Impact of swine manure on soil health properties: A systematic review

Purpose

As the campaign to improve agricultural soil health has gained momentum among conservationists and researchers worldwide, a comprehensive assemblage of outcomes from manure and soil health-related research studies is important. Particularly, the identification of knowledge gaps is an important step to direct future research that informs soil health improvement outreach programs. A thorough review of data reporting the effects of swine manure on soil health properties that is applicable to agricultural producers is lacking. Although previous research studies have looked at the effects of manure on individual soil properties, there are conflicting conclusions. Livestock manure literature reviews fail to consider inconsistent methodologies between individual research studies and whether research is applicable to producers utilizing manure as amendments to improve soil health, and none of the reviews focus on swine manure or swine manure by-products. The objectives of this review were (a) to synthesize literature describing effects of swine manure on soil properties that affect soil health and (b) to identify knowledge gaps and research needs to further our understanding of this topic.

What Did We Do?

We conducted a systematic literature review based on peer-reviewed studies that evaluated the effect of swine manure on soil health properties. First, we identified studies using three criteria: species (swine, pig, hog), manure source (i.e., solid [SM] or liquid manure [LSM], compost, deep pack), and soil property (i.e., soil organic carbon [SOC], total nitrogen, soil pH, bulk density, available water capacity). Second, studies had to meet the following criteria in order to be included: (a) the studies were replicated field experiments, (b) manure was the only differing factor between or among treatments, and (c) data means of organically amended treatments and controls were included. In total, 40 peer-reviewed studies were included in this review.

What Have We Learned?

Recycling of manure locally prior to importing inorganic fertilizer (IF) has the potential to reduce nutrient imbalances and improve soil health. Based on this review, swine manure has the potential to add significant amounts of organic carbon to the soil and to improve soil health metrics. In general, the application of swine manure increases soil organic matter (SOM) and SOC, decreases soil bulk density, and increases microbial biomass carbon Soil organic carbon and total N tended to be highest when manure and inorganic fertilizer were applied to the field (Figure 1). Soil chemical properties did not seem to change much when manure was applied to the soil surface or incorporated into the topsoil. The duration of swine manure application (annually) did not seem to increase the percent change in most chemical properties; however, this could be due to a lack of data. The percent change in SOC did increase when the swine manure was applied for a longer time period (Figure 1), and we would expect to see a similar trend with SOM and total carbon if there were more data. Few articles had data on soil physical and biological properties. Depending on soil type, swine manure has the potential to increase available water holding capacity and saturated hydraulic conductivity. Although more research is needed, it can be inferred that swine manure additions increase microbial activity, which promotes healthier soils and better crop yields.

Figure 1: Average percent change in soil organic carbon (SOC) and total nitrogen (TN) based on amendment type, application method, soil texture, and duration of swine manure application. Black circles represent outlier data, and diamonds represent mean. IF = inorganic fertilizer; LSM = liquid swine manure; M + IF = manure (liquid and solid) plus inorganic fertilizer; SM = solid swine manure

Future Plans

Previous literature reviews failed to account for differences in methodologies between individual research studies and whether research is applicable to producers utilizing swine manure as amendments to improve soil health (i.e., unreasonable application rates of swine manure, overapplication of nutrients). The evaluation of the effect of swine manure on soil health properties is difficult to do based on current literature because (a) there are few comprehensive studies (i.e., only one study reported properties from chemical, physical, and biological categories) and (b) there are non-consistent research methodologies between studies. Therefore, we recommend redirecting research studies to demonstrate the value of manure to the suitability of agricultural cropping systems. Future swine manure research should include (a) a range of soil physical, chemical, and biological properties, (b) initial soil data prior to manure application, and (c) manure type, application method, application rate, total carbon and nitrogen of the manure, duration of swine manure application, and swine manure application timing. In addition, future research should also focus on the short- and long-term effects of a single application of manure to support an effort to identify optimal frequency of application for improving soil health. More research is also needed to compare the effects of manure and inorganic fertilizer additions on crop yield and soil health by balancing nitrogen, phosphorus, and potassium additions.

Authors

Jenifer L. Yost, Research Soil Scientist, USDA-ARS

Corresponding author email address

jenifer.yost@usda.gov

Additional authors

Amy M. Schmidt, Livestock Manure Management Engineer, University of Nebraska-Lincoln; Rick Koelsch, Livestock and Bio Environmental Engineer, University of Nebraska-Lincoln; Kevin Kruger, Research Support Scientist, University of Idaho; Linda R. Schott, Nutrient and Waste Management Extension Specialist, University of Idaho

Additional Information

For more information about this project, please check out our Open Access journal article. The citation for the journal article is:

Yost, J.L., Schmidt, A.M., Koelsch, R., and Schott, L.R. (2022). Effect of swine manure on soil health properties: A systematic review. Soil Science Society of America Journal.

https://doi.org/10.1002/saj2.20359

This research was presented at the ASA, CSSA, SSSA International Annual Meeting in Salt Lake City, Utah, in November of 2021. The link to the recorded presentation is found in the citation below:

Yost, J. L., Schmidt, A. M., Koelsch, R., & Schott, L. R. (2021). Impact of Swine Manure on Soil Health Properties: A Systematic Review [Abstract]. ASA, CSSA, SSSA International Annual Meeting, Salt Lake City, UT. https://scisoc.confex.com/scisoc/2021am/meetingapp.cgi/Paper/138180

Acknowledgements

This project was supported by funding from the National Pork Checkoff. The authors would also like to thank Meg Clancy and Drew Weaver for their assistance.

 

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. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

The Poultry Mega-Manureshed that is the Southeastern USA: Is It Sustainable?

Purpose

Scientists from across the Long-Term Agroecosystem Research (LTAR) network are working to address nutrient management challenges that confront the poultry industry (broilers, layers, pullets, and turkeys) in the context of a “manureshed” – the geographic area surrounding one or more livestock and poultry operations where excess manure nutrients can be recycled for agricultural production. This study focuses on poultry manuresheds identified east of the Mississippi across the Southeast and Mid-Atlantic regions where over 55% of the U.S. poultry production is located. Poultry manure has been used as a fertilizer most extensively on forage and pasture crops grown near poultry houses. Poultry is a highly specialized production system, with a portion of feed grains grown at substantial distance from where the animals are raised. Consequently, nutrients excreted in manure often exceed the nutrient requirements for local crop production. This situation results in surpluses in local soils that receive manure. The surpluses in turn lead to eutrophication of water bodies; that is, the biological enrichment of water bodies derived from nutrient pollution. Without a mechanism to redistribute manure nutrients more widely, the production and manure management system is unsustainable.

What Did We Do

Central to the concept of the manureshed are sources and sinks, which represent spatial extents where the nutrients in livestock and poultry manure produced exceeds the nutrient needs of crops in the area (sources) or falls short of crop needs (sinks). Although manure nitrogen (N) and phosphorus (P) must be co-managed, we focus our analysis on P since the ratio of plant-available N:P in poultry manure is low (< 4:1) relative to crop needs (~ 10:1). We used data from the U.S. Census of Agriculture and estimates from the International Plant Nutrition Institute’s (IPNI) Nutrient Use Geographic Information System (NuGIS) to identify manure-based P produced annually by poultry production, crop nutrient needs for all crops, and fertilizer applied to farmland in each of the 3109 U.S. counties of the 48 conterminous U.S. states in 2012. A classification approach was then used to determine whether each county was a source or a sink. The next step was a step-wise spatial analysis to identify the nearest sink counties available for redistribution of manure-based P from each source county cluster. The result was a “mega-manureshed,” the largest contiguous area of source and sink counties in the United States.

What Have We Learned

The poultry mega-manureshed extends from the Mid-Atlantic, across the southeast to the Mississippi River and beyond (Figure 1). In the Georgia Coastal Plain manureshed, a component of the megamanureshed, the maximum distance that manure would need to be hauled from source area to sink area is only nine miles. However, in the Southern Piedmont and the Shenandoah manuresheds, the maximum distance that manure would have to be hauled is 65 and 146 miles, respectively. These are conservative estimates. Our analysis does not account for the presence of a large swine manure source area in North Carolina. If those manure nutrients are to be land applied, then additional sink areas would be needed. Additionally, we do not have data on soils that allow us to identify areas where P levels are already excessively high such that additional P should not be added. Both factors would greatly expand the size of the manureshed and increase the maximum hauling distance. Since hauling manure a hundred miles or more is not economically feasible, alternatives, such as pelletizing; use as feedstock for bioenergy and biochar production; and biological, physical, or chemical removal and recovery of nutrients, are needed in order to sustain the poultry industry.

Figure 1. Poultry mega-manureshed: Sources and sinks for P from the Mid-Atlantic across the southeast. Counties shown in white are neither sources nor sinks; P inputs are roughly in balance with crop uptake. The blue area in North Carolina is a P source area from swine

The vertical integration that is characteristic of meat and egg production components of the poultry industry lends itself well to the infrastructure requirements and collective decision making needed to achieve manureshed management. As manure treatment innovations evolve, the U.S. poultry industry is poised to take advantage of insights gained from the manureshed approach to target manure nutrient redistribution efforts.

Future Plans

Over the next 10 years, LTAR researchers will be working with producer partners to conduct long-term field research on the economic and environmental costs and benefits of importing manure nutrients to cropland and grazing land in different climates. Beyond traditional land management and technology research, we will also be working to build societal awareness of the benefits and challenges of the manureshed approach and determine what is needed for widespread support of the concept. LTAR scientists will work to improve or develop new manure treatment technologies. We plan to conduct economic research on the cost effectiveness of different types of management practices, as well as the need for economic incentives.

Authors

Ray B. Bryant, Research Soil Scientist, USDA ARS Pasture Systems and Watershed Management Research Unit, University Park, PA
Ray.Bryant@usda.gov

Additional Authors

    • Dinku M. Endale, USDA-ARS Southeast Watershed Research Laboratory, Tifton, GA (Retired)
    • Sheri A. Spiegal, USDA-ARS Jornada Experimental Range, Las Cruces, NM
      -K. Colton Flynn, USDA-ARS Grassland Soil and Water Research Laboratory, Temple, TX
    • Robert J. Meinen, Senior Extension Associate, Dept. Animal Science, The Pennsylvania State University
    • Michel A. Cavigelli, USDA-ARS Sustainable Agricultural Systems Laboratory, Beltsville, MD
    • Peter J.A. Kleinman, USDA-ARS Soil Management and Sugar Beet Research Unit, Fort Collins, CO

Additional Information

Bryant RB, Endale DM, Spiegal SA, Flynn KC, Meinen RJ, Cavigelli MA, Kleinman PJA. Poultry manureshed management: Opportunities and challenges for a vertically integrated industry. J Environ Qual. 2021 Jul 26. doi: 10.1002/jeq2.20273. Epub ahead of print. PMID: 34309029.

Spiegal, S., Kleinman, P. J. A., Endale, D. M., Bryant, R. B., Dell, C., Goslee, S., … Yang Q. (2020). Manuresheds: Recoupling crop and livestock agriculture for sustainable intensification. Agricultural Systems. 181: 1-13. 102813. Doi: 10.1016/j.agsy.2020.102813.

https://youtu.be/8P2cI4BzLpY

Acknowledgements

This research was a contribution from the Long-Term Agroecosystem Research (LTAR) network. LTAR is supported by the U.S. Department of Agriculture, which is an equal opportunity provider and employer.

 

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. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Conservation Planning for Air Quality and Atmospheric Change (Getting Producers to Care about Air)

Purpose

The United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) works in a voluntary and collaborative manner with agricultural producers to solve natural resource issues on private lands. One of the key steps in formulating a solution to those natural resource issues is a conservation planning process that identifies the issues, highlights one or more conservation practice standards that can be used to address those issues, and allows the agricultural producer to select those conservation practices that make sense for their operation. In this conservation planning process, USDA-NRCS looks at natural resource issues related to soil, water, air, plants, animals, and energy (SWAPA+E). This presentation focuses on the resource concerns related to the air resource.

What Did We Do

In order to facilitate the conservation planning process for the air resource, USDA-NRCS has focused on five main issues: emissions of particulate matter (PM) and PM precursors, emissions of ozone precursors, emissions of airborne reactive nitrogen, emissions of greenhouse gases, and objectionable odors. Each of these resource concerns are further subdivided into resource concern components that are mainly associated with different types of sources or activities found on agricultural operations. By focusing on those agricultural sources and activities that have the largest impact on each of these air quality and atmospheric change resource concerns, USDA-NRCS has developed a set of planning criteria for determining when a resource concern exists. We have also identified those conservation practice standards that can be used to address each of the resource concern components.

What Have We Learned

Our focus on the agricultural sources and activities that have the largest impact on air quality has helped to evolve the conservation planning process by adding resource concern components that are targeted and simplified. This approach has led to a clearer definition of when a resource concern is identified, as well as how to address it. For example, the particulate-matter focused resource concern has been divided into the following resource concern components: diesel engines, non-diesel engine combustion equipment, open burning, pesticide drift, nitrogen fertilizer, dust from field operations, dust from unpaved roads, windblown dust, and confined animal activities. Each of these types of sources can produce particles directly or gases that contribute to fine particle formation. In order to know whether a farm has a particulate matter resource concern, a conservation planner would need to determine whether one or more of these sources is causing an issue. Once the source(s) of the particulate matter issue is identified, a site-specific application of conservation practices can be used to resolve the resource concern.

We expect that increased clarity in the conservation planning process will lead to a greater understanding of the air quality and atmospheric change resource concerns and how agricultural producers can reduce air emissions and impacts. Simple and clear direction should eventually lead to greater acceptance of addressing air quality and atmospheric change resource concerns.

Future Plans

USDA-NRCS will continue to refine our approach to addressing air quality and atmospheric change resource concerns. As we gain a greater scientific understanding of the processes by which air emissions are generated and air pollutants are transported from agricultural operations, we can better target our efforts to address these emissions and their resultant impacts. Internally, we will be working throughout our agency to identify those areas where we can collaboratively work with agricultural producers to improve air quality.

Authors

Greg Zwicke, Air Quality Engineer, USDA-NRCS National Air Quality and Atmospheric Change Team
greg.zwicke@usda.gov

Additional Authors
Allison Costa, Air Quality Engineer, USDA-NRCS National Air Quality and Atmospheric Change Team

Additional Information

General information about the USDA-NRCS can be found at https://www.nrcs.usda.gov. An overview of the conservation planning process is available at https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/programs/technical/cta/?cid=nrcseprd1690815.

The USDA-NRCS website for air quality and atmospheric change is https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/air/.

 

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. 2022. Title of presentation. Waste to Worth. Oregon, OH. April 18-22, 2022. URL of this page. Accessed on: today’s date.

Field Technology & Water Quality Outreach

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Purpose

In 2015, Washington State Department of Agriculture (WSDA) partnered with local and state agencies to help identify potential sources of fecal coliform bacteria that were impacting shellfish beds in northwest Washington.  WSDA and Pollution Identification and Correction (PIC) program partners began collecting ambient, as well as rain-driven, source identification water samples. Large watersheds with multiple sub-basins, changing weather and field conditions, and recent nutrient applications, meant new sites were added almost daily. The increased sampling created an avalanche of new data. With this data, we needed to figure out how to share it in a way that was timely, clear and could motivate change. Picture of water quality data via spreadsheet, graphs, and maps.

Conveying complex water quality results to a broad audience can be challenging. Previously, water quality data would be shared with the public and partners through spreadsheets or graphs via email, meetings or quarterly updates. However, the data that was being shared was often too late or too overwhelming to link locations, weather or field conditions to water quality. Even though plenty of data was available, it was difficult for it to have meaningful context to the general public.

Ease of access to results can help inform landowners of hot spots near their home, it can link recent weather and their own land management practices with water quality, as well as inform and influence decision-making.

What Did We Do?

Using basic GIS tools we created an interactive map, to share recent water quality results. The map is available on smartphones, tablets and personal computers, displaying near-real-time results from multiple agencies.  Viewers can access the map 24 hours a day, 7 days a week.

We have noticed increPicture of basic GIS tool.ased engagement from our dairy producers, with many checking the results map regularly for updates. The map is symbolized with graduated stop light symbology, with poor water quality shown in red and good in green. If they see a red dot or “hot spot” in their neighborhood they may stop us on the street, send an email, or call with ideas or observations of what they believe may have influenced water quality. It has opened the door to conversations and partnerships in identifying and correcting possible influences from their farm.

The map also contains historic results data for each site, which can show changes in water quality. It allows the viewer to evaluate if the results are the norm or an anomaly. “Are high results after a rainfall event or when my animals are on that pasture?”

The online map has also increased engagement with our Canadian neighbors to the north. By collecting samples at the US/Canadian border we have been able to map streams where elevated bacteria levels come across the border. This has created an opportunity to partner with our Canadian counterparts to continue to identify and correct sources.

What Have We Learned?

You do not need to be a GIS professional to create an app like this for your organization. Learning the system and fine-tuning the web application can take some time, but it is well worth the investment. GIS skills derived from this project have proven invaluable as the app transfers to other areas of non-point work.  The web application has created great efficiencies in collaboration, allowing field staff to quickly evaluate water quality trends in order to spend their time where it is most needed. The application has also provided transparency to the public regarding our field work, demonstrating why we are sampling particular areas.

From producer surveys, we have learned that viewers prefer a one-stop portal for information. Viewers are less concerned about what agency collected the data as they are interested in what the data says. This includes recent, as well as historical water quality data, field observations; such as wildlife or livestock presence or other potential sources. Also, a brief weekly overview of conditions, observations and/or trends has been requested to provide additional context.

Future Plans

The ease and efficiency of the mobile mapping and data sharing has opened the door to other collaborative projects. Currently we are developing a “Nutrient Tracker” application that allows all PIC partners to easily update a map from the field. The map allows the user to log recent field applications of manure. Using polygons to draw the area on the field, staff can note the date nutrients were identified, type of application, proximity to surface water, if it was a low-, medium- or high-risk application, if follow-up is warranted, and what agency would be the lead contact. This is a helpful tool in learning how producers utilize nutrients, to refer properties of concern to the appropriate agency, and to evaluate recent water quality results against known applications.

Developing another outreach tool, WSDA is collecting 5 years of fall soil nitrate tests from all dairy fields in Washington State. The goal is to create a visual representation of soil data, to demonstrate to producers how nitrate levels on fields have changed from year to year, and to easily identify areas that need to be re-evaluated when making nutrient application decisions.

As part of a collaborative Pollution Identification and Correction (PIC) group, we would like to create a “Story Map” that details the current situation, why it is a concern, explain potential sources and what steps can be taken at an individual level to make a difference. A map that visually demonstrates where the watersheds are and how local neighborhoods really do connect to people 7 miles downstream.  An interactive map that not only shows sampling locations, but allows the viewer to drill down deeper for more information about the focus areas, such as pop-ups that explain what fecal coliform bacteria are and what factors can increase bacteria levels. We envision a multi-layer map that includes 24-hour rainfall, river rise, and shellfish bed closures. This interactive map will also share success stories as well as on-going efforts.

Author

Kerri Love, Dairy Nutrient Inspector, Dairy Nutrient Management Program, Washington State Department of Agriculture

klove@agr.wa.gov

Additional Information

Results Map Link: http://arcg.is/1Q9tF48

Washington Shellfish Initiative: http://www.governor.wa.gov/issues/issues/energy-environment/shellfish

Mobile Mapping Technology presentation by Michael Isensee, 2016 National CAFO Roundtable

Sharing the Data: Interactive Maps Provide Rapid Feedback on Recent Water Quality and Incite Change by Educating the Public, Kyrre Flege, Washington State Department of Agriculture and Jessica Kirkpatrick, Washington State Department of Ecology,  2016 National Non-Point Source Monitoring Workshop

Whatcom County PIC Program: http://www.whatcomcounty.us/1072/Water-Quality

Skagit County, Clean Samish Initiative: https://www.skagitcounty.net/Departments/PublicWorksCleanWater/cleansamish.htm

Lower Stillguamish PIC Program: http://snohomishcountywa.gov/3344/Lower-Stilly-PIC-Program

GIS Web Applications: http://doc.arcgis.com/en/web-appbuilder/

Acknowledgements

The web application was a collaborative project developed by Kyrre Flege, Washington State Department of Agriculture and Jessica Kirkpatrick, Washington State Department of Ecology.

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.

Performance of Mitigation Measures in the Dairy Sector under Future Climate Change

 

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Purpose

Climate change is an economic, environmental and social threat, and worthy of scientific study. Immediate action must be taken to reduce greenhouse gas emissions and mitigate negative impacts of future climate change. Proposed action can start at the farm level and has the potential of making a contribution to mitigation of climate change. Dairy farmers are able to significantly reduce their emissions by implementing better management practices, primarily through feed production, enteric fermentation, and manure management. We model the corresponding changes in emissions from proposed mitigation efforts to understand their impact on global climate change.

What did we do?

Best Management Practices (BMPs) for dairy systems have been identified and simulated using the Integrated Farm System Model (IFSM). Simulations representative of a large New York farm (1500 cows) and a small Wisconsin farm (150 cows) estimated the emission of greenhouse gases for a whole farm system. Percent reductions were calculated by comparing a baseline scenario without any implemented mitigation, to scenarios that included the identified BMPs. Refer to Table 1 for emission and percent reduction estimates for the simulated BMPs.Table 1. Emissions and percent reductions from baseline for simulated mitigation strategies

Percent reduction estimates were then applied to a projected “business as usual” emission scenario. This scenario prescribes anthropogenic emissions through 2100 and excludes any climate action or policy after 2015. Taking 2020 as a reference year and 2050 as a target year, we applied the estimated percent reductions to the projected global agricultural emissions. Emission reductions were decreased linearly from 2020 to 2050, and held constant between 2050 and 2100 (Figure 1). This assumes that all farms globally can reduce emissions despite increases in production. To compare the performance of the mitigation measures under future climate change, we employed a fully coupled earth system model of intermediate complexity – the Integrated Global System Model (IGSM). The model includes an interactive carbon-cycle capable of addressing important feedbacks between the climate and terrestrial biosphere.

Figure 1. Global agricultural emissions for mitigation strategiesWhat have we learned?

Action taken globally in the agricultural sector to reduce greenhouse gas emissions over the first half of the 21st century is likely to have an impact in mitigating global warming. Following a “business as usual” emission scenario without any climate policy or action beyond 2015, an increase in global mean surface temperature by the end of the 21st century (2081-2100) relative to pre-industrial (1961-1990) levels is projected to be 2.8 C to 3.5 C (Figure 2). This exceeds the 2 C temperature target described as the maximum warming allowed to avoid dangerous and irreversible climate change. An associated net radiative

forcing for the “business as usual” scenario is projected to be 7.4 W/m^2 by 2100 (Figure 3). Adopting the identified BMPs in the dairy sector and decreasing global agricultural emissions by 2050 is projected to decrease global mean surface temperatures for 2100 by 0.2 C and net radiative forcing by 0.4 W/! m^2 on av erage. In summary, this modeled experiment demonstrates that ongoing efforts to decrease greenhouse gas emissions in the dairy and agricultural sector are effective at reducing the overall warming of climate change.

Figure 2. Projected global mean surface temperature and changes for mitigation scenarios

Figure 3. Projected radiative forcing for mitigation scenarios over the 21st century

Future Plans

Future work will look further into the evolution of regional temperature and rainfall profiles for the mitigation scenarios. Then, ecological risk assessment methodologies will be applied to determine the probable impacts of climate change by each scenario on agricultural production.

Corresponding author, title, and affiliation

Kristina Rolph – Graduate Student, The Pennsylvania State University.

Corresponding author email

kar5469@psu.edu

Other authors

Chris Forest – Associate Professor of Climate Dynamics, The Pennsylvania State University.

Rob Nicholas – Research Associate, Earth & Environmental Systems Institute.

Additional information

  1. The Sustainable Dairy Project, funded by the USDA, researches alternative management practices in the dairy industry. http://www.sustainabledairy.org
  2. The Integrated Farm System Model simulates all major farm components to represent the many biological and physical processes on a farm. https://www.ars.usda.gov/northeast-area/up-pa/pswmru/docs/integrated-farm-system-model/
  3. The MIT Integrated Global System Model is a fully coupled earth system model of intermediate complexity designed to analyze interactions between human activities and the Earth system. https://globalchange.mit.edu/research/research-tools/global-framework

Acknowledgements

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2013-68002-20525. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

Analysis of total Carbon, Nitrogen, and Phosphorus Contents in Soil Cores Over 10+ Years from Horicon Marsh in Dodge County, Wisconsin


Why Look at Marsh Soil Nutrients?

The purpose of this project was to evaluate changes in carbon (C), nitrogen (N), and phosphorus (P) in samples from identical locations taken ten years apart from Horicon Marsh in Dodge County, Wisconsin.

The area surrounding the marsh is primarily agricultural and has the potential to contribute nutrients to the marsh, affecting the fertility of the soils and changing the ecosystem.

What did we do?  

We hypothesized that carbon, nitrogen, and phosphorus would show significant increases over the ten-year interval between samplings.

Sample sites were positioned every ¼ mile along east-west transects throughout the marsh. A soil core was obtained at each sample site in the winter of either 2002 or 2003. The same sites were revisited and new samples collected in winter of either 2012 or 2013, ten years after the initial visits. The top five centimeters of each soil core were oven dried at 105°C for 72 hours.

Total carbon and nitrogen were analyzed by combustion using a PerkinElmer 2400 series II CHNS/O Analyzer. Total phosphorus was analyzed by the Olsen P-extraction method on a QuikChem FIA+ 8000 series Lachat analyzer.

A paired t-test (α=0.05) was used to compare nitrogen and phosphorus values. Carbon data were compared with a Mann-Whitney ranked sum test at the 95% confidence interval.

What have we learned?  

Carbon and nitrogen did not increase significantly over the time period. Carbon is generally bound in soil organic matter; in histic wetland soils, changes attributable to land use might be difficult to detect due to the already high organic matter content. Nitrogen accumulation was likely mitigated by denitrification processes.

Phosphorus concentrations were greater in the second set of samples. Phosphorus adsorbs tightly to sediment and organic material, which would prevent its removal by flowing water. Changes in land use, especially row crop agriculture in the Horicon marsh area, could contribute runoff inputs of soil particles carrying phosphorus with them. This may explain significantly increased phosphorus levels between the start and end of the study period.

Future Plans  

Future studies might quantify land use changes, their extent, and their impacts on the marsh ecosystem; analyze spatial patterns of phosphorus accretion to determine if it is cycling equally throughout the marsh; and determine the impact of denitrifying bacteria and anaerobic conditions on nitrogen accumulation. Additional research could include testing the water column of the marsh for dissolved nutrients; and sampling the Rock River at its inlet to and outlet from the Horicon Marsh to determine nutrient flux to the stream from the marsh.

Authors

Ashley Hansen, University of Wisconsin-Stevens Point ashleyhansen891@gmail.com

Anna Radke, University of Wisconsin-Stevens Point; Sarah Shawver, University of Wisconsin-Stevens Point

Additional information

Ashley Hansen, ahans891@uwsp.edu; Anna Radke, aradk591@uwsp.edu; Sarah Shawver, sshaw497@uwsp.edu

Acknowledgements

Dr. Robert Michitsch

Soils Professor and Research Advisor

Dr. Kyle Herrman

Water Resource Professor and Research Advisor

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.

Sources of Agricultural Greenhouse Gases

The conversation about climate change largely revolves around greenhouse gases. Agriculture is both a source and sink for greenhouse gases (GHG). A source is a net contribution to the atmosphere, while a sink is a net withdrawal of greenhouse gases.  In the United States, agriculture is a relatively small contributor, with approximately 8% of the total greenhouse gas emissions, as seen in Figure 1.

Most agricultural emissions originate from soil management, enteric fermentation (microbial action in the digestive system), energy use, and manure management (Figure 2).  The primary greenhouse gases related to agriculture are (in descending order of magnitude) methane, nitrous oxide, and carbon dioxide.

Fact sheet: Contribution of Greenhouse Gases: Animal Agriculture in Perspective (look below the preview box and title for a download link)

U.S. GHG Inventory Figure 1: U.S. greenhouse gas inventory with electricity distributed to economic sectors (EPA, 2013) 

Ag Sources of GHGs

Figure 2: U.S. agricultural greenhouse gas sources (Adapted from Archibeque, S. et al., 2012)

Animal Agriculture’s Contribution to Greenhouse Gas Emissions

Within animal production, the largest emissions are from beef followed by dairy, and largely dominated by the methane produced in during cattle digestion (Figure 3).

Greenhouse gas emissions from livestock in 2008

Figure 3: Greenhouse gas emissions from livestock in 2008 (USDA, 2011)

Excess nitrogen in agriculture systems can be converted to nitrous oxide through the nitrification-denitrification process. Nitrous oxide is a very potent greenhouse gas, with 310 times greater global warming potential than carbon dioxide.  Nitrous oxide can be produced in soils following fertilizer application. This includes both commercial, inorganic fertilizer as well as organic fertilizers like manure or compost.

As crops grow, photosynthesis removes carbon dioxide from the atmosphere and stores it in the plants and soil life. Soil and plant respiration adds carbon dioxide back to the atmosphere when microbes or plants breakdown molecules to produce energy.  Respiration is an essential part of growth and maintenance for most life on earth. This repeats with each growth, harvest, and decay cycle, therefore, feedstuffs and foods are generally considered to be carbon “neutral.”

Some carbon dioxide is stored in soils for long periods of time.  The processes that result in carbon accumulation are called carbon sinks or carbon sequestration.  Crop production and grazing management practices influence the soil’s ability to be a net source or sink for greenhouse gases.  Managing soils in ways that increase organic matter levels can increase the accumulation (sink) of soil carbon for many years.

Enteric Fermentation

The next largest portion of livestock greenhouse gas emissions is from methane produced during enteric fermentation in ruminants – a natural part of ruminant digestion where microbes in the first chamber of the stomach, the rumen, breaks down feed and produces methane as a by-product. The methane is released  primarily through belching.

As with plants, animals respire carbon dioxide, but also store some in their bodies, so they too are considered a neutral source of atmospheric carbon dioxide.

Manure Management

A similar microbial process to enteric fermentation leads to methane production from stored manure.  Anytime the manure sits for more than a couple days in an anaerobic (without oxygen) environment, methane will likely be produced.  Methane can be generated in the animal housing, manure storage, and during manure application. Additionally, small amounts of methane is produced from manure deposited on grazing lands.

Nitrous oxide is also produced from manure storage surfaces, during land application, and from manure in bedded packs & lots. Related: Archived webinar on GHG Emissions Research in Animal Ag

Other sources

There are many smaller sources of greenhouse gases on farms. Combustion engines exhaust carbon dioxide from fossil fuel (previously stored carbon) powered vehicles and equipment.  Manufacturing of farm inputs, including fuel, electricity, machinery, fertilizer, pesticides, seeds, plastics, and building materials, also results in emissions.

To learn more about how farm emissions are determined and see species specific examples, see the Carbon Footprint resources.

To learn about how to reduce on-farm emissions through mitigation technology and management options, see the Reducing Emissions resources.

Carbon Footprint

Definition: carbon footprint is the total greenhouse gas emissions for a given person, place, event or product.

Carbon footprints are created using a process called life cycle assessment. Life cycle assessment or LCA is a method of resource accounting where quantitative measures of inputs, outputs and impacts of a product are determined.

Life cycle assessment is commonly used to:

  • find process or production improvements
  • compare different systems or products
  • find the ‘hot spots’ in a product’s life cycle where the most environmental impacts are made
  • help businesses or consumers make informed sourcing decisions

diagram

Key Assumptions

boundaries of the system: each higher tier provides a more complete picture of the product’s impacts, however requires more time and resources to complete.

  1. Gate to Gate (LCA Tier I) – inventories the direct emissions for a single product of process
  2. Cradle to Gate (Tier II) – inputs are taken back to the initial extraction as natural resources up to a certain point in the product’s life such as its sale from the farm, i.e. farm gate.  This will include both direct  and indirect emissions from the product.
  3. Cradle To Grave (Tier III) – the product is followed through the consumer to its eventual recycling or disposal.

Sources of variation

Different researchers may get different results when performing a LCA on the same product. This can happen for many reasons:

  • System boundary definition
  • Inclusion/exclusion of secondary/ indirect sources
  • Inclusion/exclusion of biogenic carbon (stored in organisms)
  • Inclusion/exclusion of carbon dioxide from fuel combustion
  • Functional relationships used
  • Global warming potential indexes
  • Inclusion/exclusion of carbon sequestration

Related: Six archived webinars on the sources of animal ag ghg’s (some are general and some are species-specific)

Educator Materials

If you would like to use the video, slides, or factsheet for educational programs, please visit the curriculum page for download links for this and other climate change topics.

Recommended Reading – How Many Greenhouse Gases Does Agriculture Emit?

U.S. Agriculture Emissions

International Agriculture Emissions

Carbon Footprints and Life Cycle Analysis

Greenhouse Gas Regulations for Animal Agriculture

Visit Climate Change Regulation, Policy, and Market Opportunities

Acknowledgements

Author: Crystal A. Powers – University of Nebraska-Lincoln cpowers2@unl.edu

This material was developed through support from the USDA National Institute for Food and Agriculture (NIFA) under award #2011-67003-30206.

Impacts of the Michigan Agriculture Environmental Assurance Program

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Abstract

The Michigan Agriculture Environmental Assurance Program (MAEAP) is a holistic approach to environmental protection. It helps farmers evaluate their entire operation, regardless of size or commodity, and make sustainable management decisions balancing society’s needs, the environment, and economics. MAEAP is a partnership effort that aims to protect natural resources and build positive communities by working with farmers on environmentally responsible agricultural production practices.

To become MAEAP verified, farmers must complete three comprehensive steps: educational seminars, an on-farm risk assessment, and development and implementation of an action plan addressing potential environmental risks. The Michigan Department of Agriculture and Rural Development (MDARD) conducts an on-farm inspection to verify program requirements related to applicable state and federal environmental regulations, including the Generally Accepted Agricultural and Management Practices (GAAMPs). MAEAP benefits Michigan by helping to protect the Great Lakes by using proven scientific standards to improve air, water, and soil quality. Annual phosphorus reduction through MAEAP is over 340,451 pounds per year which is enough to grow almost 85,104 tons of algae in lakes and streams.  Farming is an environmentally intense practice and the MAEAP-verification process ensures farmers are making choices that balance production and environmental demands. The measures aimed at protecting air, soil, water, and other environmental factors mean that MAEAP-verified farmers are committed to utilizing farming practices that protect Michigan’s natural resources.

Purpose

The Michigan Agriculture Environmental Assurance Program (MAEAP) is an innovative, proactive program that assists farms of all sizes and all commodities voluntarily prevent or minimize agricultural pollution risks. MAEAP is a collaborative effort of farmers, Michigan Department of Agriculture and Rural Development, Michigan Farm Bureau, commodity organizations, universities, conservation districts, conservation groups and state and federal agencies. MAEAP teaches farmers how to identify and prevent environmental risks and work to comply with state and federal environmental regulations. Farmers who successfully complete the three phases of a MAEAP system (Farmstead, Cropping or Livestock) are rewarded by becoming verified in that system.

What Did We Do?

To become MAEAP-verified, farmers must complete three comprehensive steps: educational seminars, a thorough on-farm risk assessment, and development and implementation of an action plan addressing potential environmental risks. The Michigan Department of Agriculture and Rural Development (MDARD) conducts an on-farm inspection to verify program requirements related to applicable state and federal environmental regulations, including the Generally Accepted Agricultural Management Practices. To retain MAEAP verification, a farm must repeat all three steps including MDARD inspection every three years.

Local MAEAP farm verified in the Cropping System

What Have We Learned?

The MAEAP program is positively influencing Michigan producers and the agriculture industry. Annually, an average of 5,000 Michigan farmers attend an educational session geared toward environmental stewardship and MAEAP verification. To date, over 10,000 farms are participating with over 1,500 MAEAP verifications. On a yearly basis, over $1.2 million is spent for practice implementation by producers working towards MAEAP verification. In 2012; the sediment reduced on MAEAP-verified farms could have filled 28,642 dump trucks (10 yards each), the phosphorus reduced on MAEAP farms could have grown 138,056 tons of algae in surface waters, and the nitrogen reduced on MAEAP farms could have grown 45,515 tons of algae in surface waters.

An example of the partnership between MAEAP and Michigan Farm Bureau

Future Plans

Michigan Governor Rick Snyder has taken a vested interest in the value of the MAEAP program. In March of 2011, Governor Snyder signed Public Acts 1 and 2 which codify MAEAP into law. This provides incentives and structure for the MAEAP program. It is a goal of Governor Snyder’s to have 5,000 farms MAEAP-verified by 2015. Most importantly, through forward thinking MAEAP strives to connect farms and communities, ensure emergency preparedness and protect natural resources.

Authors

Jan Wilford, Program Manager, Michigan Department of Agriculture & Rural Development – Environmental Stewardship Division,    wilfordj9@michigan.gov

Shelby Bollwahn, MAEAP Technician – Hillsdale Conservation District

shelby.bollwahn@mi.nacdnet.net

Additional Information

www.maeap.org – MAEAP Website

http://michigan.gov/mdard/0,4610,7-125-1567_1599_25432—,00.html – MDARD MAEAP Website

http://www.facebook.com/mimaeap – MAEAP Facebook Page

Acknowledgements

MDARD MAEAP Program Office Communications Department

Michigan Farm Bureau

Michigan Association of Conservation Districts

Hillsdale County Farm Bureau

Hillsdale Conservation District

Handout version of the poster (8.5 x 11; pdf format)

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