Bioenergy for cattle and cars: a switchgrass production system that engages cattle producers.

摘要

Switchgrass (Panicum virgatum L.) produced for bioenergy is expected to compete with land resources used for stocker cattle (Bos taurus) grazing in the southern Great Plains. The objective was to determine the effect of stocking rate on animal performance, biomass yield, and quality. Three stocking rates (light [2.5 steers ha-1], moderate [4.9 steers ha-1], and heavy [7.4 steers ha-1]) and an ungrazed control were randomly assigned to twelve 0.81-ha paddocks in 2008, 2009, and 2010. Animal and biomass responses were analyzed using mixed ANOVA models. Average daily gain (P=0.05) was 0.83, 1.04 and 1.05 kg head (hd)-1 for the light, moderate and heavy stocking rates, respectively. Grazing duration was affected (P<0.001) by stocking rate treatment, realizing 81, 43, and 28 d of grazing, respectively. Steer grazing days were not different (P=0.22) between stocking rates treatments, producing 81, 86, and 84 d ha-1, respectively. Total gain by treatment were 167, 215, and 199 kg ha-1, respectively, and were different (P=0.04). The ungrazed control produced more (P<0.001) harvested biomass at the end of the growing season (15.3 Mg ha-1) compared to the grazed treatments (10.6, 8.1, and 7.8 Mg ha-1, respectively). Forage quality decreased (P<0.05) throughout the growing season for all treatments. Results indicate switchgrass has the potential to extend the cool-season grazing season in the region while also allowing for the production of an annual supply of bioenergy feedstock for conversion into biofuel.Digital Object Identifier http://dx.doi.org/10.2134/agronj2012.0384