Environmental Planning – Page 18 – Livestock and Poultry Environmental Learning Community

Purpose

This presentation will review the existing multi-species literature on nutrient cycling and how it is affected by the horse’s diet and rotational grazing.

Grazed pastures, particularly rotationally grazed pastures, recycle nutrients faster than ungrazed pastures. Nutrients on pasture land enter through animal waste, and waste feed or fertilizer; they leave through removal of forage, leaching/runoff, or animal product/waste removal. Taking away the animal component removes about half of the inputs needed to recycle the nutrients. Dietary nitrogen (N), phosphorus (P) and potassium (K) are required for basic maintenance of horses; however, not all of what is consumed is used by the animal, therefore the dietary concentrations of these nutrients will impact the nutrient cycling. Digestibility of N, P and K in horses is approximately 80, 25 and 75 %, respectively. What does not get digested will end up excreted back into the soil.

What did we do?

For example, in one study eight Standardbred mares were divided into two groups and received diets of grass hay and grain. The high P (HP) group received 142 g/d of NaH2PO4, formulated to provide 4.5-times the dietary P requirement, or 65 g phosphorus/d. The low P (LP) group received 28 g of phosphorus/d in the basal diet. Data showed that horses receiving the HP diet excreted higher P and water extractable P in the manure than those fed the LP diet (Table 1; Westendorf and Williams, 2015). The same goes for N, where one study used a treatment group that was supplemented with 700 g/d of soybean meal top dressed on 500 g of sweet feed per day (TRT; 1042 g protein/d DM total), while the control group received the sweet feed meals without the soybean meal (CON; 703 g protein/d total). Both groups were also fed 8 kg/d of a grass hay mix (562 g protein /d DM), water and salt ad libitum. Horses fed the TRT diet excreted more N and NH3 than horses fed the CON diet (Figure 1; Williams et al., 2011).

What have we learned?

More intensive grazing also creates an increased rate of nutrient cycling due to the added animal inputs on the land. Even though no horse related studies have been performed on this topic studies in cattle have found that plant-available N levels doubled when cattle were rotationally grazed with five grazings per season instead of three (Baron et al., 2002). Kenny (2016) looked at horses grazed under either a continuous or rotational grazing system (see Pictures 1 and 2, Left to Right, respectively) and found no differences in system after one year of grazing, however, the author concludes that more time on the system could have generated differences.

Other factors that affect the rate of nutrient cycling include amount of legumes in the pasture, distribution of manure on pastures (i.e. relation to water, shelters and fencing), and use or rates of fertilizer.

Future Plans

More equine specific studies need to be performed looking at how grazing systems and equine diets affect nutrient cycling and how horse farm owners can utilize this to best manage their farm for optimal nutrient utilization.

Corresponding author, title, and affiliation

Carey A. Williams, Equine Extension Specialist, Rutgers, the State University of New Jersey, Department of Animal Science

Corresponding author email

carey.williams@rutgers.edu

Additional information

References:

Baron, V. S., E. Mapfumo, A. C. Dick, M. A. Naeth, E. K. Okine, and D. S. Chanasyk. 2002. Grazing intensity impacts on pasture carbon and nitrogen flow. J. Range Manage. 55:525-541.

Kenny, L. B. 2016. The Effects of Rotational and Continuous Grazing on Horses, Pasture Condition, and Soil Properties. Master thesis, Rutgers, the State University of New Jersey, New Brunswick, NJ.

Westendorf, M. L., and C. A. Williams. 2015. Effects of excess dietary phosphorus on fecal phosphorus excretion and water extractable phosphorus in horses. J. Equine Vet. Sci. 35:495-498. doi:10.1016/j.jevs.2015.01.020

Williams, C. A., C. Urban, and M. L. Westendorf. 2011. Dietary protein affects nitrogen and ammonia excretion in horses. J. Equine Vet. Sci. 31:305-306.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

March 5, 2019March 4, 2021

Closing Abandoned Livestock Lagoons Effectively to Utilize Nutrients and Avoid Environmental Problems

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Purpose

In Nebraska alone, nearly 400 earthen manure storage structures are in operation; approximately four dozen requests to cease operation of permitted lagoons were received by the Nebraska Department of Environmental Quality in the prior decade with many more non-permitted storage structures being in need of proper closure. Abandoned livestock lagoons, earthen manure storage basins, and other manure storages (e.g. concrete pits) need to be decommissioned in a manner that controls potential environmental risk and makes economical use of accumulated nutrients. Currently, limited guidance is available to support lagoon closure planning and implementation and few professionals who support livestock producers have experience planning or participating in the manure storage closure process. The main focus of this project was to produce two videos that document the processes for planning and executing a lagoon closure.

What did we do?

The University of Nebraska Haskell Ag Laboratory, located near Concord, NE, had an anaerobic lagoon that was operated for over 20 years, but has not received swine manure additions since 2009 when the swine unit was depopulated. The decommissioning of this storage structure was proposed in 2014 and provided our team an opportunity to plan, implement and document the procedures necessary to properly close this structure. When we went to find material on how to accomplish this properly, we did not find suitable material. Two grants were secured in 2016 from the U.S. Pork Center of Excellence (USPCE) to fund our team efforts to document the closure process – from planning to completion – with two separate videos. The first video is focused on the planning activities necessary to prepare for removal and utilization of stored liquid and sludge. The second is focused on the liquid and sludge removal and utilization activities, decommissioning of conveyance structures, and deconstruction of the lagoon berm to return the site to a natural grade.

Activities conducted to execute the lagoon closure have included:

1) Mapping of sludge levels with sonar and analyzing sludge samples to estimate volume and nutrient content of sludge, which enabled development of a land application plan for utilizing the products

Figure 1. Sonar sludge mapping

Figure 1. Sonar sludge mapping.

2) De-watering the lagoon (effluent used for sprinkler irrigation and flood irrigation)

3) Hosting a demonstration event during which participants:

a. observed sludge removal and land application processes,

b. participated in a manure spreader calibration,

c. inspected the soil beneath the lagoon liner,

d. viewed the abandoned production buildings and heard about options for eliminating conveyance of liquid from the building to the lagoon,

e. explored alternative sludge removal methods, and

f. participated in a classroom session where presenters shared details of the closure planning process, cost-share opportunities for closure of manure storage structures, and expectations for re-grading and re-seeding the site following removal of sludge.

Figure 2. Participants learned about planning land application of the sludge

Figure 2. Participants learned about planning land application of the sludge.

Figure 3. Land application of the sludge and calibration of the manure spreader

Figure 3. Land application of the sludge and calibration of the manure spreader.

4) Removing the sludge and applying it to cropland following the demonstration event.

Documentation of all planning, demonstration, and closure execution activities have been captured via extensive video footage, still photos, and participant interviews. Production of the videos is in process with completion and release of videos anticipated in summer 2017.

What have we learned?

Although every manure storage closure process is expected to present its own unique challenges and opportunities for learning, the process documented during this project has provided a number of insights:

1) While this process involved pumping liquid from the lagoon prior to attempting sludge removal in order to observe the sludge layer and document the volume present, a more appropriate, and likely more effective, process is to agitate the storage prior to and during pumping activities to enable handling all of the material as a slurry;

2) Dewatered sludge volume (nearly 200,000 gallons) and nutrient content (44.2 lbs. TKN, 37.5 lbs. organic N, 89.3 lbs. P2O5 and 7.6 lbs. K2O per 1,000 gallons) for this system yielded enough nutrients to apply to 80-100 acres, based on a phosphorus removal rate. It is unknown what the release of the organic N component of the sludge will be, but using just the phosphorus content, application of 1000 gallons per acre would provide enough phosphorus for what would be removed from 220 bushels of corn, which is worth approximately $35 with winter 2017 prices.;

3) Given the high phosphorus content in the sludge and that the nearby fields at the Haskell Ag Lab were not in need of phosphorus, an appropriate application rate for the sludge was determined as 8-10 tons/acre;

4) Soil beneath the lagoon liner yielded a phosphorus concentration of 556 ppm, likely a result of an inadequate liner in the lagoon as originally constructed in the 1960s; and

5) Installation of a bentonite clay liner during renovation of the structure in 1992 appeared to be effective as the liner was fully intact when observed during closure activities.

Pre-post surveys completed by 33 attendees of the demonstration event revealed that attendees improved their confidence in performing six key tasks identified by the team as being impactful. Results are summarized in Figure 4.

Figure 4. Impacts of the lagoon closure demonstration event

Figure 4. Impacts of the lagoon closure demonstration event.

Future Plans

We plan to continue the decommissioning process by:

1) Completing sludge removal and application to cropland;

2) Deconstructing the berms, leaving the liner intact, and returning the area to natural grade;

3) Seeding the area to establish ground cover and mitigate runoff and erosion; and

4) Plugging the inlet pipes in manure pits within the animal housing in lieu of removing buried conveyance pipes.

The two videos are in production and will be made available through the Pork Information Gateway (www.porkgateway.org) during summer 2017.

Corresponding author, title, and affiliation

Leslie Johnson, Research Technologist, University of Nebraska – Lincoln

Corresponding author email

ljohnson13@unl.edu

Other authors

Charles Shapiro and Amy Schmidt, University of Nebraska – Lincoln

Additional information

https://water.unl.edu/article/animal-manure-management/lagoon-closure-and-your-environmental-responsibility

Acknowledgements

The authors would like to recognize the U.S. Pork Center of Excellence (USPCE) for funding the development of the videos documenting this process and enabling us to complete this project. We would also like to acknowledge that without the support of the industry, who provided equipment and advice, we would not have been able to get this project off the ground. Also a special thanks to the Agricultural Research Division for their support.

March 5, 2019March 6, 2019

Assessment of Coordinated Anaerobic Digestion of Dairy Manure

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Purpose

Improving the economic feasibility of anaerobic digestion projects for processing dairy manure.

What did we do?

We completed a study that evaluated the economics of dairy manure granulation as means to export phosphorus from P-sensitive watersheds. To achieve this goal we developed a techno-economic optimization model that considers all dairy farms within the watershed simultaneously to determine the minimum break-even price for the granulated manure.

A second study was developed to assess the economics of anaerobic digestion using a techno-economic optimization model. We incorporated different revenue sources (power sale, methane destruction credits, renewable energy certificates (RECs) and tipping fee (if co-substrate is available). The model evaluated the project feasibility over ranges of values for technical and economic parameters to quantify the project resilience to uncertainty in process conditions.

What have we learned?

The results from the first study indicated that multi-farm participation can significantly improve feasibility and overall economics of manure granulation. Herd sizes were found to be a critical parameter in deciding whether a farm can economically participate in coordinated management. For manure granulation projects, liquid-solid separation followed by transportation of separated solids was always more economical than transporting raw manure from satellite farm to central processing facility. In the second study, electricity sale price was found to be the key parameter that determines the feasibility of anaerobic digesters. The hub-spoke configuration, where a large central farm hosts the digester and smaller surrounding farms contribute to it was found to be the most favorable arrangement. The size of the hub farm was critical to the feasibility of the project. Similarly, transportation distance was a critical factor that constrained the extent of cooperative digesters.

Future Plans

The information generated from these studies is being written into peer-review publications and factsheets to share insights of collaborative manure management with a wider audience.We are currently expanding the model by adding the option for manure transportation via pipelines. Furthermore, we are also incorporating additional biogas utilization technologies,i.e., natural gas sale over pipelines and also the utilization of power/heat on-site in manure upgrading and processing.

Corresponding author, title, and affiliation

Troy M. Runge, Associate Professor, University of Wisconsin-Madison

Corresponding author email

trunge@wisc.edu

Other authors

Mahmoud A. Sharara, Rebecca Larson

Additional information

1. http://www.are.wisc.edu/

2. Sharara, Mahmoud, Apoorva Sampat, Laura W. Good, Amanda S. Smith, Pamela Porter, Victor M. Zavala, Rebecca Larson, and Troy Runge. “Spatially explicit methodology for coordinated manure management in shared watersheds.” Journal of Environmental Management 192 (2017): 48-56.

3. Sharara, Mahmoud, Qiang Yang, Thomas L. Cox, and Troy Runge. “Techno-economic assessment of dairy manure granulation.” In 2016 ASABE Annual International Meeting, p. 1. American Society of Agricultural and Biological Engineers, 2016.

Acknowledgements

This work is based on research supported by the USDA National Institute of Food and Agriculture for its financial support (USDANIFABRDI Grant No. 2012-10006-19423) and funding from Dane County, Wisconsin under Award Number 12486.

March 5, 2019March 20, 2019

A Quantitative Assessment of Beneficial Management Practices to Reduce Carbon and Reactive Nitrogen Footprints of Dairy Farms in the Great Lakes Region

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Purpose

Assessing and improving the sustainability of dairy production is essential to secure future food production. Implementation of Beneficial Management Practices (BMPs) can reduce carbon and reactive nitrogen footprints of dairy farms. BMPs can and have been developed for different farm components, including feed, manure management and field cultivation practices. It is practically and economically infeasible to empirically test all combinations of BMPs at a whole farm scale. We therefore use whole-farm process-based models to assess the impact of several Beneficial Management Practices (BMPs) on carbon and reactive nitrogen footprints of dairy farms in the Great Lakes region. Specifically the aim of this study is to evaluate the influence of Beneficial Management Practices (BMPs) on carbon, reactive nitrogen and phosphorus footprints of dairy farms in the Great Lakes region.

What did we do?

1. Baseline farms

We developed two baseline model farms, a small 150 cow herd farm and a large 1500 cow herd farm, that are thought to be representative for current dairy farming practices in the Great Lakes region, particularly Wisconsin and New York State (Table 1). The two baseline dairy farms were developed based on individual team members’ expertise and a consultation with external experts (Dane County Conservationists, Madison, Wisconsin). For the 1500 cow farm, the baseline scenario was partly based on a previously-studied commercial dairy farm in NY state. Since this commercial dairy farm already employs some BMPs (e.g. anaerobic digestion as BMP in manure management), the farm was ‘downgraded’ to derive the baseline.

2. Beneficial Management Practices

Farm-specific BMPs were developed for three farm components, i.e. “Feed”, “Manure Management & Storage” and “Field management”. These BMPS were developed based on expert judgement and are expected or known to reduce whole-farm GWPs.

To ensure a meaningful integration of BMPs and a consistent comparison of whole-farm BMPs to the baseline and to each other, we used the following set of rules (per farm type): i) Total cultivated area was fixed (areas of individual crops can vary per scenario); ii) Herd size was fixed; iii) Milk production was allowed to float, however, only if the production increased (no decreases in milk production); iv) Purchases of crops and protein mixes were minimized as far as possible.

3. Process model simulation

The Integrated Farm System Model (IFSM4.3) was used to simulate the two baseline farms (i.e. 1500 cow farm in NY and 150 cow farm in WI) and all the individual BMPs. IFSM was used as a baseline model. The other process-based models, that is DNDC, APEX and CNCPS, were used to check IFSM predictions.

4.Whole-farm mitigation strategy

The individual BMPs were analyzed in terms of potential reduction in carbon and reactive nitrogen footprint. The best performing individual BMPs were combined into a whole-farm mitigation strategy and this whole-farm mitigation strategy was subsequently modeled in IFSM.

What have we learned?

A comparison of model simulations of feed BMPs to the baseline shows that an integrated feed BMP (low forage, corn silage:alfalfa 3:1, ~2% NDF digestibility, reduced protein 14%, added fat, increased feed efficiency) can potentially reduce carbon and reactive nitrogen footprints with ~20% and ~24%, respectively, while remaining cost effective (18% increase in net return in $/cow), for both farm sizes.

For the small farm, replacing the bedded-pack barn with a free stall barn for the heifers, substantially reduces the carbon and the reactive nitrogen footprint with 12% and 11%, respectively. The manure management BMP ‘sealed with flare’ provides the largest potential reduction in carbon footprint for both farms (11% – 20%), primarily through a mitigation of CH4 emissions from manure storage.

Field management BMPs only provide a minimal reduction in carbon footprint (~3%), however, the field BMP ‘no-till with injection’ substantially reduces the reactive N footprint (~16%) for both farm sizes. This reduction is primarily achieved by a reduction in ammonia volatilization.

Based on the results for the individual BMPs, two combined whole-farm mitigation strategies were developed per farm and simulated in IFSM (Figure 1). For both the large farm and the small farm, the integrated whole-farm BMPs show an overall potential to reduce carbon and reactive nitrogen footprints with 33% to 37% and 15% to 42% respectively, simultaneously increasing milk production and the net return per cow with 10% to 12% and 20% to 42%, respectively.

This analysis suggests that BMPs can be applied to reduce greenhouse gas emissions and reactive nitrogen losses without sacrificing productivity or profit to the farmer.

Future Plans

Future research plans include a further comparison and analysis of IFSM predictions with predictions from other process models, including CNCPS, APEX, and ManureDNDC. In addition, we will assess the impact of climate change on the reactive nitrogen and carbon footprint of the baseline farms and the developed whole-farm mitigation strategies.

Corresponding author, title, and affiliation

Karin Veltman, PhD, University of Michigan, Ann Arbor

Corresponding author email

veltmank@umich.edu

Other authors

Alan Rotz, Joyce Cooper, Larry Chase, Richard Gaillard, Pete Ingraham, R. César Izaurralde, Curtis D. Jones, William Salas, Nick Stoddart, Greg Thoma, Peter Vadas, Olivier Jolliet

Additional information

Veltman et al. (2017) Comparison of process-based models to quantify nutrient flows and greenhouse gas emissions associated with milk production. Agricultural Ecosystems and Environment, 237, 31–44

DairyCAP project, www.sustainabledairy.org, aims to reduce the life cycle environmental impact of dairy production systems in the US.

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.

March 5, 2019March 20, 2019

Manure Treatment and Natural Inactivation of Porcine Epidemic Diarrhea Virus in Soils

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Purpose

The porcine epidemic diarrhea virus (PEDv) outbreak in North America has substantially impacted swine production, causing nearly 100% mortality in infected newborn piglets. Because manure may remain a source of reinfection, proper manure management practices to limit outbreaks need to be developed and evaluated. Two laboratory studies simulating manure pit treatment with increasing amounts of quicklime were conducted to determine PEDv susceptibility to increasing pH. Additionally, two laboratory soil incubation studies contrasting manure liming, multiple soil types, and two antecedent soil moistures were conducted over several months with incubation conditions mimicking the climates in Minnesota, Missouri, and Oklahoma to determine whether current manure application practices reduce the potential for PEDv reinfection via manure-amended soil. Quantitative PCR and live swine bioassays were used to enumerate PED virus and to determine whether manure and soil samples contained infectious PEDv.

What did we do?

Quicklime-Manure Slurry Incubations: An initial short-term manure slurry study was conducted on fresh PEDv-positive manure slurry collected in 2015 from the shallow pit of a commercial swine facility in southeast Nebraska. Manure was sampled prior to treatment (0 h) and then distributed among glass beakers (250 mL) to accommodate triplicates of three treatments: liming to pH 10, liming to pH 12, and unlimed manure. Following pH adjustment, aliquots of each sample were collected at 1 and 10 h, immediately neutralized with 10 mM HCl and stored at -80°C for subsequent analysis. In a second manure slurry incubation, triplicate PEDv-positive manure samples collected from a commercial swine operation in south central Nebraska site in December 2016 were mixed in equal portion (w:v) with distilled water to mimic manure slurry consistency observed in swine production pit storages. Quicklime was added stepwise (0.25 g addition) to each manure slurr! y sample with continuous stirring to gradually increase manure slurry pH. After each addition of quicklime, pH was measured and an aliquot of manure slurry was collected for subsequent quantitative PCR PEDv enumeration and infectivity in a pig bioassay.

Long-term manure and soil incubation. Initial tests determined appropriate initial soil moisture contents (representing a ‘dry’ and ‘moist’ soil condition) and manure:soil ratios (1 g slurry:3 g soil) to best represent the manure:soil within an injection furrow when slurry is injected into soil, and appropriate liming source (ag lime vs. quicklime). PEDv-positive manure slurry collected from a commercial swine operation in southeast Nebraska was divided between two 3-L containers, one for limed treatment (LIME) and the other for the control, or no-lime, treatment (CNL). Quicklime (30 g) was added to one 3 L portion (equivalent to an application of 80 lbs. quicklime per 1000 gallons of slurry) to achieve a final pH of 12. Both treated and untreated slurry stocks were incubated at room temperature for 24 hours. Distilled water was added to two soils, a silty clay loam (pH 7.0) and a loamy fine sand (pH 6.9), to attain 10% and 30% water holding capacity! (dry and moist soil condition). Thirty grams (dry weight) of soil was apportioned to multiple 50 mL screw top conical tubes and a cavity was made in the center of the soil by pressing a 10 mL pipet tip into the soil. Ten mL of slurry (LIME or CNL) were then added to each soil tube via pipet. Four replicate tubes were immediately frozen at -80°C for each combination of soil, moisture, and manure treatment to represent initial soil application (day 0). The tubes were loosely capped and placed into one of three incubators operated independently throughout the trial to simulate soil temperatures between November 1 and May 1 at one of three geographic locations: southern Minnesota, northern Missouri, and central Oklahoma (Figure 1). Twenty replicate tubes were created for each combination of soil, moisture, incubation, and manure treatment, and a set of four tubes were collected for each treatment combination on days 30, 60, 90, 120 and 150 of the incubation and immediately transfer! red to a -80°C freezer for storage.

Molecular detection and quantification of PEDv. Prior to analysis, soil and manure samples were removed from -80°C storage and allowed to thaw at room temperature. The RNA in each sample was extracted using the RNA PowerSoil Total RNA Isolation kit (Mo Bio, Carlsbad, CA). PEDv was detected in samples by reverse transcription and quantitative polymerase chain reaction (RT-qPCR).

Swine bioassay. To confirm that conditions yielding a PCR negative result actually inactivated the PED virus and rendered the manure non-infectious, a live pig bioassay was conducted with the limed and non-limed manure slurry samples from the initial short-term manure slurry incubation (quicklime addition). Fifteen pigs, approximately 21 days old, were sourced from a high-health facility whose dams tested negative for PEDv antibodies and virus by PCR. Piglets were tested for PEDv upon arrival and confirmed negative. Piglets were randomly assigned to individual housing in BSL-2 rooms at the University of Nebraska-Lincoln Life Sciences Annex as follows: control (3 piglets), pH 10 (6 piglets), and pH 12 (6 piglets), and allowed to acclimate for three days. Each pig was then administered a 10-mL oral gavage of manure slurry: three piglets in the control room received one of the three un-limed slurry samples; six piglets in the pH 10 room received one of the six limed (pH 10) sl! urry samp les (three limed for 1 h and three limed for 10 h); and six pigs in the pH 12 room received one of the six limed (pH 12) slurry samples (three limed for 1 h and three limed for 10 h). Piglets were monitored for fecal shedding of PEDv for four days until control animals began to demonstrate clinical signs of PEDv infection, at which time all piglets were humanely euthanized. Fecal swabs, and duodenum, ileum, jejunum, and cecum samples were collected from each animal and fixed in formalin. All fecal and tissue samples were analyzed for the presence of detectable PED virus by immunohistochemistry and PCR.

PEDv, log # g soil

What have we learned?

Manure Slurry Incubation: Manure limed to pH 10 and pH 12 for 1 and 10 h yielded no detectable PEDv RNA. Live swine bioassay results confirmed that these samples were not infective while control samples resulted in PEDv infection of piglets. These results indicate that a final manure slurry pH of 10 (equivalent to 50 lbs. of quicklime added to 1000 gallons manure slurry) is sufficient to reduce PEDv RNA to an undetectable concentration after 1 hour of contact time. All pigs receiving limed manure (pH 10 or 12 maintained for 1 or 10 h) during the live swine bioassay tested negative for PEDv infection while control pigs (un-limed treatment) all tested positive for PEDv infection (Figure 1). The pig bioassay results confirmed that the PCR assay is a reliable predictor for the presence of infectious PEDv in these matrices and that lime addition to achieve pH 10 for just one hour is sufficient to deactivate the virus in stored manure.

Soil Incubations: At the completion of the long-term (150-day) soil incubation, a subset of the frozen samples (LIME and CON soil samples collected on day 0 and 30) was selected for RNA extraction and qPCR analysis. The qPCR results from days 0 and 30 yielded no detectable PEDv RNA in either the limed or un-limed manure-amended soils (Figure 1). Furthermore, manure-amended soils did not differ from soil-only controls even though PEDv RNA was still detectable in the original manure slurry at high concentrations. No differences in PEDv abundance were detected on either day when initial soil moisture (10% vs 30% water holding capacity), incubation condition (MN vs. MO vs. OK), or soil type (silty clay loam and loamy fine sand) were varied. For these soils, the concentration of PEDv in limed or un-limed manure decreased immediately to a non-detectable level. These results indicate that manure-amended soil with pH 6.9 or greater is not a vector for transmission of the PED virus.

A consistent finding from all of the studies is that pH of media (slurry or soil) strongly influences PED virus survival.

Future Plans

Additional studies are underway to identify the lowest pH at which the PED virus is rendered non-infectious in slurry manure.

Corresponding author, title, and affiliation

Amy Millmier Schmidt, Assistant Professor, Departments of Biological Systems Engineering and Animal Science, University of Nebraska – Lincoln

Corresponding author email

aschmidt@unl.edu

Other authors

Stevens, E., A. Schmidt, D. Miller, J.D. Loy and V. Jin

Additional information

Dr. Amy Millmier Schmidt, corresponding author, can also be reach at (402) 472-0877.

Acknowledgements

Funding for this research was provided by the National Pork Board. Gratitude is extended to Ashley Schmit for assistance with laboratory activities and animal care. Special thanks to the Nebraska pork producers who granted access to their farms for collection of PEDv-positive manure.

March 5, 2019July 14, 2020

Results of Nutrient Recovery System Installed on Large Scale Dairy Operation After 2-years of Operation

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*Do not make slides downloadable

Purpose

For centuries, farmers have disposed of manure by simply spreading it on the land. It is a natural fertilizer. Today, that practice is no longer considered the best solution. Field spreading is now understood to contribute to a growing global problem of the pollution of water, soil, and air. Consequently, U.S. dairy farmers face increased fiscal and operational pressure from the progression of ever tightening environmental regulations. Conventional handling of manure also imposes a number of operational challenges (limitations for storage, land application and irrigation, settlement in lagoons, high manure hauling costs, etc.) and typically requires a relatively large land base to allow adequate nutrient management.

In Indiana, a dairy that was daily producing thousands of tons of livestock waste was investigating how technology could capture the valuable nutrients remaining in their cow manure after it had gone through the farm’s anaerobic digestion process. Their goal was to convert the manure/digestate into a nutrient rich cake that could be easier managed and made into fertilizer, and the liquid clean enough to be used unrestricted for land application.

The farm’s key operational deliverables were 1) to reduce the manure’s handling and transportation costs, 2) allow for precision applications of the processed manure as carbon-based fertilizer and 3) allow for re-use of nutrient reduced liquid for field irrigation.

What did we do?

The dairy farm chose to implement a nutrient recovery technology from Trident Processes LLC. The technology separates the manure/digestate into three fractions: 1) cellulosic fiber, 2) a concentrated cake of nutrient enriched solids, and 3) water with about 1% remaining solids.

Trident’s turn-key system, consisting of different mechanical and chemical components, processes the manure and diverts each separated fraction into their separate spaces. Sensors and programmable controls (PLC) allow for smooth operation, requiring minimal operator attendance. The entire system can be monitored, controlled and diagnosed remotely.

The manure is fed into the system following the digestion process. The initial step is the extraction of the large fiber, which is done via a rotary screen conditioner. The wetted material separates, with the effluent water and fine solids sifting down through the screen while the larger fiber is retained. This step is critical as it ensures the fine particles, which contain the nutrients, are sent down stream for further treatment.

FIBER: The extracted fiber is sent to a screw press for further dewatering. This renders it as a 30% dry cellulosic fiber biomass that is ideal for recycling as cow bedding or other biomass use. Any liquid squeezed from the fiber is diverted to join the fine solids stream.

SOLIDS: The effluent water and solids are sent to a dissolved air flotation (DAF) tank. Polymerization ensures effective flocculation of the feedstock, resulting in a concentration of the nutrient rich particles that float to the surface. The sludge formed on the surface is skimmed off the top and gravity fed into a multi-disc press for second-stage dewatering. The press gently dewaters and thickens the recovered solid/nutrient sludge into a 25% solids, nutrient rich cake.

WATER: The final effluent water, now nutrient reduced, contains less than 1.2% solids and is sent to the lagoon for storage. The water is then reused for irrigation through efficient pivot systems or as operational water on the farm.

What have we learned?

By implementing Trident’s Nutrient Recovery System, the farms’ objectives have been met and/or exceeded. After running for nearly two years the system is producing the following statistics:

• Fully automated operation requiring about 1 hr/shift for operator attendance (visual checks)

• 98% system uptime

• Polymer costs: $0.06 – $0.08/day/cow

• Reduction of handling and irrigation costs: $ 0.01/gal (conventional) vs $0.003/gal (center pivot)

• $250,000/yr electrical power savings with MD Press vs. centrifuge

• 73,000+ ton/yr nutrient cake produced

• 81% P, 70% organic N (54% TKN), and 20% K is the average nutrient capture rate

• 1% (max.) solids in the effluent water sent to lagoons

• 99% Suspended solids captured

Future Plans

Dairy farm: A fertilizer plant will go live in the near future, allowing the farm to sell their concentrated nutrients to the plant as feedstock for custom fertilizer production.

Technology provider: 2nd Phase effluent treatment to capture and retain the solid and nutrient fraction of the existing process, allowing to meet stream discharge standards and comply with BOD / COD levels. Bench scale testing is completed. Farm scale pilot testing is scheduled to run from March 2017-December 2017.

Corresponding author, title, and affiliation

Richard Shatto (Senior Partner at Point Nexus Consulting), Frank Engel (Director Marketing at KPD Consulting Ltd.)

Corresponding author email

frank.engel@kpdconsulting.ca

Additional information

https://youtu.be/PvaTGmyws-w (Carl Ramsey’s presentation at Indiana Dairy Forum)

http://www.progressivedairy.com/topics/manure/prairie-s-edge-dairy-on-pa… (Progressive Dairyman article)

http://tridentprocesses.com/documents/case-study-trident-nutrient-recove… (Newtrient case study)

https://are.wisc.edu/manure-processing/ (manure management project with University of Wisconsin)

http://www.foodqualityandsafety.com/article/nutrient-recovery-improves-s… (Nutrient Recovery Improves Sustainability article in Food Quality & Safety Magazine)

Acknowledgements

Carl Ramsey, Environmental Manager at Prairie’s Edge Dairy Farm

Soil Net LLC, Dr. Aicardo Roa (strategic partner for chemical separation process)

Leap Tech, R.C. Ludke (strategic partner for automation)

March 5, 2019March 20, 2019

Developing a Comprehensive Nutrient Management Plan (CNMP)

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Purpose

Livestock producers are presented with a number of challenges and opportunities. Developing a quality Comprehensive Nutrient Management Plan (CNMP) can effectively help landowners address natural resource concerns related to soil erosion, water quality, and air quality from manure management. As livestock operations continue to expand and concentrate in certain parts of the country, utilizing a CNMP becomes even more important. Following the NRCS 9-step planning process is critical in developing a good plan. Effective communication is a key element between all parties involved in the planning process. A CNMP documents the decisions made by the landowner for the farmstead area, crop and pasture area, and nutrient management. Information will cover the elements essential for developing a quality CNMP.

What did we do?

Since the CNMP documents the records of decisions by the landowner, it has to be organized in such a fashion that it is understandable to and usable by the landowner. The CNMP is the landowner’s plan. Therefore, the role of the planner is to help landowners do the things that will most benefit them and the resources in the long run. This will take both time and effort. To provide consistency with other conservation planning efforts within NRCS, CNMPs following the same process outlined in the National Planning Procedures Handbook. There are several items that are essential for a quality CNMP to be developed:

• Have a good understanding of potential resource concerns especially soil erosion, water quality and air quality.

• Make the appropriate number of site visits. Trying to do this from the office will likely lead to a poor quality CNMP that may not be implemented.

• Address resource concerns for the Farmstead and Crop and Pasture areas.

• Ensure that all nutrient sources are addressed.

• Follow the 9 steps of planning.

• Decisions are agreed upon by the landowner. The CNMP reflects the landowner’s record of decisions.

• Follow-up to address any questions or concerns.

• Update as necessary. A CNMP is not a static document.

Field

Land application of animal manure without proper land treatment practices

Muddy field with standing water

Proper animal manure storage required to address water quality issues

Picture of lined water bed

Evaluation of storage area to adequately address surface and subsurface
water quality issues

Picture of tractor and tanker spreader

Land application and nutrient management are critical elements for a
properly prepared CNMP

What have we learned?

The quality of CNMPs varies greatly across the country. Some were becoming so large that landowners were having difficulty finding the activities that needed to be completed. The revised CNMP format and process following the NRCS Conservation Planning approach should improve both the quality and usability of the plans developed. Due to statutes in the Farm Bill, all conservation practices recorded in the record of decision of the CNMP, whether receiving financial assistance or not, must be implemented by the end of the established contract period between the landowner and NRCS. Therefore it is important to only include the practices that are going to be implemented. CNMPs should be periodically updated to account for operational changes such as animal numbers, cropping systems, or land application methods.

Future Plans

The CNMP planning process will be evaluated to determine whether landowner objectives are being met and resource concerns properly addressed. Additional evaluations will look at the consistency of the plans generated across the country and the usability by landowners.

Corresponding author, title, and affiliation

Jeffrey P. Porter, P.E.; National Animal Manure and Nutrient Management Team Leader, USDA-Natural Resources Conservation Service

Corresponding author email

jeffrey.porter@gnb.usda.gov

Additional information

References

USDA-NRCS General Manual – Title 190, Part 405 – Comprehensive Nutrient Management Plans

USDA-NRCS Handbooks – Title 180, Part 600 – National Planning Procedures Handbook

Code of Federal Register (CFR) Title 7, Part 1466 – Environmental Quality Incentives Program (1466.7 EQIP Plan of Operations and 1466.21 Contract Requirements)

Webinar

Comprehensive Nutrient Management Plans and the Planning Process – http://www.conservationwebinars.net/webinars/comprehensive-nutrient-management-plans-and-the-planning-process/?searchterm=cnmp

March 5, 2019March 20, 2019

What’s New with Comprehensive Nutrient Management Plans (CNMPs)?

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Purpose

A Comprehensive Nutrient Management Plan (CNMP) is a management plan to utilize nutrients and to manage the collection, handling, storage, application, & utilization of animal waste. The purpose of the plan is to address soil erosion, water quality, and air quality concerns. Even though a CNMP is not a regulatory document, portions can potentially be used in the permitting process. It is meant to be a dynamic plan to help the producer’s operation to be sustainable. Landowner of animal feeding operations (AFO’s) that receive technical and/or financial assistance from NRCS are required to have a CNMP. This includes dairies, beef feedlots, poultry, and swine operations. Land application of manure is not a requirement. There are no animal numbers thresholds for a CNMP.

What did we do?

In 1999 the Unified National Strategy for Animal Feeding Operations directed USDA and EPA to work together to address environmental issues with AFO’s. The CNMP was developed as a voluntary way for a landowner to take action. The original document had a ten part format and was truly comprehensive. Any planner or engineer associated with the plan had to sign it. Developing a CNMP in this format was difficult and time consuming and in some cases the document became so large in size that no one updated them.

What have we learned?

In October 2015 the format changed back to a plan that is more consistent with a conservation plan, recording the decisions of the landowner/cooperator with regard to managing waste and utilizing the nutrients.

The plan now has a four part format. The first part is the signature page where the NRCS representative and the landowner sign confirming the decisions. Section one follows the signature page and documents decisions with regard to the Production Area (Farmstead). It includes maps, animal inventory, and records of decisions for the production area only. Section two documents the decisions with regard to the Land Treatment Area (Crop and Pasture). It contains maps, resource assessments, implementation requirements and records of decision for the land treatment areas. The third section documents decisions with regard to Nutrient Management. This includes risk analyses, setbacks, nutrient applications, and field balances.

For livestock operations with greater than 300 animal units a printout of the National Air Quality Site Assessment tool (NAQSAT) is now required as supporting documentation in the CNMP. It is to increase awareness of air quality issues that may be addressed on farm.

Several parts of the original format are not included in the current format. This includes the Operation and Maintenance plan and the Emergency Response plan. Both would now be found in the case file and not in the CNMP itself.

Picture of a field

Looking at crop residue.

Slurry containment

Evaluating solid separation on the farmstead.

Picture of people in field at demo

Discussing crop rotation and setbacks.

Future Plans

States are currently integrating the new national format. The CNMP format will be reviewed periodically to make sure that the document stays on track as a usable management tool for the landowner.

Corresponding author, title, and affiliation

Sandy Means, Environmental Engineer, USDA Natural Resources Conservation Service, East National Technical Center, Greensboro, NC

Corresponding author email

Sandy.Means@gnb.usda.gov

Additional information

Resources:

NRCS General Manual, Title 190, Part 405 Comprehensive Nutrient Management Plans

March 5, 2019March 19, 2019

Effectiveness of Livestock Exclusion in a Pasture of Central North Carolina

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*Do not make slides downloadable

Purpose

Jordan Lake (Reservoir), located in central North Carolina, is a 5,650-ha impoundment with a 436,860-ha watershed of which 18% was urban, 20% agricultural, and 56% forested. Like many lakes in the eastern U.S., the use of this water resource is being threatened by excessive nutrient inputs. A proposed nutrient reduction strategy set overall nitrogen (N) and phosphorus (P) load reduction goals for the watershed at 8-35% for N and 5% for P. Because much of the agricultural land in the watershed was used for pasture, the initial focus of reduction efforts was on pastures with livestock exclusion fencing identified as having the most potential. The objective of this project was to document the effectiveness of a combination of livestock exclusion fencing and nutrient management implemented on a beef cattle pasture typical of pastures in the Jordan Lake watershed and of the Piedmont region of NC.

What did we do?

figure 1a The paired watershed experimental approach used in this project, required simultaneous monitoring of two watersheds (treatment and control), during a calibration and a treatment period. The calibration period was from 12/30/07 to 10/5/11 and the treatment period was from 10/6/11 to 12/18/15. During both periods, the rainfall and quantity and quality of discharge were monitored continuously. Land use information (number of cattle, fertilization, soil test results) was collected at least annually. The treatment watershed (Past-treat) encompassed 54.5 ha all but 7.3 ha of which was used for beef cow pasture. The control watershed (Past-cont) encompassed 78.1 ha 39.5 ha of which was pasture, while most of the remainder (27.5 ha) was wooded.

In the treatment watershed the exclusion fenceline was constructed in October, 2011 about 3 m from the top of the streambank on either side and was limited to the main stream channel only (fig. 1b). Nutrient management was also implemented which eliminated P application as soil tests showed that there was adequate P in the soil to support the growth of pasture grasses such as fescue. In the control watershed, beef cattle had unlimited access to the stream channel during the entire project (fig. 1a). Monitoring included collecting flow-proportional samples during storm events and analyzing them for total Kjeldahl (TKN), ammonia (NH3-N), and inorganic (NOx-N) nitrogen as well as total phosphorus (TP) and total suspended solids (TSS).

What have we learned?

figure 1b Statistical analyses of storm event load data documented that during the post-fencing period, mass loading of TKN (34%), NH3-N (54%), TN (33%), TP (47%), and TSS (60%) was reduced significantly in the treatment relative to the control watershed, while storm discharge and NOx-N loads were not significantly different. These data showed that even a relatively narrow exclusion corridor implemented on only the main stream channel can significantly reduce the export of nitrogen, phosphorus, and sediment from a beef cattle pasture.

Future Plans

Evaluate livestock exclusion fencing at another Piedmont site with a wider exclusion corridor.

Corresponding author, title, and affiliation

Daniel Line, Extension Specialist at NC State University

Corresponding author email

dan_line@ncsu.edu

Other authors

Deanna Osmond, Professor, NC State University

Additional information

Published in J. Environmental Quality 45:1926-1932

Acknowledgements

This project received support from the National Institute of Food and Agriculture, U.S. Department of Agriculture, Integrated Water Quality Grant award 2011-0515 as well as funding from NCDEQ-DWR as pass-through funds from U.S. EPA 319.

March 5, 2019March 6, 2019

A Model Comparison of Daily N2O Flux with DayCent, DNDC, and EPIC

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Purpose

Process-based models are increasingly used as tools for studying complex agroecosystem interactions and N2O emissions from agricultural fields. The widespread use of these models to conduct research and inform policy benefits from periodic model comparisons that assess the state of agroecosystem modeling and indicate areas for model improvement. The increasingly broad application of models requires an assessment of model performance using datasets that span multiple biogeophysical contexts. While limited in the capacity to identify specific areas for model improvement, general evaluations provide a critical perspective on the use of model estimates to inform policy and also identify necessary model improvements that require further evaluation.

What did we do?

The objectives of this model comparison were to i) calibrate and validate three process-based models using a large dataset; ii) evaluate the performance of a multi-model ensemble to estimate observed data; and iii) construct a linear model to identify and quantify possible model bias in the estimation of soil N2O flux from agricultural fields. We selected three models that have been used to evaluate N2O emissions from agricultural fields: DayCent, DNDC, and EPIC. Using data from two field experiments over five years, we calibrated and validated each model using observations of soil temperature (n = 887), volumetric soil water content (VSWC) (n = 880), crop yield (n = 67), and soil N2O flux (n = 896). Our model validations and comparisons consisted of commonly conducted statistical evaluations of root mean squared error, correlation, and model efficiency. Additionally, the large sample sizes used here allowed for more robust linear regression models that offered additional insight into relationships between model estimations and observations of N2O flux. We hypothesized that such a linear model would indicate if there was model bias in estimations of soil N2O flux. Ensemble modeling can reduce the error associated with climate projections and has recently been applied to the estimation of N2O flux from agroecosystems. Thus, we also constructed a multi-model ensemble to evaluate the use of multiple models to improve estimates of soil N2O flux.

What have we learned?

In a comparison of three process-based models, calibration to a large dataset produced favorable estimations of soil temperature, VSWC, average yield, and N2O flux when the models were evaluated using RMSE, R2, and the Nash-Sutcliffe E-statistic. However, an evaluation of linear regression models revealed a consistent bias towards underestimating high-magnitude daily N2O flux and cumulative N2O flux. Observations of soil temperature and VSWC were unable to significantly explain model bias. Calibration to available data did not result in consistent model estimation of additional system properties that contribute to N2O flux, which suggests a need for additional model comparisons that make use of a wide variety of data types. The major contribution of this work has been to identify a potential model bias and future steps required to evaluate its source and improve the simulation of nitrogen cycling in agroecosystems. Process-based models are powerful tools, and it is not our objective to undermine their past and future application. However, more work is left to be done in understanding the biogeophysical system that produces soil N2O and in harmonizing the process-based models that simulate that system and which are used to evaluate management and generate policy.

Future Plans

Future work should test our findings in additional agroecological contexts to determine the extent to which a bias towards underestimating peak N2O flux persists. A meta-analysis of published data may be the most direct method for doing so. New datasets will need to be collected that represent simultaneous observations of multiple system properties (e.g. soil NO3-, soil NH4+, and heterotrophic respiration) from different soil layers and at increased temporal frequencies. Model developers should use these rich datasets to identify the source of N2O estimation bias and improve the structure and function of process-based models.

Corresponding author, title, and affiliation

Richard K. Gaillard, Graduate Student, University of Wisconsin-Madison

Corresponding author email

rgaillard@wisc.edu

Other authors

Curtis D. Jones, Assistant Research Professor, University of Maryland; Pete Ingraham, Research Scientist, Applied Geosolutions;

Additional information

sustainabledairy.org

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.

Additional Authors:

Sarah Collier, Research Associate, University of Wisconsin-Madison;

Roberto Cesar Izaurralde, Research Professor, University of Maryland;

William Jokela, Research Scientist (retired), USDA-ARS;

William Osterholz, Research Associate, University of Wisconsin-Madison;

William Salas, President and Chief Scientist, Applied Geosolutions;

Peter Vadas, Research Scientist, USDA-ARS;

Matthew Ruark; Associate Professor; University of Wisconsin-Madison