Dryland cover crop soil health benefits are maintained with grazing in the US High and Central Plains

Cover crops are important for soil conservation efforts but can compete with cash crops for limited water in dryland agricultural systems. Grazing cover crops may provide additional income to improve the profitability of cover cropped systems, but the effect of grazing cover crops on soil health remains poorly understood in semiarid regions. We conducted on-farm research to examine the short-term effects of grazed and un-grazed springplanted cover crops compared to full summer fallow on soil health metrics and wheat yields across ten no-till, dryland producer fields over two years in eastern Colorado, western Kansas and western Nebraska, USA. Soils were evaluated at cover crop termination following two to three months of growth for differences in a suite of soil physical and chemical properties. Grazed and un-grazed cover crops increased soil aggregation relative to summer fallow by 30-50%. Surface bulk density (0-5 cm) decreased by 4% with un-grazed cover crops, while bulk density under grazed cover crop was similar to fallow. Soil moisture in the top180 cm depth was reduced by 4?22 % with cover crops, with the greatest water depletion occurring below 30 cm, and grazing did not appear to affect soil moisture compared to un-grazed cover crops. Both cover crop treatments reduced wheat yields by roughly 20 %. The short-term improvements to key soil health metrics with cover crops were largely maintained with grazing, indicating the potential for livestock integration as a management option to offset the short-term yield impacts of cover crop moisture use in water-limited environments.

Automated summary

Cover crops are important for soil conservation efforts, but can compete with cash crops for water resources in dryland agricultural systems. Grazing cover crops can increase soil aggregation, but may reduce wheat yields. In water-limited environments, grazing cover crops show potential as a management option to improve soil health metrics despite short-term yield impacts.