By Jeff Coulter
There are many advantages to planting corn after alfalfa, including greater yield potential, reduced nitrogen needs from fertilizer or manure, and reduced pest pressure compared to when corn follows other crops. The degree to which these and other benefits are achieved is contingent upon successful termination of alfalfa, as alfalfa can greatly complete with corn for water and nitrogen. Therefore, avoid compromising on best practices when rotating alfalfa to corn, even when spring field work is delayed.
In many fields where corn follows alfalfa, preplant or early postemergence applications of herbicides, along with additional time for or between field operations, may be required for adequate termination of alfalfa. Strategies for successful alfalfa termination are available at
http://z.umn.edu/rotation.
Nitrogen management guidelines for first- and second-year corn following alfalfa are available at
http://z.umn.edu/fertilizingcorn. These guidelines are based on factors such as soil texture, age of alfalfa at termination, and alfalfa termination timing.