The Feasibility of Cover Crops in Dryland Cropping Systems in SW Colorado and SE Utah.

Dryland farming in SW Colorado and SE Utah is practiced at relatively high elevations (≥ 6000 ft.), on soils that are prone to erosion and have low organic matter content. This, combined with low and erratic precipitation calls into question the sustainability of conventional farming practices such as clean fallow. A project was initiated in 2015 to determine whether cover crops grown during the fallow period between two cash crops can enhance the sustainability of dryland cropping systems in SW Colorado and SE Utah. The project is sponsored by Western SARE. By maintaining a crop cover during part of the fallow period, the hope is to improve soil fertility and biological activity, suppress weeds, and reduce soil erosion; without negatively impacting the economic viability of the cropping system. Several replicated and demonstration trials were established in 2015-2017 on farmers’ fields and at the Southeastern Colorado Research Center to determine the effects of various cover crop mixtures on soil quality and soil health and on the cash crop. The cover crop mixtures were planted in the summer, fall or spring in winter wheat-fallow and winter wheat-safflower-fallow rotations. Management practices included conventional tillage, no-till, and organic farming. The results to date indicate the importance of cover crop species selection and management (e.g., planting and termination dates), soil management, and climatic conditions. More data will be available after wheat harvest in July.