Switchgrass Management Practice Effects on Near-Surface Soil Properties in West-Central Arkansas

Abstract

Agronomic management practices that maximize monoculture switchgrass (Panicum virgatum L.) yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management practices on near-surface soil properties and processes. The objective of the study was to evaluate the effects of cultivar (“Alamo” and “Cave-in-Rock”), harvest frequency (1- and 2-cuts per year), fertilizer source (poultry litter and commercial fertilizer), and irrigation management (irrigated and non-irrigated) on near-surface soil properties and surface infiltration in a Leadvale silt loam (fine-silty, siliceous, semiactive, thermic, Typic Fragiudult) after four years (2008 through 2011) of consistent management in west-central Arkansas. Irrigating switchgrass increased (P < 0.01) soil bulk density in treatment combinations where poultry litter was applied (1.40 g?cm?3) compared to non-irrigated treatment combinations (1.33 g?cm?3). Root density was greater (P = 0.031) in irrigated (2.62 kg?cm?3) than in non-irrigated (1.65 kg?cm?3) treatments when averaged over all other treatment factors. The total infiltration rate under unsaturated conditions was greater (P = 0.01) in the 1-cut (33 mm?min?1) than 2-cut (23 mm?min?1) harvest treatment combinations when averaged over all other treatment factors, while the total infiltration rate under saturated conditions did not differ among treatment combinations (P > 0.05) and averaged 0.79 mm?min?1. Results from this study indicate that management decisions to maximize switchgrass biomass production affect soil properties over relatively short periods of time, and further research is needed to develop local best management practices to maximize yield while maintaining or improving soil quality.