Soil Organic Carbon and Nitrogen in Silvopasture with Native Warm Season Grasses.

Native warm season grasses can provide soil rehabilitation services to degraded soils by adding root biomass to enhance soil organic carbon and reduce erosion. Native warm-season grasses have low maintenance needs and provide valuable nutritive value to grazing livestock. Timber in a silvopasture creates microclimates by acting as windbreaks and provides shade to mitigate temperature and moisture extremes that can otherwise have negative impacts on grazing livestock. Both plant components of silvopasture provide potential carbon sequestration service. We evaluated soil organic carbon (SOC) and mineralizable nitrogen (minN) in an alley-cropped silvopasture with tree rows running east-west and soil sample transects perpendicular to alleys. Each sampling transect had three treatments (Pinus palustris, Pinus taeda, Quercus pagoda) replicated five times in a randomized complete block design (5 plots x 3 tree species x 12 sample locations x 3 sample depths = 540 samples). We expect that SOC and minN concentrations will be greater in the surface layer than lower in the profile. We also anticipate that SOC and minN contents will vary with proximity to the tree lines, although the direction of change may be different depending on which side of tree line is sampled.