Abstract

The 2020 cropping year had many challenges. While crops planted earlier than normal set a high yield potential, the lack of precipitation in August (Figure 1) decreased soil moisture. This impacted crop yields and the response to nitrogen (N) fertilizer in two ways—directly by inducing water stress on crop growth, and indirectly by reducing soil N mineralization and N uptake during grain fill period. Typically, 70 percent of maize N uptake is accumulated by silking, while the remaining 30 percent is accumulated during the grain filling period. This report summarizes the 2020 results from a long-term nitrogen trial (established in 2005) with two crop rotations: corn following corn (CC) and corn following soybean (CS).

How to Cite:

Archontoulis, S., (2021) “Optimum Nitrogen Fertilization Rate for Corn”, Iowa State University Research and Demonstration Farms Progress Reports 2020(1).