Soil and Water Quality with Miscanthus On a Louisiana Coastal Plain Hillside.

Second and third year yield and composition data for hybrid miscanthus (5 m x 5 m plots) at a coastal plain site in northern Louisiana (Lucy Ruston association soil) showed little effect of fertilizer source or rate (inorganic N or poultry litter at 0, 80 and 160 kg N per ha in triplicate), however, short-range spatial variability in internal drainage may have been confounding under drought in 2010 and 2011, with yields inversely related to depth to the Bt horizon.  Despite low nutrient uptake and removal, build-up of soil phosphorus and its loading into runoff is so far minor with poultry litter fertilizer.  However, the initial concentration of soil phosphorus and the overall soil chemical fertility of the site was very low, as typical of the marginally-productive soils that would presumably be used to grow biofuel grasses.  Yields of switchgrass with the same treatments in an adjacent study were about twice that of miscanthus.