Optimizing cover crop management in Eastern Nebraska: Insights from crop simulation modeling

Authors: SHIFERAW, ANDUALEM - University Of Nebraska; Birru, Girma; TADESSE, TSEGAYE - University Of Nebraska; Schmer, Marty; AWADA, TALA - University Of Nebraska; Jin, Virginia; WARDLOW, BRIAN - University Of Nebraska; IQBAL, JAVAD - University Of Nebraska; Freidenreich, Ariel; Kharel, Tulsi; KHORCHANIA, MAKKI - University Of Nebraska; MERSHA, ZELALEM - Virginia State University; Begna, Sultan; Sohoulande, Clement

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2024
Publication Date: 7/18/2024
Citation: Shiferaw, A., Birru, G.A., Tadesse, T., Schmer, M.R., Awada, T., Jin, V.L., Wardlow, B., Iqbal, J., Freidenreich, A.S., Kharel, T.P., Khorchania, M., Mersha, Z., Begna, S., Sohoulande Djebou, D.C. 2024. Optimizing cover crop management in Eastern Nebraska: Insights from crop simulation modeling. Agronomy Journal. 14(7). Article 1561. https://doi.org/10.3390/agronomy14071561.
DOI: https://doi.org/10.3390/agronomy14071561

Interpretive Summary: Optimal cover crop management in eastern Nebraska and elsewhere hinges on achieving a balance between maximizing cover crop benefits and minimizing negative impacts on the subsequent cash crop. Studies emphasize the importance of considering local conditions, crop rotation, and overall management objectives when determining the best CC termination strategy. As research continues, adaptive management approaches that consider these dynamic factors will remain key to leveraging the full potential of cover cropping systems in the region. There was a notable decrease in cover crop biomass across these different planting dates (September 25 to October 20). Specifically, for each five-day delay in planting beyond the initial date, cover crop biomass experienced an average reduction of 8.8%. Additionally, the study highlighted the critical role of the interval between cover crop termination and corn planting in terms of soil moisture retention and biomass dynamics. Longer intervals tended to enhance soil moisture conservation. The termination-planting intervals evaluated ranged from 1 to 20 days, specifically at 1-, 5-, 10-, 15-, and 20-day increments. While there was a slight upward trend in corn yield corresponding to extended intervals, these differences were not statistically significant. However, there was a noticeable reduction in cover crop biomass, averaging 19.3% (0.33 Mg ha-1) for every five-day extension in the interval. Testing 15 different cover crop (CC) termination dates from March 22 to May 31 with five-day intervals revealed that the optimal termination for balancing corn yield and soil benefits is approximately April 26th. This finding underscores the importance of strategic termination timing, particularly in late April, for optimizing both sustainability and productivity within the farming system. Our results demonstrate the importance for stakeholders in the agricultural sector to consider these factors in their decision-making processes. Our findings can lead to improved soil health, maintain crop yields, and ultimately, more sustainable agricultural practices. Future research should continue to refine these models and explore the long-term impacts of various cover crop management strategies on soil health and crop productivity. This continued effort will provide even greater insights into optimizing cover crop systems for the benefit of sustainable agriculture globally.

Technical Abstract: Cover crops (CC) offer a range of agronomic and environmental benefits, yet their impact on subsequent crop yields can vary based on various factors, including geographical location, soil characteristics, and farming practices. Such variations raise concerns about potential negative effects on subsequent crops in the absence of locally relevant management practices. To address this, we employed a crop simulation model to assess various winter cereal rye CC management strategies, focusing on planting and termination of CC, as well as the duration between CC termination and corn planting. The main objective of the study is to optimize CC benefits while enhancing corn productivity in a continuous corn system. Findings indicate minimal influence of CC planting date on simulated corn yield, with no significant differences across various planting dates. Moreover, the interval between CC termination and corn planting highlighted the significance of soil moisture and biomass dynamics, with longer intervals slightly favoring soil moisture conservation. Additionally, the termination date of the CC revealed subtle effects on simulated corn yield, underscoring the trade-off and the necessity for achieving a balance between biomass buildup and moisture availability, particularly under near-normal rainfall scenarios. in conclusion, our results suggest that strategic CC management can effectively support soil health and crop outcomes without detrimentally affecting corn yield in eastern Nebraska’s conditions. These findings provide valuable insights for farmers and practitioners seeking to implement sustainable CC practices while maintaining crop productivity.