ammonia – Page 2 – Livestock and Poultry Environmental Learning Community

April 7, 2019October 22, 2019

The Use of USDA-NRCS Conservation Innovation Grants to Advance Air Quality Improvements

USDA-NRCS has nearly fifteen years of Conservation Innovation Grant project experience, and several of these projects have provided a means to learn more about various techniques for addressing air emissions from animal agriculture. The overall goal of the Conservation Innovation Grant program is to provide an avenue for the on-farm demonstration of tools and technologies that have shown promise in a research setting and to further determine the parameters that may enable these promising tools and technologies to be implemented on-farm through USDA-NRCS conservation programs.

What Did We Do?

Several queries for both National Competition and State Competition projects in the USDA-NRCS Conservation Innovation Grant Project Search Tool (https://www.nrcs.usda.gov/wps/portal/nrcs/ciglanding/national/programs/financial/cig/cigsearch/) were conducted using the General Text Search feature for keywords such as “air”, “ammonia”, “animal”, “beef”, “carbon”, “dairy”, “digester”, “digestion”, “livestock”, “manure”, “poultry”, and “swine” in order to try and capture all of the animal air quality-related Conservation Innovation Grant projects. This approach obviously identified many projects that might be related to one or more of the search words, but were not directly related to animal air quality. Further manual review of the identified projects was conducted to identify those that specifically had some association with animal air quality.

What Have We Learned?

Out of nearly 1,300 total Conservation Innovation Grant projects, just under 50 were identified as having a direct relevance to animal air quality in some way. These projects represent a USDA-NRCS investment of just under $20 million. Because each project required at least a 50% match by the grantee, the USDA-NRCS Conservation Innovation Grant program has represented a total investment of approximately $40 million over the past 15 years in demonstrating tools and technologies for addressing air emissions from animal agriculture.

The technologies that have been attempted to be demonstrated in the animal air quality-related Conservation Innovation Grant projects have included various feed management strategies, approaches for reducing emissions from animal pens and housing, and an approach to mortality management. However, the vast majority of animal air quality-related Conservation Innovation Grant projects have focused on air emissions from manure management – primarily looking at anaerobic digestion technologies – and land application of manure. Two projects also developed and enhanced an online tool for assessing livestock and poultry operations for opportunities to address various air emissions.

Future Plans

The 2018 Farm Bill re-authorized the Conservation Innovation Grant Program through 2023 at $25 million per year and allows for on-farm conservation innovation trials. It is anticipated that additional air quality projects will be funded under the current Farm Bill authorization.

Authors

Greg Zwicke, Air Quality Engineer, USDA-NRCS National Air Quality and Atmospheric Change Technology Development Team

greg.zwicke@ftc.usda.gov

Additional Information

More information about the USDA-NRCS Conservation Innovation Grants program is available on the Conservation Innovation Grants website (https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/financial/cig/), including application information and materials, resources for grantees, success stories, and a project search tool.

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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

March 5, 2019March 20, 2019

Evaluating the Impact of Ammonia Emissions from Equine Operations on the Environment

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Purpose

In the United States, animal agriculture is the largest source of ammonia (NH3) emissions that are a major air and water pollutant contributing to eutrophication, soil acidity, and aerosol formation that can impair atmospheric visibility and human health. Ammonia volatilization occurs when excess crude protein (CP) is fed and excreted as urinary nitrogen, primarily as urea. Information regarding NH3 emissions from equine operations is limited. It is generally understood that air quality in stables can adversely affect both horse and human health, however, the effects of different housing systems and nutritional management of horses on air quality have received little investigation.

What did we do?

In the first study, 9 mature horses were used in a 3 X 3 replicated Latin square design study to determine the effects of dietary CP concentrations on potential NH3 losses from feces and urine. Horses were fed 3 diets formulated using bahiagrass and Tifton-85 bermudagrass hays and a commercial vitamin mineral supplement. The 3 diets differed in dietary CP concentration and were labelled as: LOW-CP, MED-CP, and HIGH-CP (10.6, 11.5 and 12%, respectively). Total collection of feces and urine was conducted over 3 days. For in-vitro determination of NH3 concentrations, urine samples were pooled and mixed with either wheat straw or wood shavings, while fecal samples were pooled and mixed with wheat straw. Ammonia emission by these samples was measured using a vessel emission system with an airflow rate (2.5 L min-1) at 20°C over a 7-d period. Concentration of NH3 in each vessel was measured using a photoacoustic multi-gas analyzer. Temperature, airflow rate and NH3 concentration in each vessel were used to calculate NH3 emission rate (ER).

The objective of the second study was to determine air emissions from 4 Mid-Atlantic equine operations as affected by housing type and feeding practices. A questionnaire was administered to respective farm managers to record facility and individual stall dimensions, daily cleaning practices, and feeding practices. Farm A was a University riding stable, Farm B was a University breeding farm, Farm C was a racehorse training facility, and Farm D was a Standardbred breeding facility. At least 4 stalls were chosen in each facility based upon location within barn to quantify NH3 concentrations. Body weight, breed, age, class of horse, exercise schedule, and time spent in the stall were recorded for the horses in the selected stalls. For analysis of NH3 concentration, air samples were collected from stall floors using a dynamic flux chamber and concentrations measured using a photoacoustic NH3 analyzer. To achieve a representation of NH3 emitted from stall surfaces, 5 locations were selected and measurements taken at approximately the same time each day. Temperature, airflow rate and a weighted concentration of NH3 in the flux chamber were used to calculate NH3 emissions.

Figure 1 Cumulative ammonia emissions rate of urine when mixed with A) shavings and B) straw and incubated

Figure 2. Daily ammonia emissions per horse over 3 days using the flux chamber system on 4 horse operations

What have we learned?

When measuring NH3 concentrations and calculating the ER in-vitro, urinary-N was the main source of NH3 volatilized from equine manure, potentially due to the high urea-N concentration in the urine. Cumulative fecal NH3 emissions ranged from 19.7 to 39.8 mg/m²and contributed only a small amount in comparison to the NH3lost from urine. While dietary CP intake did not influence NH3 emissions, cumulative emissions tended to be higher when horses consumed more CP. Urinary NH3 emissions were greater when mixed with wheat straw compared to wood shavings. This study shows there may be a relationship between dietary CP intake and potential NH3 losses from equine urine under laboratory conditions. When estimating NH3 emissions on the 4 equine operations, greater dietary CP intake was associated with increased urinary NH3 volatilization. Daily CP intake ranged from 149-211 % above NRC CP requirement. Estimated NH3 emissions from facilities ranged from 18.5 to 124 g d-1 horse-1 and were similar to emissions previously reported from other large livestock species. Differences in NH3 emissions could be due to several factors including cleaning practices and ventilation rate. These studies provide a better understanding of the impact equine operations are having on atmospheric NH3 levels.

Future Plans

Future research will aim to quantify NH3 emissions from entire equine operations as well as accounting for diurnal, seasonal and regional fluxes in NH3. In addition, there is interest to determine how protein quality will affect NH3 emissions from horse urine.

Corresponding author, title, and affiliation

Jessie Weir, University of Florida

Corresponding author email

jessie23@ufl.edu

Other authors

Hong Li, Assistant Professor, University of Delaware; Lori K. Warren, Associate Professor, University of Florida; Erica Macon, Graduate Student, Middle Tennessee State University; Carissa Wickens, Extension Equine Specialist, University of Florida

Additional information

Additional information regarding these projects is available by contacting Jessie Weir (jessie23@ufl.edu), or Carissa Wickens (cwickens@ufl.edu).

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

March 5, 2019March 19, 2019

Using Wet Scrubber to Reduce Ammonia Emission from Broiler Houses

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Purpose

Research on mitigating the effects of animal feeding operations (AFOs) on air quality in the US has made great strides in recent years. Development of cost-effective air emission mitigation and assessing the effectiveness of these technologies is urgently needed to improve our environmental performance and to help producers address increasing regulatory pressures. Scrubbers have been shown to be a powerful tool in reducing ammonia (NH3), dust and odor emissions. An affordable two-stage acid scrubber was developed by USDA ARS for treating exhaust air and can easily be installed onto the exhaust fans of existing poultry facilities. A field project was conducted to evaluate the efficiency of the acid scrubber under field conditions on three broiler farms, two located in Delaware (DE) and one located in Pennsylvania (PA).

What did we do?

The two-stage scrubbers were installed on the minimum fans of three farms that were using different practices and settings. One farm used 36” minimum fans and reused existing litter throughout the project while an organic farm used a 36” minimum fan, but used new bedding materials for every flock. The third scrubber was installed on a research farm with a 24” minimum fan and used litter. Sodium bisulfate was used as the acid agent. Ammonia concentration and airflow rate through each fan were continuously measured. Scrubber liquid samples were analyzed to calculate the efficiency of each scrubber. Acid, water and electricity consumption of each scrubber were recorded over multiple flocks and seasons.

What have we learned?

The mean NH3 capturing efficiencies of the three scrubbers for the three sites were 31.3, 34.3 and 11.0 %, respectively. The low efficiency (11%) of one scrubber was due to high NH3 emission rate and inadequate acid solution in the scrubber (the solution at this site was checked and replaced weekly whereas the solution at the other two sites were checked daily). For every kg NH3 captured, the average water, sodium bisulfate and electricity consumption at the three sites were 0.23 m3, 15.10 kg and 43.74 kWh, respectively.

Future Plans

Based on the field experiences of running the three scrubbers, several recommendations are suggested: 1) increase fan run time to compensate for air flow loss due to high pressure drop, 2) add insulation on drain valves, 3) heat fresh water line and add a heater in pump boxes, 4) clean dust scrubber at least twice per flock for houses with used litter, 5) replace acid solution more frequently toward end of the flock for best performance, 6) add a storage tank for spent liquid if the growers do not have crops or pasture to apply to, and 7) add an automatic acid dosing system to reduce labor requirement and improve scrubber performance.

Corresponding author, title, and affiliation

Hong Li, Assistant Professor, University of Delaware

Corresponding author email

hli@udel.edu

Other authors

Chen Zhang, Philip Moore, Michael Buser, Cathleen J. Hapeman, Paul Patterson, Gregory Martin, Jerry Martin

Additional information

Zhang, Chen, Hong Li , Philip A Moore , Michael Buser, Cathleen J. Hapeman, Paul Patterson, Gregory Martin. 2016. ASABE Annual International Conference. Paper number 2461008; Orkando,Florida, July 17 – July 20.

Acknowledgements

This study was partially supported by funds from USDA-NRCS Conservation Innovation Grant Program (Award No. NRCS 69-3A75-12-244), University of Delaware, Penn State University, Oklahoma State University, University of Maryland, and USDA-ARS. The cooperation and assistance of the collaborating producer is also acknowledged.

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

March 5, 2019March 6, 2019

Poultry Digestion – Emerging Farm-Based Opportunity

While EPA AGSTAR has long supported the adoption of anaerobic digestion on dairies and swine farms, they have not historically focused on the use of anaerobic digestion on egg laying and other poultry facilities. This has been because the high solids and ammonia concentrations within the manure make anaerobic digestion in a slurry-based system problematic. Development of enhanced downstream ammonia and solids recovery systems is now allowing for effective digestion without ammonia toxicity. The process also generates dilution water, avoiding the need for fresh water consumption, and eliminating unwanted effluent that needs to be stored or disposed of to fields. The system produces high-value bio-based fertilizers. In this presentation, a commercial system located in Fort Recovery Ohio will be used to detail the process flow, its technologies, and the co-products sold.

Why Examine Anaerobic Digestion on Poultry Farms?

The purpose of this presentation is to supply a case study on a commercial poultry digestion project for production of combined heat and power as well as value-added organic nutrients on a 1M egg-layer facility in Ohio.

What did we do?

In this study we used commercial farm information to demonstrate that poultry digestion is feasible in regard to overcoming ammonia inhibition while fitting well into an existing egg-layer manure management system. Importantly, during the treatment process a significant portion of nutrients within the manure are concentrated for value-added sales, ammonia losses to the environment are reduced, and wastewater production is minimized due to recycle of effluent as dilution water.

What have we learned?

In this study, commercial data shows that ammonia and solids/salts levels that are potentially inhibitory to the biology of the digestion process can be controlled. The control is through a post-digestion treatment that includes ammonia stripping and recovery as ammonium sulfate as well as fine solids separation using a dissolved air flotation process with the addition of a polymer. The resulting treated effluent is sent back to the front of the digester as dilution water for the high solids poultry manure. The separated fine solids and the ammonium sulfate solution are dried using waste engine heat to produce a nutrient-rich fertilizer for off-farm sales. The stable anaerobic digestion process resulting from the control of potential inhibitors that might accumulate in the return water, if no post-treatment occurred, leads to production of a significant supply of electrical power for sales to the grid.

Demonstration at commercial scale shows the promise anaerobic digestion with post-digestion treatment and effluent recycle can play in a more sustainable poultry manure treatment system including managing nutrients for export out of impacted watersheds.

Future Plans

Future plans include continued work with industry in developing and/or providing extension capabilities around novel digestion and post-treatment processes for a variety of manures and on-farm situations. Expansion of such processes to poultry and other on-farm business plans will allow for improved reductions in wastewater production, concentrate nutrients for export out of impacted watersheds and do so within a positive economic business plan.

Authors

Craig Frear, Assistant Professor at Washington State University cfrear@wsu.edu

Quanbao Zhao, Project Engineer DVO Incorporated, Steve Dvorak, President DVO Incorporated

Additional information

Additional information about the corresponding author can be found at http://www.csanr.wsu.edu while information about the poultry project and the industry developer can be found at http://www.dvoinc.net. Numerous articles related to anaerobic digestion, nutrient recovery and separation technologies for climate, air, water and human health improvements can be found at the WSU website using their searchable articles function.

Acknowledgements

This research was supported by funding from USDA National Institute of Food and Agriculture, Contract #2012-6800219814; National Resources Conservation Service, Conservation Innovation Grants #69-3A75-10-152; and Biomass Research Funds from the WSU Agricultural Research Center.

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.

March 5, 2019March 6, 2019

Scientific Evidence Indicates that Reducing NOx Emissions is the Most Effective Strategy to Reduce Concentrations of Ammonium Nitrate, a Significant Contributor to PM2.5 Concentrations in California’s San Joaquin Valley

Recently there has been increased interest in regulating ammonia emissions to reduce PM2.5 (“fine” particles with an aerodynamic diameter less than 2.5 micrometers) concentrations. However, understanding the quantity of and interactions between ammonia and nitrogen oxide (NOx) is necessary in determining whether controlling ammonia is an effective strategy for reducing PM2.5 in a particular region. Research from the California Regional Particulate Air Quality Study and other studies has demonstrated the relative abundance of ammonia in comparison to the limited concentrations of the other key precursor, nitric acid formed by NOx emissions. As a result, NOx acts as the primary limiting precursor for the formation of secondary ammonium nitrate in the San Joaquin Valley (SJV). Modeling based on data from these studies also found that controlling NOx was the most effective strategy to reduce ammonium nitrate particulate in the SJV and controlling ammonia had little effect on PM2.5 concentrations.

In summary and as explained in the San Joaquin Valley Air Pollution Control District 2012 PM2.5 Plan, the best scientific information available indicates that controlling NOx emissions is the most effective strategy to reduce secondary ammonium nitrate in the SJV. While it has been demonstrated that controlling ammonia will not significantly reduce PM2.5 concentrations in the SJV, the District has adopted stringent regulations that have significantly reduced ammonia emissions.

Purpose

The San Joaquin Valley is primarily a rural region with large areas dedicated to agriculture. Recently there has been increased interest in regulating ammonia emissions from agricultural operations and other sources as a means to reduce PM2.5 concentrations. However, understanding the quantity and interactions between ammonia and NOx are necessary in determining whether controlling ammonia emissions is an effective strategy for reducing secondary PM2.5 formation in a particular geographic region.

average of peak day pm2.5 chemical composition

The United States Environmental Protection Agency (U.S. EPA) periodically reviews and establishes health-based air quality standards (often referred to as National Ambient Air Quality Standards, or NAAQS) for ozone, particulate matter (PM), and other pollutants. Although the air quality in California’s San Joaquin Valley has been steadily improving, the region is currently classified as “serious” non-attainment for the 1997 and 2006 federal ambient air quality standards for PM2.5. The periods for which measured PM2.5 concentrations drive nonattainment of these standards occur primarily in the winter months and air quality research in the San Joaquin Valley has identified ammonium nitrate as the predominant contributor to secondary PM2.5 in the region. Ammonium nitrate particulate is formed through chemical reactions between ammonia in the air and NOx emissions produced by mobile and stationary combustion sources. As shown in Figure 1 above, ammonium nitrate is commonly the largest contributor to PM2.5 mass during the winter in the San Joaquin Valley.

What did we do?

modeled ammonium nitrate response to NH3 vs NOx Atmospheric modeling has demonstrated that controlling NOx is the most effective strategy to reduce ammonium nitrate concentrations in the San Joaquin Valley and controlling ammonia has little effect on these concentrations. The California Air Resources Board conducted multiple modeling runs to simulate the formation of PM2.5 in the San Joaquin Valley and compare the effect of reducing various pollutants on PM2.5 concentrations. As seen in Figure 2, U.S. EPA’s Community Multi-scale Air Quality (CMAQ) indicated that reducing NOx by 50% reduced nitrate concentrations by 30% to 50% reductions, while reducing ammonia by 50% resulted in less than 5% reductions in nitrate concentrations. Similarly, the UCD/CIT photochemical transport model indicated that for the conditions on January 4-6, 1996 in the San Joaquin Valley, controlling NOx emissions is far more effective for reducing nitrate concentrations than controlling ammonia.

What have we learned?

abundance of NH3 in San Joaquin Valley Ammonium nitrate particulate is limited by NOx in the San Joaquin Valley

Extensive research conducted through the California Regional Particulate Air Quality Study (CRPAQS) and other studies has demonstrated the relative abundance of ammonia in comparison to the limited concentrations of the other key precursor, nitric acid formed by NOx emissions in the San Joaquin Valley. As a result, NOx (via nitric acid) acts as the primary limiting precursor for the formation of secondary ammonium nitrate. (See Figures 3 and 4)

Future Plans

NOx control reduces ammonium nitrate more efficiently As explained in detail in the San Joaquin Valley Air Pollution Control District 2012 PM2.5 Plan, the best scientific information available indicates that controlling NOx emissions is the most effective strategy to reduce secondary ammonium nitrate in the San Joaquin Valley. While ammonia has been demonstrated to not significantly contribute to PM2.5 concentrations in the San Joaquin Valley, the District has developed control strategies, via stringent regulations (Confined Animal Facilities – Rule 4570, Organic Material Composting – Rule 4566, Biosolids, Animal Manure, and Poultry Litter Operations – Rule 4565), that have resulted in significant reductions in ammonia emissions.

Authors

Errol Villegas, Program Manager, San Joaquin Valley Air Pollution Control District errol.villegas@valleyair.org

Ramon Norman, Air Quality Engineer, San Joaquin Valley Air Pollution Control District

Additional information

California Air Resources Board Technical Symposium: Scientific Basis of Air Quality Modeling for the San Joaquin Valley 2012 PM2.5 Plan (April 27, 2012). Fresno, CA

Magliano, K. L. & Kaduwela, A. P. (2012) California Air Resources Board Technical Symposium: Technical Basis of the 2012 San Joaquin Valley PM2.5 Plan Modeling. Fresno, CA.

San Joaquin Valley Unified Air Pollution Control District. 2012 PM2.5 Plan (2012), Chapter 4 – Scientific Foundation and PM2.5 Modeling Results

Chen, J.; Lu, J.; Avise, J. C.; DaMassa, J. A.; Kleeman, M. J. & Kaduwela, A. P. (2014), Seasonal modeling of PM2.5 in Californias San Joaquin Valley, Atmospheric Environment 92, p. 182-190.

Kleeman, Michael J., Qi Ying, Ajith Kaduwela (2005) Control Strategies for the Reduction of Airborne Particulate Nitrate in California’s San Joaquin Valley. Atmospheric Environment, 39 (29), p. 5325 – 5341

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.

March 5, 2019March 6, 2019

Regulating Ammonia Emissions from Agriculture: Potential Pitfalls and Limitations

Currently, there is limited regulation of ammonia (NH3) emissions as a matter of federal policy. The Clean Air Act (CAA) provides the federal authority for regulation of these emissions. Although there are reporting requirements for NH3 under the Comprehensive Environmental Response, Compensation and Liability Act and Emergency Planning and Community Right-To-Know Act, these statutes do not provide authority to regulate emissions of NH3. There is increasing pressure to change NH3 policy primarily due to concerns about nutrient enrichment of large water bodies, such as the Chesapeake Bay and the Gulf of Mexico. Recently, the EPA has been petitioned to list NH3 as a criteria pollutant; and this request is somewhat supported by the report from the EPA’s Integrated Nitrogen Panel to the Science Advisory Board. There is also the immediate concern of EPA’s treatment of NH3 as a precursor to fine particulate matter (PM2.5). Regulation of NH3 as a precursor to PM2.5 will make it a regulated pollutant under the CAA. It will be difficult to regulate only the ‘excess’ portion of reactive N, particularly since ‘excess’ cannot be defined as a constant. Roughly 60- 85% of NH3 emissions in the U.S. are estimated to come from agricultural sources, a sector that varies considerably from the traditional industrial sources addressed by the environmental statutes. In fact, in most of these statutes, there is recognition that agricultural sources are different; and some regulatory exemptions are provided. Most likely, Congress did not anticipate the application of the CAA to agricultural sources or it would have included some exemptions in it as well. Nevertheless, regulation of NH3 emissions under the CAA will make it extremely difficult for EPA to consider the positive value and need for fertilizer NH3, which could have huge implications for the viability of the domestic and global food supply.

Purpose

Members of the U.S. Department of Agriculture’s Agricultural Air Quality Task Force (AAQTF) recognize the ever increasing pressure to change ammonia policy in the United States and to regulate sources of ammonia emissions under various environmental statutes including the Clean Air Act (CAA). Ammonia is not your ordinary air pollutant and will be difficult to regulate appropriately under the current construct of the CAA. Therefore, members of the AAQTF developed and approved a paper outlining information that regulators should consider before regulating ammonia emissions entitled, “Ammonia Emissions: What to Know Before You Regulate.”

What did we do?

Consideration of NH3 as an air pollutant will require the EPA to acknowledge and address the role of NH3 in the full nitrogen (N) cycle and specifically address emission reduction measures that do not merely transfer NH3 from one environmental medium to another. It will be difficult to regulate only the “excess” portion of reactive N, particularly since “excess” cannot be defined as a constant. Regulation of NH3 emissions under the CAA will make it extremely difficult for EPA to consider the positive value and need for fertilizer NH3, which could have huge implications for the viability of the domestic and global food supply.

To date, pollutants regulated under the CAA are considered “bad” for public health and for the environment; and the statute is designed to limit the impacts of these pollutants by reducing or eliminating their emissions. As EPA moves to regulate greenhouse gases, it is encountering difficulty in applying the existing statute in its consideration of carbon dioxide as a pollutant, which is a necessary component of the life cycle of plants and animals. Regulation of NH3 emissions within the constraints of the existing CAA will prove no less daunting and may lead to costly and illogical outcomes with little actual benefit to the environment or human health.

Prior to regulating ammonia emissions, EPA regulators must fully understand ammonia’s role in agriculture. Not only must there be an understanding of the nitrogen cycle from a chemical perspective, but there must be a full understanding from a biological perspective as well. These biological processes cannot be easily predicted or controlled and are based on many factors such as geographic region, cropping system, management practices, soil characteristics, climate and field variability. In animal production systems, there must be an understanding of diets and nitrogen use efficiency of the various species and the impacts of the housing systems, manure characteristics and management, and climate variables.

The EPA regulators must also not only understand the fate, transport, and transformation of atmospheric ammonia but must be able to quantify these processes. Any regulation of agricultural sources of ammonia should be informed by knowledge of management practices that will reduce emissions without negatively impacting animal and plant health and production levels. Ammonia reduction strategies must be considered across the entire production spectrum and not on individual aspects of production.

Underlying any regulation must be accurate measurement of the emissions and the ability to measure compliance, i.e., reductions and impacts. However, ammonia emissions are fugitive, vary spatially and temporally, and are readily influenced by many factors (e.g., source, climate, management practices, etc.) making it difficult to determine at a farm level, a precise emission factor. There are currently no easy and economical ways to directly monitor emissions from commercial livestock and cropping farms, which will make emissions estimation and enforcement challenging. Proceeding to regulation without proven methodologies for measurement of agricultural sources of ammonia and the ability to demonstrate scientifically the effectiveness of reduction practices, does not seem appropriate.

Nitrogen is essential to both crop and animal production, and when not supplied in sufficient amounts, will decrease both crop yield and animal productivity, risk declining soil system health and sustainability, and generate a loss for producers and perhaps even increase the overall environmental footprint of agricultural activities. Certain management or mitigation practices may be too costly for many producers given the current market value of agricultural commodities, so any regulation must considered how these costs will be covered.

What have we learned?

A collaborative dialogue with the agricultural community needs to occur prior to considering regulation. Current approaches of voluntary and incentive-based efforts are accomplishing significant improvements in soil health and reducing erosion and loss of nutrients, and agencies should recognize these improvements.

EPA can assist constructive dialog by avoiding regulatory silos and embracing holistic approaches in development of policies as it focuses on the agricultural sector; avoiding “One size fits all” style requirements; and avoiding multiple regulations on the same practice.

Farmers of the U.S. and the world must meet the food, fiber, and fuel needs of the predicted nine billion people by 2050. Therefore, any regulation of ammonia under the Clean Air Act must address its impact on the sustainability of domestic and global food supply as part of the mandatory statutory requirement to evaluate public health and welfare effects and the vitality of rural communities.

Future Plans

The AAQTF will continue to address these issues and attempt to facilitate future dialogue with EPA and USDA on these issues.

Authors

Sally Shaver, President, Shaver Consulting, Inc. slshaver50@aol.com

Dr. April Leytem, USDA-ARS, NW Irrigation and Soils Lab, Kimberly, ID

Dr. Robert Burns, Assistant Dean for Agriculture, Natural Resources and Community Economic Development, University of Tennessee Extension, Knoxville

Dr. Hongwei Xin, Director of Egg Industry Center, Departments of Agricultural and Biosystems Engineering and Animal Sciences, Iowa State University

Dr. Lingjuan Wang-Li, Associate Professor, Department of Biological and Agricultural Engineering, North Carolina State University

Lara Moody, Director of Stewardship Program, The Fertilizer Institute

Dr. Nicole Embertson, Resource Coordinator – Sustainable Livestock Production Program, Whatcom Conservation District, Lynden, WA

Dr. Eileen Fabian-Wheeler, Professor, Agricultural and Biological Engineering, Penn State University.

Additional information

The paper, Ammonia Emissions: What to Know Before You Regulate, is located on the USDA website

Acknowledgements

The contributions of members of the AAQTF to the discussions of these issues and to the development of the paper are recognized and greatly appreciated.

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.

March 5, 2019March 20, 2019

Factors Affecting Nitrous Oxide Emissions Following Subsurface Manure Application

[Abstract] Subsurface manure application is theoretically susceptible to greater denitrification losses and nitrous oxide (N2O) emissions compared to surface application methods – primarily attributed to manure being placed in a more anaerobic environment. A review of field studies suggest N2O emissions typically range from 0.1% to 3% of total applied N from subsurface application methods, but there is considerable variation in emissions depending on pre- and post-application soil moisture conditions, readily-available carbon content in manure compared to background levels in soil, localized nitrogen form and oxygen concentration at the application site, and application depth. This paper will summarize peer-reviewed literature of field studies that quantify N2O emissions subsequent to subsurface manure application and identify the most prominent determining factors cited by authors.

Why Study Nitrous Oxide Emissions of Manure?

Ammonia abatement efficiencies of up to 90 percent have been documented with subsurface application and incorporation of animal manures compared to conventional surface application methods. While reducing ammonia emissions has positive implications for air and water quality, a portion of the nitrogen conserved may come at the expense of increased nitrous oxide emissions produced during denitrification and nitrification processes in the soil. As a greenhouse gas 300 times more potent than carbon dioxide at trapping heat, nitrous oxide has been linked to anthropogenic climate change and depletion of stratospheric ozone. Release of nitrous oxide from agriculturally-productive soils into the atmosphere also represents a loss of crop nutrients. Understanding the circumstances and manageable factors that contribute to nitrous oxide formation in soils subsequent to manure application is important for retaining crop nutrients and preventing greenhouse gas emissions.

What did we do?

A literature review was performed to investigate the factors that contribute to nitrous oxide emissions following subsurface application of animal manure to both grassland and arable land, compare results from different application techniques, and examine the conditions and circumstances that lead to nitrous oxide emissions.

What have we learned?

Several studies demonstrate significant increases in nitrous oxide emissions (from 0.1 to 3 percent) attributable to factors including increasing soil moisture content, high concentrations of readily-available carbon in manure substrate, increased nitrate concentration in soil, shallow application depth, high soil temperature, and ambient conditions during and immediately following application (table 1). Other studies show no difference in nitrous oxide emissions as compared to surface application methods. Reasons that subsurface application techniques will not necessarily result in greater nitrous oxide emissions were: 1) the length of the diffusion path from the site of denitrification to the soil surface may lead to a greater portion of denitrified nitrogen being emitted as nitrogen gas; 2) the soil moisture conditions and aeration level at the time of application may not be suitable for increased nitrous oxide production; 3) prior to manur e application, soils may already contain readily-metabolizable carbon and mineral nitrogen, thus any increase in nitrous oxide emission following application may not have a significant impact; and 4) weather events subsequent to manure application may effect soil moisture content and water-filled-pore-space, thereby affecting nitrous oxide emissions. Several studies document nitrous oxide emissions due to subsurface application methods (including manure incorporation and shallow injection) but research comparing nitrous oxide emissions from different subsurface application techniques and application depth is limited. Lack or absence of data in literature about manure chemistry, nitrogen application rates, application technique or method, as well as soil and atmospheric conditions during and after application made it more difficult to draw specific conclusions on factors affecting nitrous oxide emissions from subsurface-applied manure.

Further research is needed to determine the environmental and economic tradeoffs of implementing subsurface manure application methods for abatement of NH₃ considering different future greenhouse gas emissions and market scenarios. Recent work suggests a link between denitrifier community density, organic C, and N₂O emissions. Characterization of these biological mechanisms and identification of genetic markers for key enzymes should continue, particularly with respect to various subsurface manure application techniques, different manure types and N application rates, soil types, environmental conditions, and soil chemistry. Subsurface application depth plays an important role in determining the proportion of N₂O to N₂ emitted during denitrification; however, the number of field studies that examine the impact of application depth is limited. More research is needed to determine optimal manure application depth as influenced by soil type, soil chemistry, timing of application, and vegetative cover. Finally, future research on subsurface manure application will allow existing and future prediction models to improve estimation of annual N₂O emissions at landscape scale and airshed levels. Refinement of greenhouse gas inventories, including N₂O emissions from agricultural production systems, will assist agriculture producers, scientists, and policy makers in making informed decisions on greenhouse gas emission mitigation.

research articles reporting factors of Nitrous Oxide

Future Plans

Future agricultural greenhouse gas regulations and/or carbon market incentives have potential implications for agricultural producers, including the method and timing of manure application. Controlled, replicated, and well-documented research on subsurface manure application and subsequent nitrous oxide release is critical for estimating the costs and benefits of different manure application techniques.

Authors

David W. Smith, Extension Program Specialist, Texas A&M AgriLife Extension DWSmith@ag.tamu.edu

Dr. Saqib Mukhtar, Professor and Associate Department Head for Extension, Texas A&M AgriLife Extension

Additional information

The publication ‘Estimation and Attribution of Nitrous Oxide Emissions Following Subsurface Application of Animal Manure: A Review’ has been accepted for publication in Transactions of the ASABE.

Acknowledgements

Funding for this effort provided by USDA-NIFA grant No. 2011-67003-30206.

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.

March 5, 2019March 28, 2019

Open Lot Dairy Ammonia Losses and Nitrogen Balance: A New Mexico Study

Purpose

Animal agriculture is a significant source of ammonia (NH3). Dairy cattle excrete most ingested nitrogen (N); most urinary N is converted to NH3, volatilized and lost to the atmosphere. This fugitive NH3 can contribute to negative environmental effects such as degraded air quality and excessive N in ecosystems. Open lot dairies on the southern High Plains are a growing industry and face challenges that include reporting requirements for NH3 emissions and potential regulation. However, producers and regulators lack a clear quantitative understanding of NH3 losses from the open lot production system.

What did we do?

We quantified NH3 emissions from the open lot and wastewater lagoons of a typical open lot New Mexico dairy during two weeks in summer, 2009. The 3500-cow dairy consisted of open lot, manure-surfaced corrals (22.5 ha). A flush system using recycled water removed manure from the feed alley to three lagoons (1.8 ha). Most manure was retained on the corral surface. Open path lasers measured atmospheric NH3 concentration downwind from the open lot and lagoon sources, sonic anemometers characterized turbulence, and inverse dispersion analysis (Windtrax) was used to quantify emissions every 15 minutes (Fig. 1). A dairy N balance was constructed using measured and calculated values to partition N to different stores in the dairy system. Milking cows comprised 73% of the herd, with the remainder dry or fresh cow. Dry matter intake averaged 22.5 kg/cow/d, with a mean crude protein content of 16.7% (Table 1).

What have we learned?

Most NH3 loss was from the open lot. Ammonia emission rate averaged 1061 kg/d from the open lot and 59 kg/d from the lagoons; 95% of NH3 was emitted from the open lot (Table 2). The per capita NH3 emission rate was 304 g/cow/d from the open lot (41% of N intake) and 17 g/cow/d from lagoons (2% of N intake). Mean N intake was 612 g/cow/d and N exported in milk averaged 145 g/cow/d. The dairy N balance showed that most N was lost as NH3. Daily N input at the dairy was 2139 kg/d, with 43, 36, 19 and 2% of the N partitioned to NH3 emission, manure/lagoons, milk, and cows, respectively (Fig. 2). The NH3 production intensity was 13.7 g NH3/kg milk. We estimated that on an annual basis, from 30 to 35% of fed N would be lost as NH3. Ammonia loss from open lot dairies is more similar to that from open lot beef feedyards than from dairies with closed housing where manure is more intensively managed.

Future Plans

Next steps include sampling during additional seasons to better characterize annual emissions.

Corresponding author, title, and affiliation

Richard W. Todd, Research Soil Scientist at USDA ARS Conservation and Production Research Laboratory, Bushland TX

Corresponding author email

richard.todd@ars.usda.gov

Other authors

N. Andy Cole, Res. Animal Scientist at USDA ARS CPRL, Bushland, TX; G. Robert Hagevoort, Ext. Diary Specialist at New Mexico State University; Kenneth D. Casey, Air Quality Engineer and Brent W. Auvermann, Agricultural Engineer at Texas A&M AgriLife.

Additional information

For more information, contact Richard Todd, 806-356-5728.

Acknowledgements

Research was partially funded with a USDA NIFA Special Research Grant through the Southern Great Plains Dairy Consortium.

$Table 1. Cow population, feed dry matter intake (DMI) and crude protein (CP), and the fraction of N fed for each cow class$

Table 1.

$Table 2. Mean NH3 flux density, emission rate, per capita emission rate (PCER), and the fraction of N intake lost as NH3-N from either the open lot or lagoons.$

Figure 1.

Figure 2. Nitrogen partitioning at the New Mexico dairy. Daily N input was 2139 kg d-1. Milk N and NH3-N were measured, N partitioned to cows was estimated as 2% of N intake and N partitioned to manure and lagoons was the residual of the N balance.

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.

March 5, 2019March 6, 2019

Development of a New Manure Amendment for Reducing Ammonia Volatilization and Phosphorus Runoff from Poultry Litter

Adding alum to animal manures greatly reduces ammonia (NH3) emissions and phosphorus (P) runoff. Improvements in poultry production, lower energy costs and environmental benefits from alum have led to widespread use by the poultry industry. Over one billion broilers are grown with alum in the U.S. each year. However, the price of alum has increased dramatically, creating a need for cheaper products that control NH3 and P losses. The goal of this research was to develop an inexpensive manure amendment that is as effective as alum in reducing NH3 volatilization and P runoff from poultry litter. Sixteen manure amendments were created using various ratios of alum mud, bauxite ore, sulfuric acid, liquid alum and water. Alum mud is the waste product that is left over from the manufacture of alum when made by mixing sulfuric acid with bauxite. A laboratory NH3 volatilization study was conducted using a total of 11 treatments; untreated poultry litter, litter treated with liquid or dry alum and litter treated with eight of the new mixtures. All amendments tested resulted in significantly lower NH3 losses than the controls. Ammonia losses with dry and liquid alum were reduced by 86% and 75%, respectively. Ammonia losses with the eight new amendments ranged from 62 to 73% less than controls and were not significantly different from liquid alum and the three most effective mixtures were not significantly different from dry alum. All of the amendments also significantly reduced water extractable P (WEP); three of which resulted in significantly lower WEP than with dry alum. The most promising products were mixtures of alum mud, bauxite, and sulfuric acid. The potential impact of these products could be enormous, since they could be produced for less than half the price of alum, while being equally effective at reducing both NH3 emissions and P runoff.

Authors

Moore, Philip philip.moore@ars.usda.gov USDA/ARS

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.

March 5, 2019August 14, 2019

Impact of Manure Incorporation on Greenhouse Gas Emissions in Semi-Arid Regions

Purpose

Gaseous emissions from animal feeding operations (AFOs) can create adverse impacts ranging from short-term local effects on air quality, to long-term effects due to greenhouse gas generation. This study evaluates gaseous emissions from manure application with differing times to incorporation. The purpose of the study is to identify ways to improve manure management and land application BMPs in semi-arid regions with a high soil pH.

What did we do?

Manure application and incorporation methods were evaluated in a field setting on a soil with high pH. Scraped dairy manure was surface applied at a rate of 50 tons/acre to a Millville silt loam. Incorporation events occurred immediately, 24hrs after application, 72 hrs after application, and no incorporation. Gaseous emissions were monitored using a closed dynamic chamber with a Fourier Transformed Infrared (FTIR) spectroscopy gas analyzer, which is capable of monitoring 15-pre-programmed gases simultaneously including ammonia, carbon dioxide, methane, nitrous oxide, oxides of nitrogen, and volatile organic compounds. Emissions were monitored for 15 days.

What have we learned?

Emissions for methane (CH4) and ammonia (NH3) stopped when the manure was incorporated. For methane, 33% of the emissions occurred within the first 24 hours, 61% within the first 72 hrs. For ammonia, 50% of the emissions occurred within the first 24 hours, 88% within the first 72 hours. Carbon dioxide (CO2) emissions were reduced, but continued at a baseline level after incorporation. Immediate incorporation reduced total CO2 emissions for the 15 days by approximately 50%. Incorporation within 24 hours and 72 hours, reduced total CO2 emissions for the 15 days by 40% and 18%, respectively. Based on this data, incorporation greatly reduces NH3, CH4, and CO2 emissions. Rapid incorporation is needed to have a meaningful impact on NH3 and CH4 emissions. Best management practices should emphasize the need for immediate incorporation.

(Click to enlarge the graphs below).

Future Plans

Examine the impact of tannins on gaseous emissions.

Authors

Rhonda Miller, Ph.D.; Agricultural Systems Technology and Education Dept.; Utah State University rhonda.miller@usu.edu

Pakorn Sutitarnnontr, Ph.D.; South Florida Water Management District; Naples, FL Markus Tuller, Ph.D.; Soil, Water, and Environmental Science Dept.; University of Arizona Jim Walworth, Ph.D.; Soil, Water, and Environmental Science Dept.; University of Ar

Additional Information

Sutitarnnonntr, P., E. Hu, R. Miller, M. Tuller, and S. B. Jones. 2013. Measurement Accuracy of a Multiplexed Portable FTIR- Surface Chamber System for Estimating Gas Emissions. ASABE 2013 Paper and Presentation No. 131620669. St. Joseph, MI: American Society of Agricultural and Biological Engineers.

Website: http://agwastemanagement.usu.edu

Acknowledgements

The authors gratefully acknowledge support from a USDA-CSREES AFRI Air Quality Program Grant #2010-85112-50524.

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.