Yield and profit comparison of diversified versus conventional crop rotation systems in South Dakota

Authors: BANSAL, SANGEETA - University Of California, Davis; WANG, TONG - South Dakota State University; Osborne, Shannon

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2024
Publication Date: 9/12/2024
Citation: Bansal, S., Wang, T., Osborne, S.L. 2024. Yield and profit comparison of diversified versus conventional crop rotation systems in South Dakota. Agronomy Journal. p. 1-13. https://doi.org/10.1002/agj2.21688.
DOI: https://doi.org/10.1002/agj2.21688

Interpretive Summary: Despite the many agroecosystem benefits of diversified crop rotations, producers are reluctant to adopt them due to uncertainty in economic returns. We conducted an economic analysis to compare diversified vs. simplified crop rotations for 1) economic performance (gross revenue, net revenue, production cost) and 2) sensitivity to nitrogen-fertilizer price. The economic analysis was performed on a long-term experiment initiated in 2000 in South Dakota, with this analysis performed for fifth crop rotational cycle (2017-2020). Crop rotations included four, 4-year rotations, (i)corn-soybean-spring wheat-sunflower (CSSwSf), (ii) corn-soybean-spring wheat-pea (CSSwP), (iii) corn-pea-winter wheat-soybean (CPWwS), (iv) corn-oat-winter wheat-soybean (COWwS), compared to (v) 2-year corn-soybean (CS), and (vi) continuous corn (CCC). Greater net revenue and yields were observed for corn following pea in CSSwP, and soybean following winter wheat in CPWwS. Crop rotations (CSSwP and CPWwS) with multiple legumes (pea and soybean) were more economically resilient to higher nitrogen prices (using 2017-2020 average nitrogen cost as the baseline, and increasing it by 2 times, 3 times and 4 times in three different scenarios) compared to other rotations. Overall, diversified crop rotations improved corn and soybean yield and net revenue compared to 2-yr CS and CCC. Moreover, 4-year diversified systems (CPWwS and CSSwP) were found to be economically resilient and may help restore soil health.

Technical Abstract: Diversified crop rotations with no-till management are considered fundamental to sustainable agroecosystems, however, associated uncertainty in economic returns may hinder farmers’ decisions to adopt these practices. The objectives of this study were to compare economic performance (gross revenue, net revenue, production cost) among various low-input diversified vs. conventional crop rotations. The experiment was initiated in fall of 2000 with winter wheat planting and planting of remaining crops in the spring of 2001 near Brookings, South Dakota. Economic analysis was performed from data collected during the fifth complete 4-year crop rotational cycle (2017-2020) of six crop rotations: (i) 4-year corn (Zea mays L.)-soybean [Glycine max L. (Merr.)]-spring wheat (Triticum aestivum L.)-sunflower (Helianthus annus L.) (CSSwSf), (ii) 4 year corn-soybean-spring wheat-pea (Pisum sativum L.) (CSSwP), (iii) 4-year corn-pea-winter wheat-soybean (CPWwS), (iv) 4-year corn-oat (Avena sativa L.)-winter wheat-soybean (COWwS), (v) 2-year corn-soybean (CS), and (vi) continuous corn (CCC, treatment initiated in 2017). Corn yield in CSSwP rotation, where corn followed peas, was greater (P < 0.05) by 20%, 25%, 45%, and 89%, compared to CPWwS, CSSwSf, CS, CCC rotations, respectively. Similarly, soybean yields following winter wheat were significantly higher by 16-38% in COWwS and 13-38% in CPWwS compared to CSSwP, CSSwSf and CS. Overall, diversified crop rotations improved both corn and soybean yield and net revenue compared to 2-yr CS and monoculture CCC rotations. Moreover, 4-year diversified systems, specifically COWwS, CPWwS and CSSwP, demonstrated economic resilience by maintaining stable production costs.