Effects of Adding Clinoptilolite Zeolite on Dairy Manure Composting Mix on the Compost Stability and Maturity

The purpose of this project was to demonstrate the effects of adding natural clinoptilolite zeolites to a dairy manure compost mix at the moment of initiating the composting process on characteristics of the final compost and nitrogen (N) retention. On-farm composting of manure is one Best Management Practice (BMP) available to dairy producers. Composting reduces the volume of composted wastes by 20 to 60% and weight by 30 to 60%, which allows the final product to be significantly more affordable to transport than raw wastes. When done properly, composting can convert a considerable fraction of the N present in the raw manure into a more stable form, which is released slowly over a period of years and thereby not partially lost to the environment (Rynk et al., 1992; Magdoff and Van Es, 2009). During the manure handling and composting process, between 50 and 70% of the N can be lost as ammonia (NH3) if additional techniques are not used to increase nitrogen retention. Most of the time, manures from dairies and other livestock operations don’t have the proper carbon to nitrogen ratio (C:N) to be composted efficiently without added carbon. A balanced mix for composting should be between C:N of 30:1 to 40:1 (Rynk et al., 1992; Fabian et al., 1993). Since manures are richer in nitrogen (C:N ratios below 15:1), and bedding doesn’t add enough carbon during most of the year, a great proportion of the available N is lost as NH3 due to the lack of carbon to balance the composting process, resulting in a lower grade compost that can generate local and regional pollution due to NH3 emissions. In many arid zones there are not enough sources of carbon to balance the nitrogen present in the manure. Due to this lack of adequate carbonaceous material, additional methods to reduce the loss of N as NH3 during the composting process are needed. Several amendments have been evaluated in the past to achieve this reduction in N loss (Ndegwa et al., 2008). Zeolites are minerals defined as crystalline, hydrated aluminosilicates of alkali and alkaline earth cations having an infinite, open, three-dimensional structure. Clinoptilolite zeolite is mined in several western states including Idaho, where mining is near the dairy production areas.

This paper showcases an on-farm project that explored the effects of adding clinoptilolite to dairy manure at the time of composting as a tool to reduce NH3 emissions, retain N in the final composted product, and evaluate its effect on the final product.

What did we do?

This on-farm research was conducted at an open-lot dairy in Southern Idaho with 100 milking Jersey cows. Manure stockpiled during the winter and piled after the corral’s cleaning was mixed with fresh pushed-up manure from daily operations and straw from bedding and old straw bales, in similar proportions for each windrow. The compost mixture was calculated using a compost spreadsheet calculator (WSU-Puyallup Compost Mixture Calculator, version 1.1. Puyallup, WA). Moisture was adjusted by adding well water to reach approximately 50% to 60% moisture on the initial mix. Windrows were mixed and mechanically turned using a tractor bucket. Three replications were made for control and treatment. The control (CTR) consisted of the manure and straw mix as described. The treatment (TRT) consisted of the same mix as the control, plus the addition of 8% w/w (15%DM) of clinoptilolite zeolite during the initial mix. Windrows were actively composted for 149 days on average. Ammonia emissions were measured using passive samplers (Ogawa & Co. Kobe, Japan) and results were described in a previous Waste to Worth proceeding paper (de Haro Martí, et al. 2017). Complete initial manure (compost feedstock mix) and final screened compost nutrient lab analyses were performed for each windrow. Compost maturity tests were performed using the SOLVITA® test (Woods End Laboratories, Mt Vernon, ME). Statistical analyses were conducted using SAS 9.4 (SAS Institute, Cary, NC). Analyses included ANOVA (PROC MIXED) and paired t-test when applicable.

What have we learned?

The initial mix lab analysis revealed no significant differences in all parameters between control and treatment, except for ammonium (NH4+) where a tendency was observed. Many of the most stable parameters were very close to one another numerically, indicating a good management of the on-farm feedstock formulation and mixing. Ammonium at 553.4±100 mg/kg for CTR and 256.77±100 mg/kg for TRT showed a tendency (0.05<p≤0.1, Figure 1).

Figure 1. Ammonium ppm before and after composting   
Figure 1. Ammonium ppm before and after composting

This difference from the beginning of the process indicates that clinoptilolite has an immediate impact on NH4+ when added to the compost mix, changing the NH4+ and NH3 behavior and volatilization even during the construction of the windrow.

Nitrate (NO3) concentration in the TRT compost, 702±127 mg/kg was three times higher than the CTR, 223±127 (p= 0.05, Figure 2).

Figure 2. Nitrate ppm before and after composting
Figure 2. Nitrate ppm before and after composting

The presence of such high amount of NO3 compared to the control indicates a strong prevalence of nitrification processes (Sikora and Szmidt, 2001; Weil and Brady, 2017). Elevated NO3 concentrations are desirable in high quality compost used in plant nurseries, green houses, and horticulture, and are usually obtained from feedstock with much higher carbon content than the one used in this research. The NO3 to NH4+ ratio (NO3:NH4) in the treated windrows is also indicative of a much more stable compost than what is to be expected in a dairy compost with such low initial C:N (Sikora and Szmidt, 2001). High NO3 concentrations in compost could, however, generate a concern for NO3 leaching if the compost is not managed properly during storage and at the time of application (Miner et al., 2000; Weil and Brady, 2017). Total nitrogen (TN) on the compost was 14,933±1,379 mg/Kg (1.5%) for CTR and 11,300±1,379 mg/Kg (1.1%) for TRT (p=0.13), showing no significant difference.

Table 1. Solvita® test results on finished compost
Sample TRT or CTR

CO2
Index

NH3
Index

Maturity Index Compost Condition O2 depletion Phytotoxicity Noxious hazard pH NH4+ Estimate (ppm) N-Loss potential
W 1 CTR 6.5 3.5 5.5 Curing 1.60% Medium/ Slight Moderate /Slight 9.1 500 Moderate/Low
W 2 CTR 6.5 2 4.5 Active 2.50% High Severe 9.3 1500 M/ High
W 5 CTR 6.5 2 4.5 Active 2.50% High Severe 9.8 1500 M/ High
W 3 TRT 7 5 7 Finished 0.70% None None 9.5 <200 V Low-None
W 4 TRT 7 5 7 Finished 0.70% None None 8.9 <200 V Low-None
W 6 TRT 6 5 6 Curing 1.20% None None 9.3 <200 V Low-None

The Solvita® test results from the screened composts (Table 1) show a significant difference (p=0.007) in the NH3 test results between CTR, index 2.5±0.35 and TRT, index 5.0±0.35. Carbon Dioxide (CO2) test results showed no significant differences between CTR and TRT. All other calculated parameters showed a significant difference between control and treatment. Maturity index was 4.8±0.33 for CTR and 6.7±0.33 for TRT (p<0.02). Oxygen depletion was 0.022±0.002 for CTR and 0.009±0.002 for TRT (p<0.02). NH4+ estimate was 1167 for CTR and <200 for TRT (p=0.05). Other estimated test parameters indicate a significant difference between CTR and TRT results. Control windrows showed more unstable conditions, reaching the active or curing status, medium to high phytotoxicity, moderate to severe noxious hazard, and moderate to low N-loss potential. In contrast, treatment windrows showed more stable conditions, including reaching finished and curing status, no phytotoxicity or noxious hazard, and very low to no N-loss potential.

These results, coupled with the NO3:NH4 ratio and much higher NO3 values in the zeolite amended compost, indicate that the addition of clinoptilolite zeolite to a dairy manure compost mix in this study induced nitrification processes, produced NH4+ retention, NH3 emissions reduction, and lower oxygen depletion without significantly modifying the CO2 production. It also led to compost maturity characteristics that are regularly achieved only in compost mixes with much higher carbon content  and C:N ratios, usually associated with high quality composts. No negative effects were observed in the composting process or final product.

Future Plans

A greenhouse trial on silage corn comparing treatment and control compost effects followed. Results need to be analyzed and published.

Authors

Mario E. de Haro-Martí. Extension Educator. University of Idaho Extension, Gooding County, Gooding, Idaho. mdeharo@uidaho.edu  

Mireille Chahine. Extension Dairy Specialist. University of Idaho Extension, Twin Falls R&E Center, Twin Falls, Idaho.

Additional information

 

References:

de Haro-Martí, M.E., H. Neibling, M. Chahine, and L. Chen. 2017. Composting of dairy manure with the addition of zeolites to reduce ammonia emissions. Waste to Worth, Advancing Sustainability in Animal Agriculture conference. Raleigh, North Carolina.

Fabian, E. E., T. L. Richard, D. Kay, D. Allee, and J. Regenstein. 1993. Agricultural composting: a feasibility study for New York farms. Available at:  http://compost.css.cornell.edu/feas.study.html . Accessed 04/28/2011.

Lorimor, J., W. Powers, A. Sutton. 2000. Manure Characteristics. Manure Management System Series. Midwest Plan Service. MPWS-18 Section 1. Iowa State University.

Magdoff, F., & Van Es, H. (2009). Building soils for better crops – Sustainable soil management (3rd ed.). Brentwood, MD, USA: Sustainable Agriculture Research and Education program.

Miner, J. R., Humenik, F. J., & Overcash, M. R. 2000. Managin livestock wastes to preserve environmental quality (First ed.). Ames, Iowa, USA: Iowa State University Press.

Mumpton, F.A. 1999. La roca magica: Uses of Natural Zeolites in Agriculture and Industry. Proceedings of the National Academy of Sciences of the United States of America, Vol.     96, No. 7 (Mar. 30, 1999), pp. 3463-3470

Ndegwa, P. M., Hristov, A. N., Arogo, J., & Sheffield, R. E. 2008. A review of ammonia emission mitigation techniques for concentrated animal feeding operations. Biosystems Eng. (100), 453-469.

Rink, R., M. van de Kamp, G.B. Willson, M.E. Singley, T.L. Richard, J.J. Kolega, F.R. Gouin, L.L. Laliberty Jr., D.K. Dennis. W.M. Harry, A.J. Hoitink, W.F.Brinton. 1992. On-Farm Composting Handbook. NRAES-54. Natural Resource, Agriculture, and Engineering Service. Cooperative Extension. Ithaca, New York.

Sikora, L. J., & Szmidt, R. A. 2001. Nitrogen sources, mineralization rates, and nitrogen nutrition benefits to plants from composts. In P. J. Stofella, & B. A. Kahn (Eds.), Compost utilization in horticultural cropping systems (pp. 287-306). Boca Raton, Florida, USA: CRC Press LLC.

Weil, R. R., & Brady, N. C. 2017. The nature and properties of soils (Fifteenth. Global Edition ed.). Harlow, Essex, England: Pearson Education Limited.

Acknowledgements

This project was made possible through a USDA- ID NRCS Conservation Innovation Grants (CIG) # 68-0211-11-047. The authors also want to thank the involved dairy farmer and colleagues that helped during this Extension and research project. Thanks to USDA-ARS Kimberly, ID for the loan and sample analysis of the Ogawa passive samplers.

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.

 

Comparison of Sulfuric vs. Oxalic Sulfuric When Forming Struvite from Liquid Dairy Manure

Purpose

The purpose of this project was to demonstrate a mobile fluidized-bed cone for extraction of phosphorus in the form of struvite (magnesium-ammonium phosphate) from undigested (raw) liquid dairy manure. Since Ca binds inorganic P, a particular emphasis was placed on evaluating the effect of oxalic acid as an acidifier and Ca binder.

Dairies often have excess P in manure in relation to the need for on-farm crop production. Easily mineable reserves of phosphorus (P) worldwide are limited, with a majority residing in Morocco (USGS 2013). One approach to recycling P is to capture excess P from dairy manure in the form of struvite for off-farm export as a nutrient source for crop production.

What we did

A portable trailer-mounted fluidized-bed cone (volume of 3200 L) was used to extract phosphorus in the form of struvite (magnesium-ammonium phosphate) from undigested (raw) liquid dairy manure. Batches of 13,000 liters of manure were evaluated and the system was operated at a flow rate of ~ 32 liters per minute.  Sulfuric acid or oxalic acid-sulfuric acid were used to decrease the pH, and sodium hydroxide was used to raise the pH. Oxalic acid was chosen for evaluation due to its dual ability to decrease pH and bind calcium.

What we learned

Results of concentration of total P or ortho-P (OP) after manure treatment through the fluidized bed suggested no advantage of the combination of oxalic acid with sulfuric acid to decrease the concentration of P (see Figures 1 and 2). More detailed analyses of centrifuged post-bed samples of manure effluent indicated that the oxalic acid was binding the free calcium, but the resulting Ca compounds remained suspended in the effluent. Centrifuged manure samples had Ca contents ~23% of un-centrifuged samples when oxalic/sulfuric acid was used as a pH reducer. Centrifuged manure samples had Ca contents ~84% of un-centrifuged samples when sulfuric acid was used as a pH reducer. With raw manure, oxalate does not appear to be beneficial, unless there is a more effective step to drop Ca-oxalate out of suspension, such as centrifuging.

Figure 1. Concentration of OP or P in manure after pre-treatment with oxalic and sulfuric acid.
Figure 1. Concentration of OP or P in manure after pre-treatment with oxalic and sulfuric acid.

 

Figure 2. Concentration of OP or P in manure after pre-treatment with sulfuric acid.
Figure 2. Concentration of OP or P in manure after pre-treatment with sulfuric acid.

Future Plans

Anaerobically digested (AD) manure will be evaluated with the same set of conditions that were utilized with raw dairy manure to determine potential benefits of using oxalic acid with AD manure.

Authors

Joe Harrison1, Kevin Fullerton1, Elizabeth Whitefield1, and Keith Bowers2.

1Washington State University

2Multiform Harvest

jhharrison@wsu.edu

Citations and video links

U.S. Geological Survey, Mineral Commodity Summaries, January 2013. http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mcs-2013-phosp.pdf

The Mobile Struvite Project Overview Video: Capturing Phosphorus from Liquid Dairy Manure and Cost Efficient Nutrient Transport

Dairy Struvite Video: Capturing Phosphorus from Dairy Manure in the Form of Struvite on 30 Dairy Farms in WA state

Alfalfa Struvite Video: Struvite, a Recycled Form of Phosphorus from Dairy Manure, used as Fertilizer for Alfalfa Production

Acknowledgements

This project funded by the USDA NRCS CIG program and the Dairy Farmers of Washington.

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.

Comparison of Struvite to Mono-Ammonium-Phosphate as a Phosphorus Source on Commercial Alfalfa Fields

The purpose of this project was to demonstrate a regional nutrient (phosphorus (P)) recycling relationship between the dairy industry and alfalfa forage growers. Dairies often have excess P in manure in relation to the need for crop production on-farm. Easily mineable reserves of phosphorus (P) worldwide are limited, with a majority residing in Morocco (USGS 2013). One approach to recycling P is to capture excess P from dairy manure in the form of struvite for off-farm export for use as a nutrient source of crop production. Washington State produces a significant amount of alfalfa for domestic and international sales.

What did we do

Struvite (Magnesium Ammonium Phosphate – NH4MgPO4· 6H2O) and Mono Ammonium Phosphate (MAP) were applied to 33 and 30 acres (control and treatment, Farm 1); and 60 and 55 acres (control and treatment, Farm 2) sections of alfalfa fields at two commercial forage producers in Eastern Washington. Fertilizer (struvite or MAP) was applied on an equivalent P2O5 basis in August 2017 and September 2018 (Farm 1 – existing stand) and September 2017 and September 2018 (Farm 2 – new seeding).

What have we learned

Accumulative yield of alfalfa in 2018 for Farm 1 was struvite = 7.14 tons, MAP = 7.51 tons. Accumulative yield (2 of 3 cuttings) of alfalfa in 2018 for Farm 2 was struvite = 3.08 tons, MAP = 2.95 tons. Average P concentration of alfalfa in 2018 for Farm 1 was struvite = 0.27, MAP = 0.27 (% DM).  Average P concentration in alfalfa in 2017 for Farm 1 was struvite = 0.31, MAP = 0.32 (% DM). Average P concentration of alfalfa in 2018 for Farm 2 for struvite and MAP was 0.27 and 0.28 % DM, respectively. Average accumulative P uptake of alfalfa in 2018 for Farm 1 was 38 and 39 lbs P/acre for struvite and MAP, respectively. Average accumulative P uptake (2 of 3 cuttings) of alfalfa in 2018 for Farm 2 was struvite = 15 lbs, MAP = 16 lbs P/acre. Results indicate that struvite is equivalent to MAP as a P source for commercial production of alfalfa.

Future Plans

The nutrient recycling project will continue through 2019. In addition, companion replicated plots studies are underway to evaluate the effects of ratio of MAP:Struvite and amount of P application for yield and quality of alfalfa.

Authors

Joe Harrison1, Steve Norberg1, Kevin Fullerton1, Elizabeth Whitefield1, Erin Mackey1, and Keith Bowers2.

1Washington State University, jhharrison@wsu.edu

2Multiform Harvest

Citations and video links

U.S. Geological Survey, Mineral Commodity Summaries, January 2013. http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mcs-2013-phosp.pdf

    The Mobile Struvite Project Overview Video: Capturing Phosphorus from Liquid Dairy Manure and Cost Efficient Nutrient Transport

    Dairy Struvite Video: Capturing Phosphorus from Dairy Manure in the Form of Struvite on 30 Dairy Farms in WA state

    Alfalfa Struvite Video: Struvite, a Recycled Form of Phosphorus from Dairy Manure, used as Fertilizer for Alfalfa Production

Acknowledgements

This project funded by the USDA NRCS CIG program and the Dairy Farmers of Washington.

 

 

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.

USDA-NRCS and the National Air Quality Site Assessment Tool (NAQSAT) for Livestock and Poultry Operations

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Purpose

The National Air Quality Site Assessment Tool (NAQSAT) was developed as a first-of-its-kind tool to help producers and their advisors assess the impact of management on air emissions from livestock and poultry operations and identify areas for potential improvement related to those air emissions.

What did we do?

In 2007, several land-grant universities, with leadership from Michigan State University, began developing NAQSAT under a USDA-NRCS Conservation Innovation Grant (CIG). The initial tool included beef, dairy, swine, and poultry operations. A subsequent CIG project, with leadership from Colorado State University, made several enhancements to the tool, including adding horses to the species list. In 2015, USDA-NRCS officially adopted NAQSAT as an approved tool for evaluating air quality resource concerns at livestock and poultry operations. USDA-NRCS also contracted with Florida A&M University in 2015 to provide several regional training workshops on NAQSAT to NRCS employees. Six training workshops have been completed to date (Raleigh, NC; Modesto, CA; Elizabethtown, PA; Lincoln, NE; Richmond, VA; and Yakima, WA) with assistance from multiple NAQSAT development partners. Additionally, USDA-NRCS revised its comprehensive nutrient management plan (CNMP) policy in October 2015 to make the evaluation of air quality resource concerns mandatory as part of CNMP development.

Snippet from website of the National Air Quality Site Assessment Tool

Group photo of team in field

Zwicke in class lecturing

Zwicke and group in animal housing facility

What have we learned?

NAQSAT has proven to be a useful tool for bench-marking the air emissions impacts of current management on confinement-based livestock and poultry operations. In the training sessions, students have been able to complete NAQSAT runs on-site with the producer or producer representative via tablet or smartphone technologies. Further classroom discussion has helped to better understand the questions and answers and how the NAQSAT results can feed into the USDA-NRCS conservation planning process. Several needed enhancements and upgrades to the tool have been identified in order to more closely align the output of the tool to USDA-NRCS conservation planning needs. NAQSAT has also proven to be useful for evaluating the air quality resource concern status of an operation in relation to the CNMP development process.

Future Plans

It is anticipated that the identified needed enhancements and upgrades will be completed as funding for further NAQSAT development becomes available. Additionally, as use of NAQSAT by USDA-NRCS and our conservation planning and CNMP development partners expands, additional training and experience-building opportunities will be needed. The NAQSAT development team has great geographic coverage to assist in these additional opportunities.

Corresponding author, title, and affiliation

Greg Zwicke, Air Quality Engineer – Air Quality and Atmospheric Change Team, USDA-NRCS

Corresponding author email

greg.zwicke@ftc.usda.gov

Other authors

Greg Johnson, Air Quality and Atmospheric Change Team Leader, USDA-NRCS; Jeff Porter, Animal Nutrient and Manure Management Team Leader, USDA-NRCS; Sandy Means, Agricultural Engineer – Animal Nutrient and Manure Management Team, USDA-NRCS

Additional information

naqsat.tamu.edu

https://lpelc.org/naqsat-for-swine-and-poultry

https://lpelc.org/naqsat-for-beef-and-dairy/

Acknowledgements

C.E. Meadows Endowment, Michigan State University

Colorado Livestock Association

Colorado State University

Florida A&M University

Iowa Turkey Federation

Iowa Pork Producers

Iowa Pork Industry Center

Iowa State University

Iowa State University Experiment Station

Kansas State University

Michigan Milk Producers Association

Michigan Pork Producers Association

Michigan State University

Michigan State University Extension

National Pork Board

Nebraska Environmental Trust

Oregon State University

Penn State University

Purdue University

Texas A&M University

University of California, Davis

University of Georgia

University of Georgia Department of Poultry Science

University of Idaho

University of Maryland

University of Maryland Department of Animal and Avian Sciences

University of Minnesota

University of Missouri

University of Nebraska

USDA-ARS

Virginia Tech University

Washington State University

Western United Dairymen

Whatcom County (WA) Conservation District

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.

Nitrogen and Phosphorus Cycling Efficiency in US Food Supply Chains – A National Mass-Balance Approach


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Purpose 

Assessing and improving the sustainability of livestock production systems is essential to secure future food production. Crop-livestock production systems continue to impact nitrogen (N) and phosphorus (P) cycles with repercussions for human health (e.g. secondary particle formation due to ammonia emission and drinking water contamination by nitrate) and the environment (e.g. eutrophication of lakes and coastal waters and exacerbation of hypoxic zones). Additionally, P is a limited resource, and sustaining an adequate P supply is a major emerging challenge. To develop strategies for a more sustainable use of N and P, it is essential to have a quantitative understanding of the flows and stocks of N and P within the society. In this study, we developed detailed national N and P budgets to assess nutrient cycling efficiency in US (livestock) food supply chains, to identify hotspots of nutrient loss and to indicate opportunities for improvement!

What did we do? 

1. National nutrient mass-balance

A mass-balance framework was developed to quantify nutrient flows within the US. In this framework, the national US system is represented by 9 major sectors are relevant in terms of nutrient flows: mining (relevant for P only), industrial production, agriculture, food & feed processing industry, retail, households and other consumers, energy and transport, humans, and waste treatment. These sectors can exist of several sub-sectors. For example, the agricultural sector consists of several secondary sub-systems including pasture, agricultural soil, livestock and manure management (WMS – waste management system).

Different livestock categories can have distinct environmental impacts and nutrient use efficiencies (e.g. (Hou et al. 2016), (Eshel et al. 2014), (Herrero et al. 2013)), we therefore distinguish six livestock categories (dairy cattle, beef cattle, poultry (meat), poultry (layers), sheep, hogs) and

 their associated food commodities (dairy products, beef from dairy cattle, beef, poultry, eggs, lamb, pork).

For each sub-system, we identify and quantify major flows to and from this compartment. All flows are expressed in a common unit, i.e. metric kiloton N per year (kt N/yr) for nitrogen and metric kiloton P per year (kt P/yr) for phosphorus. Quantified flows include nutrient related emissions to the environment and waste flows.

At present, the waste sectors and environmental compartment are outside the system boundaries, that is, we quantify flows to these compartments, but we do not attempt to balance these sectors. We do, however, keep track of the exact chemical species (e.g. emission of N2O-N to air instead of N to air) emitted as far as possible. The municipal waste treatment (MSW) and municipal waste water treatment (WWTP) are treated in more detail: major flows from and to these compartments are quantified. These sub-sectors are treated in more detail because of their role in nutrient recycling through e.g. sewage sludge application on agricultural soils.

Data were collected in priority from national statistics (e.g. USDA NASS for livestock population) and peer-reviewed literature, and were supplemented with information from industrial reports and extension files if needed. If available, data were collected for the years 2009 to 2012 and averaged, when unavailable, we collected data for the closest year.

2. Scenario analysis

In the scenario analysis, we test the opportunity for dairy livestock production systems to contribute to a more efficient nutrient use through anaerobic co-digestion of dairy manure and organic food waste. Recently, Informa Economics assessed the national

 market potential of anaerobic digester products for the dairy industry (Informa Economics 2013). Next to a reduction in greenhouse gas emissions, anaerobic co-digestion of dairy manure and organic food waste can contribute to improve nutrient cycling efficiency (Informa Economics 2013). Dairy manure contains high levels of nitrogen and phosphorus, which can be used as a natural crop fertilizer, if recuperated from manure. Presently, non-farm organic substrates such as food waste are typically disposed of in landfills, which causes greenhouse gas (GHG) emissions and also results in a permanent removal of valuable nutrients from the food supply chain (Informa Economics 2013). By anaerobic co-digestion, a part of the nutrien! ts contai ned in dairy manure and food waste can be recovered. These nutrients can be used to fertilize crops and substitute synthetic fertilizer application. In the scenario analysis, we test to what extent anaerobic co-digestion of dairy manure and food waste can contribute to improve nutrient cycling efficiency, particularly by substituting synthetic fertilizers. We develop the scenario based on data provided in the InformaEconomics report.

What have we learned? 

In general, our results show that livestock production is the least efficient part of the total food supply chain with large losses associated with manure management and manure and fertilizer application to crops. In absolute terms, the contribution of the household stage to total and N and P losses from the system is small, approximately 5 and 7% for N and P, respectively. However, households ‘waste’ a relatively large percentage of purchased products, (e.g. 16% and 18% of N and P in dairy products end up as food waste), which presents an opportunity for improvement. A scenario was developed to test to what extent anaerobic co-digestion of dairy manure and food waste can contribute to improving nutrient cycling efficiency on a national scale. Results suggest that 22% and 63% of N and P applied as synthetic fertilizer could potentially be avoided in dairy food supply chains by large scale implementation of anaerobic co-digestion o! f manure and food waste.

Future Plans     

Future research plans include a further development of scenarios that are known to reduce nutrient losses at the farm scale and to assess the impact of these scenarios on national nutrient flows and losses.

Corresponding author, title, and affiliation        

Karin Veltman, PhD, University of Michigan, Ann Arbor

Corresponding author email    

veltmank@umich.edu

Other authors    

Carolyn Mattick, Phd, Olivier Jolliet, Prof., Andrew Henderson, PhD.

Additional information                

Additional information can be obtained from the corresponding author: Karin Veltman, veltmank@umich.edu

Acknowledgements       

The authors wish to thank Ying Wang for her scientific support, particularly for her contribution in developing the anaerobic co-digestion scenario.

This work was financially supported by the US Dairy Research Institute.

 

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.

How Well Do We Understand Nitrous Oxide Emissions from Open-lot Cattle Systems?

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Purpose

Nitrous oxide (N2O) emissions from concentrated animal feeding operations, including cattle feedyards, have become an important research topic. However, there are limitations to current measurement techniques, uncertainty in the magnitude of feedyard N2O fluxes, and a lack of effective mitigation methods. There are uncertainties in the pathway of feedyard N2O production, the dynamics of nitrogen transformations in these manure-based systems, and how N2O emissions differ with changes in climate and feedyard management.

What Did We Do?

A literature review was conducted to assess the state-of-the-science of N2O production and emission from open-lot beef cattle feedyards and dairies. The objective was to assess N2O emission from cattle feedyards, including comparison of measured and modeled emission rates, discussion of measurement methods, and evaluation of mitigation options. In addition, laboratory, pilot-scale, and field-scale chamber studies were conducted to quantify and characterize N2O emissions from beef cattle manure. These studies led to new empirical model to predict feedyard N2O fluxes as a function of temperature and manure nitrate and water contents. Organic matter stability/availability was important in predicting manure-derived N2O emissions: inclusion of data for dissolved organic carbon content and Ultraviolet-visible (UV-vis) spectroscopic indices of molecular weight, complexity and degree humification improved model performance against measured data.

What Have We Learned?

Published annual per capita flux rates for beef cattle feedyards and open-lot dairies in arid climates were highly variable and ranged from 0.002 to 4.3 kg N2O animal-1 yr-1. On an area basis, published emission rates ranged from 0 to 41 mg N2O m-2 h-1. From these studies and the Intergovernmental Panel on Climate Change emission factors, calculated daily per capita N2O fluxes averaged 18 ± 10 g N2O animal-1 d-1 (range, 0.04–67 g N2O animal-1 d-1). Some of this variability is inherently derived from differences in manure management practices and animal diets among open-lot cattle systems. However, it was proposed that other major causes of variation were inconsistency in measurement techniques, and irregularity in N2O production due to environmental conditions.

For modeling studies, N2O emissions were measured during 15 chamber studies (10 chambers per study) on commercial Texas feedyards, where N2O emissions ranged from below detection to 101 mg N2O m-2 h-1. Numerous feedyard and manure data were collected and regression analyses were used to determine key variables involved in feedyard N2O losses. Based on these data, two models were developed: (1) a simple model that included temperature, manure water content, and manure nitrate concentration, and (2) a more complex model that included UV-vis spectral data that provided an estimate of organic matter stability. Overall, predictions with both models were not significantly different from measured emissions (P < 0.05) and were within 52 to 61% agreement with observations. Inclusion of data for organic matter characteristics improved model predictions of high (>30 mg m-2 h-1) N2O emissions, but tended to overestimate low emission rates (<20 mg N2O m-2 h-1). This work represents one of the first attempts to model feedyard N2O. Further refinement is needed to be useful for predicting spatial and temporal variations in feedyard N2O fluxes.

Future Plans

This work clearly identified that neither the magnitude nor the dynamics of N2O emissions from open-lot cattle systems were well understood. Five primary knowledge gaps/problem areas were identified, where current understanding is weak and further research is required. These include: (i) the need for accurate measurement of N2O emissions with appropriate and more standardized methods; (ii) improved understanding of the microbiology, chemistry, and physical structure of manure within feedyard pens that lead to N2O emissions; (iii) improved understanding of factors that influence feedyard N2O emissions, including manure H2O content, porosity, density, available nitrogen and carbon contents, environmental temperatures, and use of veterinary pharmaceuticals; (iv) development of cost-effective and practical mitigation strategies to decrease N2O emissions from pen surfaces, manure stockpiles, composting windrows, and retention ponds; and (v) improved process-based models that can accurately predict feedyard N2O emissions, evaluate mitigation strategies, and forecast future N2O emission trends.

Given the potential for future regulation of N2O emissions, feedyard managers, nutritionists, and researchers may play increasingly important roles in on-farm nitrogen management. Current management practices may need modification or refinement to balance production efficiency with environmental concerns. There is a need for data derived from both large-scale micrometerological measurement campaigns and small-scale chamber studies to assess the overall magnitude of feedyard N2O emissions and to determine key factors driving its production and emission. Refined empirical and process-based models based on manure physicochemical properties and weather could provide a dynamic approach to predict N2O losses from open-lot cattle systems.

Corresponding author (name, title, affiliation):

Heidi Waldrip, Research Chemist, USDA-ARS Conservation and Production Laboratory, Bushland, TX

Corresponding author email address

heidi.waldrip@ars.usda.gov

Other Authors

Rick Todd, Research Soil Scientist, USDA-ARS Conservation and Production Laboratory, Bushland, TX

David Parker, Agricultural Engineer, USDA-ARS Conservation and Production Research Laboratory, Bushland, TX

Al Rotz, Agricultural Engineer, USDA-ARS Pasture Systems and Watershed Management Research Unit, University Park, PA

Andy Cole, Animal Scientist, USDA-ARS Conservation and Production Research Laboratory (retired), Bushland, TX.

Ken Casey, Associate Professor, Texas A&M AgriLife Research, Amarillo, TX

Additional Information

“Nitrous Oxide Emissions from Open-Lot Cattle Feedyards: A Review”. Waldrip, H. M., Todd, R. W., Parker, D. B., Cole, N. A., Rotz, C. A., and Casey, K. D. 2016. J. Environ. Qual. 45:1797-1811. Open-access article available at:  https://dl.sciencesocieties.org/publications/jeq/pdfs/45/6/1797?search-r…

USDA-ARS Research on Feedyard Nitrogen Sustainability: http://www.beefresearch.org/CMDocs/BeefResearch/Sustainability_FactSheet…

Acknowledgements

This research was partially funded by the Beef Checkoff: http://www.beefboard.org/

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.

Estimating the Economic Value of the Greenhouse Gas Reductions Associated with Dairy Manure Anaerobic Digestion Systems Located in New York State

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Purpose

There is a worldwide concern in controlling the anthropogenic emissions of greenhouse gas (GHG) emissions. GHGs pertinent to this paper, include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) and are measured in CO2 equivalents (CO2 eq.). On a 100-year basis, CH4 is 34 times as potent as CO2, while N2O is 298 times as potent as CO2 (IPCC, 2013); CO2 eq. is referred to as the global warming potential (GWP) of these gases. The carbon from feed used on a dairy farm originally comes from CO2 recently removed from the atmosphere during photosynthesis and so has a neutral impact on climate change. However, carbon that is converted to CH4 and N2O is a significant concern since their GWPs are much higher. Dairy farms create GHG emissions when they use fossil fuel-based sources to provide energy for the farm, when importing fertilizer to grow crops and to harvest milk. However, emissions from the animals in the form of enteric CH4 and GHGs from manure management ! are much more significant due to the GWP. While every farm is different, estimates from Thoma et al. (2012) show that of the 34.9 Tg of CO2 eq. in the US dairy supply chain, 19% comes from feed production and 53% comes from milk production. Of the milk production, CO2 eq., 49% is from enteric emissions while 44% is from manure management, predominately from CH4 emissions from manure storages.

New York State, the third largest dairy state in the nation (NASS, 2015), has established ambitious overall renewable energy goals including incorporating 50% renewable energy in the electricity used in the State by 2030 (Energy to Lead, 2015) and reducing GHG emissions 40% by 2040 based on 1990 year baseline values (Executive Order, 2009). The New York State Public Service Commission (PSC) is charged with the responsibility of developing a system that encourages utilities to help meet these goals. This includes reforming the energy vision, a new clean energy standard that is being developed to value electric products from distributed energy sources that includes an economic value for the environmental attributes (E).

An attempt at quantifying the environmental benefits of AD (E) might be expressed as follows:

Etotal=∑▒〖Eghg+Eair quality+Ewater quality+Esoil quality+E…〗

As the State’s renewable energy goals are realized, there needs to be a way for the process to include special provisions for those renewable energy sources that have extra societal benefits, including economic and environmental, and that support the rural character of upstate NY. The dairy industry is New York’s leading agricultural sector, accounting for more than one-half of the state’s total agricultural receipts. The increased milk supply has been very important in helping to meet the tremendous growth in the production of yogurt in NYS. However, the margin between the cost of producing milk and the price received for milk sales, is shrinking. Investing in farm facilities like ADSs will need to be analyzed carefully to ensure a return on investment that merits their implementation. An economic value for the environmental attributes of electricity produced from an ADS would aid in the analysis, showing a more positive overall benefit.

Dairy farms are also under increasing pressure to improve conditions environmentally. The New York State Department of Environmental Conservation (NYSDEC) proposed revisions for the CAFO state permit, regulating the water quality impact of farms with more than 300 cows, will require manure storages to be built to limit spreading on at-risk fields during the winter and early spring seasons. These are farm sizes where manure-based ADSs have been built in the past and where many more could be implemented, given a reasonable rate of return. Manure storages are an important best management practice (BMP) to reduce the potential for water pollution by allowing farms to avoid manure spreading during inappropriate times. Unfortunately, if the manure system does not have a way to capture the GHGs produced, they are released into the atmosphere. Manure-based ADSs installed on farms would be a win-win-win to capture and reduce GHGs and to produce renewable energy from the captured! CH4, fur thermore helping to meet the NYS renewable energy and GHG reduction goals. ADSs installed on farms would stimulate the rural economy and also provide the farm and rural community with all the additional benefits contained in Appendix A.

This paper presents an analysis of the GHG reduction potential for a NYS dairy manure management system that includes AD, post-digestion solid-liquid separation (SLS) and long-term manure storage of SLS liquid effluent. This system is representative of almost all of the 27 ADSs currently operating on-farm in NYS today.

METHODS

The mass of GHG emission reductions (i.e., the mass of carbon dioxide equivalents [MT CO2 eq.]) associated with AD (in this analysis, AD followed by SLS with liquid effluent stored long-term) located in New York State (NYS), was quantified and is discussed in this paper. The following protocols were used: IPCC (2006), AgSTAR (2011), and EPA (Federal Register, 2009) combined with reasonable input values that are representative of a farm’s baseline condition (long-term manure storage with no pre-treatment by ADS). The reductions quantified include: 1) the replacement of fossil fuel-based electrical energy by using AD produced biogas to operate an on-site engine-generator set, and 2) GHG emissions from CAFO required (for water quality purposes) long-term manure storages. The difference between the baseline condition and the conditions post-implementation of an ADS yields the farm’s net GHG emission associated with manure storage. To quantify the economic value! of the G HG emission reductions, the EPA social cost of carbon (SC-CO2) was used (EPA, 2016).

What did we do? *

PROCEDURE

The baseline condition is represented in Figure 1. Typical liquid/slurry long-term manure storages have manure that consists of urine plus feces, solid bedding and milking center washwater, added continuously as is produced on the farm. A natural crust may form as lighter organic material floats to the surface. The storages are constructed as a designed earthen storage with 2:1 side slopes or fabricated from concrete or steel. The fabricated structures have straight sides so less surface area is exposed. A few storages have a SLS prior to storage, while very few have a manure storage cover. Without a cover, they are exposed to rainfall from both annual precipitation and from extreme storms. To determine the baseline condition, storage with no SLS and with a natural crust was considered.

Figure 1. Baseline emissions from dairy farm with no renewable energy system (per cow, per year)

Figure 1. Baseline Emissions from Dairy Farm with No Renewable Energy System (Per cow per year)

Establish Long-Term Manure Storage Baseline Emissions

Part I – Estimating typical CH4 emissions from a long-term manure storage

An independent panel of experts agreed (USDA, 2014) that GHG emission reductions are best estimated using the Intergovernmental Panel on Climate Change (IPPC) Tier 2 method. For long-term manure storages, the daily methane emissions can be calculated by using Equation 1.

Equation 1. ECH4 = VS x Bo x 0.67 x (MCF/100)

where:

ECH4 = Mass of CH4 emissions (kg CH4/cow-day)

VS = Mass of volatile solids in manure going to storage (kg/cow-day)

Bo = Maximum volume of CH4 producing capacity for manure (m3 CH4/kg VS)

= 0.24 m3 CH4/kg VS (for dairy cow manure)

0.67 = Conversion factor for m3 CH4 to kg CH4

MCF = CH4 conversion factor for the manure management system

Yearly CH4 emissions (kg CH4/cow-yr.) can be estimated by summing the daily emissions (or multiplying an average representative daily emission by 365 days). The MCF is largely dependent on the temperature and the type of manure management system. The MCF will change throughout the year as the manure storage temperature changes. Using a summer ambient temperature representative of Upstate New York, of 18°C (64°F) and a winter ambient temperature of < 10°C (< 50°F), a farm can limit the amount stored and the time in storage during the warmer months to reduce the average yearly MCF. Different manure systems also have a different MCF based on the oxygen levels, interception of CH4 gases, and moisture content.

The two variables that can be controlled by the farm management are the VS loading per cow and the methane conversion factor (MCF). The VS loading rate can be reduced by any pre-manure storage treatment process that reduces the storage organic loading rate; fine tuning the diet to reduce VS in the manure and SLS are examples of two methods used to control the VS.

Typically in NYS, manure is stored both in the summer and winter in a liquid/slurry system with no natural crust. Using average typical winter and summer manure storage temperatures, average MCF values can be used in Equation 1 to estimate average methane emissions for these 6-month storage periods. The MCF values are shown in Table 1.

Table 1. Typical Long-Term Manure Storage Methane Conversion Factors for Storage Periods in NYS1

Storage Period

Winter

Summer

Average Manure Storage Temperature (°C)

<10

18

MCF

17

35

1These numbers are based on liquid/slurry storage without a natural crust cover.  (Source:  IPCC, 2006)

Using these MCF values shown in Table 1 and a per-cow VS excretion rate of 7.7 kg/cow-day (representative of high producing NY dairy cows – ASABE, 2006), manure storages could be estimated to produce 38 kg CH4/cow (for the winter storage period) and 79 kg CH4/cow (for the summer storage period) or an average of 4 metric tons (MT) of CO2 eq. per cow per year since 1 kg of CH4 = 34 kg CO2 eq.

Part II – Estimating typical N2O emissions from a long-term manure storage

There could be N2O emissions from a raw manure storage facility. The CO2 equivalent from N2O emissions can be estimated by using Equation 2.

Equation 2. CO2eq = 298 CO2/N2O GWP x EF3 x N x44 N2O/28 N2O-N

where:

CO2eq = Equivalent global warming potential expressed as carbon dioxide

298 CO2/N2O = GWP factor for N2O

EF3 = Emission Factor for N2O-N emissions from manure management

N = Mass of N excreted per cow per day = 0.45 kg/cow-day (ASAE, 2005)

Using an EF3 value of 0.005 (USEPA, 2009) for long-term storage of slurry manure with a crust and multiplying it by 0.45 kg of N/cow-day and by 365 days per year yields an additional 0.38 MT of CO2 eq. per cow per year from N2O emissions from a long-term manure storage facility.

Summary of long-term storage GHG emissions

Combining both the CO2 eq. per cow per year from CH4 emissions and the CO2 eq. per cow per year from N2O emissions from a manure storage facility provides a baseline emission of 4.38 MT of CO2 eq. per cow per year from the manure storage systems that the NYS CAFO permit requires. These emissions can be mitigated by implementing a renewable energy system including an ADS with SLS of the digestate before storage.

Establish GHG Emissions and Emission Reductions for an ADS

If a manure-based ADS was installed on a farm, it could reduce the GHG emissions from manure management as well as replace fossil fuel use or energy for both the farm and other users. By capturing the CH4 produced, and combusting it for energy or simply flaring the excess, CH4 releases are converted back to the neutral CO2 originally consumed by the animals in the form of feed products. The ADS could help to meet NYS renewable energy and GHG reduction goals, however, farms with an ADS would need to manage the system to minimize leaks. With no incentives to control leaks, the CH4 produced potentially could add to overall farm GHG emissions.

Part I – Estimating typical CH4 emissions and emission reductions

There are a number of factors that need to be taken into consideration when estimating the GHG reductions that an ADS will provide. Leaks in the ADS can be very detrimental as more methane is produced in an ADS than is emitted naturally from a manure storage facility in the baseline condition. In addition, there are uncombusted CH4 losses from flares and even some from the engine as well. Although every farm system is different, typical values can be determined from the literature, on-farm measurements, and experience.

ADSs designed and built to supply only the quantity of electricity consumed on-farm and to reduce odors may not be as effective as systems designed specifically to reduce GHG emissions. The conservative values in Table 2 could be used to describe these types of systems. ADSs built specifically to reduce GHG emissions in addition to maximizing the renewable energy produced would achieve significantly better GHG reductions. The optimum numbers are achievable, while the obtainable values are based on ADSs that consider GHG emissions and are built to optimize CH4 production.

Table 2. ADS variables that can be controlled by the system equipment, operation, and management

Conservative

Optimum

Obtainable

Reference

Leaks from system (% CH4)

10

0

1

AgSTAR (2011) and on-farm
Flare Efficiency (%)

90

99

95

AgSTAR (2011) and on-farm
Engine capacity factor (decimal)

0.85

0.97

0.95

On-farm measurements
Engine efficiency (%)

38

42

38

On-farm measurements
ADS Parasitic load

(kWh/cow-yr)

0.30

0.07

0.18

On-farm measurements
Biodegradability post-digestion (%)

70

50

60

On-farm measurements
VS left after SLS (%)

60

20

50

On-farm measurements

The additional societal benefit of this technology can be calculated using EPA’s SC-CO2 of $47.82 as the 2017-2019 average SC CO2 value per metric ton of C02 eq. (at a 3% discount rate) for the methane and nitrous oxide emissions (EPA, 2016).

Part II – Estimating typical N2O emissions and emission reductions for an ADS

An EF3 value of 0 (IPCC, 2006) for an uncovered liquid manure storage describes the typical emission factor from an ADS with SLS since post-digestion there would be no free oxygen, and after solids removal, there would not be a crust forming.

The resulting calculations from the conservative, optimum and obtainable ADS values are shown in Table 3. The fossil fuels avoided are based on the kilo-Watt hours (kWh) produced minus the parasitic load. The uncombusted CH4 from the engine is based on a rich burn engine. The CO2 equivalents from the system leaks and the digestate storage are the major emissions in the conservative scenario, the uncombusted emissions from the flare and the digestate storage are minor emissions from the optimum scenario, while storage contributes the most to the continuing emissions from the obtainable scenario.

Table 3. GHG Emissions from electric production converted with a $47.82 SC-CO2 into a value of E for conservative, optimum and obtainable ADS with solid separation of the digestate before storage.

Units Conservative Optimum Obtainable
Fossil Fuels Avoided
MT CO2 eq/cow-yr

0.70

1.16

0.99

Engine uncommuted CH4 MT CO2 eq/cow-yr

2.5 x 10-3

3.2 x 10-3

3.1 x 10-3

Flare uncommuted CH4 MT CO2 eq/cow-yr

0.19

0.00

0.03

System Leaks CH4 MT CO2 eq/cow-yr

1.41

0.00

0.14

Storage emissions CH4 MT CO2 eq/cow-yr

2.98

0.50

1.9

ƩCO2eq emitted – FF avoided MT CO2 eq/cow-yr

3.81

0.65

1.06

Baseline MT CO2 eq/cow-yr

4.38

4.38

4.38

Reduction in CO2eq MT CO2 eq/cow-yr

0.57

5.03

3.32

SC-CO2 Benefit $/cow-yr

$27

$240

$149

Gross Electricity produced kWh/cow-yr

1,590

2,229

1,955

Value of E $/kWh

0.017

0.11

0.081

Summary of long-term storage GHG emissions

The obtainable value of E $0.081/kWh, for an ADS with SLS of the digestate could be used to better determine the value of renewable energy in meeting NYS’s goals of reducing GHG emissions, increasing renewable energy, and supporting the dairy industry and the upstate NY economy.

More specific values for each individual ADS could be determined as a more granulated value (i.e., a value based on a more detailed/thorough analysis) through the implementation of NYS’s renewable energy vision. By using a value of E that reflects the actual environmental benefit of an ADS, this would incentivize dairy farms with an ADS to improve their CH4 production to produce more electrical energy. This would also increase the interest of more dairy farms in controlling GHG emissions and producing renewable energy by investing in ADS on their farms.

What have we learned?

ADSs can be used to reduce the manure management generated GHG emissions from dairy farms. With careful management, 3.32 MT of CO2 eq. per cow-year can be credited to the ADS. Using EPA’s SC-CO2 average price during 2017-2019 of $47.82, this could amount to a GHG benefit of over $140/cow-year. At this time, the benefit to society is unrewarded and high costs for ADSs both to construct and to operate, discourage farms from installing them. Working towards New York State’s renewable energy goals, as well as the reduction in GHG emission goals by compensating farms for the societal value of $0.081 per kWh of electricity produced from a well-run ADS would better incentivize farms to both install and operate ADSs to the advantage of the State.

Future Plans

DISCUSSION

ADSs can provide additional GHG reductions by utilizing organic wastes that currently go to landfills or aerobic waste treatment facilities. Some landfills may be able to capture a portion of the CH4 that the organic waste produces as renewable energy, but typically the leaks from a landfill gas recovery system are greater than those of farm-based ADS. NYS has some interest in diverting organic waste from landfills to reduce: the fill rate, the potential GHG emissions, and O&M costs in landfills. The value of the diverted organic waste can be best recovered by society if the energy is recovered through manure-based AD since the nutrients would also be recovered by mixing the food waste with manure, digesting it and recycling the nutrients in the effluent to the land for growing crops.

Nutrients to grow crops that are currently utilized in the form of commercial fertilizer, could be offset by the nutrients contained in a post-digested liquid, which would also reduce the energy and accompanying fossil fuel emissions now emitted when manufacturing commercial nutrients.

Aerobic treatment of organic wastes requires additional energy that adds to the fossil fuel-based carbon dioxide emissions and typically does not recover nutrients. While anaerobic digestion creates renewable energy and preserves nutrients.

Typical ADSs produce a large portion of energy from CH4 as waste heat from the engine(s). Operating a Combined Heat and Power (CHP) system in conjunction with an enterprise that would utilize the heat produced, would enable the system to harvest even more renewable energy.

ADSs could improve GHG mitigation efforts if the effluent storage was covered and if the gas collected was included in the biogas utilization system, eliminating any emissions from the effluent storage while producing even more renewable energy.

Farm Disadvantages

Managing a complex and expensive ADS requires dedication and a sophisticated management effort that clearly competes for time with other tasks on the farm. There is the potential to emit excess CH4 if: 1) leaks are not properly controlled, 2) the engine generator, boiler and/or flare are not efficient or 3) if the effluent storage continues to produce uncontained CH4. These can all be compounded if off-site organics are imported to the farm. The existing NYS net metering program makes the current price paid for exported electricity, very low. This reduces the motivation to produce and capture the maximum amount of CH4 from the ADS.

Planning and installing an on-farm ADS takes time to consider the benefits and costs so that a business decision can be reached. Capital costs of ADSs vary, but can range from $4,000 to $5,500 per kW of generation capacity. Operating costs have been estimated at $0.02 to $0.03 per kWh. Much of the capital investment is considered lost capital by lenders. The existing manure management system should be examined to determine any disadvantages from extra solids, contaminants, or dilution. If the successful operation of the ADS depends on tipping fees from imported organics, the reliability and quality of these sources needs to be determined. If electricity is to be sold, the utility should be consulted to determine how/if the distribution lines to the farm can handle what is expected to be generated.

Corresponding author, title, and affiliation

Peter Wright, Agricultural Engineer, Cornell University

Corresponding author email

cag26@cornell.edu

Other authors

Curt Gooch, Dairy Environmental Systems and Sustainability Engineer, Cornell University

Additional information

www.manuremanagement.cornell.edu

Talking Climate with Animal Agriculture Advisers


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Purpose             

The Animal Agriculture in a Changing Climate (AACC) project was established to leverage limited Extension expertise across the country in climate change mitigation and adaptation, with the goal of building capacity among Extension professionals and other livestock advisers to address climate change issues.

What did we do? 

The Animal Agriculture in a Changing Climate project team created a suite of educational programs and products to build capacity across the United States. Key products of the project:

  • Online courses: 363 participants registered with a 35% completion rate (Whitefield et al., JOE, 2016)
  • National and regional symposia and workshops: 11 face-to-face conferences with approximately 1,350 attendees.
  • Website: Over 5,900 users with over 21,100 total views. Project videos have received nearly 8,900 views.
  • Social media: AACC weekly blog (990 subscribers); daily Southeast Climate Blog (38,506 site visits); regional newsletters (627 subscribers); Facebook & Twitter (280 followers)
  • Ready-to-use videos, slide sets, and fact sheets
  • Educational programming: 390 presentations at local, regional, and international meetings
  • Collaboration with 14 related research and education projects

What have we learned? 

A survey was sent out to participants in any of the project efforts, in the third year of the project and again in year five. Overall, participants found the project resources valuable, particularly the project website, the online course, and regional meetings. We surveyed two key measures: abilities and motivations. Overall, 60% or more of respondents report being able or very able to address all eight capabilities after their participation in the AACC program. A sizeable increase in respondent motivation (motivated or very motivated) existed after participation in the program, particularly for helping producers take steps to address climate change, informing others about greenhouse gases emitted by agriculture, answering client questions, and adding new information to programs or curriculum.

The first challenge in building capacity in Extension professionals was finding key communication methods to engage them. Two key strategies identified were to: 1) start programming with a discussion of historical trends and agricultural impacts, as locally relevant as available, and 2) start the discussion around adaptation rather than mitigation. Seeing the changes that are already apparent in the climatic record and how agriculture has adapted in the past and is adapting to more recent weather variability and climatic changes often were excellent discussion starters.

Another challenge was that many were comfortable with the science, but were unsure how to effectively communicate that science with the sometimes controversial discussions that surround climate change. This prompted us to include climate science communication in most of the professional development opportunities, which were then consistently rated as one of the most valuable topics.

Future Plans    

The project funding ended on March 31, 2017. All project materials will continue to be available on the LPELC webpage.

Corresponding author, title, and affiliation        

Crystal Powers, Extension Engineer, University of Nebraska – Lincoln

Corresponding author email    

cpowers2@unl.edu

Other authors   

Rick Stowell, University of Nebraska – Lincoln

Additional information

lpelc.org/animal-agriculture-and-climate-change

Acknowledgements

Thank you to the project team:

Rick Stowell, Crystal Powers, and Jill Heemstra, University of Nebraska – Lincoln

Mark Risse, Pam Knox, and Gary Hawkins, University of Georgia

Larry Jacobson and David Schmidt, University of Minnesota

Saqib Mukhtar, University of Florida

David Smith, Texas A&M University

Joe Harrison and Liz Whitefield, Washington State University

Curt Gooch and Jennifer Pronto, Cornell University

This project was supported by Agricultural and Food Research Initiative Competitive Grant No. 2011-67003-30206 from the USDA National Institute of Food and Agriculture.

 

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.

Adapting to Climate Change in the Pacific Northwest: Promoting Adaptation with Five-Minute Videos of Agricultural Water Conservation and Management Practices


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Purpose            

In a multimedia-based world, short videos are an effective visual means to provide information. A series of short (5-minute) climate change videos focusing on water conservation and efficiency were developed to connect innovative farming practices to other farmers, their advisers, consultants and the agricultural community.

What did we do? 

Profiled stories include: water-efficient measures, featuring ‘low irrigation spray application’ (LISA) irrigation and ‘low elevation precision application’ (LEPA) irrigation in Eastern Washington; a video focused on dry-land farming of vegetables and fruit in Oregon using regionally adapted long taproot varieties from California; and a video featuring an Eastern Washington dairy farm’s reactive adaptation management after 2015, preparing for future growing seasons with less water. In each of the short videos, farmers, their advisers, and university experts are interviewed to provide their perspectives, knowledge and economic information.

What have we learned?             

These videos are shared to highlight successful practices of conserving water while remaining profitable. Each video suggests evaluating a climate compatible management practice or crop variety on a part of a field, or when replacing outdated irrigation sprinklers and pumps.

Future Plans   

Future plans include regional promotion of these successful practices.

Corresponding author, title, and affiliation        

Elizabeth Whitefield, Research Associate, Washington State University

Corresponding author email    

e.whitefield@wsu.edu

Other authors   

Joe Harrison, Livestock Nutrient Management Extension Specialist, Washington State University

Additional information               

Please visit https://puyallup.wsu.edu/lnm/ to view the videos and to find more information.

Acknowledgements       

This effort was fully supported by Western Region Sustainable Agriculture and Research Education Program (EW15-012, Implications of Water Impacts from Climate Change: Preparing Agricultural Educators and Advisors in the Pacific Northwest)

Scenario Planning for the New York State Dairy Industry in a Changing Climate

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Purpose

Climate change is a slow and continual process that has been gradually changing our weather, and it will continue to occur. In order to adapt to such gradual changes, much foresight and planning is needed. The input-gathering process undertaken for this exercise was intended to compile information from stakeholders that was used to determine various scenarios of what future dairy production will look like, under specific climate change scenarios.

A survey of producers’ perspectives performed in 2014 yielded useful information regarding the beliefs of many New York State (NYS) dairy farmers. The survey showed that the majority of these farmers believe that they and their peers must adapt to climate changes they are currently facing, in the coming decades, in order to continue to grow and expand the industry in a sustainable manner. The scenario planning process will aid producers and their advisors in determining which adaptation strategies will be most effective to become more resilient to the climate changes that are projected in the near-term future for New York.

What did we do?

A Scenario Planning exercise was conducted throughout 2016 in preparation to help NYS producers imagine a future that involves the changes in climate that are projected over roughly the next 50 years. Scenario planning is a process that involves stakeholder input to develop multiple future scenarios based on a few key variables that will affect and change the way a system functions currently. It is a unique process in that it is not probability-based rather, it is based on the views of stakeholders and experts who choose the variables to be presented in a divergent fashion.

A workshop was held in July 2016 which gathered input from 12 stakeholders, and this input was then combined with current climate projections and other resources, to develop 8 comprehensive scenarios, 4 for the winter season and 4 for the growing season. The final scenarios are visual representations and are paired with qualitative narratives to explore the impacts of the divergent situations that are created. The final narratives provide a useful communications tool to share with farmers and other stakeholders, to explore the impacts of the climate variables involved.

Growing season scenarios 1Winter scenarios

What have we learned?

The exercise focused on temperature and precipitation changes for New York State, and the impacts to various aspects of the farmstead on a typical New York dairy farm. Scenarios were created for both winter and growing seasons, since the range of impacts is highly season dependent. The divergent scenarios created are presented in Figure 1 (growing season scenarios) and Figure 2 (winter season scenarios). Qualitative narratives were developed to describe in-depth the interactions that occur in each situation, for example, impacts to: the herd, the farmstead, manure management, farm economics, and finally with the farmer and personnel. Furthermore, once each situation is described fully, the next level of impact explores outside variables, for example, regional economic or political changes, population growth or social changes, or nation-wide or world-wide events that could have a significant impact on the specific farm situation presented.!

Future Plans

Next steps include identifying the best management strategies to handle the challenges presented in each resulting scenario. The final scenarios are presented in such a fashion that they will be useful tools to inform farm management, planning and decision making. The final scenarios can be used to examine how a certain set of management actions would perform under various future climatic conditions. “Robust” management actions need to be identified that would be the most highly effective under all scenarios considered, in other words, best management practices need to be identified that make the most sense to invest in, to be prepared for as many of the scenarios created as possible. In the same effort, it is important to identify management actions that are ineffective or that have little impact for a majority of the future scenarios developed. Pursuing actions that only work under a few of the projected scenarios is not in! line wit h smart planning to make the farm as resilient as possible. This preparation is a significant step towards helping farms be resilient in the face of unexpected future changes.

Corresponding author, title, and affiliation

Jennifer Pronto, Co-founder, BioProcess Analytics, LLC

Corresponding author email

jenny.pronto@gmail.com

Other authors

Curt Gooch, PE, Cornell University

Additional information

http://animalagclimatechange.org/

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