Stover harvest increases yield stability in continuous corn systems

Authors: CRESPO, CECILIA - Orise Fellow; O'Brien, Peter; Rogovska, Natalia; MARTINEZ, DIONISIO - Orise Fellow; Ruis, Sabrina; Kovar, Andrew

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Continuous corn production systems – where corn is grown on the same land every year – remains popular throughout the Midwestern United States because of high productivity and profitability, especially when considering corn stover harvest as an additional byproduct. Weather conditions, especially temperature and precipitation, strongly influence how well corn crops grow. Current trends for this region indicate that more precipitation will occur in spring and fall with much less occurring in the summer. Similarly, air temperatures are projected to increase both spring and fall, which contributes to longer potential growing seasons for crops. We need to identify management practices that are best equipped to deal with these changing weather patterns to maintain stable and high crop yields into the future. We compiled data from a 13-year experiment in continuous corn systems in central Iowa to determine the corn yield stability using different management practices, including tillage, corn stover removal, and biochar application. We found the highest, most stable corn yields when at least 50% of corn stover was removed. Notably, stover removal increased yields and yield stability across both chisel plow and no-tillage types and biochar applications, which shows that it is the most important factor at this research site. Yields were improved with stover removal because excessive crop residue in continuous corn systems may harm crop yields by altering soil nitrogen cycling and delaying soil warming in the spring. We also found that the cause for more variable yields when stover was not removed was linked with temperatures over the growing season, while yields in all management systems were affected by annual rainfall. These findings will be especially valuable to growers, researchers, and crop advisors for how best to manage continuous corn systems for consistent, high yields under a range of weather conditions.

Technical Abstract: Studying the effects of corn (Zea mays L.) stover removal on yields and yield stability across management systems is key to understanding how crops respond to varying climatic conditions. The objectives of this study were to: (i) evaluate yield stability under varying levels of stover harvest in continuous corn systems, and (ii) determine the effects of thermal time and precipitation on yield stability in those systems. A long-term experiment in a continuous corn system with different levels of stover harvest, tillage systems, and biochar rates was carried out from 2008 to 2020. Corn yield and yield stability were evaluated, and multiple regression models were developed to determine which factors best explained differences across treatments. Both corn yield and yield stability were highest with 50 to 90% stover harvest. Yields increased 6 to 15% when stover was harvested, likely due to more rapid soil warming in spring and reduced nitrogen immobilization. The negative impacts of stover retention on yield stability were offset when high rates of biochar were applied. Tillage system did not affect yield stability, but yields were greater under chisel plow than no-tillage. Precipitation explained 43-49% of yield variability in all treatments. Conversely, the relationship between thermal time and yield was only significant for treatments without residue removal, where GDD explained 34% of yield variability. Our results show that yield stability in continuous corn systems is more heavily influenced by stover harvest than biochar application or tillage. Thus, despite other potential environmental drawbacks of continuous corn systems, incorporating stover harvest may improve resilience to projected weather fluctuations.