Effect of protein supplementation of low-quality forage diets on enteric methane production of beef steers


Purpose: 

Cattle are a significant source of agricultural greenhouse gas (GHG) emissions; with enteric methane being the major GHG produced under most management systems.  Decreasing enteric methane production of grazing cattle presents the greatest opportunity to reduce beef cattle GHG emissions because 1) enteric methane release is greater on forage-based than concentrate-based diets; 2) cattle fed high-fiber diets have lower rates of gain and thus require more time to reach market weight than cattle fed concentrate-based diets and 3) the vast majority of feed used to produce beef from conception to plate is forage-based.  Throughout the world cattle frequently graze low-quality forages that are deficient in protein.  While research has studied the effects of protein supplementation of low-quality forages on weight gain, feed intake and digestibility, effects on GHG emissions are lacking.  Therefore, the objective of this study was to identify the effects of protein supplementation to low-quality forage diets on GHG emissions.

What did we do? 

Twenty-three British-cross steers were utilized in a three-period crossover design.  Steers were provided ad libitum access to a low quality grass hay (4.9% crude protein) and assigned to one of three supplemental treatments: 1) no supplement (control), 2) cottonseed meal (CSM 0.29% of body weight), or ) dried distillers grain (DDGS 0.41% of body weight).  Supplemental protein intake was similar for the CSM and DDGS treatments.  Enteric CH4 and metabolic CO2 emissions were measured using a GreenFeed system (C-Lock Inc., Rapid City, SD).  Steers were offered supplement at 0800h each day in Calan headgates and hay was delivered after steers had consumed the supplement.  Data were analyzed using a mixed model (SAS,2013).   

What did we learn?

Supplementation with CSM or DDGS increased hay intake (P < 0.01) by an average of 53% compared to control.  Supplementation also increased (P < 0.01) total CO2 and total CH4 emissions compared to control, but no difference was noted between CSM and DDGS.  The increases in total production of CO2 and CH4 are attributed to the large increase in hay intake.  However, supplementing with CSM or DDGS decreased (P < 0.05) methane loss as a proportion of gross energy (GE) intake, compared to control steers.  Steers supplemented with DDGS tended (P < 0.10) to have a lower methane loss as a percentage of GE intake (Ym) than steers supplemented with CSM; probably because of the higher fat intake in cattle fed the DDGS.  Collectively, these data suggest that protein supplementation decreases the carbon footprint of beef cattle by decreasing methane emissions per unit of energy intake and per unit of production. 

Table 1. Effect of protein supplementation on greenhouse gas emissions and energy losses of steers

Future Plans

Additional studies will attempt to further define the effects of supplement composition and intake level on GHG emissions.

Authors

N. Andy Cole, Supervisory Research Animal Scientist and Lab Director, USDA-ARS-Conservation & Production Research Laboratory, Bushland, TX  Andy.cole@ars.usda.gov

Adam Shreck, ORISE Fellow sponsored by USDA-ARS-CPRL, Bushland, TX;

Jenny Jennings, Animal Nutritionist, Texas A&M AgriLife Research; Amarillo;

Richard Todd, Research Soil Scientist, USDA-ARS-CPRL, Bushland, TX.

Additional Information  

For more information contact Andy Cole, 806-356-5748

Acknowledgements

This research was partially funded by a USDA-NIFA-CAP Grant titled “Resilience and vulnerability of beef cattle production in the Southern Great Plains under changing climate, land use and markets”.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Effect of Temperature on Methane Production from Field-Scale Anaerobic Digesters Treating Dairy Manure

Why Study Temperature and Anaerobic Digestions?

Anaerobic digestion is a process that results in the production of biogas that can be used a renewable source of electricity on-farm or sold to the distribution grid. Temperature is a critical parameter for anaerobic digestion since it influences both system heat requirements and methane production. Although anaerobic digestion can take place under psychrophilic (15-25°C), mesophilic (35-40°C), and thermophilic (50-60°C) conditions, temperatures of 35-37°C are typically recommended for methane production from animal manure. However, digesters require significant amount of heat energy to maintain temperatures at these levels. There is limited information about methane production from dairy digesters at temperatures less than 35°C and results in the literature are presented from laboratory-scale rather than field-scale systems.

The objective of this study was to evaluate the effect of two relatively low digestion temperatures (22 and 28°C) on methane production using replicate continuously-fed, field-scale dairy manure digesters at two organic loading rates. The results were compared with those from identical digesters operated at 35°C.

field scale anaerobic digesters

Field scale (FS) anaerobic digesters

What did we do?

Anaerobic digestion experiments were carried out using six modified Taiwanese-model field-scale (FS) on-site digesters (Fig. 1) at the USDA Beltsville Agricultural Research Center (BARC). Each FS digester has a total capacity of 3 m3 and was operated at a liquid capacity of 67% (2 m3 working volume) with 33% headspace for biogas collection. The FS digesters are plug-flow reactors and operated without mixing. First, duplicate field-scale (FS) anaerobic digesters were maintained at one of three set temperatures (22 ± 2, 28 ± 2 and 35 ± 2°C) and fed with solids-separated manure for 80 days (period 1). The digesters were subsequently operated under the same temperature regime (22 ± 2, 28 ± 2 and 35 ± 2°C) but were fed at a higher organic loading rate (OLR) using solids-separated manure amended with manure solids for 56 days (period 2). The hydraulic retention time (HRT) was 17 days for all digesters throughout the study. Digesters were fed once daily five days a week with 160 L d-1 of separated manure for period 1, and 148 L d-1 of separated manure amended with 16 kg d-1 (wet weight) manure solids (roughly 12 L in volume) for the period 2.

What have we learned?

Our results suggest that anaerobic digesters treating dairy manure at lower temperatures can be nearly as effective as digesters operated at 35°C, even with a relatively short 17-day retention time. Methane production from digesters operated at 28°C was about 90% of that from digesters operated at 35°C but the differences were not statistically significant. Digesters operated at 22°C produced about 70% as much methane as digesters operated at 35°C without affecting digester stability. Small farm digester systems that may not have access to waste heat from electrical generation, could efficiently operate at these lower temperatures to produce methane and reduce greenhouse gas emissions and odors. Larger digester systems could also choose to operate at these lower temperatures if reducing digester heating would allow for more valuable uses of their heat energy such as drying solids or treating liquids to remove nutrients.

Future Plans 

We are currently investigating the fate and effect of antibiotics and feed additives during the anaerobic digestion of manure.

Authors     

Osman Arikan, Assoc. Prof., Istanbul Technical Univ., Dept. of Environmental Eng., Istanbul, Turkey. Visiting Scientist, USDA-ARS, BARC, Beltsville, MD, Visiting Assoc. Prof., University of Maryland, Dept. of Environmental Science&Tech., College Park, MD. arikan@itu.edu.tr

Walter Mulbry, Research Microbiologist, USDA-ARS, Beltsville Agricultural Research Center, Beltsville, MD. Stephanie Lansing, Assistant Professor, University of Maryland, Department of Environmental Science and Technology, College Park, MD.

Additional information

Data is to be published.

Acknowledgements

The authors gratefully acknowledge Jose Colina and Lorianny Rivera for assistance in operating the digesters and Anna Kulow for analyzing biogas and effluent samples.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Feasible Small-Scale Anaerobic Digestion – Case Study of EUCOlino Digestion System.

 

* Presentation slides are available at the bottom of the page.

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Abstract

While large-scale farms have typically been the focus of anaerobic digestion systems in the U.S., an emerging need has been identified to serve smaller farms with between 50 and 500 head of cattle. Implementing such a small, standardized, all-in-one system for these small farm applications has been developed. Small-scale digesters open the playing field for on-farm sustainability and waste management.

Unloading the first biodigester unit.

This presentation on small-scale digestion would discuss the inputs, processing, function, and outputs of BIOFerm™ Energy Systems’ small agitated plug flow digester (EUCOlino). This plug-and-play digester system has the ability to operate on dairy manure, bedding material, food waste, or other organic feedstocks with a combined total solids content of 15-20%. A case study would be presented that describes the site components needed, the feedstock amount and energy production, as well as biogas end use. Additional details would include farm logistics, potential sources of funding, installation, operation, and overall impact of the project.

This type of presentation would fill an information gap BIOFerm™ has discovered among dairy farmers who believe anaerobic digestion isn’t feasible on a smaller scale. It would provide farmers who attend with an understanding of the technology, how it could work on their specific farm and hopefully reveal to them what their “waste is worth”.

Why Study Small-Scale Anaerobic Digestion

To inform and educate attendees about small-scale anaerobic digestion surrounding the installation and feasibility of the containerized, paddle-mixed plug flow EUCOlino system on a small dairy farm <150 head.

Biodigester unit being installed at Allen Farms.

What Did We Do?

Steps taken to assist in financing the digestion system include receiving grants from the State Energy Office and Wisconsin Focus on Energy. Digester installation includes components such as feed hopper, two fermenter containers, motors, combined heat and power unit, electrical services, etc…

What Have We Learned?

Challenges associated with small project implementation regarding coordination, interconnection, and utility arrangements.

Future Plans

Finalize commissioning phases and optimize operation.

Authors

Amber Blythe, Application Engineer, BIOFerm™ Energy Systems blya@biofermenergy.com

Steven Sell, Biologist/Application Engineer, BIOFerm™ Energy Systems

Gabriella Huerta, Marketing Specialist, BIOFerm™ Energy Systems

Additional Information

Readers interested in this topic can visit www.biofermenergy.com and for more information on our plants, services and project updates please visit us on our website at www.biofermenergy.com. You will also see frequent updates from us in industry magazines (BioCycle, REW Magazine, Waste Age). BIOFerm will also be present at every major industry conference or tradeshow including the Waste Expo, Waste-to-Worth and BioCycle– stop by our booth and speak with one of our highly trained engineers for further information.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Direct Measurements of Methane Emissions from a Dairy Lagoon in Northeast Colorado

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Abstract

Methane (CH4) emissions from cattle feedlots and dairies could represent a large component of agriculture’s greenhouse gas (GHG) inventory.  A significant source of CH4 is anaerobic lagoons used to store and process manure slurries.  Understanding these systems is a crucial step in quantifying the carbon budgets of livestock operations.  New open-path CH4 analyzers provide a method for measuring CH4 emissions from waste lagoons on a near continuous basis.  The resulting data will help to better quantify GHG emissions related to beef and milk production. At a commercial dairy in northeastern Colorado during 2011 – 2012, emissions of CH4 were measured at the on-site waste lagoon (3.1-ha) using a micrometeorological measurement technique called eddy covariance (EC). The only method to directly measure fluxes of energy and trace gases at the field-scale, EC is widely utilized around the globe to quantify carbon and water budgets for a variety of ecosystems and landscapes. Methane fluxes peaked around 7 mol m^-2 d^-1 in mid- to late-summer 2012, with much variability from Jul – Oct (5 +/- 1.4 mol m^-2 d^-1). Yearly carbon budgets for the release of methane from the lagoon will be examined as well.

Authors

Kira Shonkwiler, Colorado State University, Dept of Atmospheric Science              kshonk@atmos.colostate.edu

Dr. Jay Ham, Colorado State University, Dept of Soil and Crop Sciences, Christina Williams, Colorado State University, Dept of Soil and Crop Sciences

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Greenhouse Gas Emissions from a Typical Cow-Calf Operation in Florida, USA

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Purpose

The purpose of this study was to investigate greenhouse gas (GHG) emission sources in a typical cow-calf operation in Florida and to calculate its total carbon footprint. The most important greenhouse gas source found was enteric fermentation, hence further investigation of this factor is being developed with field trials.

Why Study the Carbon Footprint of Cow-Calf Systems?

We estimated the carbon footprint of the cow-calf operation held in Buck Island Ranch, with data from 1998 to 2008. This production system has around 3000 cows and 250 bulls, has low fertilizer and lime inputs and feeding is pasture and hay based with some use of molasses and urea. Natural mating is used and calves are kept in the farm until 7 months old.  The Intergovernmental Panel on Climate Change (IPCC, 2006) methodology was used along with emission factors from USDA (EPA, 2009) to estimate emissions at different levels of complexity (Tier 1 being the least complex and Tier 3 the most), according to data availability, and transformed in carbon dioxide equivalent (CO2eq). A field trial to measure ruminal methane emissions was held at the North Florida Research and Education Center in Marianna, Florida, from June 26th to September 18th. The experiment treatments consisted of three stocking rates (1.2, 2.4 and 3.6 AU/ha, where one animal unit is 360) with four replicates each. The ruminal methane emissions were measured three times using the sulfur hexafluoride (SF6) tracer technique (Johnson et al., 1994). Experimental weight gain and average initial weight of each experimental unit were used to estimate emissions with the IPCC’s Tier 3 methodology.

Table 1. Sources of greenhouse gases in units of carbon dioxide equivalent (CO2eq). Data retrieved from Buck Island Ranch from 1998 to 2008.

Figure 2. Animal with SF6 sample collection apparatus. Marianna, Florida, August 2012.

What Have We Learned?

Results of the carbon footprint calculation are shown in Table 1. We can observe that enteric fermentation is responsible for almost 60% of total emissions in this production system, varying with feed quality, age of animal (since calves under 7 months age are not considered to produce any methane), and number of animals in the farm. It was also found that this model is most sensitive to variations in weight gain. The second most important source of GHG is manure with more than 23 of emissions. The yearly variation in emissions is a result of the use of nitrogen fertilization and lime or burning of the pasture. On average 477,936 kg of live weight are produced every year in the ranch, resulting in an average of 24.6 kg CO2eq/kg live weight that leaves the farm. Results from the field trials were compared with default values from IPCC’s Tier 1 methodology and USDA, and to IPCC’s Tier 3. We can see that on Period 2 the weight gain on the 2.4 AU/ha treatment was greater than on the 3.6 AU/ha (Figure 1). Since the model used is highly sensitive to weight gain, the prediction resulted in higher methane emissions from the 2.4 AU/ha treatment. The field measurements (Figure 2), however, showed more emissions in the 3.6 AU/ha treatment showing that other factors besides weight gain might play an important role on enteric fermentation methane emissions.

Future Plans

Our future plans include the use of field data to perform a prediction analysis with the model under study. Also, we plan to do in vitro gas production technique (IVGPT) to simulate ruminal fermentation and have a better understanding of emissions.

Authors

Marta Moura Kohmann, M.S. student, Agricultural and Biological Engineering Department, University of Florida. mkohmann@ufl.edu

Clyde W. Fraisse, PhD., Associate Professor, Agricultural and Biological Engineering Department, University of Florida.

Hilary Swain, PhD., Executive Director, Archbold Biological Station.

Martin Ruiz-Moreno, PhD, Post-doctoral, Animal Science Department, University of Florida

Lynn E. Sollenberger, PhD., Professor and Associate Chair, Agronomy Department, University of Florida

Nicolas DiLorenzo, PhD., Animal Science Department, University of Florida

Francine Messias Ciríaco, M.S. student, Animals Science Department, University of Florida

Darren D. Henry, M.S. student, Animals Science Department, University of Florida

Additional Information

The Carbon Footprint for Florida Beef Cattle Production Systems: A Case Study with Buck Island Ranch. Available in

<http://www.archbold-station.org/statiohttps://www.archbold-station.org/documents/agro/Kohmann,etal.-2011-FlaCattleman-carbonfootprint.pdfn/documents/publicationspdf/Kohmann,etal.-2011-FlaCattleman-carbonfootprint.pdf>

Acknowledgements

The author would like to thank Faculty and Staff at the North Florida Research and Education Center for the assistance during the field trial.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Inhibition Of Total Gas Production, Methane, Hydrogen Sulfide, And Sulfate-Reducing Bacteria From In Vitro Stored Swine Manure Using Condensed Tannins

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Abstract

Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use.  Odor produced during storage has increased the tension among rural neighbors and among urban and rural residents, and greenhouse gas emissions may contribute to climate change.  Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacterial populations present during storage.  We have been studying the bacterial populations of stored manure to develop methods to reduce bacterial metabolic activity and production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria.  Quebracho and other condensed tannins were tested for effects on total gas, hydrogen sulfide, and methane production and levels of sulfate-reducing bacteria in in vitro swine manure slurries.  Quebracho condensed tannins were found to be most effective of tannins tested, and total gas, hydrogen sulfide, and methane production were all inhibited by greater than 90% from in vitro manure slurries.  The inhibition was maintained for at least 28 days.  Total bacterial numbers in the manure were reduced significantly following addition of quebracho tannins, as were sulfate-reducing bacteria.  These results indicate that the condensed tannins are eliciting a collective effect on the bacterial population, and the addition of quebracho tannins to stored swine manure may reduce odorous and greenhouse gas emissions.

Why Would We Want to Inhibit Gas Production of Stored Manure?

Develop methods for reducing odor and emissions from stored swine manure.

What Did We Do?

Tested the effects of addition of condensed tannins to in vitro swine manure slurries on  production of total gas, hydrogen sulfide, methane, and on the levels of hydrogen sulfide-producing sulfate reducing bacteria.

What Have We Learned?

Addition of condensed tannins to in vitro swine manure slurries reduces production of total gas, with quebracho condensed tannins being the most effective.  0.5% w/v Quebracho condensed tannins reduced total gas, hydrogen sulfide, and methane by at least 90% over a minimum of 28 days.  Levels of sulfate reducing bacterial were also significantly reduced by addition of the tannns.  This technique should assist swine producers in lowering emission and odors from stored manure.

Future Plans

We are interested in scaling up the testing to on-farm sites and also testing the tannins for reducing foaming from manure storage pits.

Authors

Terence R. Whitehead, Research Microbiologist, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604, terry.whitehead@ars.usda.gov

Cheryl Spence, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604

Michael A. Cotta, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604

Additional Information

Whitehead, T.R., Spence, C., and Cotta, M.A.  Inhibition of Hydrogen Sulfide, Methane and Total Gas Production and Sulfate-Reducing Bacteria in In Vitro Swine Manure Slurries by Tannins, with Focus on Condensed Quebracho Tannins. (2012) Appl. Microbiol. Biotech. http://link.springer.com/article/10.1007/s00253-012-4562-6/fulltext.html

Development and Comparison of SYBR Green Quantitative Real-Time PCR Assays for Detection and Enumeration of Sulfate-Reducing Bacteria in Stored Swine Manure.  (2008) J. Appl. Microbiol. 105: 2143-2152.  http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2008.03900.x/pdf

USDA-ARS-NCAUR Bioenergy Research Unit Home Page: http://ars.usda.gov/main/site_main.htm?modecode=36-20-61-00

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Combination of Borax and Quebracho Condensed Tannins Treatment to Reduce Hydrogen Sulfide, Ammonia and Greenhouse Gas Emissions from Stored Swine Manure

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Abstract

Livestock producers are acutely aware for the need to reduce gaseous emissions from stored livestock waste and have been trying to identify new technologies to address the chronic problem.  Besides the malodor issue, toxic gases emitted from stored livestock manure, especially hydrogen sulfide (H2S) and ammonia (NH3) are environmental and health hazards for humans and animals and under scrutiny by the Environmental Protection Agency for regulatory control of concentrated animal farm operations (CAFOs). 

These odorous and toxic gases are produced by bacteria during the fermentation of the stored manure.  Sulfate reducing bacteria convert sulfate (SO4) to sulfide (H2S) during the fermentation.  During storage of swine manure, about 60% of NH3 nitrogen is also loss.  If NH3 loss can be prevented, the fertilizer value of swine manure would improve and reduce the need for additional commercial nitrogen fertilizer.

There are very few technologies available to reduce H2S, NH3 and greenhouse gas emissions from stored livestock manure, which meet the criteria of being: inexpensive, safe for farmers and animals, and environmentally sustainable. Previous research has shown that borax and quebracho condensed tannin are effective in inhibiting H2S production in stored swine manure. The present research demonstrates that a combination of borax and quebracho condensed tannin is highly effective in reducing all gaseous emissions (H2S, NH3, CO2, CO, N2O and CH4) and in retaining more nitrogen in swine manure. Lesser amounts of borax and quebracho condensed tannin are needed when combined to achieve a similar reduction in H2S production to using much larger amounts of either product alone. 

Phytotoxicity studies show that the level of tolerance of crops to borax-tannin combination treated swine manure is:  alfalfa > corn > wheat > soybean >> dry beans.  Quebracho condensed tannin does not appear to be toxic to crops.

Why Study Tannins?

Develop methods for reducing emissions from stored swine manure.

What Did We Do?

Tested the effects of addition of combinantions of borax and quebracho condensed tannins to swine manure slurries on  production of gaseous emissions and more retaining nitrogen in the manure.

What Have We Learned?

Addition of various combinations of borax and quebracho condensed tannins to swine manure slurries was highly effective in reducing all gaseous emissions (H2S, NH3, CO2, CO, N2O, and CH4) and in retaining more nitrogen in swine manure.  Lesser amounts of borax and tannin are needed when combined to achieve  a similar reduction in H2S production to using much larger amounts of either product alone.   Phytotoxicity studies show that the level of tolerance of crops to borax-tannin combination treated swine manure is:  alfalfa > corn > wheat > soybean >> dry beans. 

Future Plans

We are interested in transferring this research to on-farm sites.

Authors

Melvin Yokoyama, Professor, Dept. of Animal Science, Michigan State University, E. Lansing, MI 48824, yokoyama@msu.edu

Terence R. Whitehead, Research Microbiologist, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604

Cheryl Spence, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604

Michael A. Cotta, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604

Donald Penner, Dept. of Crops and Soil Sciences, Michigan State University, E. Lansing, MI 48824

Susan Hengemuehle, Dept. of Animal Science, Michigan State University, E. Lansing, MI 48824

Janis  Michael, Dept. of Crops and Soil Sciences, Michigan State University, E. Lansing, MI 48824

Additional Information

Whitehead, T.R., Spence, C., and Cotta, M.A.  Inhibition of Hydrogen Sulfide, Methane and Total Gas Production and Sulfate-Reducing Bacteria in In Vitro Swine Manure Slurries by Tannins, with Focus on Condensed Quebracho Tannins. (2012) Appl. Microbiol. Biotech. http://link.springer.com/article/10.1007/s00253-012-4562-6/fulltext.html

Development and Comparison of SYBR Green Quantitative Real-Time PCR Assays for Detection and Enumeration of Sulfate-Reducing Bacteria in Stored Swine Manure.  (2008) J. Appl. Microbiol. 105: 2143-2152.  http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2008.03900.x/pdf

USDA-ARS-NCAUR Bioenergy Research Unit Home Page: http://ars.usda.gov/main/site_main.htm?modecode=36-20-61-00

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Anaerobic Digestion of Finishing Cattle Manure

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Purpose

The concept of utilizing feedlot manure in an anaerobic digester to power an ethanol plant, which then produces feed for cattle, has been called a closed loop system.  In this system inputs are minimized and outputs are used by another component.  This research looked at differences in manure quality within this system.  Trial 1 considered incorporating distillers grains into the cattle diet and the effects on methane potential of the manure.  For this system to be utilized by the feedlot industry in Nebraska, the manure collected for anaerobic digestion must be collected from soil-based open feedlot pens which account for over 95% of the feedlot cattle raised in Nebraska.  Trial 2 addressed the methane potential of open-lot feedlot manure and its feasibility for anaerobic digestion.

An integrated biorefinery utilizes distillers grains for cattle feed and cattle manure for biogas generation to power an ethanol plant.  This system has been referred to as a “closed loop” system due to energy recycling within the segments.

What Did We Do?

Seven continuously stirred anaerobic digesters were used to compare degradation of manure from 2 cattle diets (Trial 1) and 2 cattle housing methods (Trial 2).  In Trial 1 manure was collected from confinement cattle on a control diet with 82.5% dry rolled corn or 40% of the corn was replaced with wet distillers grains plus solubles (WDGS), a byproduct of the ethanol industry.  For Trial 2, manure was collected from cattle in complete confinement or soil-based open feedlot pens with all cattle on a similar byproduct diet.  In both trials, organic matter (OM) degradation and methane production was measured for digesters on each treatment.  In Trial 1, samples of effluent removed from the digesters were also used to identify differences in microbial community structure (Eubacterial and Archaeal) due to treatment.

What Have We Learned?

Trial 1.  Organic matter degradation was slightly improved for manure from cattle fed WDGS (P = 0.10).  Methane production was 0.137 L/g OM fed for WDGS manure and 0.116 L/g OM fed for the corn-based diet (P = 0.05).  Microbial communities identified using 454-pyrosequencing revealed structuring of the microbial community based on diet (P < 0.001).  This suggests that the microbial food chain that contributes to methane production is greatly influenced by the diet fed to cattle, and dietary manipulation may provide opportunities to increase or decrease methane production from cattle manure.

Trial 2.  Manure collected from open-lot pens had an OM content of 26% compared to 88% for manure from complete confinement.  This resulted in decreased methane production and OM degradation (P < 0.01) for digesters fed open-lot manure.  However, methane was produced from open-lot manure suggesting that if ash buildup can be avoided open lot manure may be a viable feedstock for anaerobic digestion.

Future Plans

We are currently exploring new technologies that may enhance the use of open lot manure in anaerobic digestion.  We are also identifying key microbes involved in methane production in order to better understand how things such as cattle diet affect methane production.

Authors

Andrea Watson, graduate student, University of Nebraska awatson3@unl.edu

Samodha Fernando, assistant professor, University of Nebraska

Galen Erickson, professor, University of Nebraska

Terry Klopfenstein, professor, University of Nebraska

Additional Information

A summary of these trials is available at beef.unl.edu/reports; 2013 Beef Report pg. 98-99.

Acknowledgements

Funding provided by Nebraska Center for Energy Sciences Research

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Money from Something: Carbon Market Developments for Agriculture

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Abstract

* Presentation slides are available at the bottom of the page.

For more than a decade, the potential to earn revenue from climate-saving activities in agriculture has been touted throughout farm-related industries. This presentation will assume a basic knowledge of the concept of carbon markets as a kind of ecosystem service market. The focus will instead be put on current market opportunities and the importance of learning from past mistakes. Included in the discussion will be carbon offset opportunities for methane capture from manure digesters and composting and nitrous oxide reduction from controls on nitrogen fertilization. Participants will learn about voluntary and compliance market opportunities and the value of offsets versus transactions costs in today’s markets. Sources of market information will also be discussed.

Topics:

  • Ecosystem services markets: Carbon credits and more.
  • Types of offsets relevant to livestock and crop producers (e.g., methane and nitrous oxide).
  • Rules of the road: How to read the key parts of project protocols.
  • Once and future markets: Consider the differences between voluntary and compliance markets.
  • Show us the money: Have any producers really made money from carbon markets?

Purpose

During the past decade, the potential to earn revenue from greenhouse gas reductions in agriculture, especially from anaerobic digestion projects, generated some enthusiasm for this emerging ecosystem market. In 2005, dairies in Washington and Minnesota received the first carbon credit payments for their digesters through the Chicago Climate Exchange (CCX), a pilot cap-and-trade market established in 2003. With the failure of the 111th Congress to complete passage of a national cap-and-trade law in the summer of 2010, the CCX closed shop. What has happened since that time? What is the potential today for livestock producers to benefit from carbon markets or carbon pricing? We look at current markets and summarize the opportunities.

What Did We Do?

The Washington State University (WSU) Energy Program monitors technology, policy and market developments about anaerobic digestion as part of its land-grant mission to support industry and agriculture in Washington state. Because of the potential value of digesters to dairy producers, we follow developments in a wide range of existing and potential ecosystem markets, including renewable energy and fuels, carbon/GHGs, nutrients, and water. Preparation for this presentation included surveys of academic and popular literature, interviews with project developers and market insiders, and analysis of the participation in carbon trading by existing livestock digester projects in the U.S.

What Have We Learned?

The existing landscape of livestock anaerobic digestion projects illustrates three major types or models of carbon market finance: utility-based programs, voluntary carbon markets and compliance-based cap-and-trade markets.

Utility-Based Opportunities

Vermont is home to at least 15 operational dairy-based digesters. Only two digesters serve farms with more than 2,000 cows. Of the balance, about half are below and half above 1,000 cows. All of the Vermont digesters produce renewable electricity and participate in one or more utility-based incentive programs. One example is the Vermont’s Sustainably Priced Energy Enterprise Development (SPEED) program, which establishes standard offer contracts between utilities and renewable energy project developers. The goal of the SPEED program is to support in-state production of renewable power from hydro, solar PV, wind, biomass, landfill gas and farm methane with an overall portfolio target of 20 percent by 2017.

A key mechanism of the program is the long-term (20-year) Standard Offer contract and default pricing for the different types of renewable power. Default prices were calculated to allow developers to recover their costs with a positive return on investment. The default prices established for the first two rounds of farm methane projects were $0.16/kWh and $0.14/kWh, respectively. This compares to an average retail price of $0.146/kWh for electricity in the state. The default prices do not account for the environmental attributes of the green power for farm methane projects.

Many of the Vermont digesters participate in the Cow Power Program, established by  the former Central Vermont Public Service (CVPS), now a part of Green Mountain Power, in 2004. The Cow Power Program offers customers the opportunity to purchase the environmental attributes (renewable energy and GHG reduction) from participating dairy digester projects at a rate of $0.04/kWh. This value was passed along to the suppliers of the dairy-based green power.

These two Vermont programs continue to operate in tandem and provide maximum benefit to Vermont’s diary digester projects. By one estimate, customers participating through the Cow Power program have provided to dairy digester operators more than $3.5 million in value for the environmental attributes created in the past eight years.

Other examples of this type of type of utility-based standard offer or incentive pricing for farm power can be found in North Carolina and Wisconsin.

Voluntary Carbon Offsets Opportunities

Voluntary carbon markets are built on decisions by utilities, corporations, and other businesses to offset their carbon footprint impacts through the purchase of third-party verified carbon credits. While the voluntary carbon market has suffered ups and downs, especially during the recent economic downturn, corporations continue to respond to pressures such as corporate stewardship policies or carbon disclosure programs that require accounting for environmental and greenhouse gas impacts. 

The voluntary market is inhabited by both nonprofit and for-profit organizations that bring sellers and buyers together. The types and value of offsets are more varied, depending on the appetites and budgets of the buyers.

For example, the voluntary carbon market has been a preferred option for Washington-based Farm Power, which has agreements with The Carbon Trust (Portland, OR) and Native Energy (Burlington, VT) for carbon credits generated from the capture and destruction of methane from its farm digester projects in Washington state. Both The Carbon Trust and Native Energy use designated registries and protocols, such as the Carbon Action Registry (CAR) or Verified Carbon Standard (VCS), as the vehicle through which credits are registered, verified, and eventually retired on behalf of their customers.

The Climate Trust – Retires registered carbon offsets on behalf of at least five Oregon-based utilities that are required by state law to offset the GHG impacts that occur from installing new power plants in the state. The Trust also sources offsets for the Smart Energy program created by NW Natural as an opportunity for customers to support production of “carbon-neutral” natural gas through farm-based biodigesters.

Native Energy – Has a diverse base of individual and business customers. They source carbon offsets for a wide range of large, environmentally conscious businesses, such as eBay, Stonyfield Farm, Brita, and Effect Partners, who provided some funding up front for offsets from Farm Power’s Rainier Biogas project. Offset values vary widely depending on demand, supply, and the “value” of the project’s story. In a few cases, offset values may loosely track the prices for compliance-grade carbon offsets with a discount for funding provided in advance of project implementation.

Compliance Cap-and-Trade Offsets Opportunities

Finally, the compliance market opportunity refers to cap-and-trade programs established by state governments to reduce GHG pollution. These are formal regulatory systems. The government establishes caps on GHGs for targeted sources and issues permits or allowances that are distributed, sold, or auctioned to regulated entities for each ton of emissions they generate. Allowances are typically tradable instruments, so entities can easily manage their allowance needs and accounts. The goal of cap-and-trade systems is to use market-based mechanisms to achieve pollution reductions at the lowest possible cost and with the least disruption to the economy.

Systems might also allow covered entities to use offsets generated voluntarily by non-covered entities to meet some portion of their emission reduction target. Allowed offsets are generated using approved protocols, verified by approved third-party verifiers, and registered/sold through approved registries. 

Two domestic cap-and-trade programs survived the past decade and are in operation today—the Regional Greenhouse Gas Initiative (RGGI), which involves nine Northeastern states, and the California market, established by Assembly Bill 32 (AB 32) and administered by the California Air Resources Board (CARB). Each of these systems operates under its own sets of rules.

The table below highlights features of these two market approaches.

Regional Greenhouse Gas Initiative (RGGI)

AB 32 – California Market

Nine states: Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont

California only (may establish a market connection with Ontario, Canada)

Covers the electricity sector: 200 power plants

Covers power and industrial entities that generate more than 25,000 metric tons of CO2e annually; will expand to include the transportation fuel sector in 2015

Allowances based on U.S. short tons of CO2

Allowances based on metric  tons of CO2

Allowances are auctioned

Allowances are auctioned, with a minimum floor price of $10/MtCO2e

Offsets are very limited – few types, very strict rules, only 3% of compliance allowed

Offsets are allowed in four categories: livestock methane, forestry, urban forestry, and ozone-depleting substances; entities may use offsets for up to 8% of their compliance obligation

Current auction prices: ~ $2.00

Current auction prices: ~$13.50; offset values are estimated to lag allowance prices by about 25%

 

Among farm digester project developers, interest in the California market is guarded. Agricultural methane capture and destruction is one of just four approved offset categories. The demand for these offsets could become strong, and the rules allow projects from any state to participate. On the other hand, the costs for monitoring equipment can be significant, $15,000 or more for start up, with similar sums every year for verification and registration.  These monitoring and transaction costs will tend to favor projects with larger livestock numbers (1,500+ dairy animal units, or AUs). To date, 60 existing digester projects have listed with the Climate Action Registry—a first step to participation in the California market. Of these projects, 36 have registered more than 800,000 verified carbon credits.

Conclusions:

Values for carbon (i.e., GHG reductions) can be observed in the marketplace and measured in terms of market goodwill or as prices for environmental attributes or carbon credits from voluntary and compliance markets.

Developers of smaller farm digester projects (<1,500 AUs) may find their best value through utility-based incentive programs or through participation in voluntary carbon markets.

Developers of larger farm digester projects (>1,500 AUs) should explore the potential costs and benefits of registering to participate as an offset project in the California carbon market.

Future Plans

The WSU Energy Program will continue to monitor market developments related to this topic and encourage livestock producers to consider methane capture and anaerobic digestion as means to control odors, manage nutrients, and produce valuable biogas resources.

Authors

Jim Jensen, Sr. Bioenergy and Alternative Fuel Specialist, Washington State University Energy Program jensenj@energy.wsu.edu

Additional Information

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.

Influence of Swine Manure Application Method on Concentrations of Methanogens and Denitrifiers in Agricultural Soils

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Abstract

Soil microbial communities have been proposed as indicators of soil quality due to their importance as drivers of global biogeochemical cycles and their sensitivity to management and climatic conditions. Despite the importance of the soil microbiota to nutrient transformation and chemical cycling, physio-chemical properties rather than biological properties of soils are traditionally used as measures of environmental status. In general, much is unknown regarding the effect of management fluctuations on important functional groups in soils systems (i.e., methanogens, nitrifiers and denitrifiers). It is only recently that it has been possible, through application of sophisticated molecular microbiological methods, to sensitively and specifically target important microbial populations that contribute to nutrient cycling and plant health present at the field-scale and in differentially managed soil systems.

Fig. 1. Swine slurry surface application.

In this study, quantitative, real-time PCR (qPCR) was used to quantify changes in denitrifiers (narG) and methanogens (mcrA) in agricultural soils with three different swine effluent application methods including surface application, direct injection, and application in combination with soil aeration. Results show that concentrations of bacteria were high in all treatments (2.9 ± 1.4 X 109 cells per gram of soil); about 25% higher than in controls with no slurry added. Concentrations of methanogens and denitrifiers were slightly higher (around 50%) when slurry was applied by injection or aeration (5.3 ± 2.4 X 107 cells and 2.8 ± 1.8 X 107 cells per gram of soil, respectively) as compared to no till  (2.4 ± 1.6 X 107 cells and 1.6 ± 1.0 X 107 cells per gram of soil, respectively).

These results suggest that application method has little influence on concentrations of functional groups of microorganisms. These results will be discussed in light of results of GHG sampling conducted during the same study.

Fig. 2. Swine slurry application by direct injection.

Why Study Greenhouse Gases and the Manure-Soil Interaction?

Although agricultural production has been identified as a significant source of green house gas (GHG) emissions, relatively little scientific research has been conducted to determine how manure management strategies effect GHG production upon land application. Even fewer studies have taken into consideration the microorganisms associated with applied manures. Microbial communities are responsible for nutrient transformation and chemical cycling in soil systems and many important functional groups (i.e., methanogens, nitrifiers and denitrifiers) are extremely sensitive to environmental management and climate conditions. The goal of this study was to evaluate how swine slurry land application methods effect microbial communities associated with nitrogen cycling and GHG production.

Fig. 3. Swine slurry application in combination with soil aeration.

What Did We Do?

We used molecular microbial methods to quantify changes in nitrifiers (amoA), denitrifiers (nirK, nosZ and narG) and methanogens (mcrA) in agricultural soils receiving swine slurry applied by (A) surface application (Fig. 1) (B) direct injection (Fig. 2) or (C) application in combination with soil aeration (Fig. 3). Soil samples were taken from triplicate plots 13 days after effluent application.

Above – Fig. 4. Concentration of methanogens (mcrA) and nitrate reducing bacteria (narG) as measured by quantitative, real-time PCR analysis of targeted genes (in parentheses). Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.
Below – Fig. 5. Concentration of nitrifying bacteria or archaea as measured by quantitative, real-time PCR analysis of the amoA specific for each group. Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.

What Have We Learned?

  1. Sampling cell concentrations at different soil depths (1.3 cm or 5 cm) from plots with surface applied slurry significantly influenced results (Fig. 4, Fig. 5 and Fig 6).
  2. Slurry applied by any method significantly increased (7 logs) concentrations of nitrate reducing bacteria and methanogens (Fig 4). Methanogens were present in the slurry while nitrate reducers were not measurable in slurry or control plots.
  3. Nitrifying bacteria significantly increased in concentration after slurry addition (i.e. 7, 31, 2 and 68 times higher than control plots for slurry applied by injection, aeration or surface application (1.3 cm and 5 cm), respectively); concentrations of nitrifying archaea did not change from initial levels after slurry addition (Fig. 5).
  4. Concentrations of bacteria, fungi and denitrifiers on plots with slurry applied were two to nine times higher than concentrations in controls with no slurry (Fig. 6).

Future Plans

Findings from this study underscore the importance of measuring both microbial populations and gas production when evaluating the impact of manure application on emissions. Emission data provided important information about the kind and rate of GHG emissions (see reference below for details; Sistani et al (2011) Soil Sci. America J. 74(2): 429-435). However, microbial analyses showed that select groups of nitrifiers and denitrifiers (but not all groups) were affected by manure application. Findings from microbial analyses will be the basis for development of future studies to target and manipulate specific microbial populations in ways that inhibit their ability to produce GHG.

Fig. 6. Change in concentration of targeted population in each treatment relative to that in the control with no slurry or fertilizer added. Concentrations of bacteria (16S RNA gene), fungi (18S RNA gene), nitrite reducing bacteria (nirK) or nitrous oxide reducing bacteria (nosZ) were measured by quantitative, real-time PCR analysis of targeted genes (in parentheses). Swine slurry was applied by three methods surface, direct injection (Inj) or in combination with aeration (Aer). Chemical fertilizer (Fert) and plots with no fertilizer (Control) were also included. Initial slurry was removed before application. Cells in soils from plots with surface applied slurry were sampled at two depths (1.3 cm and 5.1 cm). Error bars represent the standard deviation of triplicate plot samples.

Authors

Dr. Kimberly Cook, Research Microbiologist, USDA Agricultural Research Service, kim.cook@ars.usda.gov

Dr. Karamat Sistani, Research Soil Scientist, USDA Agricultural Research Service

Additional Information

USDA-ARS Bowling Green, KY Location Webpage: http://www.ars.usda.gov/main/site_main.htm?modecode=64-45-00-00

 

Relevant Publications:

Sistani, K.R., Warren, J.G., Lovanh, N.C., Higgins, S., Shearer, S. 2010. Green House Gas Emissions from Swine Effluent Applied to Soil by Different Methods. Soil Sci. America J. 74(2): 429-435.

Acknowledgements

We would like to thank Jason Simmons and Rohan Parekh for valuable technical assistance. This research is part of USDA-ARS National Program 214: Agricultural and Industrial By-products

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.