ARS | Publication request: It's still true: plowing up alfalfa releases plenty of N for corn

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 23, 2010
Publication Date: November 16, 2010
Citation: Russelle, M.P., Yost, M., Coulter, J., Sheaffer, C., Kaiser, D. 2010. It's still true: plowing up alfalfa releases plenty of N for corn [abstract]. In: 2010 Minnesota Forage Research Symposium, November 17-18, 2010, St. Cloud, Minnesota. p. 22.

Technical Abstract: Farmers and their advisors question the accuracy of published fertilizer N replacement values that alfalfa provides to first-year corn. Their skepticism has risen as corn yields have increased, but higher fertilizer prices have heightened the need to trim unproductive inputs. Recent Minnesota data confirm reports in the literature--corn rarely responds to extra N after good stands of alfalfa are tilled in. Corn also allows the soil to recharge with fall and spring rain, promoting leaching. Adding extra N reduces your bottom line and leaves too much nitrate in the crop and soil, which threatens herd health and water quality. After good alfalfa stands (four or more plants per square foot) are plowed down, limit N application to first-year corn to starter N only.