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.

Potential soil health improvement through the integration of cover crops and manure in the upper Midwest

Purpose

Oftentimes fall manure application is associated with significant offsite transport of nitrogen and phosphorus into nearby bodies of water and the atmosphere. Mechanisms of losses include leaching, runoff, sediment transport, and volatilization processes. This is becoming more common as there has been a trend of increased wet springs that create difficult planting conditions. This prolonged period without an active root system leaves more time for nutrient loss from fall-applied manure to occur.

A strategy to offset nutrient losses in the fall and early spring is to plant a cover crop. The uptake of nutrients during this time in the field, which would otherwise be left fallow, allows for nutrients to be stored in the tissue of the cover crops, minimizing nutrient loss risk. Upon terminating the cover crops, the decomposing residues can supply nutrients to the succeeding row-crop. However, cover crop adoption is low in the upper Midwest US stemming from a short cover crop growing season due to the cold climate. This is especially the case for crops utilizing manure. A strategy to expand the cover crop growing season may be to interseed a cover crop into a maturing row-crop prior to harvest. Previous studies investigating the integration of manure and cover crops have seeded the cover crop after manure application. We wanted to measure the impacts of first planting a cover crop then applying manure once the cover crop has had ample time to get established. This may help expand the cover crop growing season and potentially limit the offsite transfer of pollutants to our water and air.

What Did We Do?

A small plot study was started in fall 2019 at the University of Minnesota West Central Research and Outreach Center near Morris, MN. We tested the effect of nitrogen source and cover crops on soil health, nutrient cycling, and agronomic responses using a randomized complete block design with split plots.

Cover crop mixtures of cereal rye and annual ryegrass were interseeded near corn’s fifth leaf collar (V5) growth stage, physiological maturity (R5 to R6 growth stage), or drilled after corn harvest. Dairy manure was sweep-injected to minimize soil disturbance in early and late fall, when soil temperatures were above and below 10°C (50°F), respectively. Non-manured plots received urea in the spring prior to corn planting. Urea applied plots (no manure) with no cover crops served as the control. Soil samples were taken throughout the cover crop and row-crop growing season from the 0-15, 15-30, and 30-60 cm (0-6, 6-12, and 12-24 in) soil layers. Cover crop biomass samples were taken in the late fall prior to the first frost event and prior to cover crop termination in the spring.

What Have We Learned?

Sweep injection is a reliable method to apply liquid manure to a field with an established stand of cover crops with minimal noticeable damage to the cover crops in the spring (Figure 1). Planting cover crops as soon as possible ensures more biomass is produced; planting after harvest consistently had lower cover crop yield than interseeding. Spring cover crop yield, right before termination, was highest when planted near physiological maturity [110 kg ha-1 (98 lb ac-1)] compared to drilling after harvest [87 kg ha-1 (78 lb ac-1)]. Nutrient source had a significant effect on silage yield. Manure, either applied in the early or late fall, had greater silage yield [58.5 and 58.7 Mg ha-1 (26.1 and 26.2 ton ac-1), respectively] than spring applied urea [53.6 Mg ha-1 (23.9 ton ac-1)]. Plots with cover crops interseeded at V5 had greater silage yield [59.5 Mg ha-1 (26.5 ton ac-1)] than all other treatments [54-56 Mg ha-1 (24-25 ton ac-1)] except no cover crops [57.8 Mg ha-1 (25.8 ton ac-1)].

Figure 1. Cover crops planted prior to late manure application. Photo was taken in the spring at cover crop termination.

Future Plans

Soil samples collected throughout the study are currently being analyzed for nutrient content and other soil health parameters. Results from this study will be used to develop best management practices for integrating cover crops and liquid injected manure in the upper Midwest.

Authors

Manuel J. Sabbagh, Graduate Research Fellow, University of Minnesota

Corresponding author email address

sabba018@umn.edu

Additional authors

Melissa L. Wilson, Assistant Professor, University of Minnesota; Paulo H. Pagliari, Associate Professor, University of Minnesota

Additional Information

Twitter: @mannyandmanure @manureprof

Lab website: https://wilsonlab.cfans.umn.edu/

Acknowledgements

This work is supported by the Conservation Innovation Grants program at the Natural Resources Conservation Service of the USDA, the Minnesota Corn Research and Promotion Council, and the Foundation for Food and Agriculture Research.

How are Filth Flies Involved in Wasting Nitrogen?

Purpose

Filth flies are species from the Diptera order associated with animal feces and decomposing waste. Beef cattle raised on open pastures are especially susceptible to two species of filth flies: Face flies (Musca autumnalis De Geer) and Horn flies (Haematobia irritans (L.))  because these flies develop exclusively in fresh cattle manure. Filth fly impact on cattle health is related not only to the loss of body weight but also to the transmission of diseases like pink eye and mastitis (Basiel, 2020; Campbell, 1976; Hall, 1984; Nickerson et al., 1995).

Nitrogen losses from cattle’s manure has been reported for domestic flies (Musca domestica) and bottle flies (Neomyia cornicina) (Iwasa et al., 2015; Macqueen & Beirne, 1975). Despite the regular presence of face fly and horn fly in pastures, their effect on the nutrient cycles is little known. The purpose of this study is to understand the relationship between filth fly’s presence in cattle manure with the nitrogen losses caused by an increase in ammonia and nitrous oxide emissions.

What Did We Do?

The study was conducted in four pastures in the Georgia Piedmont: two near Watkinsville and two near Eatonton during June, July, and August of 2021. Ammonia volatilization and nitrous oxide emissions were measured on days 1, 4, 8, and 15 following dung deposition. Manure samples were collected on days 1 and 15. A static chamber was sealed for 24 h on each sampling date to capture manure’s ammonia and nitrous oxide emissions. In each chamber, a glass jar with boric acid was used to trap ammonia, and gas samples were collected. The gas samples were analyzed for nitrous oxide with a Varian Star 3600 CX Gas Chromatograph using an electron capture detector.

The number of filth flies was determined using a net trap covered by a black cloth that was set after 1 min of manure deposition, allowing the flies to oviposit for 10 min. On the days in which ammonia was not measured, a net trap was set to avoid additional oviposits, and record the emergence of filth flies. On the 15th day, we collected the filth flies that emerged from the eggs deposited in the manure during the first day.

What Have We Learned?

We found that cattle’s manure nitrogen loss as nitrous oxide (N2O) and ammonia (NH3) emissions have a direct relationship with the number of horn flies and face flies in the dung, Figure 1. Eighty percent of the flies trapped were horn flies. Dung with less than 5 flies can emit as little as 0.11 mg of N/kg of manure per day, while cattle manure with more than 30 flies can increase this emission by more than 10 times.

Figure 1 Nitrogen emissions such as nitrous oxide and ammonia (mg/kg of manure) and number of filth flies.

Every extra filth fly in manure can increase N emissions by 0.03 mg per kg of manure per day. According to NRCS, 59.1 lbs. of fresh manure is produced by a cow (approx. 1 000 pounds animal) every day (NRCS, 1995). Considering an average of 85 % relative humidity, 4.03 kg of dry manure can be produced per cow day. The actual economic threshold for horn fly is 200 flies per animal (Hogsette et al., 1991; Schreiber et al., 1987), considering a 1 to 1 sex ratio during emergence (Macqueen & Doube, 1988) we are assuming 100 female flies. Since the capacity of horn flies is 8-13 eggs per day (Lysyk, 1999), 100 female horn flies can generate approximately 1,000 new flies every day.  Calculating the nitrogen emissions (4.03 kg of dry manure X 0.03 mg N kg manure x 1,000 flies per day) results in 121 mg of N loss per cow per day when assuming the number of flies is just at the economic threshold. In January of 2022, USDA released the Southern Region Cattle Inventory with a total of 91.9 million head, from which 30.1 million were beef cows (USDA, 2022). Considering the earlier numbers, the horn fly presence in the beef cattle of the Southern Region could be emitting 3,639 kg of Nitrogen to the atmosphere every day.

Future Plans

We will continue the study on ammonia and nitrous oxide emissions under the same conditions during another year to confirm the trends and accuracy of the results. Also, we will implement a study to analyze the effect of the introduction of a parasitic wasp Spalangia endius as a biological control on horn fly and face fly populations and therefore on the manure’s nitrogen losses.

Authors

Presenting author

Natalia B. Espinoza, Research Assistant, Department of Crop and Soil Science, University of Georgia

Corresponding author

Dr. Dorcas H. Franklin, Professor, Department of Crop and Soil Sciences, University of Georgia

Corresponding author email address

dfrankln@uga.edu or dory.franklin@uga.edu

Additional authors

Anish Subedi, Research Assistant, Department of Crop and Soil Science, University of Georgia

Dr. Miguel Cabrera, Professor, Department of Crop and Soil Sciences, University of Georgia

Dr. Nancy Hinkle, Professor, Department of Entomology, University of Georgia

Dr. S. Lawton Stewart, Professor, Department of Animal and Dairy Science, University of Georgia

Additional Information

Basiel, B. (2020). Genomic Evaluation of Horn Fly Resistance and Phenotypes of Cholesterol Deficiency Carriers in Holstein Cattle [PennState University]. Electronic Theses and Dissertations for Graduate Students.

Campbell, J. B. (1976). Effect of Horn Fly Control on Cows as Expressed by Increased Weaning Weights of Calves. Journal of Economic Entomology, 69(6), 711-712. https://doi.org/DOI 10.1093/jee/69.6.711

Hall, R. D. (1984). Relationship of the Face Fly (Diptera, Muscidae) to Pinkeye in Cattle – a Review and Synthesis of the Relevant Literature. Journal of Medical Entomology, 21(4), 361-365. https://doi.org/DOI 10.1093/jmedent/21.4.361

Hogsette, J. A., Prichard, D. L., & Ruff, J. P. (1991). Economic-Effects of Horn Fly (Diptera, Muscidae) Populations on Beef-Cattle Exposed to 3 Pesticide Treatment Regimes. Journal of Economic Entomology, 84(4), 1270-1274. https://doi.org/DOI 10.1093/jee/84.4.1270

Iwasa, M., Moki, Y., & Takahashi, J. (2015). Effects of the Activity of Coprophagous Insects on Greenhouse Gas Emissions from Cattle Dung Pats and Changes in Amounts of Nitrogen, Carbon, and Energy. Environmental Entomology, 44(1), 106-113. https://doi.org/10.1093/ee/nvu023

Lysyk, T. J. (1999). Effect of temperature on time to eclosion and spring emergence of postdiapausing horn flies (Diptera : Muscidae). Environmental Entomology, 28(3), 387-397. https://doi.org/DOI 10.1093/ee/28.3.387

Macqueen, A., & Beirne, B. P. (1975). Influence of Some Dipterous Larvae on Nitrogen Loss from Cattle Dung. Environmental Entomology, 4(6), 868-870. https://doi.org/DOI 10.1093/ee/4.6.868

Macqueen, A., & Doube, B. M. (1988). Emergence, Host-Finding and Longevity of Adult Haematobia-Irritans-Exigua Demeijere (Diptera, Muscidae). Journal of the Australian Entomological Society, 27, 167-174. <Go to ISI>://WOS:A1988P906100002

Nickerson, S. C., Owens, W. E., & Boddie, R. L. (1995). Symposium – Mastitis in Dairy Heifers – Mastitis in Dairy Heifers – Initial Studies on Prevalence and Control. Journal of Dairy Science, 78(7), 1607-1618. https://doi.org/DOI 10.3168/jds.S0022-0302(95)76785-6

NRCS, N. R. C. S. (1995). Animal Manure Management. RCA Publication Archive(7). https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcs143_014211

Schreiber, E. T., Campbell, J. B., Kunz, S. E., Clanton, D. C., & Hudson, D. B. (1987). Effects of Horn Fly (Diptera, Muscidae) Control on Cows and Gastrointestinal Worm (Nematode, Trichostrongylidae) Treatment for Calves on Cow and Calf Weight Gains. Journal of Economic Entomology, 80(2), 451-454. https://doi.org/DOI 10.1093/jee/80.2.451

USDA. (2022). Southern Region News Release Cattle Inventory. https://www.nass.usda.gov/Statistics_by_State/Regional_Office/Southern/includes/Publications/Livestock_Releases/Cattle_Inventory/Cattle2022.pdf

Can Grazing Systems Affect Plant Available N and P?

Purpose

A large percentage of the carbon (C), nitrogen (N), and phosphorus (P) cattle consume is released or deposited as cattle dung and urine.  If we can develop grazing systems that retain these nutrients within the grazing system that is a first step in turning cattle manure into a resource rather than a waste.  The second step is distributing the nutrients to the whole of the pasture.  The third step is making the complex molecules of N and P plant available. The final step is keeping cattle manure in the grazing system to rebuild soil health.  We explored the impact of two grazing systems we named 1) conventional with hay distribution (CHD) and 2) strategic grazing (STR) on  soil C, N, P, bulk density (soil compaction, BD), and cattle density (CD) with the hypothesis that grazing systems can improve soil health and thereby retain and recycle C, N and P. Said more plainly rather than sacrificing areas of the pasture we hoped to regenerate areas that were less productive (cattle camping areas) and make them more productive.

What Did We Do?

We compared a conventional grazing system, baseline (year 2015) factors: C, N, P, BD, and CD to the same factors after two years of CHD and STR. We took soil samples every 50 m at three soil depths (0-5, 5-10 and 10-20 cm) in 2015 (Baseline) and in 2018 (post treatment).  Project design follows:

    • Year 1 – Continuous Grazing in eight ~40 ac (16 ha) pastures
      • Waterers, shade, hay and mineral provided in same location
    • Year 2 and 3 – Improved Grazing systems applied:
      • CHD – 4 of eight in continuous with hay distribution and
      • STR – 4 of eight in strategic grazing
        Mixture of better grazing practices

        1. Manure distribution through Lure management of cattle
          Portable shades, Portable waterers, Portable hay rings
        2. Exclusion of compacted areas vulnerable to nutrient loss
        3. Over seeding of exclusions with forage mix
        4. Flash/Mob grazing of excluded areas for short time
        5. Moderate rotational grazing in the sub-paddocks

What Have We Learned?

We found that both the CHD and the STR significantly increased the amount of N and P in the top 5 cm of soil Figure 1. The increase in plant available N in 2018 (sum of ammonium and nitrate) in the top five cm of soil was 5.6 times more in CHD and 5.8 times more in STR when compared to Baseline (2015) (Dahal et al., 2020).  The 2018 increase in plant available P was 6.1 times more in CHD and 4.9 times more in STR compared to 2015.  We attribute the greater increase in P in CHD to the greater number of hay bales needed during an extensive drought in 2016 (Subedi et al., 2021).

Figure 1. Plant available P (Mehlich-1, left), plant available N (inorganic N, middle), and carbon (loss-on-ignition, right) during Baseline in black and two years after treatments in red.

The impact of cattle management on bulk density varied greatly depending on where you were in the pasture which depended on improved management system.  While there was a slight increase in bulk density in 0-5 cm soil layer from 2015 to 2018 for both CHD and STR the increases were not significant and would not cause any restrictions on forage growth (Figure 2).  In the 5-10 cm soil layer, BDs in both the CHD and STR were significantly reduced.  The STR did reduce BD slightly more than in the CHD pastures. Percent change in 2018 BD for STR was -10.5 and for CHD was -8.6.

Figure 2 Bulk density (BD) for the 0-5 cm soil layer (left) and the 5-10 cm soil layer (right).

The reduced compaction in the improved pasture management systems is important for several reasons but here we will discuss only the importance on root growth and nitrogen availability.  Bulk density or compaction can restrict forage root growth.  During Baseline pastures had median BD values of greater than 1.6 g cm-3 (Hendricks et al., 2019) which can restrict forage growth.  After two years of the improved grazing systems BD was reduced to below 1.45 g cm-3 a value which is usually not restrictive to plant growth. We believe that the decrease in compaction allowed rainfall to move manures into the soil and allow for greater microbial activity.  Above we noted the increase in nitrogen and phosphorus but we did not as yet mention the decrease in the Loss-on-ignition (LOI) carbon.  The LOI carbon is composed of larger molecules and requires a great amount of microbial activity to break down and release the plant available nutrients within the molecule. We speculate with the reduced bulk density and associated greater ability of rainfall to move nutrients into the soil, the N and P associated with the cattle manure was able to be decomposed into plant available forms of nitrogen and phosphorus.  These assumptions are supported with two indicators of soil microbial activity: greater CO2 emissions and an increase in a labile form of carbon (permanganate oxidizable carbon, in 2018 compared to 2015 (Dahal et al., 2020).  The labile form of carbon was also found to increase with depth to 20 cm of soil which suggests that the carbon may not be lost to the atmosphere but maybe moving down in the soil profile.

Take-home messages

    • Cattle grazing can increase nitrogen and phosphorus soil content with improved grazing managements practices: hay distribution and strategic grazing practices designed to distribute cattle dung throughout the pasture and away from areas that are vulnerable to erosion.
    • Improved grazing practices can reduce soil compaction when cattle grazing is well distributed throughout the whole pasture.

Future Plans

We were greatly concerned with the decrease in carbon in both improved grazing systems. However, upon greater analysis of our data (in press) we have found additional information to indicate that carbon (LOI and the labile) is moving down the soil profile.  We are in process of studying the C, N, P movement to greater depths and the impact this could also have on the grazing system to also capture and retain rainfall.

Authors

Corresponding and first Author

Dr. Dorcas H. Franklin; Professor; Department of Crop and Soil Sciences; University of Georgia; dfrankln@uga.edu or dory.franklin@uga.edu

Presenting Author

Anish Subedi; Department of Crop and Soil Sciences; University of Georgia; as07817@uga.edu

Additional Authors

Dr. Miguel Cabrera; Professor; Department of Crop and Soil Sciences; University of Georgia; mcabrera@uga.edu

Dr. Subash Dahal; Department of Crop and Soil Sciences; University of Georgia; dahal.green@gmail.com

Amanda McPherson; Department of Crop and Soil Sciences; University of Georgia; Amanda.McPherson@uga.edu

Additional Information

Dahal, S., Franklin, D., Subedi, A., Cabrera, M., Hancock, D., Mahmud, K., Ney, L., Park, C., & Mishra, D. (2020). Strategic grazing in beef-pastures for improved soil health and reduced runoff-nitrate-a step towards sustainability. Sustainability, 12(2), 558.

Subedi, A., Franklin, D., Cabrera, M., McPherson, A., & Dahal, S. (2020). Grazing Systems to Retain and redistribute soil phosphorus and to reduce phosphorus losses in runoff. Soil Systems, 4(4), 66.

Hendricks, T., Franklin, D., Dahal, S., Hancock, D., Stewart, L., Cabrera, M., & Hawkins, G. (2019). Soil carbon and bulk density distribution within 10 Southern Piedmont grazing systems. Journal of Soil and Water Conservation, 74(4), 323-333.

Acknowledgements

Funding: This research was funded by NRCS-USDA, Conservation Innovation Grant. Grant number 69-3A75-14-251.

Acknowledgments: The authors are grateful to USDA-NRCS for their assistance with the first-order soil survey, and to the Sustainable Agriculture Laboratory team, John Rema, and Charles T. Trumbo at the University of Georgia for their endless help in the laboratory and the field.

Predicting Manure Nitrogen and Phosphorus Characteristics of Beef Open Lot Systems

This project involves the analysis of a new data set for manure characteristics from open lot beef systems demonstrating both average characteristics and factors contribution to variability in manure characteristics among these systems. Defining the characteristics and quantities of harvested manure and runoff from open earthen lot animal systems is critical to planning storage requirements, land requirements for nutrient utilization, land application rates, and logistical issues, such as equipment and labor requirements. Accuracy of these estimates are critical to planning processes required by federal and state permitting programs. Poor estimates can lead to discharges that result in court action and fines, neighbor nuisance complaints, and surface and ground water degradation. Planning procedures have historically relied upon standard values published by NRCS (Stettler et al., 2008), MWPS (Lorimor et al., 2000), and ASABE (2014) for average characteristics.

What Did We Do?

A large data set of analyses from manure samples collected over a 15-year period from 444 independent cattle feedlot pens at a single eastern Nebraska research facility was reviewed to provide insight to the degree of variability in observed manure characteristics and to investigate the factors influencing this variability. No previous efforts to define these characteristics have included data gathered over such a wide range of dietary strategies and weather conditions. This exclusive research data set is expected to provide new insights regarding influential factors affecting characteristics of manure and runoff harvested from open lot beef systems. The objective of this paper is to share a preliminary summary of findings based upon a review of this data set.

What Have We Learned?

A review of this unique data set reveals several important preliminary observations. Standard values reported by ASABE and MWPS for beef manure characteristics in open lot systems are relatively poor indicators of the significant variability that is observed within open lot feeding systems. Our data set reveals significant differences between manure characteristics as a function of feeding period (Table 1) and substantial variability within feeding period, as illustrated by the large coefficients of variation for individual characteristics. Differences in winter and summer conditions influence the characteristics and quantities of solids, organic matter, and nutrients in the harvested manure. The timing of the feeding period has substantial influence on observed differences in nitrogen loss and nitrogen in manure (Figure 1). Nitrogen recovery for the warmer summer feeding periods averaged 51 and 6 grams/head/day in the manure and runoff, respectively, with losses estimated to be 155 grams/head/day.  Similarly, nitrogen recovery in manure and runoff for the winter feeding period was 90 and 4 grams/head/day, respectively, with losses estimated at 92 grams/head/day (Figure 1 and Koelsch, et al., 2018). In addition, differences in weather and pen conditions during and following winter and summer feeding periods impact manure moisture content and the mixing of inorganics with manure (Table 1).

Table 1. Characteristics of manure collected from 216 and 228 cattle feedlot pens during Summer and Winter feeding periods, respectively1.
University of Nebraska Feedlot in East Central Nebraska Standard Values
Summer Winter ASABE NRCS MWPS3
Mean CV2 Mean CV2 Mean Mean
Total Manure (wet basis), kg/hd/d 9.3 99% 13.1 43% 7.5 7.9
DM    % 71% 10% 63.2% 15% 67% Collected 55%
    kg/hd/d 5.4 80% 8.0 41% 5.0 manure 4.3
OM    % 24% 28% 25.3% 41% 30% is not 50%
    kg/hd/d 1.00 52% 1.87 41% 1.5 reported. 2.2
Ash    % 76% 9% 74.7% 14% 70% 50%
    kg/hd/d 4.16 72% 6.10 49% 3.5 2.2
N    % 1.3% 36% 1.19% 23% 1.18% 1.2%
    g/hd/d 51 50% 90 33% 88 95
P    % 0.37% 41% 0.34% 29% 0.50% 0.35%
    k/hd/d 17.7 55% 26.0 42% 37.5 27.7
DM = dry matter; OM = organic matter (or volatile solids)

1    Summer = April to October feeding period, Winter = November to May feeding period

2    Coefficient of variation, %

3    Unsurfaced lot in dry climate with annual manure removal.

two pie charts
Figure 1. Distribution of dietary nitrogen consumed by beef cattle among four possible ed points for summer and winter feeding periods.

Dietary concentration of nutrients was observed to influence the harvested manure P content (Figure 2) but produce minimal impact on harvested manure N content (not shown). Diet was an important predictor in observed N losses, especially during the summer feeding period. However, its limited value for predicting harvested manure N and moderate value for predicting harvesting manure P suggests that other factors such as weather and management may be influential in determining N and P recovered (Koelsch, et al., 2018).

scatter plot with trendlines
Figure 2. Influence of dietary P concentration on harvested manure P.

Significant variability exists in the quantity of total solids of manure harvested with a factor of 10 difference between the observed low and high values when compared on a mass per finished head basis (note large CVs in Table 1). This variability has significant influence on quality of the manure collected as represented by organic matter, ash content, and moisture content.

Although individual experimental trials comparing practices to increase organic matter on the feedlot surface have demonstrated some benefit to reducing nitrogen losses, the overall data set does not demonstrate value from higher pen surface organic matter for conservation of N in the manure (Koelsch, et al., 2018). However, higher organic matter manure is correlated to improved nitrogen concentration in the manure suggesting a higher value for the manure (Figure 3).

scatter plot with trendlines
Figure 3. Influence of pen surface organic matter measured as organic matter in the harvested manure) on nitrogen concentration in the manure.

It is typically recommended that manure management planning should be based upon unique analysis for manure characteristics representative of the manure being applied.  The large variability in harvested manure from open lot beef systems observed in this study further confirms the importance of this recommendation. The influence of weather on the manure and the management challenges of collecting manure from these systems adds to the complexity of predicting manure characteristics.  In addition, standard reporting methods such as ASABE should consider reporting of separate standard values based upon time of the year feeding and/or manure collection period. This review of beef manure characteristics over a 15 year period further documents the challenge of planning based upon typical or standard value for open lot beef manure.

Future Plans

The compilation and analysis of the manure and runoff data from these 444 independent measure of feedlot manure characteristics is a part of an undergraduate student research experience. Final review and analysis of this data will be completed by summer 2019 with the data published at a later time. The authors will explore the value of this data for adjusting beef manure characteristics for ASABE’s Standard (ASABE, 2014).

References

ASABE. 2014.  ASAE D384.2 MAR2005 (R2014):  Manure Production and Characteristics. ASABE, St. Joseph, Ml. 32 pages.

Koelsch, R. , G. Erickson2, M. Homolka2, M. Luebbe. 2018. redicting Manure Nitrogen, Phosphorus, and Carbon Characteristics of Beef Open Lot Systems. Presented at the 2018 ASABE Annual International Meeting. 15 pages.

Lorimor, J., W. Powers, and A. Sutton. 2000. Manure characteristics. Manure Management Systems Series MWPS-18. Midwest Plan Service. Ames Iowa: Iowa State University.

Stettler, D., C. Zuller, D. Hickman. 2008. Agricultural Waste Characteristics.  Chapter 4 of Part 651, NRCS Agricultural Waste Management Field Handbook. pages 4-1 to 4-32.

 

Authors

Richard (Rick) Koelsch, Professor of Biological Systems Engineering and Animal Science, University of Nebraska-Lincoln

rkoelsch1@unl.edu

Megan Homolka, student, and Galen Erickson Professor of Animal Science, University of Nebraska-Lincoln

Additional Information

Koelsch, R. , G. Erickson2, M. Homolka2, M. Luebbe. 2018. Predicting Manure Nitrogen, Phosphorus, and Carbon Characteristics of Beef Open Lot Systems. Presented at the 2018 ASABE Annual International Meeting. 15 pages.

 

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

Spatial and Temporal Soil Nitrogen Distribution After Shallow Disk Manure Injection in Corn

The purpose of this field research was to explore nitrogen (N) distribution in the form of nitrate and ammonium in both a spatial and temporal manner over two seasons in manure injection plots in central Pennsylvania. The description of N movement from high concentration at the manure band through the season can aid in understanding of nutrient migration and utilization efficiencies. The work was complimentary to previous soil sampling protocol developed for mid-season nitrate testing in corn fields with injected manure.

Mid-season soil testing for N protocols such as the Pre-Sidedress Nitrate Test in corn can be valuable tools to examine nutrient efficiencies. Economic benefit can result when producers use test information to determine if current soil N will allow maximum crop growth or if additional N sidedressing is needed to reach yield goals. Environmental benefits of the test include optimizing in-field N while minimizing excess application of the nutrient. However, conducting the test on soils where manure injection has occurred presents accuracy challenges due to uneven nutrient distribution. A soil sampling protocol for these scenarios was presented at the 2017 Waste to Worth Conference. The protocol calls for composite collection of four sets of soil samples, with each set containing five soil cores of 12-inch depth collected six inches apart from each other in a line perpendicular to the direction of manure injection (Figure 1).

Figure 1. Earlier work determined that collecting and compositing four sets of five soil samples that were 12-inches deep and 6-inches apart where manure injection banding was in place was an accurate substitution for Pre-sidedress Nitrate Testing compared to soils with surface broadcasted nitrogen.
Figure 1. Earlier work determined that collecting and compositing four sets of five soil samples that were 12-inches deep and 6-inches apart where manure injection banding was in place was an accurate substitution for Pre-sidedress Nitrate Testing compared to soils with surface broadcasted nitrogen.

What did we do?

In the current research, N measurements were taken at several distances from the manure band center and analyzed at depths of 0-6 inches and 6-12 inches. Measures in manure plots were collected at five different dates through each of two growing seasons (Figure 2).

Figure 2. Current research explored nitrogen distribution through 5 dates in the growing season to develop both a spatial and temporal appreciation of nitrate distribution and efficiencies.
Figure 2. Current research explored nitrogen distribution through 5 dates in the growing season to develop both a spatial and temporal appreciation of nitrate distribution and efficiencies.

What have we learned?

Results show that N concentrations ‘peak’ in the region immediately near the injection band early in the season and then flatten through the season. A comparison of the top 6-inch samples with average of the both sampling depths indicate that the top 6 inches may be predictive of the entire 12-inch depth. This presentation will provide results and trends observed in N movement from injection bands in these soil plots.

Authors

Robert Meinen, Senior Extension Associate, Department of Animal Science, The Pennsylvania State University, rjm134@psu.edu

 

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

Sidedressing Corn: Swine Manure via Dragline Hose Produces Yields Comparable to Synthetic Fertilizer

Spring in the upper Midwest can be short, resulting in challenges for producers to apply manure and plant crops in a timely manner to maximize yield. This results in a significant       amount of manure applied in the fall after the crop is harvested. Fall applied manure has ample time to mineralize and leave the root zone before next season’s crop can utilize the nutrients. These nutrients can end up in rivers and other freshwater bodies decreasing water quality. Sidedressing manure in growing crops could provide producers with another window of opportunity to apply their manure, maximize nutrient uptake efficiency, and protect water quality. The summer of 2018 was the start of a two-year, on-farm study researching the effectiveness of sidedressing slurry swine manure to corn via dragline hose. The swine manure was compared to sidedressed anhydrous ammonia, 32% urea ammonium nitrate (UAN), and a  control that received no additional nitrogen at the time of sidedressing.

What we did

Corn was planted May 7th with a 12-row planter equipped to apply an in-furrow and top dressed liquid fertilizer. The total fertilizer applied at planting was 40.7 lbs of nitrogen (N), 19.8 lbs of P2O5 phosphorus (P), and 14.4 lbs of sulfur (S) per acre.

Sidedressing the nitrogen sources

We sidedressed all treatments on June 4-5 with 140 pounds of available N, except the control which had no additional N applied. All the equipment applied nutrients between 30-inch rows and fit a 12-row planter to match up on odd rows.

  • Anhydrous ammonia treatment = 12-row toolbar and tractor were supplied by the farmer.
  • Finishing hog manure dragline hose treatment = The toolbar for the dragline hose sidedress was supplied by Bazooka Farmstar. The toolbar is a coulter till 28-foot bar with 30-inch spacing.
  • UAN treatment = The tool bar for the UAN sidedress application was provided by a local farmer.
  • Control treatment = The control treatment did not receive any fertilizer at sidedress.
Swine manure slurry being applied via dragline hose and Bazooka Farmstar sidedress bar.
Swine manure slurry being applied via dragline hose and Bazooka Farmstar sidedress bar.

Soil data collection methods

Soil nitrate and ammonium samples were taken 5 times through the growing season, approximately every 4 weeks, to track nitrogen in the soil profile. Soil sample depths were 0-6, 6-12, and 12-24 inches from the soil surface. Soil

Two foot soil sampling with tractor probe.
Two foot soil sampling with tractor probe.

samples were taken from the middle of the interrow, 7.5 inches from both sides of the middle of the inter row and in the middle of the row. This sample method assured soil samples would be representative of the soil profile since banded fertilizer can skew results.

Yield data collection methods

Yield was harvested October 6th by a combine with a 6-row head. The combine took the middle 12 rows of the 24-row treatment reducing the side effects from neighboring treatments. A calibrated weigh wagon measured the weight of each combine pass which was calculated to find yield in bushels per acre for every sample.

What we have learned

First year data revealed all sidedressed nitrogen sources significantly increased corn yields over the control but were otherwise statistically similar (Figure 1).

Figure 1. Yield data from 2018 manure sidedress trial in bushels per acre. AA=anhydrous ammonia, UAN=urea ammonium nitrate, Control=received no additional N at sidedress, and Dragline=swine manure slurry applied via dragline hose.
Figure 1. Yield data from 2018 manure sidedress trial in bushels per acre. AA=anhydrous ammonia, UAN=urea ammonium nitrate, Control=received no additional N at sidedress, and Dragline=swine manure slurry applied via dragline hose.

When we analyzed the soil inorganic nitrogen by each date differently, nitrogen concentrations between treatments were only statistically different on the soil sample date of June 15th (Figure 2) This soil sample date was ten days after the sidedress application on June 4th.  All other soil nitrogen sample dates are not statistically different between treatments and even the control.  

Figure 2. Total soil inorganic N (ammonium and nitrate) by treatment and sample date.
Figure 2. Total soil inorganic N (ammonium and nitrate) by treatment and sample date.

Statistics have not yet been run on the whole plant nitrogen content data in the graph below but numerically there doesn’t seem to be a difference in nitrogen content between the three sidedress treatments but a difference from the control (Figure 3).

Figure 3. Percent nitrogen in harvest grain, R6 cobbs, and R6 stover between treatments.
Figure 3. Percent nitrogen in harvest grain, R6 cobbs, and R6 stover between treatments.

Future plans

The first year of data was collected during the 2018 growing season and a second year of data will be collected in the summer of 2019. This study aims to evaluate the effectiveness of sidedressed swine manure slurry compared to traditionally used synthetic fertilizers. Since we have seen promising results this first year an additional study that could follow this experiment would be a direct comparison of fall applied swine manure and sidedressed swine manure. This information would help us understand the efficiency of sidedressing compared to fall application. Soil samples from this study would also illustrate the difference in mineralization and nitrogen movement between fall-applied and sidedressed swine manure slurry.    

Authors

  • Chris Pfarr, M.S. student in the Land and Atmospheric Sciences Program, University of Minnesota, pfarr025@umn.edu
  • Melissa Wilson, Ph.D., Assistant Professor and Extension Specialist, Department of Soil, Water, and Climate, University of Minnesota, mlw@umn.edu

Additional information

Acknowledgements  

This project was partially funded by the Minnesota Soybean Research and Promotion Council and the Minnesota Pork Board.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

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


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Purpose 

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

What did we do? 

1. National nutrient mass-balance

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

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

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

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

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

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

2. Scenario analysis

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

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

What have we learned? 

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

Future Plans     

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

Corresponding author, title, and affiliation        

Karin Veltman, PhD, University of Michigan, Ann Arbor

Corresponding author email    

veltmank@umich.edu

Other authors    

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

Additional information                

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

Acknowledgements       

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

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

 

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

Nutrient Leaching Under Manure Staging and Sludge-Drying Areas

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Purpose

Even well managed lagoons need to have sludge removed periodically. Hauling of sludge is expensive and time consuming. Drying of the sludge before hauling would greatly reduce the volume and therefore the number of trips required. This would result in both an economic and time savings. In Utah, sludge drying is currently not permitted due to the potential for groundwater contamination since it is considered a liquid.

What did we do?

Two studies examined leaching under sludge drying and manure staging areas. The first study compared the leachate under a sludge drying area (liquid manure), versus the leachate produced under a manure staging area (solid manure). Both treatments were placed in the field in July. The second study compared manure staging areas with manure placed at three different times (November, January, and March) and two different bedding materials (straw, no straw).

Leachate was collected by means of zero-tension lysimeters installed under the sludge drying and manure staging areas and analyzed for ammonium nitrogen using Method 10-107-06-2-O and nitrate nitrogen using Method: 10-107-04-1-C on a Lachat FIA analyzer. Soil samples were taken to a depth of 90 cm and analyzed for nitrate nitrogen using Method 12-107-04-1-F on a Lachat FIA analyzer.

Graph of leachate collected by manure type in 2015 and 2016 with straw and with no straw
Total leachate collected under winter manure staging areas by manure type.

Graph of leachate collected by placement time in 2015 and 2016
Total leachate collected under winter manure staging areas by placement time.

What have we learned?

The sludge dried in 8-10 weeks. Observed volume reduction for the July applications was 81.1% and 35.7% for the sludge and manure piles, respectively. Leachate under the sludge drying areas tended to seal off quickly producing little leachate after the initial leaching event. Likewise, there was little leachate under the manure staging piles placed in July. Significant leachate was produced under the manure staging piles placed during the winter months, with the manure with no straw (sand bedding) producing more leachate than the manure with straw (straw bedding). Preliminary results indicate that sludge drying produces less leachate than a manure staging area placed at the same time, and much less leachate than manure staging areas placed during the winter months.

Future Plans

We plan to continue this study and report the findings to the Utah Division of Water Quality. The results of this study and another study examining sludge drying in southern Utah will likely be used to revisit the decision as to whether or not sludge-drying should be allowed in Utah.

Corresponding author, title, and affiliation

Rhonda Miller, Ph.D.

Corresponding author email

rhonda.miller@usu.edu

Other authors

Mike Jensen, Trevor Nielson, Jennifer Long

Additional information

Website: http://agwastemanagement.usu.edu

Acknowledgements

The authors gratefully acknowledge support from Utah State University Experiment Station.