Perennial species for optimum production of herbaceous biomass in the Piedmont

Abstract

We have investigated eight biomass candidates grown on marginal Piedmont sites. The species include four grasses; sorghum-sundangrass hybrid, switchgrass, weeping lovegrass, and tall fescue; and four legumes: birdsfoot trefoil, crownvetch, flatpea, and sericea lespedeza. The candidate species were planted using no-till methods on twelve sites underlain by three different soils, Davidson, Cecil, and Appling. Initial establishment was good, but some plots had to be replanted after freezes and/or drought reduced stands. The two warm-season perennial grasses, switchgrass and weeping lovegrass, consistently provided the most biomass across all sites; average biomass yields in years following establishment ranged from 8 to 16 Mg/ha for the two. The legumes were generally lower than the grasses in biomass production, with sericea being the most productive legume overall, averaging about 6 Mg/ha/yr. Other studies indicated the experimental sites were quite variable in key soil morphological and chemical characteristics. Rooting depth of switchgrass was particularly notable, exceeding 0.7 m in all the soils studied. Erosion estimates using the Universal Soil Loss Equation suggested no-till production of perennial species limits soil losses. Economic analyses showed distinct differences among the candidates in costs of production. Physiological studies of switchgrass seed dormancy and photosynthesis were also conducted. 19 refs.,more » 11 figs., 49 tabs.« less