IMPACTS OF BIOMASS SORGHUM FEEDSTOCK PRODUCTION ON CARBON SEQUESTRATION AND GREENHOUSE GAS EMISSIONS IN THE SOUTHCENTRAL REGION

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 0224230
• Grant No.: 2011-67009-30050
• Cumulative Award Amt.: $995,100.00
• Proposal No.: 2010-03853
• Project Start Date: Feb 1, 2011
• Project End Date: Jan 31, 2017
• Grant Year: 2012
• Program Code: [A6121]- Sustainable Bioenergy: Sustainable Bioenergy Research

Project Director
Hons, F.

Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001

Performing Department
Soil & Crop Sciences

Non Technical Summary
The U.S. Energy Independence and Security Act of 2007 mandates production of renewable fuels: 9 billion gallons/year currently, increasing to 36 billion/year by 2022. This increase will require an estimated 50 million acres of cropland, greatly intensifying demands on sustainable agricultural systems. To help meet these goals, conversion of high biomass sorghum into biofuels shows great promise. A negative outcome of biofuel production, however, would be to address near-term problems (over reliance on imported fossil fuels), while creating or aggravating longer-term problems (reduction in the productive capacity of soils). Field experiments, studies under laboratory conditions, and computer modeling will be used to accomplish our overall goal of developing advanced crop production systems utilizing improved nutrient management, crop rotation, and decreased soil tillage, among other practices, to increase carbon sequestration, mitigate greenhouse gas (GHG) emissions, and improve the sustainability of biomass sorghum feedstock production in the south central region. The integration of field and laboratory experiments and modeling will allow us to identify the relative importance of the different factors that influence biomass sorghum yield and quality, nutrient cycling, carbon sequestration, GHG emissions, and economic viability. The proposed research will accomplish these objectives and allow us to determine the carbon footprint of biomass sorghum production through a life cycle (cradle to grave) analysis.

Animal Health Component

50%

Research Effort Categories

Basic

30%

Applied

50%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
102	0110	2000	35%
102	0110	1103	15%
131	1630	3010	15%
204	1630	1010	10%
205	1630	1010	25%

Knowledge Area
204 - Plant Product Quality and Utility (Preharvest); 102 - Soil, Plant, Water, Nutrient Relationships; 205 - Plant Management Systems; 131 - Alternative Uses of Land;

Subject Of Investigation
0110 - Soil; 1630 - Summer annual grasses;

Field Of Science
1103 - Other microbiology; 1010 - Nutrition and metabolism; 2000 - Chemistry; 3010 - Economics;

Keywords

biomass sorghum production

greenhouse gas emissions

sustainability

carbon sequestration

soil quality

soil organic carbon

life cycle analysis

process-based modeling

no-tillage

nitrogen fertilization

crop rotation

nutrient removal

nutrient cycling

economic analysis

residue removal

Goals / Objectives
Overall Long-Term Goal - To develop advanced biomass sorghum cropping systems utilizing improved nutrient management, rotation, and decreased soil disturbance, among other practices, to increase C sequestration, reduce GHG emissions, and improve the sustainability of biomass sorghum feedstock production in the south central US. Specific Objectives: 1) Determine the effects of tillage, fertilization, biomass return, and crop rotation on sustainability, especially with regards to: a) quality and yield of biomass sorghum: b) C sequestration, soil quality, and nutrient cycling; and c) GHG emissions. 2) Elucidate how the above management practices alter C and N cycling and GHG emissions across varying soil types and climate, and 3) Determine which combinations of integrated practices are most environmentally and economically sustainable based on a life cycle assessment (LCA) for C and net returns. Objective/Task Descriptions/Task Managers/Timeline 1) Determine the effects of tillage, fertilization, biomass return and crop rotation on : a) quality and yield of biomass sorghum/ Wight, Osuji/2011, 2012, 2013, 2014, 2015* b) Soil quality and nutrient cycling/Wight, Dou, Hons/2011, 2012, 2013, 2014, 2015* c) Greenhouse gas emissions/Hons, Wight/2011, 2012, 2013, 2014, 2015* 2) Determine how biomass sorghum management practices alter C and N cycling and GHG emissions across varying soil type and climate/Hons, Dou/2012, 2013, 2014, 2015* 3) Economic analysis to determine profitability and sustainability based on a LCA for C and energy/Hons, Mjelde, Wight/2011, 2012, 2013, 2014, 2015* 4) Transfer technology developed for sustainable biomass sorghum production in the south central US to scientists, producers, and regulators/All/2014, 2015* * Refinement only. Expected outcomes include conducting and analyzing lab and field experiments, field days for producers, enhanced collaboration with other scientists, improved skills of postdocs and graduate students, and dissemination of information through refereed scientific publications and presentations at scientific and producer conferences. Outcomes will also include development of management practices that increase sustainability and maintain or enhance soil and environmental quality, and a LCA for carbon in biomass sorghum feedstock production.

Project Methods
Objective 1 and its subobjectives will be achieved using field experiments and laboratory analyses. Factorial combination of the following factors will be used: Rotation- continuous biomass sorghum vs. rotated biannually with corn; stover return- 0, 25, or 50% of sorghum biomass produced; and nitrogen rate- 0 vs. 250 kg N ha-1. The sorghum used in all studies is a photoperiod-sensitive, one-cross hybrid recommended for high biomass yield. A second experiment compares sorghum's dry matter yield and nutrient removal response to five rates of nitrogen addition (0, 75, 150, 225 or 300 kg N ha-1), while a third determines effects of conventional vs. no-till management on sorghum yield and nutrient removal. Aboveground biomass will be harvested once each season in October for yield and determination of quality characteristics in order to estimate potential biofuel production from various treatments. Biomass subsamples will be further analyzed for total concentrations of C, N, P, K, and other selected nutrients, in order to determine treatment effects on nutrient removal. Soil samples will be collected to a depth of 1 m prior to planting each year and analyzed for total C and N and extractable nutrients. Direct measurement of soil emissions of CO2, N2O, and CH4 will be made in selected treatments using field flux chambers and a photoacoustice gas analyzer. Gas measurements will be made during both growing and fallow seasons. Cropping, soil, and gas flux results will be combined with production input data to delineate treatment effects on the net C balance of sorghum for biofuel using the GREET model to develop life cycle analyses (LCA). A biogeochemical model (DAYCENT) will be used in Objective 2 to simulate the effects of management practices and environmental factors on C cycling and GHG emissions during biomass sorghum production. This model will determine how changing soil, environmental and management characteristics influence C sequestration and GHG emissions over decadal time periods. Life cycle analysis (GREET) will be used for Objective 3 to assess environmental performance of bioenergy systems in their totality from production input to crop production through combustion of the biofuel. Cropping, soil, and GHG results from objective 1 will be combined with production input data to delineate treatment effects on the economics and net energy and C balances of biomass sorghum for biofuel. In the proposed economic model, state variables will include soil characteristics. Sorghum yield and biomass will be stochastic in the model based on climatic conditions, current management practices, and the current soil characteristic state variables. Stochastic Markov transition matrices based on current soil conditions, management practices including residue removal, and climate conditions will be developed which govern how soil characteristics evolve over time. Sorghum price will also be a state variable in the model. Price will be modeled as a first order Markov process. The model will be iterated until a convergent decision rule is obtained. Specifics of the model will depend on field and laboratory results.

Progress 02/01/11 to 01/31/17

Outputs
Target Audience:Soil and carbon sequestration scientists; sorghum and bioenergy crop producers; environmental scientists; agronomists; bioenergy and climate change scientsists, modelersand policy makers; Efforts: scientific and producer conferences, formal presentations, publications. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training support for an assistant research scientist and a graduate student durinig the reporting period. These opportunities enhanced their knowledge and appreciation of field and lab methodologies associated with soil and plant research, especially as related to soil carbon sequestration, nutrient cycling, soil quality assessment, and sustainability. Modeling of results created additional learning opportunities. How have the results been disseminated to communities of interest?Results have been disseminated via publication in scientific journals, a book chapter, abstracts, and presentations at scientific and project directors' meetings and individual discussions with researchers and producers. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Bioenergy sorghum has the potential to be a very important cellulosic feedstock if it can be produced without degrading soil quality. Two important factors for achieving that goal are N management and the amount of residue (i.e. carbon) returned to the soil. This study evaluated two cropping sequences (continuous bioenergy sorghum or biannual rotation of bioenergy sorghum and corn), two N rates (0 or 280 kg ha−1 yr−1) and three levels of residue return (0, 25%, or 50%) on Weswood silty clay loam near College Station, TX USA from 2009 through 2014. Maximum dry biomass yield (23 Mg ha−1) was produced with added N and 25% residue return in a year with above average precipitation. Overall, N fertilization increased biomass yield by 43 to 104%, while residue return enhanced yield from < 1 to 23% during the six years of the study. Averaged for the six years, biomass production for the 0, 25%, and 50% residue return treatments was 16, 20, and 18 Mg ha−1, respectively. Returning 25% of the crop residue significantly increased K uptake in all years. Sorghum fertilizer N uptake efficiency (FNUE) with residue return by 2014 was significantly increased compared to 2009 values, indicating decreased amounts of residual available nitrogen over time. Non-limiting N fertilization and 25% residue return significantly increased NO3-N, P, K, and soil organic C (SOC) concentrations in surface (0 to 5 cm) samples and soil total N (TN) and K concentrations within the 60 to 90 cm layer. With 25% residue return, SOC to 90-cm depth increased by 39.2 Mg ha-1. Increases in SOC were much greater for contionuous (51%)vs. rotated sorghum (10%). For both continuous and rotated sorghum, changes in SOC stocks were greater at lower depths, principally at 30-60 and 60-90 cm, implying that SOC increases at these depths were mostly associated with bioenergy sorghum roots. Results indicate that N fertilization will be required to achieve high biomass sorghum yield and suggests that developing a harvest strategy to return 25% of the crop residue may be sufficient to maintain soil quality.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Shahandeh, H., Hons, F.M., Storlien, J.O., and Wight, J.P. 2016. Long-term bioenergy sorghum harvest strategy and soil quality. AIMS Energy 4(4):633-657. doi:10.3934/energy.2016.4.633.
• Type: Book Chapters Status: Awaiting Publication Year Published: 2016 Citation: Wang, Y., Dou, F., Storlien, J.O., Wight, J.P., Paustian, K.H., Del Grosso, S.J., and Hons, F.M. 2017. Chapter 15. Simulating Impacts of Bioenergy Sorghum Residue Return on Soil Organic Carbon and Greenhouse Gas Emissions Using the DAYCENT Model. In: D. Field et al. (eds.) Global Soil Security, Progress in Soil Science. Springer International Publishing, Switzerland. doi: 10.1007/978-3-319-43394-3_15 (In Press).
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Storlien, J.O., Hons, F.M., and Lewis, K.L. 2016. Nitrification inhibitor impacts on soil trace gas emissions and nitrogen cycling. Abstract, 2016 Meeting of ASA, Phoenix, AZ.
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Wang, Y., Dou, F., and Hons, F.M. 2016. Life cycle analysis of net greenhouse gas emissions under different tillage practices in bioenergy sorghum production. Abstract, 2016 Meeting of ASA, Phoenix, AZ.
• Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Wang, Y., Dou, F., and Hons, F.M. 2016. Net greenhouse gas emissions in major crops in Texas. Abstract, 2016 Meeting of ASA, Phoenix, AZ.

Progress 02/01/15 to 01/31/16

Outputs
Target Audience:Soil and carbon sequestration scientists; sorghum and bioenergy crop producers; environmental scientists; agronomists; bioenergy and climate change scientsists and policy makers; Efforts: scientific and producer conferences, formal presentations, publications. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provided training support for an assistant research scientist and graduate andundergraduate students durinig the reporting period. These opportunities enhanced their knowledge and appreciation of field and lab methodologies associated with soil and plant research, especially as related to soil carbon sequestration, nutrient cycling, soil quality assessment, and sustainability. Modeling of results created additional learning opportunities. How have the results been disseminated to communities of interest?Results have been disseminated via publication in scientific journals, abstracts, and presentations at scientific and project directors' meetings and individual discussions with researchers and producers. What do you plan to do during the next reporting period to accomplish the goals?We will continue to conduct the prescribed research and will place increasing emphasis on determining the contribution of biomass sorghum to soil organic carbon as determined by 13C analyes.Emphasis will be continued for simulation modeling of biomass yields, soil carbon sequestration, and greenhouse gas emissions.

Impacts
What was accomplished under these goals? Bioenergy sorghum has the potential to be a very important cellulosic feedstock if it can be produced without degrading soil quality. Two important factors for achieving that goal are N management and the amount of residue (i.e. carbon) returned to the soil. This study evaluated two N rates (0 or 280 kg ha−1 yr−1) and three levels of residue return (0, 25%, or 50%) on Weswood silty clay loam near College Station, TX USA. Biomass sorghum was grown continuously from 2009 through 2014. Maximum dry biomass yield (23 Mg ha−1) was produced with added N and 25% residue return in a year with above average precipitation. Overall, N fertilization increased biomass yield by 43 to 104%, while residue return enhanced yield from < 1 to 23% during the six years of thestudy. Averaged for the six years, biomass production for the 0, 25%, and 50% residue return treatments was 16, 20, and 18 Mg ha−1, respectively. Returning 25% of the crop residue significantly increased K uptake in all years. Sorghum fertilizer N uptake efficiency (FNUE) with residue return by 2014 was significantly increased compared to 2009 values, indicating decreased amounts of residual available nitrogen over time. Non-limiting N fertilization and 25% residue return significantly increased NO3-N, P, K, and soil organic C (SOC) concentrations in surface (0 to 5 cm) samples and soil total N (TN) and K concentrations within the 60 to 90 cm layer.Resultsindicate that N fertilization will be required to achieve high biomass sorghum yield and suggests that developing a harvest strategy to return 25% of the crop residuemay be sufficient to maintain soil quality.

Publications

• Type: Journal Articles Status: Published Year Published: 2015 Citation: Shahandeh, H., Hons, F.M., Wight, J.P. and Storlien, J.O. 2015. Harvest strategy and N fertilizer effects on bioenergy sorghum production. AIMS Energy 3:377-400. doi: 10.3934/energy.2015.3.377
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Hons, F., Shahandeh, H., Mjelde, J., Dou, F., Osuji, G. and Storlein, J. 2015. Impacts of biomass sorghum production on carbon sequestration and greenhouse gas emissions in the south central region. Abstract, 2015 USDA-NIFA Bioenergy Project Directors Meeting, Denver, CO.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wang, Y., Dou, F. and Hons, F.M. 2015. Simulating impacts of bioenergy sorghum residue return on aboveground biomass carbon, soil organic carbon, and greenhouse gas emissions. Abstract, 2015 SSSA Soil Security Symposium, College Station, TX.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wang, Y., Dou, F., Paustian, K., Del Grosso, S. and Hons, F. 2015. Daycent simulations to test the influence of nitrogen fertilization in bioenergy sorghum production. Abstract, 2015 Meeting of ASA, Minneapolis, MN.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wang, Y., Dou, F., Storlien, J.O., Wight, J.P., Paustian, K., Del Grosso, S.J. and Hons, F.M. 2015. Simulating impacts of bioenergy sorghum residue return on soil organic carbon and greenhouse gas emissions using the Daycent model. Abstract, 2015 Meeting of ASA, Minneapolis, MN.
• Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Storlien, J.O., Hons, F.M., Shahandeh, H. and Wight, J.P. 2015. Soil organic carbon influenced by bioenergy sorghum cropping systems. Abstract, 2015 Meeting of ASA, Minneapolis, MN.

Progress 02/01/14 to 01/31/15

Outputs
Target Audience: Sorghum and bioenergy crop producers; soil and carbon sequestration scientists; agronomists; environmental scientists; bioenergy and climate change scientists and policy makers; Efforts: scientific and producer conferences, formal presentations, publications. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has provided training and support for an assistant research scientist, undergraduate students, and a post-doctoral research associate associated with the research. These opportunities enhanced their knowledge and appreciation of field and lab methodologies associated with plant and soil research, especially as related to carbon sequestration, nutrient cycling, soil quality assessment, and sustainability. Measurement and calculation of greenhouse gas emissions and life cycle analyses have also been significant learning opportunities. How have the results been disseminated to communities of interest? Results have been disseminated through publications in scientific journals, abstracts and presentations at scientific and project directors' meetings, and individual discussions with scientists and producers. What do you plan to do during the next reporting period to accomplish the goals? We will continue to conduct the prescribed research, and will place increasing emphasis on simulation modeling of biomass yields, soil carbon sequestration, and greenhouse gas emissions.

Impacts
What was accomplished under these goals? Crop management inputs must be both environmentally and economically sustainable.Rotation very significantly increased bioenergy sorghum yields in past years and is a practice that likely will have to be used to maintain crop yields. Nitrogen fertilization continued to increase biomass yields, tissue nitrogen concentrations, and total carbon photosynthetically fixed by sorghum, but also increased greenhouse gas emissions of carbon dioxide and nitrous oxide. Nitrogen fertilizer increased biomass yield of continuous sorghum by as much as 143%, while increasing the grain yield of corn rotated with sorghum by as much as 500%. Returning a portion of the biomass produced by continuous sorghum in previous years did not affect biomass yield in 2014 where no nitrogen fertilizer was added, but 25% return resulted in significantly greater yield compared with the no return control where nitrogen was applied (16% increase). Soil carbon sequestration under biomass sorghum has been high compared to results for most crops, being as high as 3 Mg C/ha/year to a meter depth, which has offset greenhouse gas emissions and other carbon inputs and resulted in a favorable life cycle analysis for biomass sorghum for carbon. Most of the accrued carbon is associated with biomass sorghum roots since return of differentamounts of aboveground biomass sorghum has not altered soil organic carbon. High biomass yields remove significant quantities of nutrients, especially nitrogen, phosphorus, and potassium, and soil nutrient availabilty over time continues to be monitored as to long-term productivity and sustainability. Research also showed that nitrification inhibitors can be used to decrease nitrous oxide emissions from added urea fertilizer in bioenergy cropping systems, but ammonia losses were enhanced.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Amatya, P., J.P. Wight, J.W. Mjelde, and F.M. Hons. 2014. Sustainable bioenergy sorghum [Sorghum bicolor (L). Moench.]production for biofuel and its net-returns. Bioenergy Research 7:1144-1154.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Storlien, J.O., F.M. Hons, J.P. Wight, and J.L. Heilman. 2014. Carbon dioxide and nitrous oxide emissions impacted by bioenergy sorghum management. Soil Sci. Soc. Am. J. 78:1694-1706.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Dou, F., F.M. Hons, A.L. Wright, T.W. Boutton, and X.Yu. 2014. Soil carbon sequestration in sorghum cropping systems: Evidence from stable isotopes and aggregate-size fractionation. Soil Sci. 179:68-74.
• Type: Journal Articles Status: Published Year Published: 2015 Citation: Dou, F., J.P. Wight, L.T. Wilson, J.O. Storlien, and F.M. Hons. 2014. Simulation of biomass yield and soil organic carbon under bioenergy sorghum production. PLOS ONE 9(12): e115598 doi:10.1371/journal.pone.0115598.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Wight, J.P., F.M. Hons, and G.O. Osuji. 2014. Responses of bioenergy sorghum cell wall metabolism to agronomic practices. Advances in Biological Chemistry 4:67-78.?
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Wight, J., F. Hons, J. Storlien, F. Dou, and H. Shahandeh. Management, productivity, and nutrient relationships in biomass sorghum systems. Abstract, 2014 Meeting of USDA NIFA Bioenergy Project Directors, Washington, DC.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Graham, P.T., J.P. Wight, L. Hoffmann, Jr., J.L. Foster, C. Masiello, W.L. Rooney, and F.M. Hons. Cell wall characterization methods for use in bioenergy cropping systems. Abstract, 2014 Meeting of ASA, Long Beach, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Haegelin, B., J.O. Storlien, F.M. Hons, and K.L. Lewis. Greehouse gas fluxes as affected by urea fertilizer, nitrification inhibitor, and biomass sorghum residue application to soil. Abstract, 2014 Meeting of ASA, Long Beach, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Wight, J.P., F.M. Hons, J.O. Storlien, F. Dou, and H. Shahandeh. Soil carbon and macronutrient changes following four years of bioenergy sorghum production. Abstract, 2014 Meeting of ASA, Long Beach, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Dou, F., J.O. Storlien, Y. Wang, J.P. Wight, and F.M. Hons. Simulating the effects of residue removal and nitrogen application on nitrous oxide and carbon dioxide emissions in biomass sorghum production. Abstract, 2014 Meeting of ASA, Long Beach, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Storlien, J.O., F.M. Hons, F. Dou, and J.P. Wight. Agronomic management impacts on carbon dioxide and nitrous oxide emissions over four years of bioenergy sorghum production. Abstract, 2014 Meeting of ASA, Long Beach, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Wight, J., F. Hons, J. Storlien, J. Mjelde, F. Dou, and G.O. Osuji. Impacts of biomass sorghum feedstock production on carbon sequestration and greenhouse gas emissions in the south central region. Abstract, 2014 Meeting of USDA NIFA Bioenergy Project Directors, Washington, DC.

Progress 02/01/13 to 01/31/14

Outputs
Target Audience: Sorghum and bioenergy crop producers; soil and carbon sequestration scientists; agronomists; environmental scientists; bioenergy and climate change scientists and policy makers. Efforts: Scientific and producer conferences, formal presentations, publications. Changes/Problems: Glyphosate herbicide drift from a source extraneous to thestudy in June significantly affected results. Biomass yields were decreased due to the injury. Yields of rotated sorghum were reduced more than continuous sorghum due to the pattern of the drift, resulting in the first time that rotated sorghum yields were not greater than continuous. Efforts have been made to help prevent such injury in the future. What opportunities for training and professional development has the project provided? The project has provided training and professional development opportunities for an assistant research scientist, graduate and undergraduate students, and a post-doctoral research associateassociated with the research. These opportunities have enhanced their knowlege and appreciation of field and laboratory scientific methodologies associated with soil and plant research, especially regarding carbon sequestration, nutrient cycling, and soil quality assessment. Measurement and calculation of greenhouse gas emissions and life cycle analyes have also been key development opportunities. How have the results been disseminated to communities of interest? Results have been disseminated through publications in scientific journals, abstracts and presentations at scientific meetings, and dicussions with individual scientists and producers. What do you plan to do during the next reporting period to accomplish the goals? We will continue to conduct the prescibed field and laboratory research to address the objectives of this project. Additional emphasis will also be placed on simulation modeling and economic analysis of the system.

Impacts
What was accomplished under these goals? Crop management inputs and practices must be sustainable both environmentally and economically. Rotation very significantly increased yields of bioenergy sorghum in past years and is a practice that likely will have to be used in order to maintain production levels of this bioenergy crop. In 2013, however, rotation did not increase yield, likely due to glyphosphate herbicide drift that more negatively impacted the rotated sorghum section of thestudy.Nitrogen fertilization continued to increase yields, sorghum tissue nitrogen concentrations, total carbon photosynthetically fixed by sorghum, and residual soil nitrate, but also resulted in increased greenhouse gas emissions of carbon dioxide and nitrous oxide.Monoculture biomass sorghum continued to increase soil organic carbon sequestration compared to rotated sorghum. Soil carbon sequestration by biomass sorghum has been relatively high compared with available information for other crop species, and is imporatnt for offsetting greenhouse gas emissions.High biomass production removes significant quantities of nutrients, especially nitrogen and potassium, and soil nutrient and quality changes over time will also be important considerations as to sustainability. All treatments reduced plant-available soil concentrationsof phosphorus and potassium compared to original levels, and the continuous sorghum treatment exhibited lower plant-available soil concentrations of potassium compared with rotated sorghum.Sorghum biomass quality was assessed via peroxidase enzyme analysis and indicated that mangement practices do influence enzyme activity and associated yields of cellulose and lignin. Life cycle analyseswere conducted to determine ultimate effects on sustainability, and showed that bioenergy sorghum can be sustainably produced, especially as related to carbon.

Publications

• Type: Journal Articles Status: Published Year Published: 2013 Citation: Dou, F., F.M. Hons, W.R. Ocumpaugh, J.C. Read, M.A. Hussey, and J.P. Muir . 2013. Soil organic carbon pools under switchgrass grown as a bioenergy crop compared to other conventional crops. Pedosphere 23:409-416.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Storlien, J., F. Hons, J. Wight, F. Dou, and T. Gentry. Changes in soil organic carbon following five years of bioenergy sorghum production. Abstract, 2013 Meeting of ASA, Tampa, FL.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Storlien, J., F. Hons, J. Wight, F. Dou, and T. Gentry, and J. Heilman. Assessment of life cycle greenhouse gas emissions from bioenergy sorghum production in central Texas. Abstract, 2013 Meeting of ASA, Tampa, FL.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Wight, J., F. Hons, J. Storlien, F. Dou, and H. Shahandeh. Management, productivity, and nutrient relationships in biomass sorghum systems. Abstract, 2013 Meeting of ASA, Tampa, FL.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Dou, F., J. Storlien, F. Hons, and J. Wight. Residue removal, nitrogen application, and crop rotation effects on soil organic carbon and nitrogen in biomass sorghum production: an application of the DNDC model. Abstract, 2013 Meeting of ASA, Tampa, FL.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Storlien, J., F. Hons, J. Wight, F. Dou, and T. Gentry, and J. Heilman. Assessment of life cycle greenhouse gas emissions from bioenergy sorghum production in central Texas. Abstract, 2013 Meeting of AAIC, Washington, DC.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: J.O. Storlien and F.M. Hons. A review of soil trace gas quantification methodologies: focus on modern mobile FTIR applications in sustainable agricultural research. 2013. US Dairy Forage Research Center, USDA-ARS, Madison, WI.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Wight, J., F. Hons, J. Storlien, F. Dou, and H. Shahandeh. Management, productivity, and nutrient relationships in biomass sorghum systems. Abstract, 2013 Meeting of AAIC, Washington, DC.
• Type: Theses/Dissertations Status: Published Year Published: 2013 Citation: Storlien, J.O. The carbon footprint of bioenergy sorghum production in central Texas: production implications on greenhouse gas emissions, carbon cycling, and life cycle analysis. PhD Dissertation. Texas A&M University
• Type: Theses/Dissertations Status: Published Year Published: 2013 Citation: Amatya, P. Sustainable bioenergy sorghum [Sorghum bicolor (L). Moench.] production for biofuel and its net-returns. MS Thesis. Texas A&M University.

Progress 02/01/12 to 01/31/13

Outputs
OUTPUTS: Soil is the fundamental resource in agricultural systems and maintaining soil quality is key to ensuring sustainable production. Productivity and soil quality may be affected by cropping sequence complexity, fertilization, and residue removal. The goal of this research was to optimize the efficiency of crop management and soil and environmental quality in high biomass (bioenergy) sorghum systems. This field study, utilizing fourteen management treatments, took place near College Station in southcentral Texas. The study utilized a complete factorial design with four replications of the following factors: Rotation: continuous biomass sorghum vs. biannual rotation with corn; Biomass Return: 0, 25, or 50% of the sorghum biomass and all corn stover; and N Rate: 0 vs. non-limiting N. The bioenergy sorghum used was a high-yield photoperiod-sensitive hybrid. All other inputs and practices were those commonly used. Sorghum was harvested for yield and total concentrations of C, N, P, K, and other selected nutrients were determined. Soil samples were taken at the beginning of the study, with additional samples being collected annually. Samples were analyzed for soil quality parameters including total organic (SOC) and inorganic carbon and nitrogen (TN), residual nitrate and other extractable nutrients. The winter and spring of 2012 were much wetter than normal, but the summer and fall have been very dry. Rotation was the dominant factor, significantly influencing (p < 0.05) sorghum yield, uptake of carbon, nitrogen, phosphorus and potassium, and extractable soil nitrate, phosphorus, potassium and SOC and TN. Nitrogen fertilization also affected (p < 0.001) yield, sorghum tissue nitrogen, and soil nitrate. Nitrogen fertilization increased biomass yield by 53%. A linear regression was developed that related biomass yield to rotation, nitrogen rate, soil TN, and extractable phosphorus and explained 75% of the yield variation. Residue return did not affect sorghum yield, SOC, or TN. Soil under continuous biomass sorghum sequestered more soil organic carbon compared with rotated sorghum. Continuous sorghum increased (p<0.001) SOC and TN to 1-m depth, while nitrogen addition increased TN at 0-20 cm. All treatments reduced extractable soil phosphorus and potassium compared to original levels, and the continuous sorghum treatment had less extractable soil potassium than rotated. Greenhouse gas emissions (carbon dioxide and nitrous oxide) were increased by nitrogen addition and biomass return. Continuous sorghum and biomass return significantly increased soil microbial biomass. A life cycle analysis for carbon is being conducted. PARTICIPANTS: Individuals: Frank Hons, Professor and Co-Principal Investigator; Jason Wight, Assistant Research Scientist and Co-Principal Investigator; Fugen Dou, Assistant Professor and Co-Principal Investigator; Terry Gentry, Assistant Professor and Co-Principal Investigator; Godson Osuji, Associate Professor and Co-Principal Investigator; James Mjelde, Professor and Co-Principal Investigator. TARGET AUDIENCES: Sorghum and bioenergy crop producers; soil and carbon sequestration scientists; agronomists; environmental scientists; bioenergy and climate change scientists and policy makers; sustainability scientists; life cycle analysis modelers. Efforts: Conferences, formal presentations, publications. PROJECT MODIFICATIONS: Nothing significant to report during the current reporting period.

Impacts
Crop management inputs and practices must be sustainable both environmentally and economically. Rotation very significantly increased yields of bioenergy sorghum and is a practice that likely will have to be used in order to maintain production levels of this bioenergy crop. Nitrogen fertilization increased yields, but also resulted in increased greenhouse gas emissions. Continuous biomass sorghum increased soil organic carbon sequestration compared to rotated sorghum, but biomass yields are decreased in continuous compared to rotated sorghum. High biomass production removes significant quantities of nutrients, especially nitrogen and potassium, and soil nutrient and quality changes over time will also be important considerations as to sustainability. Life cycle analyses are being conducted to determine ultimate effects on sustainability.

Publications

• Wight, J.P., Hons, F.M., Storlien, J.O., Provin, T.L., Shahandeh, H. and Wiedenfeld, R.P.. 2012. Management effects on bioenergy sorghum growth, yield, and nutrient uptake. Biomass and Bioenergy 46:593-604.
• Wight, J.P., Hons, F.M., South, S.M., and Osuji, G.O. 2012. Free solution isoelectric focusing purification of active peroxidase isoenzymes of biomass sorghum and kinetic properties. American J. Plant Sci. 3:1422-1429.
• Barrera, C., Storlien, J. and Hons, F. 2012. Effect of agronomic management practices on soil microbial biomass C and N under bioenergy sorghum production. Abstract, 2012 Meeting of ASA, Cincinnati, OH.
• Storlien, J., Hons, F., Wight, J., Heilman, J., Gentry, T. and Dou, F. 2012. Impacts of biomass feedstock production on carbon sequestration and greenhouse gas emissions in the south central region. Abstract, 2012 Meeting of ASA, Cincinnati, OH.
• Storlien, J., Hons, F.,Heilman, J., Wight, J. and Tokumoto, I. 2012. Emissions of carbon dioxide and nitrous oxide from bioenergy sorghum production under integrated agronomic management practices. Abstract, 2012 Meeting of ASA, Cincinnati, OH.
• Storlien, J., Hons, F., Wight, J., Heilman, J. and Gentry, T. 2012. Carbon pool dynamics within bioenergy sorghum production systems in central Texas. Abstract, 2012 Meeting of ASA, Cincinnati, OH.
• Dou, F., Storlien, J., Wight, J. and Hons, F. 2012. Assessing the potential effects of biomass sorghum production on soil C sequestration an GHG emissions. Abstract, 2012 Meeting of ASA, Cincinnati, OH.
• J. Wight, Hons, F., Storlien, J., Shahandeh, H., Dou, F. and Provin, T. 2012. Bioenergy sorghum management affects yield, nutrient uptake, and soil quality. Abstract, 2012 Meeting of ASA, Cincinnati, OH.

Progress 02/01/11 to 01/31/12

Outputs
OUTPUTS: Soil is the fundamental resource in agricultural systems and maintaining soil quality is key to ensuring sustainable production. Productivity and soil quality may be affected by cropping sequence complexity, fertilization, and residue removal. The goal of this research was to optimize the efficiency of crop management and soil and environmental quality in high biomass (bioenergy) sorghum systems. This field study, utilizing fourteen management treatments, took place near College Station in southcentral Texas. The study utilized a complete factorial design with four replications of the following factors: Rotation: continuous biomass sorghum vs. biannual rotation with corn; Biomass Return: 0, 25, or 50% of the sorghum biomass and all corn stover; and N Rate: 0 vs. non-limiting N. The bioenergy sorghum used was a high-yield photoperiod-sensitive hybrid. All other inputs and practices were those commonly used. Sorghum was harvested for yield and total concentrations of C, N, P, K, and other selected nutrients were determined. Soil samples were taken at the beginning of the study, with additional samples being collected annually. Samples were analyzed for soil quality parameters including total organic and inorganic carbon and nitrogen, residual nitrate and other available nutrients. Rotation, fertilization, and residue return affected yields, plant growth, and soil quality (p <0.05). Biomass sorghum rotated biannually with corn yielded 29% more biomass than continuous sorghum. Nitrogen addition increased sorghum biomass yield 35% compared to the no nitrogen control in 2011. Returning 25% of the sorghum biomass produced to soil increased yield by 18% compared to no return, while 50% return increased yield by 9%. Rotation increased biomass concentrations of carbon, nitrogen, and calcium, while decreasing those of phosphorus, potassium, magnesium, manganese, zinc, iron, and copper. Nitrogen application increased biomass nitrogen, magnesium and copper concentration, but decreased phosphorus, calcium, and manganese. Residue return did not affect biomass elemental concentrations. Chlorophlyy meter readings correlated with nitrogen application. Soil under continuous biomass sorghum sequestered more soil organic carbon compared with rotated sorghum. Greenhouse gas emissions (carbon dioxide and nitrous oxide) were increased by nitrogen addition and biomass return. Peroxidases in sorghum biomass were extracted, purified and separated into 14 groups. Nitrogen application and rotation resulted in different enzyme groups compared to continuous sorghum or sorghum without nitrogen addition. PARTICIPANTS: Individuals: Frank Hons, Professor and Co-Principal Investigator; Jason Wight, Assistant Research Scientist and Co-Principal Investigator; Fugen Dou, Assistant Professor and Co-Principal Investigator; Terry Gentry, Assistant Professor and Co-Principal Investigator; Godson Osuji, Associate Professor and Co-Principal Investigator; James Mjelde, Professor and Co-Principal Investigator TARGET AUDIENCES: Sorghum and bioenergy crop producers; soil and carbon sequestration scientists; agronomists; environmental scientists; bioenergy and climate change scientists and policy makers. Efforts: Conferences, formal presentations, publications. PROJECT MODIFICATIONS: Nothing significant to report during the current reporting period.

Impacts
Crop management inputs and practices mest be sustainable both environmentally and economically. Rotation very significantly increased yields of bioenergy sorghum and is a practice that likely will have to be used in order to maintain production levels of this bioenergy crop. Nitrogen fertilization increased yields, but also resulted in increased greenhouse gas emissions. Life cycle analyses are being initiated to determine ultimate effects on sustainability. Continuous biomass sorghum increased soil organic carbon sequestration compared to rotated sorghum. High biomass production removes significant quantities of nutrients, especially nitrogen and potassium, and soil nutrient and quality changes over time will also be important considerations as to sustainability.

Publications

• J.P. Wight, F.M. Hons, T.L. Provin, H. Shahandeh, and J.O. Storlien. Management effects on yield, nutrient uptake, and soil quality in bioenergy sorghum production. Abstracts, 2011 Meeting of ASA, San Antonio, TX.
• Dou, F., J.P. Wight, and F.M. Hons. Early effects of bioenergy sorghum production on greenhouse gases and carbon sequestration. Abstracts, 2011 Meeting of ASA, San Antonio, TX.
• Storlien, J., F. Hons, J. Heilman, J. Wight, and I. Tokumoto. Effects of specific integrated practices on greenhouse gas fluxes from bioenergy sorghum production in central Texas. Abstracts, 2011 Meeting of ASA, San Antonio, TX.
• J.P. Wight, F.M. Hons, T.L. Provin, H. Shahandeh, and J.O. Storlien. Management effects on yield, nutrient uptake, and soil quality in bioenergy sorghum production. Abstracts, 2011 Meeting of TPPA, College Station, TX.
• Storlien, J., F. Hons, J. Heilman, J. Wight, and I. Tokumoto. Effects of specific integrated practices on greenhouse gas fluxes from bioenergy sorghum production in central Texas. Abstracts, 2011 Meeting of TPPA, College Station, TX.