Northern Research and Demonstration Farm
Crop yield can be significantly affected by the crops in rotation. Crop characteristics and associated management practices influence soil physical and chemical properties, water availability, and incidence of diseases, weeds, and pests. Including legumes in a rotation usually increases soil nitrogen (N) supply for corn. A crop rotation study was started in 1954 to study the effect on crop yields of seven crop sequences and N fertilization rates for corn. Table 1 shows the crop rotations and N rates used since 1984. Granulated urea was applied only for corn in spring (except for the fall timing treatment for continuous corn), and was incorporated by tillage. Oats were always undersown with alfalfa, but no hay was harvested the seeding year. Alfalfa hay yields are not shown in this report.
Iowa State University
Mallarino, Antonio P. and Rueber, David, "Yield of Corn, Soybean, and Oats as Affected by Long-term Crop Rotation and Nitrogen Fertilization of Corn" (2011). Iowa State Research Farm Progress Reports. 249.