Annual Forages Grown After Wheat Grain Harvest: A Double Cropping Opportunity for Producers in the Northern Midwest.

Midwestern grain and livestock producers often utilize wheat in their crop rotations for grain and straw production. Many southern Midwest USA producers follow wheat with double cropped soybean harvested as grain; however double cropping soybean is not an option for northern Midwest producers. Forages that can be produced during this seasonal niche should be evaluated to not only increase the forage production potential of a livestock operation, but to also provide cover to the soil to protect against erosion and to keep late emerging weeds from germinating. Additionally, much discussion has taken place about acceptable nitrogen rates for double crops following wheat, with little consensus.  A randomized complete block design experiment with a split plot was established following wheat grain harvest during the summer months of 2010-2012. Whole plots consisted of ten annual crops; brown midrib sorghum- sudangrass, pearl millet, foxtail millet, tef, amaranth, spring oat, forage turnip, oilseed radish, cowpea, and soybean. Split plots of either 56 or 112 kg N/hectare were applied to each crop with the exception of the legumes. Herbage from each treatment was analyzed for fiber and nitrogen content to determine suitability as a livestock feed. Results indicate no significant difference between nitrogen rates for yield, nitrogen content, or fiber content. Fiber contents of the forages ranged from 110 to 710 g/kg dry matter neutral detergent fiber, and 91 to 450 g/kg dry matter acid detergent fiber. Forage nitrogen content ranged from 9.8 to 31 g/kg dry matter.  Results from this study will allow producers to make more informed decisions about which forage crop should follow wheat given their particular production system.