Source: Corliss, Julie. 1991. Conserving cropland for the future. Agric. Res. 39(6):12-15.

Erosion is a serious agricultural problem. Crop yields drop with every bit of topsoil lost. Changing the way plowing and sowing are done by employing a practice known as conservation tillage can slow this erosion. Corliss wishes to educate the general public about erosion problems and about a possible solution. She is also trying to influence farmers to use conservation tillage by illuminating the technique's ecological and economical benefits. Corliss cites an integrated pest management project in Washington's Palouse region that holds the key to overall success for the farmer. Frank L. Young, a weed scientist at the ARS Weed Research Unit in Pullman, heads this research. Conservation tillage leaves 50 to 60% of the residues from the last year's crop on the soil surface to cover and protect fields during the cold and rainy season. Conventional tillage leaves only 10% to do the same. Though this helps retain topsoil, it leaves the ground moist and allows weed seedlings to emerge and thrive. To achieve the same yields with conservation tillage, herbicides are substituted for tillage. The levels of herbicides had to be boosted for a period of time but the maximum rates used in the study never exceeded the rates recommended on the herbicide labels. Eventually, farmers may be able to lower chemical use. In addition, studies in the future will be on less toxic herbicides that do not persist in nature, and on non-chemical techniques for weed control such as choosing more competitive varieties and using different crop-planting patterns. Economic benefits (through farm profits and government assisted programs) are numerous for farmers who employ conservation tillage. Conservation tillage saves both soil and water, and both of these factors contribute to higher crop yields. A system using crop rotation, conservation tillage and safe doses of herbicides ranked the highest for farm profits when several alternative cropping systems were compared. The conservation tillage system often has additional benefits, including reduction of soilborne pathogens and help in natural control of weeds. In conclusion, the best systems of farming use the most economical methods and slow erosion. The key to this type of system is to control weeds, alternate crops each year, and practice conservation tillage. Herbicides currently address the problem of weeds, but studies will soon be underway to develop alternative methods of weed control.

Abstract author: Laura H. Chan, 17 November 1994.

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