Phosphorus loss with surface runoff as affected by bioenergy-based residue and nutrient managment systems for an Iowa loam soil

Growing interest in biofuel generation with cellulosic biomass from row crop residues necessitates research to investigate biomass and nutrient management systems impacts water quality. The objective of this research was to evaluate the impact of a range of cropping and corn biomass harvest systems on P loss with surface runoff as affected by N-P management based on inorganic fertilizers or liquid swine manure. A 2-year rainfall simulation study was conducted on established field plots with Clarion loam soil (mixed, superactive, Typic Hapludolls). Eight treatments, each replicated three times, were set up in a completely randomized block design using 174 m 2 plots. Treatments consisted of continuous corn (CC) harvested for total above-ground biomass or grain managed with N-P fertilizer or N-based liquid swine manure for corn (four); CC harvested for grain plus a fraction of cornstalks managed with N-P fertilizer (one); corn-soybean rotation harvested for grain managed with N-based manure for corn (one treatment, but each crop phase was planted each year); and switchgrass managed with N-P fertilizer or in plots with a long history of manure application (two) harvested once per year for total biomass. The P