Short-term effects of livestock on northern, semi-arid US Great Plains spring wheat grain yield

Abstract

Integrated crop-livestock systems, where livestock and crops are produced in rotation or simultaneously, have long been a common agricultural practice. However, the shift toward specialization in the latter half of the 20th century led to separating livestock from crop production, resulting in environmental and economic challenges. To address these issues, this study examines the short-term effects of integrating cattle grazing on annual forages and its impact on subsequent spring wheat (Triticum aestivum) yields. Conducted from 2020 to 2023 at South Dakota State University's West River Research Farm, the study used a randomized complete block design with four treatments: grazed cover crops (CG), swathed grazed cover crops (SG), ungrazed monoculture sorghum-sudangrass (Sorghum × drumondii) hay (C1), and ungrazed cover crops (C2), all followed by spring wheat. Results showed that grazing treatments, especially SG, led to a 20% increase in wheat yield compared to C1. Soil health indicators showed no significant differences between grazed and control plots. However, grazed treatments had higher soil NO₃-N levels, indicating increased nitrogen availability. Protein content in wheat remained consistent across treatments, suggesting that yield gains were due to enhanced nitrogen availability during early growth stages. These findings support that livestock integration can boost crop yields by improving short-term nitrogen availability. Further research is needed to assess long-term impacts on soil health, crop productivity, and to determine sustainable grazing practices for integrated systems.