Transport of phosphorus (P), nitrogen (N), sediment, and pathogens via runoff from crop fields, especially where manure has been applied, can contribute to degradation of surface waters, leading to eutrophication and potential health effects. In the dairy cropping system of Wisconsin and most of the northern dairy belt, the silage corn phase of the rotation is the most susceptible to runoff and erosion losses because of the lack of protective crop residue and regular applications of livestock manure. We initiated this study to evaluate cropping systems to minimize adverse water quality impact, while maintaining or increasing nutrient efficiency and productivity.
The objective of this study was to evaluate field runoff losses of nutrients and pathogens from different manure/crop/tillage management systems for silage corn production. We chose to use a paired watershed design, rather than conventional replicated field plots, because the larger field-scale units provide data that more adequately reflects the more complex hydrology of the real-world landscape.