Submitted to: Integrated Crop Management Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 24, 2007
Publication Date: November 29, 2007
Citation: Singer, J.W., Cambardella, C.A., Moorman, T.B. 2007. Coupling Manure Injection with Cover Crops to Enhance Nutrient Cycling. Integrated Crop Management Conference Proceedings, November 28-29, 2007, Ames, IA. p. 255-258.
Large-scale hog (Sus scrofa) production is a major agricultural enterprise in the Midwest. Large numbers of confined hogs produce about 50 million tons per year of swine manure in Iowa alone. Rapid expansion of concentrated animal feeding operations (CAFOs) has resulted in increased concentrations of manure nutrients in surface waters which contribute about 15% of the total nitrate load in the Mississippi River Basin. Producers are being encouraged to develop manure management practices that fulfill crop production requirements, while minimizing the potential for environmental pollution. Fall planted annual cover crops can capture manure nutrients and immobilize them in plant biomass, subsequently reducing the potential for nutrient loss through run-off or leaching. Decomposition of cover crop residue the following spring may help synchronize manure N availability and corn N uptake, improving nutrient-use efficiency within the crop rotation. Our results demonstrated that a rye/oat cover crop reduces soil inorganic N after liquid swine manure injection. Cover crop impacts on soil N are observed within a month after application and persist into the following spring. Cover crop N uptake was higher than the no manure cover crop control in the spring when at least 200 lb manure N/ac was applied. These results quantify the potential for cover crops to enhance plant nutrient uptake and reduce N leaching potential in farming systems utilizing manure. Future research will investigate the fate of manure N and cover crop nutrient availability for subsequent rotation crops.