Soil Carbon Sequestration by Switchgrass and No-Till Maize Grown for Bioenergy

Net benefits of bioenergy crops, including maize and perennial grasses such as switchgrass, are a function of several factors including the soil organic carbon (SOC) sequestered by these crops. Life cycle assessments (LCA) for bioenergy crops have been conducted using models in which SOC information is usually from the top 30 to 40 cm. Information on the effects of crop management practices on SOC has been limited so LCA models have largely not included any management practice effects. In the first 9 years of a long-term C sequestration study in eastern Nebraska, USA, switchgrass and maize with best management practices had average annual increases in SOC per hectare that exceed 2 Mg C year−1 (7.3 Mg CO2 year−1) for the 0 to 150 soil depth. For both switchgrass and maize, over 50 % of the increase in SOC was below the 30 cm depth. SOC sequestration by switchgrass was twofold to fourfold greater than that used in models to date which also assumed no SOC sequestration by maize. The results indicate that N fertilizer rates and harvest management regimes can affect the magnitude of SOC sequestration. The use of uniform soil C effects for bioenergy crops from sampling depths of 30 to 40 cm across agro-ecoregions for large scale LCA is questionable.

[1]  John P Reganold,et al.  No-till: the quiet revolution. , 2008, Scientific American.

[2]  Bryce J. Stokes,et al.  U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry , 2011 .

[3]  Robert D. Perlack,et al.  Current and potential U.S. corn stover supplies. , 2007 .

[4]  Robert B. Mitchell,et al.  Quantifying Actual and Theoretical Ethanol Yields for Switchgrass Strains Using NIRS Analyses , 2011, BioEnergy Research.

[5]  H. Gollany,et al.  Predicting Agricultural Management Influence on Long‐Term Soil Organic Carbon Dynamics: Implications for Biofuel Production , 2011 .

[6]  D. Andress,et al.  Soil carbon changes for bioenergy crops. , 2004 .

[7]  Xinhua Yin,et al.  Soil carbon and nitrogen changes as influenced by tillage and cropping systems in some Iowa soils , 2005 .

[8]  Jane M. F. Johnson,et al.  Corn Stover to Sustain Soil Organic Carbon Further Constrains Biomass Supply , 2007 .

[9]  W. Wilhelm,et al.  No-tillage increases soil profile carbon and nitrogen under long-term rainfed cropping systems , 2011 .

[10]  Rattan Lal,et al.  Corn Stover Removal for Expanded Uses Reduces Soil Fertility and Structural Stability , 2009 .

[11]  T. Boutton 10 – Stable Carbon Isotope Ratios of Natural Materials: I. Sample Preparation and Mass Spectrometric Analysis , 1991 .

[12]  N. Dudai,et al.  Effect of Irrigation with Secondary Treated Effluent on Essential Oil, Antioxidant Activity, and Phenolic Compounds in Oregano and Rosemary , 2009 .

[13]  Gary E. Varvel,et al.  No-Till Corn after Bromegrass: Effect on Soil Carbon and Soil Aggregates , 2009 .

[14]  J. S. Schepers,et al.  Simultaneous determination of total C, total N, and 15N on soil and plant material , 1989 .

[15]  Mark A. Liebig,et al.  Soil carbon under switchgrass stands and cultivated cropland , 2005 .

[16]  G. Marland,et al.  A synthesis of carbon sequestration, carbon emissions, and net carbon flux in agriculture: comparing tillage practices in the United States , 2002 .

[17]  B. Stewart,et al.  Assessment Methods for Soil Carbon , 2000 .

[18]  W. Parton,et al.  Life-cycle assessment of net greenhouse-gas flux for bioenergy cropping systems. , 2007, Ecological applications : a publication of the Ecological Society of America.

[19]  Stan D. Wullschleger,et al.  Soil carbon dynamics beneath switchgrass as indicated by stable isotope analysis. , 2000 .

[20]  K. P. Vogela,et al.  Comparison of corn and switchgrass on marginal soils for bioenergy , 2007 .

[21]  D. Walters,et al.  Switchgrass biomass production in the Midwest USA: harvest and nitrogen management. , 2002 .

[22]  Rattan Lal,et al.  No-tillage and soil-profile carbon sequestration : An on-farm assessment , 2008 .

[23]  Richard M. Cruse,et al.  Sustainable Biofuels Redux , 2008, Science.

[24]  S. Leavitt,et al.  POTENTIAL USE OF SOIL C ISOTOPE ANALYSES TO EVALUATE PALEOCLIMATE , 2002 .

[25]  E. Va,et al.  Changes in soil organic carbon under biofuel crops , 2009 .

[26]  Jacinto F. Fabiosa,et al.  Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change , 2008, Science.

[27]  C. D. Keeling,et al.  Exchanges of Atmospheric CO2 and 13CO2 with the Terrestrial Biosphere and Oceans from 1978 to 2000. IV. Critical Overview , 2001 .

[28]  R. B. Mitchell,et al.  Soil Carbon Storage by Switchgrass Grown for Bioenergy , 2008, BioEnergy Research.

[29]  Gary A. Peterson,et al.  Carbon isotope ratios of great plains soils and in wheat-fallow systems , 1997 .

[30]  T. Ochsner,et al.  Tillage and soil carbon sequestration—What do we really know? , 2007 .

[31]  Rattan Lal,et al.  Soil Carbon Sequestration and the Greenhouse Effect , 2001 .

[32]  Michael Wang,et al.  Development and use of GREET 1.6 fuel-cycle model for transportation fuels and vehicle technologies. , 2001 .

[33]  W. Wilhelm,et al.  Simulating soil organic matter with CQESTR (v. 2.0): model description and validation against long-term experiments across North America. , 2009 .

[34]  Rattan Lal,et al.  Soil Organic Carbon Stocks with Depth and Land Use at Various U.S. Sites , 2009 .

[35]  Vance N. Owens,et al.  Switchgrass and Soil Carbon Sequestration Response to Ammonium Nitrate, Manure, and Harvest Frequency on Conservation Reserve Program Land , 2007 .

[36]  S. Polasky,et al.  Land Clearing and the Biofuel Carbon Debt , 2008, Science.

[37]  Markus Leuenberger,et al.  Carbon isotope composition of atmospheric CO2 during the last ice age from an Antarctic ice core , 1992, Nature.

[38]  S. Polasky,et al.  Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[39]  Mark A. Liebig,et al.  Biomass and carbon partitioning in switchgrass. , 2004 .

[40]  David B Lobell,et al.  Greenhouse gas mitigation by agricultural intensification , 2010, Proceedings of the National Academy of Sciences.

[41]  D. Coleman,et al.  Carbon isotope techniques , 1991 .

[42]  W. Parton,et al.  DAYCENT and its land surface submodel: description and testing , 1998 .

[43]  J. Fontes,et al.  The Terrestrial environment , 1980 .

[44]  J. Balesdent,et al.  Soil Organic Matter Turnover in Long-term Field Experiments as Revealed by Carbon-13 Natural Abundance , 1988 .