Enhancing Ecosystem Services of Marginally-Productive Agricultural Lands with Dedicated Bioenergy Crops.

Dedicated bioenergy crops such as perennial warm-season grasses (i.e., switchgrass) may potentially provide low-input cellulosic feedstocks while maintaining or enhancing soil and environmental quality. Studies comparing differences in soil properties between dedicated bioenergy crops and crop residue removal are not, however, available, particularly in marginally productive croplands. We assessed short-term (2 and 3 years) effects of perennial warm-season grasses and corn residue removal on soil properties including wind and water erosion potential, water infiltration and retention, soil organic C, and soil fertility parameters on a bioenergy crop experiment established in 2012 on a poorly drained soil at the University of Nebraska-Lincoln’s Agricultural Research Development Center (Ithaca, NE). The treatments were switchgrass, low-diversity grass mixture (big bluestem, indiangrass, and sideoats grama), and big bluestem under two N fertilization levels (56 and 112 kg N/ha) and no-till continuous corn with 0 and 50% residue removal. The corn with no stover removal treatment had triticale as a cover crop. Corn stover removal reduced dry and wet soil aggregate stability in the upper 7.5 cm soil depth compared with perennial grasses with biomass harvested and corn with no stover removed, indicating that corn stover removal increased wind and water erosion potential. Differences in wind and water erosion potential between perennial grasses with biomass harvested and corn with no stover removed were not, however, significant. Stover removal also reduced water retention capacity in the 0-15 cm depth, but had no effects on water infiltration, soil organic C, and soil fertility properties. Overall, perennial grasses can be a potential alternative to corn stover removal for cellulosic biomass production while maintaining soil ecosystem services in marginally productive croplands.