Location: Wheat, Sorghum and Forage ResearchTitle: Perennial warm-season grasses for producing biofuel and enhancing soil properties: an alternative to corn residue removal
|BLANCO-CANQUI, HUMBERTO - University Of Nebraska|
|Mitchell, Robert - Rob|
|ESKRIDGE, KENT - University Of Nebraska|
Submitted to: Global Change Biology Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2017
Publication Date: 3/15/2017
Publication URL: http://handle.nal.usda.gov/10113/5801795
Citation: Blanco-Canqui, H., Mitchell, R., Jin, V.L., Schmer, M.R., Eskridge, K.M. 2017. Perennial warm-season grasses for producing biofuel and enhancing soil properties: an alternative to corn residue removal. Global Change Biology Bioenergy. doi:10.1111/gcbb.12436.
Interpretive Summary: Cellulosic ethanol plants are operating in the US using corn residue as the primary feedstock. Growing dedicated bioenergy crops including switchgrass, big bluestem, and warm-season grass mixtures is an alternative to corn residue removal. Dedicated bioenergy crops can supply feedstocks for bioenergy while providing essential soil ecosystem services like soil carbon sequestration and erosion control. Marginally productive lands provide opportunities for growing perennial grasses for bioenergy. The short-term soil response to perennial grass energy crops and corn residue removal on marginally productive cropland in eastern Nebraska indicated that removing 50% of the corn residue increased wind and water erosion potential compared with perennial grasses with biomass removal and no-till corn and a cover crop. Harvesting residues from no-till corn consistently reduced soil dry and wet aggregate stability near the surface unlike biomass removal from the perennial grasses. Corn residue removal reduced plant available water, indicating that removing residues from water-limited soils may have adverse effects on water capture and storage. Short-term residue removal did not reduce water infiltration, soil carbon, or total N concentrations relative to perennial grasses and corn and a cover crop. Perennial grasses grown for biomass on marginally productive croplands are a reasonable alternative to corn residue removal as they can reduce risks of wind and water erosion and improve soil water retention without reducing feedstock yields.
Technical Abstract: Removal of corn (Zea mays L.) residues at high rates for biofuel and other off-farm uses may negatively impact soil and the environment in the long term. Biomass removal from perennial warm-season grasses (WSGs) grown in marginally productive lands could be an alternative to corn residue removal as biofuel feedstocks while controlling water and wind erosion, sequestering carbon (C), cycling water and nutrients, and enhancing other soil ecosystem services. We compared wind and water erosion potential, soil compaction, soil hydraulic properties, soil organic C (SOC), and soil fertility between biomass removal from WSGs and corn residue removal from rainfed no-till continuous corn on a marginally productive site on a silty clay loam in eastern Nebraska after 2 and 3 years of management. The field-scale treatments were as follows: (i) switchgrass (Panicum virgatum L.), (ii)big bluestem (Andropogon gerardii Vitman), and (iii) low-diversity grass mixture [big bluestem, indiangrass (Sorghastrum nutans (L.) Nash), and sideoats grama (Bouteloua curtipendula (Michx.) Torr.)], and (iv) 50% corn residue removal with three replications. Across years, corn residue removal increased wind-erodible fraction from 41% to 86% and reduced wet aggregate stability from 1.70 to 1.15 mm compared with WSGs in the upper 7.5 cm soil depth. Corn residue removal also reduced water retention by 15% between -33 and -300 kPa potentials and plant-available water by 25% in the upper 7.5 cm soil depth. However, corn residue removal did not affect final water infiltration, SOC concentration, soil fertility, and other properties. Overall, corn residue removal increases erosion potential and reduces water retention shortly after removal, suggesting that biomass removal from perennial WSGs is a desirable alternative to corn residue removal for biofuel production and maintenance of soil ecosystem services.