Wednesday, November 7, 2007 - 2:15 PM
306-5

Impacts of Harvesting Corn Stover for Biofuel Feedstocks on Soil and Agronomic Productivity.

Humberto Blanco-Canqui, Ohio State University - Columbus, School of Natural Resources, 412 Kottman Hall 2021 Coffey Road, Columbus, OH 43210-1085 and Rattan Lal, 2021 Coffey Road, Ohio State University - Columbus, Ohio State University, Carbon Management & Sequestration Center, Columbus, OH 43210.

Corn (Zea mays L.) stover is one of the potential lignocellulosic feedstocks for producing biofuel. While producing renewable energy from biomass is a plausible goal, implications of harvesting corn stover on soil organic carbon (SOC) sequestration, soil properties, agronomic productivity, and environmental quality have not been well elucidated. We conducted a 3-yr study of stover management in long-term (>8 yr) no-tillage continuous corn systems across three contrasting soils in Ohio to determine changes in SOC sequestration, CO2 emissions, soil mechanical, physical, and chemical properties, and agronomic productivity. The three soils were Rayne silt loam with 6% slope, Celina silt loam with 2% slope, and Hoytville clay loam with <1% slope. The experimental design of this ongoing project consists of removing 0, 25, 50, 75, and 100%, and adding 100% of corn stover following each harvest in 3 × 3 m triplicated plots laid out in a randomized complete block design. At the start of the project in May 2004, these percentages of removal corresponded to 5, 3.75, 2.5, 1.25, and 0 Mg ha-1yr-1 of stover left on the soil surface, respectively. Annual stover removal rate reduced the SOC and nutrient content, altered soil properties, and reduced crop yields, but the magnitude of impacts varied with soil series. Stover removal altered both macro- and micro-scale soil physical properties. Stover removal impacts were greater on unglaciated, sloping, and erosion prone soils than on nearly level and clayey soils. Results from this short-term study suggest that only a small fraction (<25%) of the total corn stover produced can be removed for biofuel feedstocks particularly from sloping and erosion-prone soils. Further details on the implications of stover removal will be discussed at the meeting.