In the United States, commercial-scale cellulosic-ethanol production using corn (Zea mays L.) stover has become a reality. As the industry matures and demand for stover increases, it is important to determine the amount of biomass that can be sustainably harvested while safe-guarding soil quality and productivity. Specific study objectives were to measure indices of soil hydrological and aggregate stability responses to harvesting stover; since stover harvest may negatively impact soil hydrological and physical properties. Responses may differ with tillage management; thus, this paper reports on two independent studies on a tilled (Chisel field) and untilled field (NT1995 field). Each field was managed in a corn/soybean (Glycine max [Merr.]) rotation and with two rates of stover return: (1) all returned (Full Return Rate) and (2) an aggressive residue harvest leaving little stover behind (Low Return Rate). Unconfined field soil hydraulic properties and soil aggregate properties were determined. Hydrological response to residue treatments in the Chisel field resulted in low water infiltration for both rates of residue removal. In NT1995 field, Full Return Rate had greater capacity to transmit water via conductive pathways, which were compromised in Low Return Rate. Collectively, indices of soil aggregation in both experiments provided evidence that the aggregates were less stable, resulting in a shift toward more small aggregates at the expense of larger aggregates when stover is not returned to the soil. In both fields, aggressive stover harvest degraded soil physical and hydrological properties. No tillage management did not protect soil in absence of adequate residue.
Bibliographical noteFunding Information:
Funding for this project provide by the USDA-Agricultural Research funding, as part of the USDA-ARS-REAP project. Additional funding the North Central Regional SunGrant Center at South Dakota State University through a grant provided by the US-DOE − Office of Biomass Products (now known as the Biomass Energy Technology Office) through a USDA-NIFA Sun Grant Association under award number DE-FC36-05GO85041 and provided by customers of Xcel Energy 1 1 through a grant from the Renewable Development Fund .
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- Cellulosic bioenergy
- Residue management
- Soil quality