By Sotirios Archontoulis
The effect of cover crop on crop yields, soil health, and nitrate-nitrogen (N) leaching is complex and variable from year to year. From an environmental point of view, the higher the rye biomass production at termination day, the higher the likelihood of increasing soil organic carbon and decreasing N leaching. However, common asked questions are whether the magnitude of rye biomass is proportionally related to yield benefits or losses and how much water and N does rye use?
To answer these questions, we:
- Synthesized existing knowledge and developed a conceptual diagram to illustrate the mechanisms by which the rye can affect corn yield and nitrate-N leaching, which can serve as a framework for understanding cover crop effects on corn.
- Synthesized six years of experimental data from the Comparison of Biofuels Systems (COBS) site near Kelly, Iowa (central Iowa); rye literature data from Midwest and APSIM model simulations; and developed robust relationships to support decision making.
- In this analysis, we considered the following data: crop yields, rye biomass, rye C/N ratio, rye root/shoot ratio, nitrate-N leaching and drainage, soil moisture and temperature, and spring nitrate tests.
The results from this work are reported in the study “Rye cover crop effects on maize: A system-level analysis,” which was recently published in the Field Crops Research Journal by Rafael Martinez-Feria, Ranae Dietzel, Matt Liebman, Matt Helmers, and Sotirios Archontoulis.