Lynn D. Hoffman and W. Scott Harkcom

Penn State University

Corn following alfalfa consistently yielded twenty-one bushels more than corn following corn in a crop rotation study now in its thirtieth year at Penn State.

The presence of alfalfa in this study affects the economics of crop production. Compared to the continuous corn or corn-soybean rotation, it favorably affects soil physical properties. Decreased soil pentitrometer resistance and better water infiltration are consistent advantages found in the alfalfa plots compared to other rotations. A relatively new evaluation for soil quality — Phosphataise enzyme-measuring the soil microbial activity suggests better soil quality and a "healthier soil" in the alfalfa rotation. This measurement has promise to better explain the prevailing changes in conditions influencing the consistently higher corn yields following alfalfa. Corn yields of second and third year corn following alfalfa usually become consistent with continuous corn yields. This has economic implications to the seed industry as shorter rotations would increase frequency of alfalfa establishment and increase seed sales. We know the value of alfalfa as a forage crop. Data from this study validate its importance in farm management decisions to increase net returns in the overall farm enterprise.