Date of Award
12-1-2025
Degree Name
Doctor of Philosophy
Department
Agricultural Sciences
First Advisor
Brevik, Eric
Second Advisor
Sadeghpour, Amir
Abstract
Sustainable sweet corn (Zea mays L.) production in southern Illinois requires practices that maintain sweet corn yield and profitability while improving soil health and reducing environmental impacts. Winter cereal cover crops including cereal rye (Secale cereale L.) are widely recognized for their capacity to improve soil structure, enhance nutrient cycling, and reduce nitrogen (N) and phosphorus losses. However, the adoption of winter cereal cover crops is still limited in specialty crop production systems due to high seed costs, management challenges, and concerns about N immobilization and yield reduction.This dissertation explored practical and economically feasible cover crop management strategies to overcome these limitations and support sustainable sweet corn production. Field experiments were carried out between 2021 and 2023 at the Agronomy Research Center (ARC) in Carbondale and the Belleville Research Center (BRC) in Belleville, Illinois. The research focused on evaluating six management approaches to cover cropping: (1) solid planted cereal rye; (2) precision planting of cereal rye; (3) solid planted crimson clover (Trifolium incarnatum L.); (4) precision planting of crimson clover; (5) use of a cereal rye-crimson clover mixture; and (6) no cover crop. Each was evaluated to assess its ability to improve the performance and sustainability of sweet corn production systems. Precision planting was designed to skip cover crop seeding into future sweet corn rows to lower seed costs and reduce competition between the cover crop and the cash crop. Crimson clover is a legume that fixes N, has low C:N in its tissues, and thus does not cause N immobilization. The mixture combined cereal rye and crimson clover to balance biomass production with N supply, drawing on the complementary benefits of each species. These treatments were compared to a no cover crop control that represented the typical southern Illinois sweet corn cropping system. Results indicated that precision planting of both rye and clover produced biomass, N uptake, and sweet corn yields comparable to those of the solid planting method, while reducing establishment costs by as much as 25%. The mixture of cereal rye and crimson clover had the greatest cover crop biomass and N uptake, resulting in the highest sweet corn yield and net profit. Across treatments, sweet corn sweetness (Brix) and soil moisture were consistent, while soil temperature declined slightly under cover crops, suggesting a more stable soil condition for sweet corn growth. Overall, the study shows that precision planting and cover crop mixtures were most effective in improving sweet corn production and farm profit. Adopting these strategies into sweet corn production systems can help farmers reduce cover crop seed cost, sustain or improve yields, and enhance soil health.
Access
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