Location: Integrated Cropping Systems ResearchTitle: Cover crop effects on cash crops in Northern Great Plains no-till systems are annually variable and possibly delayed
Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2021
Publication Date: 10/20/2021
Citation: Chim, B., Osborne, S.L., Lehman, R.M., Schneider, S.K. 2021. Cover crop effects on cash crops in Northern Great Plains no-till systems are annually variable and possibly delayed. Communications in Soil Science and Plant Analysis. 53(2):153-169. https://doi.org/10.1080/00103624.2021.1984512.
Interpretive Summary: Producers have shown interest in including cover crops in their cropping system to improve soil health and crop yield. However, it has not become a common practice partially due to the lack of specific research results applicable to their region. This research was conducted in a small grain-cover crop/corn/soybean crop rotation at three locations in South Dakota. Our research objective was to evaluate the influence of fall-planted grass, legume and brassica cover crops on the performance of the following corn and soybean crops under no-till conditions. Fall and spring cover crop growth varied each year with varying weather conditions. Corn yield, nitrogen, and phosphorus uptake, and biomass at harvest were greater in cover crop treatments compared to no-cover crop in one year. In the other two years, the same parameters for the no cover crop treatment had equal or better conditions than cover crops treatment. Similar results occurred during the corn growing season (V6 and R1 growth stage) for corn biomass and nutrient uptake. However, soybean yields two years following cover crop were higher than no cover crop in two of the three study years. We found the impact of cover crops on the following cash crop under no-till condition may vary with fall and spring cover crop biomass production and the timing and amount of precipitation received during the cash crop growing season. In conclusion, cover crops in no-till systems may produce more consistent, but possibly delayed benefits by boosting yields of cash crops in later years as cover crop residues decompose.
Technical Abstract: Commodity crop producers have shown interest in diversifying their cropping systems with cover crops that often improve soil properties and may improve crop growth and yield. However, due to the lack of regionally-specific research results on the impact of cover crops on crop growth and soil parameters, there has been limited adoption. We conducted a three-year field study to evaluate the impact of fall-planted grass, legume, and brassica cover crops on biomass, nutrient uptake, and grain yield of the immediately-following corn (Zea mays L.) crop and yield of the succeeding soybean (Glycine max L.) crop under no-till conditions in a small grain/cover crop-corn-soybean crop rotation. Each year, seasonal growth of the fall-seeded cover crops varied with no spring growth in one year and minimal fall growth in another year. Corn yield, grain nitrogen (N) and phosphorus (P) uptake, and harvest biomass were significantly higher in one or more of the cover crop treatments than the no-cover crop control in one of three years. In the other two years, these parameters for the no-cover crop control were equal or higher than the cover crop treatments. Similar results were observed for corn biomass and nutrient uptake at intermediate plant development stages (V6, R1). However, soybean yields two years following the cover crop treatments were higher in all three years with cover crops compared to no cover crop. We conclude that immediate effects of cover crops on the following cash crop under no-till are variable and depend on both fall and spring cover crop biomass, which are dependent the amount and timing of precipitation and temperature patterns. Cover crops in no-till systems may produce more consistent, but possibly delayed benefits by boosting yields of cash crops in later years as cover crop residues decompose.