Potential for and implications of cover cropping and grazing cover crops in wheat agroecosystems in Montana

Abstract

Growing interest in cover cropping may provide a way to recouple crop and livestock production in semiarid Montana. This two-year field study examined edaphic and agronomic implications of cool- vs warm-season cover cropping, with and without grazing, compared to the grower standard practice of chemical-fallow. After one year of cover cropping/grazing, Olsen-P and acid phosphatase activity were higher in cover cropped/grazed treatments than the fallow treatment. Potentially mineralizable Nitrogen was higher in spray-terminated cover crop treatments than graze-terminated treatments, while soil Nitrate-N was statistically lower in cover cropped/grazed treatments than in the fallow treatment. Wheat yields were not statistically different between cover cropped/grazed and the fallow treatments; however, the fallow treatment had higher wheat seed protein than cover cropped/grazed treatments. This research also utilized the Land Suitability Analysis approach to examine four exemplary Montana counties for: 1) warm-season cover crop adoption; 2) integrated crop-livestock adoption; and, 3) warm-season cover crop use as forage in an integrated crop-livestock adoption. Fergus and Fallon Co.'s both contain portions of land highly suitable for warm-season cover crop production, while all four counties have areas where integrated crop-livestock systems appear to be a logistical possibility. The conclusions taken from this research - both the agricultural field experiment and land suitability analysis - will help inform land managers across Montana's agricultural community about these emerging practices in sustainable agriculture.