Soil erosion's side effects and long-term costs

Conservationists say US farmers cannot afford to return to the days when land was indiscriminately plowed without regard to conservation. They caution that, over the long haul, heavy erosion means many farms will become unproductive wasteland.

In the 1970s - because of prevailing economic conditions - marginal land and rangeland were extensively cultivated. Conservation practices such as terracing, dams, conservation tillage, and crop rotation ``weren't the style,'' says Terry Gillespie, a soil conservationist with the United States Department of Agriculture.

In breaking up land for cultivation, farmers also broke up fragile, more erodible soils, which were left untreated, Mr. Gillespie explains.

During the ``dust bowl'' period of the 1930s, erosion captured the public's attention. Public awareness today may not be so acute, conservationists say, but erosion costs are well documented and cannot be ignored.

In addition to loss of topsoils, there are offsite erosion costs such as contamination of ground and surface water from fertilizers and pesticides present in eroding soil.

``If you are looking at it in terms of soil and chemical movement, we are already paying indirectly through taxes,'' says Alice Jones, associate professor of agronomy at the University of Nebraska in Lincoln. She says that when soil erodes, ``The lost soil may end up in a ditch. It needs to be cleaned out, and this [is paid for with] tax dollars.''

Dr. Jones says that in many Midwest farms, much of the topsoil is already lost. Farm productivity declines, because crops depend on the uppermost 8 to 16 inches of topsoil.

Technology and research have compensated for production loss stemming from erosion. Jones says plant-breeding programs, new and improved herbicides, fertilizers and insecticides, and better harvesting techniques have improved production.

``But we are probably at a plateau with technology,'' she says. ``We are getting small changes now. We are beginning to notice some of [the negative] soil effects on crop production.''

Jones warns that if erosion is not controlled, Americans may face ``a fourfold increase in the cost of food, because our fields can no longer produce, or cost so much to produce.''