved on to another area. Today, there is no virgin land left, and the requirements of a rapidly expanding population are taxing our land resources. New superighways alone have taken land almost equivalent to the combined areas of the Netherlands and Belgium. Yet, in spite of such demands on our available land, we have the knowledge to expand the usefulness of our existing top soil. We know how to practice soil conservation and we have an effective national organization to help us do so. In 1935, Congress established the US Soil Conservation Service, an agency that has become internationally known and copied in other countries through soil conservation districts organized and controlled by the states. Technical assistance is available to land owners and operators in developing, applying, and maintaining sound conservation plans on their land. Experts working with farmers recommend specific conservation practices. Here the initial lines for contour plowing are being marked. Plowing with the contour of the land instead of up and down hills is a proven soil conservation practice that prevents water runoff. Plowing the remains of the last crop back into the soil also increases its water holding efficiency and reduces erosion. Rip wrapping of stream banks protects them from being cut away by the rush of water and grade stabilization dams at certain intervals prevent fast water runoff that causes erosion and flooding. Where wind erosion is a problem, farmland must be kept in some kind of cover. The use of winter crops, carefully planned crop rotation, and restoration of grass or forage plants are all parts of a good conservation program. Rows of trees planted at right angles to the prevailing wind have proven highly effective in reducing wind erosion. Terracing and strip cropping with the contour of the land or at right angles to the wind also help to reduce erosion by wind and water on test plots. Soil conservationists work continually to combat depletion of soil nutrients. The use of fertilizers, a longestablished practice, has become a highly developed skill in the hands of specialists. The knowledge gained in these experiments is passed on to the farmer. But the soil conservation service has responsibilities that extend beyond the use of land for agriculture. ly. Other activities include assistance in the layout of drainage and water disposal systems, farm ponds, irrigation, recreation, and preservation of the natural beauty of the land. Many farmers have added income from recreational areas that have been developed within easy driving distance from urban centers. As our population grows, the use of land becomes more competitive. Much land will be taken from highly productive soils because steep and rough areas are less desirable for urban growth and public facilities. so that there will be fewer mistakes in locating the best soils for specific use. Land use planning is a new and important conservation practice. These specially prepared maps of the soil conservation service show the capabilities and limitations for agriculture, housing and light industry, transportation and recreation within a certain area. Governments and the United Nations are making great contributions to the preservation of the precious soil resources all over the world. But much remains to be done. One of our most urgent tasks today is to create a general awareness of this problem. To feed the exploding population of the world requires wiser use of the land plus more precise and effective management practices. Until we accomplish this goal, there will continue to be areas of the world in which people are hungry.