Nutrient removal when harvesting corn stover
John Sawyer, Antonio Mallarino, Professors, Department of Agronomy, Iowa State University
September 18, 2019
Increasing demand to use corn plant biomass for producing energy and various products has spurred interest in harvesting corn stover and specific plant components in addition to grain. Harvesting more biomass means increased carbon (C) and other nutrient removal from fields. What is the nutrient removal when different corn plant components are harvested?
Corn Plant Nutrient Content
Most producers in Iowa are familiar with harvesting corn for grain, but less familiar with other plant biomass removal. Those harvesting corn silage are aware of the increase in phosphorus (P) and especially potassium (K) removal, and fertilization guidelines consider this increase. For example, with corn silage based on a bushel grain equivalent, the pounds of P as P2O5 goes from 0.32 to 0.44 and the pounds of K as K2O goes from 0.22 to 1.10, respectively, for corn grain and corn silage (15% grain moisture content, ISU Extension publication PM 1688).