Farming systems' influences on soil properties and crop yields

ABSTRACT:

Systems that reduce off-farm agricultural inputs for crop production must retain soil productivity and farm profitability in order to be sustainable. This study determined the effects of the farming systems on soil physical properties and crop yields during the establishment stages of the systems. The three farming system treatments were alternate, conventional, and ridge-till. In the alternate system, no commercial fertilizers or pesticides and no moldboard plow were used. The four-year crop rotation in the alternate system was oats overseeded with alfalfa (Avena sativa L./Medicago sativa L.)-alfalfa-soybean (Glycine max L. merr)-corn (Zea mays L.). The crop rotations in the conventional and ridge-till systems were corn-soybean-spring wheat (Triticum aestivum L.), with primary tillage occuring after the conventional spring wheat. Soil water was limited in all systems because of drought in 1988. No one system consistently maintained soil water levels different from the others. Crop residue, especially in oats overseeded with alfalfa, kept soils cool and damp in the spring. Spring soil bulk density was reduced by tillage the previous fall, but differences were eliminated by mid-season. Soybean yield was generally greater in the alternate system than in the conventional or ridge-till systems. Corn grain yield was greater in the conventional and ridge-till systems than in the alternate system until drought stress reversed the rank. Conventional wheat consistently had higher yields than ridge-till wheat. Differences in soil physical properties were related to specific management practices or environmental influences, as opposed to being characteristic of a system, and alternate systems may have their greatest potential under drought stress.