Managing Crop Residue to Reduce MRTN

Iowa landscape
Nutrient Management

Title: Managing crop residue to reduce optimum nitrogen fertilizer inputs and increase yield

Location: Ames, IA

Time Period: 2021 - Present

Research Team: Michael Castellano, Alexandria Logan, and Sotirios Archontoulis

Project Description:  There is growing evidence that the amount of both corn and soybean residue affect the optimum nitrogen fertilizer rate to the following corn crop (i.e, the Maximum Return to Nitrogen or MRTN). In the rainfed Corn Belt, high levels of residue are hypothesized to lead to higher optimum nitrogen fertilizer rates. However, recommended nitrogen fertilizer rates do not consider the amount of residue from the previous crop. This project will determine the ability for farmers to adjust optimum nitrogen fertilizer rates based on the amount of corn and soybean residue production in the previous year’s crop. A well-established relationship between residue production and optimum nitrogen fertilizer rate would allow farmers to: i) better manage nitrogen fertilizer inputs as they vary from field-to-field and year-to-year as a function of residue production, and ii) manage residue for lower optimum nitrogen rates.


Funders: Iowa Nutrient Research Center

Disclaimer: This is an active research site, please contact Michael Castellano ( prior to planning any site visits.