Agroforestry Switchgrass and Poultry Litter Fertilization: Productivity and Environmental Impacts, Northern Louisiana.

Yield of agroforestry switchgrass (Alamo, Panicum virgatum; under thinned loblolly pine, Pinus taeda) was low compared to open-field, planting; however the system offers less quantifiable services including aesthetics and game habitat.  Soil fertility management for switchgrass regrowth after harvest and / or burn with inorganic and poultry litter fertilizer gave significantly greater biomass production.  The high hydraulic conductivity of soils at the site (Wolfpen, loamy, siliceous, semiactive, thermic Arenic Paleudalfs; and Darley, fine, kaolinitic, thermic Typic Hapludults) and low initial soil phosphorus (P) resulted in small runoff volumes and low P concentrations in runoff, thus negligible loads, even when poultry litter was applied at N-based rates equal to 160 kg / ha.