Soil suitability for conservation tillage

MECHANICAL application of a conservation tillage system is but one part of the crop production package. The other part involves the soil and whether or not the soil's physical properties will permit use of conservation tillage and maintain crop yields. In the past, standard tillage techniques were altered only on those soils experiencing severe soil losses or other problems. Efforts to conserve soil focused on keeping the soil in place. Tillage techniques that encourage soil conservation have been available to farmers for years. Widespread adaptation of these techniques has not occurred, however, in part because of the uncertainty of crop yields obtained using these systems. Early conservation efforts promoted complete elimination of plowing. These efforts generally proved unsuccessful in maintaining crop yields, but they did reduce soil loss. One system promoted disking as a substitute for moldboard plowing (7). Another, called mulch tillage, used a field cultivator to stir the soil and kill the weeds in preparing the seedbed. The procedure left much of the previous crop residue on the soil surface (3). Present tillage systems are variations of these early efforts (6, 17). Thorough tilling of the soil was once regarded as a necessary agricultural practice on …