Increasing cropping intensity with cover crops
A summary of cover crop characteristics is listed in the table below. Grazing or cutting a cover crop for hay shifts it from being a true cover crop to being a forage crop. Timing of termination of cover crops is important and depends on what crop is being planted next, especially in more water-limited environments.
click image to zoom Annual forages or cover crops were grown in place of fallow in a wheat-fallow no-till cropping system between 2009 and 2012 at Garden City (see figure below). Wheat yields were similar whether the previous crop was harvested for forage or left standing as a cover crop. Wheat yield following the previous crop or fallow was dependent on precipitation during fallow and the growing season.
When moisture was limiting and wheat yields following chemfallow were less than 35 bushels per acre, growing a crop during the fallow period reduced wheat yield. When wheat yields following fallow were greater than 70 bushels per acre, only winter triticale, grain peas, and continuous wheat grown in place of fallow reduced yield.
click image to zoomAverage wheat yield response to preceding crop or fallow at Garden City from 2009 to 2012. The crop rotation was wheat-fallow. Averaged across all years, wheat yield following continuous wheat was 41 percent less, and following grain peas was 21 percent less compared to wheat-fallow. Wheat-fallow averaged 56 bushels per acre. Cover crops never increased wheat yields. Annual forages and grain peas can increase profitability, but cover crops commonly reduced profitability compared to wheat-fallow.