The introduction of winter cover crops after manure application is a viable method for significantly improving sustainable agriculture by limiting nutrient losses between fall manure application and late spring crop nutrient demands. Cover crops have often been promoted as a management option to help make agriculture more sustainable by improving overall soil quality and reducing both erosion and nutrient losses. Nutrient losses are of particular concern with manure application, as it is often applied in the fall, in part due to storage constraints and because of difficult field conditions for application in the spring. Soil fertility is consistently improved with cover crop usage, however results from numerous studies present very inconsistent findings with respect to cash crop productivity following cover crop application. As a consequence, many farmers in the Midwestern U.S. are hesitant to use cover crops, due to the potentially lower cash crop production that may result. A major factor likely to be influencing the observed short term lowered production following adoption of cover prop practices is relative nutrient availability. Studies from the Pacific Northwest reveal that plant available nitrogen is greatly influenced by stage of growth when the cover crop is destroyed, as well as when the cash crop is actually planted the following spring. In order to convince farmers to utilize cover crops in this major grain production region, there is a critical need to predict the key factors that will significantly influence how conditions of cover crop implementation affect overall soil plant available nitrogen.
Swine Manure Nutrient Fate and Pathogen Reduction for Midwestern Corn Production with Cover Crop Utilization. National Pork Board. #15-095. M. Hayes and P. Davidson.