Forage Yield and Quality Of Miscanthus Giganteus Subjected To Simulated Haying/Grazing Conditions.

As the U.S. mandate for renewable fuels takes effect the number of hectares converted to perennial species for lignocellulosic bioenergy may dramatically increase; replacing current grazing and haying lands due to their marginal characteristics. As such, this crop may be needed in years of scarce hay as those observed in 2012. Our objectives were to determine the viability of using Miscanthus x giganteus as a dual use forage crop and how this use will affect stand longevity. We conducted an experiment where Miscanthus x giganteus either as a biomass feedstock (cut once in the winter), or under three cutting strategies (single, double, triple) with the initial harvest in May followed by double and triple cuts in 6 week intervals. The material was fertilized at two N levels (0 and 75 kg/ha) and cut when plants attained a height between 75 and 100 cm. The forage was separated into leaf and stem tissue, and dried to determine dry matter yields. The material was ground and analyzed for IVTD, NDF, ADF, ADL, total ash, C, and CP. Total yields averaged 14.5, 13.7, 13.0, and 11.2 Mg ha^-1 for single, double, triple, and biomass only, respectively. Leaves had greater digestibility than stems, and these were unchanged with development. The CP, NDF, and ADF values for leaf tissue averaged 125, 681, and 327 g kg^-1 while stem tissue averaged 76, 690, and 383 g kg^-1 respectively. Using the Penn State equation TDN values averaged 635 and 574 g kg-1 for leaf and stem, respectively. Based on these values Miscanthus x giganteus as managed in this study would nearly meet the nutritional needs of lactating beef cattle.