ESTIMATION OF OPTIMAL BIOMASS REMOVAL RATE BASED ON TOLERABLE SOIL EROSION FOR SINGLE-PASS CROP GRAIN AND BIOMASS HARVESTING SYSTEM

As the demand for biomass feedstocks grows, it is likely that agricultural residue will be removed in a way that compromises soil sustainability due to increased soil erosion, depletion of organic matter, and deterioration of soil physical characteristics. Since soil erosion from agricultural fields depends on several factors including soil type, field terrain, and cropping practices, the amount of biomass that can be removed while maintaining soil tilth varies substantially over space and time. The RUSLE2 soil erosion model, which takes into account these spatio-temporal variations, was used to estimate tolerable agricultural biomass removal rates at field scales for a single-pass crop grain and biomass harvesting system. Soil type, field topography, climate data, management practices, and conservation practices were stored in individual databases on a state or county basis. Geographic position of the field was used as a spatial key to access the databases to select site-specific information such as soil, topography, and management related parameters. These parameters along with actual grain yield were provided as inputs to the RUSLE2 model to calculate yearly soil loss per unit area of the field. An iterative technique was then used to determine site-specific tolerable biomass removal rates that keep the soil loss below the soil loss thresholds (T) of the field. The tolerable removal rates varied substantially with field terrain, crop management practices, and soil type. At a location in a field in Winnebago county, Iowa, with ~1% slope and conventional tillage practices, up to 98% of the 11 Mg ha-1 total above-ground biomass was available for collection with negligible soil loss. There was no biomass available to remove with conventional tillage practices on steep slopes, as in a field in Crawford county, Iowa, with a 12.6% slope. If no-till crop practices were adopted, up to 70% of the total above-ground biomass could be collected at the same location with 12.6% slope. In the case of a soybean-corn rotation with no-till practices, about 98% of total biomass was available for removal at the locations in the Winnebago field with low slopes, whereas 77% of total biomass was available at a location in the Crawford field with a 7.5% slope. Tolerable removal rates varied substantially over an agricultural field, which showed the importance of site-specific removal rate estimation. These removal rates can be useful in developing recommended rates for producers to use during a single-pass crop grain and biomass harvesting operation. However, this study only considered the soil erosion tolerance level in estimating biomass removal rates. Before providing the final recommendation to end users, further investigations will be necessary to study the potential effects of continuous biomass removal on organic matter content and other biophysical properties of the soil.

[1]  K. Paustian,et al.  Energy and Environmental Aspects of Using Corn Stover for Fuel Ethanol , 2003 .

[2]  K. C. McGregor,et al.  TILLAGE AND RESIDUE EFFECTS ON RUNOFF AND EROSION DYNAMICS , 2004 .

[3]  Tillage and crop residue effects on soil erosion in the Corn Belt. , 1979 .

[4]  F. J. Pierce,et al.  Impacts of agricultural management practices on C sequestration in forest-derived soils of the eastern Corn Belt , 1998 .

[5]  Frank Taylor,et al.  Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks , 2000 .

[6]  J. E. Morrison,et al.  Distribution and amount of soil organic C in long-term management systems in Texas , 1998 .

[7]  S. Andrews.  Crop Residue Removal for Biomass Energy Production: Effects on Soils and Recommendations , 2006 .

[8]  S. Sokhansanj,et al.  Distribution of aboveground biomass in corn stover , 2004 .

[9]  Humberto Blanco-Canqui,et al.  Energy Crops and Their Implications on Soil and Environment , 2010 .

[10]  James R. Hettenhaus,et al.  Corn Stover Potential: Recasting the Corn Sweetener Industry* , 1999 .

[11]  Bryce J. Stokes,et al.  Biomass as Feedstock for A Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply , 2005 .

[12]  E. C. Berry,et al.  Crop residue effects on soil quality following 10-years of no-till corn☆ , 1994 .

[13]  W. D. Kemper,et al.  Soil organic matter changes resulting from tillage and biomass production , 1995 .

[14]  Joseph DiPardo.  Outlook for Biomass Ethanol Production and Demand by Joseph DiPardo , 2000 .

[15]  John J Sheehan,et al.  Methodology for estimating removable quantities of agricultural residues for bioenergy and bioproduct use , 2004, Applied biochemistry and biotechnology.

[16]  A. Kaleita,et al.  Soil erosion hazard maps for corn stover management using National Resources Inventory data and the Water Erosion Prediction Project , 2010, Journal of Soil and Water Conservation.

[17]  R. Wooley,et al.  Biomass Commercialization Prospects in the Next 2 to 5 Years , 2000 .

[18]  D. R. Linden,et al.  Crop and Soil Productivity Response to Corn Residue Removal: A Literature Review , 2004 .

[19]  R. Allmaras,et al.  Soil organic carbon sequestration potential of adopting conservation tillage in U.S. croplands , 2000 .

[20]  Jane M. F. Johnson,et al.  Estimating Source Carbon from Crop Residues, Roots and Rhizodeposits Using the National Grain-Yield Database , 2006 .

[21]  R. Nelson.  Resource assessment and removal analysis for corn stover and wheat straw in the Eastern and Midwestern United States—rainfall and wind-induced soil erosion methodology , 2002 .

[22]  D. R. Linden,et al.  Long-term corn grain and stover yields as a function of tillage and residue removal in east central Minnesota , 2000 .