compost – Livestock and Poultry Environmental Learning Community

April 21, 2022June 22, 2022

Promoting Manure Composting for Livestock Operations

Purpose

While both raw and composted manure benefit soil health and crop production, there are benefits to creating and land-applying composted manure over raw manure. Product uniformity, volume, weed seed, pathogen and parasite reduction and nutrient stability are just a few of the benefits. However, composting manure in Minnesota and North Dakota have yet to gain popularity.

A group of compost producers, who ultimately became our producer cooperators and partnered with us for workshops, were consulted on the reason composting manure is not more common. One said, “It is lack of understanding and time management that holds most other farmers back from composting manure; they do not know how much composting can help their operation.” Another mentioned, “When I started researching composting for my farm, I took a three-day class in Illinois because there wasn’t anything available in North Dakota or Minnesota. Most farmers are not willing to travel that far. There is a need for composting education programs in the two-state area.”

What Did We Do?

NDSU Extension partnered with the University of Minnesota Extension with the original plan of holding four workshops in two years (two each in ND and MN). When implications from the COVID-19 pandemic ensued, we changed our plans to host an online workshop in 2020 and were able to continue with two in-person workshops in 2021.

The online workshop consisted of 13 videos that were sent to registrants 2 weeks before an online, live discussion was held in August 2020 with the presentation team as well as 3 producer cooperators. One of the videos consisted of on-farm interviews with each of our producer cooperators to show the registrants the ability to manage compost differently with similar results. The videos are still available and have been viewed collectively 1,845 times.

The in-person workshops were held in July and August of 2021. Each workshop covered the same material as the online workshop and all three producer cooperators attended each event. The producer cooperators were responsible for helping attendees with the compost diagnostics activity as well as answering questions during a panel discussion.

What Have We Learned?

Online Workshop

- 180 people registered for the online workshop and 50 joined the live discussion with presenters and producer cooperators
- 43 responded to the immediate follow-up survey where
  - 76% thought the self-paced format was excellent
  - 64% thought the amount of material was excellent
  - 62% thought the topics covered were excellent
- 15 months after the online workshop, 21 people participated in a follow-up survey and as a result of the workshop, 58% reported they had altered their manure composting practices.
- When asked what manure composting change(s) they made, 58% reported they improved their operations adding,
  - “I have more confidence in my ability to compost successfully and have a better understanding of the environmental impacts of composting.”
  - “I no longer have to pay someone to haul away our waste”
  - “Although not composting on a commercial level, I manage several community gardens where large volumes of biomass are accumulated. After learning additional techniques, my piles were hotter and decomposed more quickly. The key? More moisture!”

Moving the workshop online for the first year allowed us to fully engage our producer cooperators. The online workshop resulted in participant comments such as,

- “Well organized and executed. Appreciated that videos were individual by topic area, short, and focused. That allowed me to watch what was relevant and fit it into my day more easily.”
- “Really enjoyed the discussion and interaction between the three cooperators. Also appreciated having enough time to flesh out the information, i.e., didn’t try to squeeze it into one hour.”

Though an in-person meeting would have allowed more hands-on experience, the online version reached a broader audience with attendees from 31 states and 3 countries.

In-person Workshops

- 31 people attended the in-person workshops in ND and MN, of which 10 participated in a 4-month follow-up survey
  - 67% of those who made changes as a result of the workshop stated they started composting manure
- 100% of those who did not make changes were either agency or university Extension/research personnel who reported the workshops impacted them, their work, and/or their relationship with their clients by:
  - “Allowing me to be more educated about manure composting so that when producers inquire about composting I am able to give them accurate information.”
  - “Using workshop information to inform clients of another manure handling method to consider; composting.”

The workshops, both online and in-person, facilitated discussion and mutual learning among experienced and novice composters of livestock manure.

Future Plans

Questions about static composting were asked during both the online and in-person workshops. This practice is not common in North Dakota or Minnesota so there is certainly a future learning and workshop opportunity.

Authors

Mary A. Keena, Extension Specialist, North Dakota State University

Corresponding author email address

mary.keena@ndsu.edu

Additional authors

Chryseis Modderman, Extension Educator, University of Minnesota; Melissa L. Wilson, Assistant Professor and Extension Specialist, University of Minnesota; William J. Gale, Extension Agent, North Dakota State University

Additional Information

1. Online Composting Workshop Videos YouTube playlist: https://youtube.com/playlist?list=PLnn8HanJ32l6uhwdS9m-G1z8Bq1U0aJzF

1. Two compost-related publications for producers were created for use while at the compost rows:

- - Manure Composting Quick Guide (NM2047)
    - https://www.ndsu.edu/agriculture/extension/publications/manure-composting-quick-guide
  - Common Manure Composting Problems and Their Solutions (NM2046)
    - https://www.ndsu.edu/agriculture/extension/publications/common-manure-composting-problems-and-their-solutions

Acknowledgements

This project was funded by North Central Sustainable Agriculture Research and Education (NC-SARE).

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.

April 20, 2022June 22, 2022

Evaluation of Agricultural Nutrient Management Technologies at Vermont Natural Ag Products, Middlebury, Vermont

Purpose

The objective of this study was to evaluate nutrient dynamics and operational costs within an existing manure Compost Aeration and Heat Recovery system (CAHR) by Agrilab Technologies, Inc. at the Vermont Natural Ag Products (VNAP) compost facility in Middlebury, Vermont in comparison to conventional windrow manure composting where aeration only occurs via turning. Constructed in 2016 and 2017, the CAHR has been fully operational since 2018 and has proven effective at reducing VNAP’s expenditures on #2 heating oil, propane, diesel fuel, and labor (Foster et al., 2018).

The basic design of the CAHR system includes compost windrows placed on a paved pad containing a shallow trench oriented longitudinally with the windrow. The trench contains perforated High Density Poly Ethelene (HDPE) piping bedded in wood chips. These pipes are connected to solid, insulated HDPE piping which runs to a shipping container outfitted with circulation fans and a heat exchanger. While the circulation fans are negatively aerating (i.e., pulling vapor from) the compost, warm vapor entering the system transfers heat energy to water piped through the heat exchanger. Heat recovered from compost windrows has been used to heat the site’s bagging building via radiant floor heating and to dry finished compost prior to the screening and bagging process. Furthermore, due to elevated oxygen levels provided by positive and negative aeration, CAHR-treated compost has been reported to mature more quickly and require less turning, reducing diesel, labor, and equipment maintenance costs (Foster et al., 2018).

What Did We Do?

Two compost windrows of equivalent feedstock contents and ratios were monitored. Our control, denoted as “TRAD”, was a conventionally treated windrow that did not receive aeration aside from periodic windrow turning with a Komptech Topturn x53 compost turner. Our experimental windrow, denoted as “CAHR”, received periodic positive and negative aeration via the CAHR system, as well as aeration through periodic turning. The initial volumes of the TRAD and CAHR windrows were 480.2 CY and 548.8 CY, respectively.

Compost samples were collected between August 24th, 2021 and December 15th, 2021. For the first thirteen weeks of the sampling period, samples were taken thrice weekly from both treatments. At the end of the thirteenth week, on November 19th, VNAP staff deemed the CAHR treatment compost suitable for market and it was pulled for processing. Sampling continued once weekly for the TRAD treatment for another four weeks, terminating on December 15th, when the TRAD windrow was pulled for processing. This resulted in a total of 43 samples of TRAD and 39 samples of CAHR composts.

What Have We Learned?

This study evaluated nutrient status, financial cost, and energy cost for a pair of commercial compost windrows in a normal production setting. From a time and space management standpoint, compost treated with a forced-aeration system was deemed suitable for market in approximately 75% of the time as a conventionally turned windrow; 13 and 17 weeks, respectively. Analysis of nitrogen species status throughout the study suggests that greater nitrogen losses occurred during conventional treatment than during CAHR treatment, presumably due to higher rates of denitrification and ammonia volatilization. Data also suggest a lower risk for phosphorus loss through leaching from CAHR-treated compost, as water extractable phosphorus (WEP) concentrations were consistently higher in the conventional treatment. During the active composting process, it was found that operational costs for CAHR compost were 2.1 times more expensive financially and 5.5 times more energy-intensive than a conventional compost on a per CY basis. However, the energy and infrastructure cost offsets provided by the CAHR system (as operated at VNAP) could provide a net savings of $4.06/CY finished compost. In this study, with paired windrows of approximately 12 feet in width, it was shown that a CAHR system produced a comparable compost product, with higher operational input, in less time.

Furthermore, the data suggest that land application of either compost treatment evaluated in this study may reduce phosphorus loss due to leaching versus direct manure application. For example, WEP concentrations in the finished composts in this study ranged between 0.256 and 0.304 g/kg on a dry weight basis, while WEP concentrations in dairy manures have been found to range between 1.98 and 4.0 g/kg (P. Kleinman et al., 2007; P. J. A. Kleinman et al., 2005). It is probable that either compost treatment, when applied to agricultural land, would release less phosphorus as WEP during rainfall events than direct manure application, providing water quality benefits.

Future Plans

The Newtrient CIG will continue to evaluate 13 more technologies over the next 2 years to determine their effect on water quality.

Authors

Mark Stoermann, Chief Operating Officer, Newtrient LLC

Corresponding author email address

Mstoerm@newtrient.com

Additional authors

Finn Bondeson, Graduate Student, University of Vermont; Joshua Faulkner, Research Assistant Professor and Farming and Climate Change Program Coordinator, University of Vermont; and Eric Roy, Assistant Professor, Interim Director of Environmental Sciences Program, University of Vermont

Additional Information

Newtrient.com

April 20, 2022June 22, 2022

Composting Pen Pack Cattle Manure for Improved Nutrient Transport

Purpose

The overall purpose of this research was to demonstrate the volume, weight and moisture reduction from composting pen pack cattle manure so that organic nutrients can be transported farther from the livestock barn. Simultaneously, through laboratory analysis, the goal was to measure the nutrient density of the compost from the start of the process to the finish. The reduction in volume will allow cattle farmers to store more manure in their dry stack (manure) barns to be land-applied at more ideal times, thus avoiding winter application on frozen and/or snow-covered ground.

Due to the overwhelming weight and volume logistics of unprocessed (raw) manure in general, often the manure is land-applied to fields relatively close to the livestock barn. This phenomenon has historically resulted in some fields or areas within fields that have high or luxury levels of soil test phosphorus and potassium. Manure is a great source of nutrients and organic matter for crop production. Avoiding application of manure on fields that are farther from the livestock barn can result in lower soil health and missed economic opportunity for these fields. Once a drier, more nutrient-dense compost is created, a second purpose of the research is to promote transfer of the compost to fields that are farther from the livestock barn or to fields with lower soil test phosphorus or potassium levels.

A final purpose of the research is to utilize compost in corn production systems to evaluate its benefit when applied at the same nutrient rate as its raw manure or commercial fertilizer counterparts. When manure or compost are added to a crop production system, the health and biology of the soil are improved.

What Did We Do

The study began by working with local cooperators who currently raise cattle and manage manure nutrients. This peer learning group included five (5) cooperators. Each cooperator was asked to build at least one windrow of pen pack (solid, dry bedded) manure removed from their cattle barn. The windrow was not to exceed 6 feet in height by 12 feet in width and could be of any length. All manure was weighed at the start of the composting process and then at the end of the process to measure weight reduction. To measure volume, windrows were measured (height x width x length) at the start and finish; cooperating farmers recorded ‘trucks in’ and ‘trucks out’. The five cooperators built eight (n=8) windrows for the purpose of this study.

For baseline data, all cooperators were asked to dedicate one windrow for weekly mechanical compost turning inside a dry stack barn for eight (8) weeks. Any additional windrows composted were to address research questions raised by cooperators. Two ‘additional’ windrows were turned every 2 weeks and a third ‘additional’ windrow was turned weekly, but in an outdoor setting. Mechanical composting was achieved with an HCL Machine Works pull-type compost turner (Figure 1). The compost turner accomplished two key things: consistently mixing compost ingredients (manure, sawdust, wheat straw), and adding oxygen into the composting system. The compost turner was pulled by a Case IH 190 Magnum tractor equipped with a continuously variable transmission (CVT). The CVT allowed for critical ultra-slow speeds (.05-.15 mph) necessary for early mixing passes with the compost turner and raw ingredients.

Figure 1. A pull-type compost turner (6 foot x 12 foot) used for this study

Another significant part of the research was manure nutrient analysis. Every windrow site (n=8) had 3 samples pulled for analysis: once at the start of composting, after every compost turn (6-8 turns on average) and when the compost was land applied or at the last turn. Key nutrients analyzed were nitrogen, phosphorus, potassium, sulfur and calcium. Additionally, temperatures were monitored using a 36” dial compost thermometer (Figure 2) prior to every turn to ensure adequate composting temperatures (120-140 deg F ideally) were maintained. Each windrow also had a HOBO temperature logger inserted in the center of the pile for temperature logging every 15 minutes for the duration of the process.

Figure 2. Compost thermometers (36”) were used to double-check pre-turn temperatures each week

Finally, cooperators were asked to work with the researcher to develop a replicated field trial in field corn utilizing the finished compost product from their farm. Generally, the goal of the field trials were to compare a ‘normal’ rate of manure against a half rate of compost (Figure 3). Yield and moisture data from field trials were collected and analyzed.

Figure 3. Land application of manure (light in color) and compost (dark in color) for replicated strip trials in corn.

What Have We Learned

This research began with an aggregated 258 tons of unprocessed (raw) pen pack cattle manure among 8 sites (windrows) and yielded 121 tons of finished compost, a 53% reduction in weight. However, the volume reduction was less significant than the reduced weight. The number of ‘trucks in’ versus ‘trucks out’ resulted in 28% reduction in volume. The average initial moisture of raw manure was 66% as compared the average final moisture of 48%.

Cooperators turned compost for a minimum of five weeks with some turning up to eight weeks. The average number of turns was seven weeks for each of the eight windrow sites.

The starting nutrient analysis of the manure on a per ton basis was 8 lbs total nitrogen (TKN), 8 lbs phosphorus (P), 14 lbs potassium (K), 1.5 lbs sulfur (S), and 4.5 lbs Calcium (Ca). The finished compost averaged 7.5 lbs TKN, 20 lbs P, 31 lbs K, 3 lbs S, and 12 lbs Ca per ton. Except for total nitrogen, nutrient density more than doubled for these key nutrients as a result of the composting process (Figure 4). It is assumed that nitrogen was consumed in the composting process resulting in increased organic matter and organic carbon.

Figure 4. Density of key nutrients doubled for phosphorus, potassium, sulfur and calcium from the start of composting to the finished product (n=8 sites)

Temperatures were monitored weekly and temperature data indicated that only one windrow dropped below 100 degrees Fahrenheit during the 8-week process. This windrow was smaller than the others and the compost was happening in below freezing temperatures that occurred in the month of February 2021.

Figure 5. Buried temperature loggers monitored compost temperatures throughout the research. Temperature drops resulted when loggers were removed for compost turning and then replaced

Finally, three replicated field trials were conducted in field corn to compare full rates of manure versus half rates of compost (Tables 1, 2, 3). One more comprehensive trial included a university recommended fertilizer rate as well (Table 4). On average, the compost was hauled 4.5 miles from the livestock barn, thus giving some promise to improved transport of manure/compost to farther field locations. The results below are from one year of data at each respective site and should be interpreted as such.

Table 1: Site 1 – Corn for grain
Treatments	Harvest Moisture (%)	Yield (bu/acre)
10 tons/ac MANURE	17.5	252 a
5 tons/ac COMPOST	17.8	245 a
		LSD: 11.5, CV 2.0

Table 2: Site 2 – Corn for grain
Treatments	Harvest Moisture (%)	Yield (bu/acre)
Check (no manure or compost)	18.0	258 a
6 tons/ac MANURE	17.9	259 a
3 tons/ac MANURE	18.1	258 a
		LSD: 9.7, CV 2.1

Table 3: Site 3 – Corn for silage
Treatments	Harvest Moisture (%)	Yield (bu/acre)
10 tons/ac MANURE	57.8	23.8 a
5 tons/ac COMPOST	57.8	22.7 a
		LSD: 1.7, CV 3.1

Table 4: Site 4 – Corn for grain
Treatments	Harvest Moisture (%)	Yield (bu/acre)
Fertilizer (22-52-120-12s/ac)	17.6	190 b
10 tons/ac MANURE	17.7	213 a
5 tons/ac MANURE	17.5	202 ab
		LSD: 14.9, CV 4.3

Future Plans

Future plans include adding 4-5 more windrow sites before this 2023 grant expires. In 2022 and 2023, the hope is to compare static windrows versus those that are turned mechanically. In the first 8 sites, compost turning was based on time (weekly or bi-weekly turn). In the future, oxygen level or temperatures should be evaluated to help determine timing of turning. From a crop yield perspective, measuring soybean yields in the year following corn where the compost, manure or fertilizer was applied would be informative for growers as they make decisions about improving placement (transport) of manure or compost further from the livestock barn or to fields that have low soil test phosphorus or potassium. Finally, a complete economic analysis of the composting plus further transport needs to be conducted via a case study model.

Authors

Eric A. Richer, Assistant Professor and Extension Educator, Ohio State University Extension
richer.5@osu.edu

Additional Authors

-Jordan Beck, Water Quality Extension Associate, Ohio State University Extension
-Glen Arnold, Field Specialist, Manure Nutrient Management, Ohio State University Extension

Additional Information

Hawkins, E. et al. 2021 eFields Report. Retrieved from https://digitalag.osu.edu/efields

OSU Extension Facebook and Twitter pages: www.fulton.osu.edu

Acknowledgements

This work is supported by a Great Lakes Sediment and Nutrient Reduction Program grant. Thanks to the five cooperating farmers who participated in this research study with Ohio State University Extension. Thanks to Stuckey Brothers Farms for use of compost turner and Redline Equipment for rental of Case IH 190 Magnum tractor.

April 30, 2019June 6, 2019

Impacts of New Phosphorous Regulations on Composting of Animal Manures

The Problem

Concerns are mounting in states that have sensitive waterways about the release of P from manure and compost into ground and surface water. P is the limiting nutrient for many freshwater ecosystems and as such regulate the rate of eutrophication and oxygen depletion. The concerns have led to new regulations that limit the application of manure and in some cases compost products that have high concentrations of P. Also, compost use in stormwater biofiltration swales has been called into question because of the potential leaching of P. There are concerns in the composting industry that the regulations will limit the application of compost and reduce the market for compost products.

Composting can theoretically increase the biological activity of the soil matrix and help the formation of aggregates that absorb nutrients. Compost also contains metals such as iron, magnesium, calcium and aluminum that help bind P to the soil particles. Composting has a substantial impact on N as the high temperatures result in losses of ammonia. Depending on the stage of composting, the bacterial thermophilic phase of composting can release P during the breakdown of plant and animal tissue. In contrast the curing or fungal phase can bind nutrients into the hyphae and to the stabilized organic substrate. Additionally, soils high in organic C have lower bulk densities and prevent runoff because of the increased water holding capacity and infiltration rates*. The concept is that even though the overall P levels in the soils are increasing with compost application, only a small portion of the P is in the liquid phase and there is sufficient soil and plant uptake to limit P losses.

*Spargo, J.T., G.K. Evanylo, and M.M. Alley. 2006. Repeated compost application effects on phosphorus runoff in the Virginia Piedmont. J. Environ. Qual. 35:2342–2351.

What did we do?

In 2014, Green Mountain Technologies (GMT) received an Animal Waste

Technology Fund (AWTF) grant from the Maryland Department of Agriculture to install an Earth Flow composting systems at Days End Farm (DEF, Fig. 1) in Howard County and Glamor View Farms in Frederick County. There were two types of manures that were tested, dry pack manure from Glamour View Farms and bedded horse manure from Days End Farm.

Days End Farm Horse Rescue is a non-profit, volunteer-based animal welfare organization established in 1989 to provide care and treatment for horses that have been abused or mistreated. DEF works to rehabilitate horses, find good homes for them and educate the public about humane treatment of horses. DEF cares for between 100-150 horses annually, rehabilitating them and preparing them for adoption.

Figure 2. Locator map for Glamor View Farms

Glamour View Farm (GVF, Fig. 2) is a 146-acre dairy operation which is a part of Lager Farms. Glamour View houses approximately 180 Holstein and Jersey cows. In 2014, Green Mountain Technologies (GMT) and GVF received an AWTF grant from the Maryland Department of Agriculture to install an Earth Flow composting system at GVF in Frederick County, Maryland.

Description of the Earth Flow Composting System

The Earth Flow (Fig. 3 & 4) is an in-vessel composting system that integrates an automated mixing system, aeration system and moisture addition system into the vessel. The Earth Flow system accelerates the composting process by providing optimum conditions for aerobic composting. The combination of these features facilitates a thermophilic composting process for horse manure and bedding in 10-14 days.

The Earth Flow has an integrated mixing system (Fig. 5) that allows the compost to be mixed on a daily basis (2-4 times per day). The traveling auger is the key to the effectiveness of the Earth Flow. It provides seven different functions that facilitate the hot composting process:

Shreds. The auger breaks up manure balls to reduce particle size and expose nutrients to the microbes.
Mixes. The auger mixes material by smearing manure onto bedding.
Aerates. The auger continually fluffs the compost to add oxygen to the compost matrix.
Distributes Moisture. The auger sweeps up wet material from the lower portions of the compost pile and elevates it to the surface.
Homogenizes. The auger homogenizes manure with bedding for an even distribution of nutrients.

Transports. The auger slowly increments compost from the load end to the discharge end.
Stacks. As compost reduces in volume, the auger continually stacks the material toward the back to maximize utilization of the space.

The Earth Flow is designed such that feedstocks are loaded on one end of the vessel and finished product is discharged from the opposite end of the vessel.

The Earth Flow at Days End Farm is operated as a continuous-flow system. In a continuous-flow system, feedstocks can be loaded at any time on the load end and the traveling auger slowly migrates compost to the discharge end. Material can be discharged once the vessel is full and/or the user is ready to discharge compost. The standard mixing pattern of the auger is shown below.

The basis of the study was to evaluate whether composting manure would reduce the amount of P, especially the water extractable P compared to raw manure. The theoretical basis for this reduction is that composting would add more carbon and also tie up P in the increased biomass making it less available to run off. While N can be lost to the atmosphere as ammonia or converted to elemental nitrogen gas, P is only transportable in liquid phase and can neither be created or destroyed by the normal biological processes. P is essentially recycled through biomass and decaying plant and animal tissues release P that is the reabsorbed by new living tissue.

Samples of raw manure were collected prior to composting and the same manure was sampled 3-4 weeks later to determine the changes in nutrient levels and water extractable P. Samples were taken every quarter for a one year period to assess any seasonal changes. One of the proposed applications for the compost product was bedding reuse so some of the focus of the study related to product quality as a recycled bedding material.

What we learned

Bedded Horse Manure

The average total Nitrogen (N) of 0.68% comprised 0.03% Ammonia-N of the loaded mixture (over the study period) with 52% moisture and 48% solids, with a total carbon content of about 40%, resulting in a C:N ratio of 29. Total P in the loaded mixture was 0.17% of which 0.40% was P₂O₅. For the compost produced during this period, the total N averaged 0.6% (5980 mg/kg) of which 0.06% was ammonia (577 mg/kg) and 0.54% was organic N (5436 mg/kg) and 470 mg/kg nitrate-nitrite N. The total carbon was 44.87% (44867 mg/kg), resulting in a C:N ratio of 214, with an average moisture content of 20% (Tables 3 and 4).

The average N:P ratio for the unloaded compost is 1.5 (5980:4140). Minerals analyzed from the manure and unloaded compost showed variability between samples collected on the different dates, but all measured concentrations of calcium, magnesium, sodium, iron, aluminum, manganese, copper, and zinc were within acceptable ranges. The nearly 30% decrease in moisture content over the composting period was measured, this is of interest as the compost process is optimal at 50% moisture content with a workable range from 40-60%. When moisture reaches 35% or less the material is suitable for screening when producing a product for landscape or horticultural uses. In addition, microbial decomposition (metabolic) activity decreases substantially resulting in insufficient metabolically generated heat within the compost mass. The TKN and C:N data indicate a substantial reduction in N during the compost process. We inquired with Waypoint about data reporting errors as the N values seemed surprisingly low. They had already disposed of the samples so they were not able to rerun the test. They did offer to retest and we may have them run the data points again. If the N data is correct, then a substantial amount of N would have been lost to the air as ammonia. In contrast, two of the three P values were higher in the compost than in the raw manure. There may be several explanations for this trend. One point of interest as the bedding reuse continues is the accumulation of P in the compost product.

Dairy Dry Pack Manure

Penn State Labs performed the lab analysis of the raw manure and compost samples on 8/7/17. The lab samples were stored at Michael Calkin’s refrigerator and shipped to Penn State. Two samples were taken at the load and unload ends of the vessel each week and combined into a single grab sample. Ammonia and Organic N were analyzed as well as P, extractable P and carbon. Because Glamor View is operated as a batch system, the initial sample on 5/28/17 represents the raw manure at both the load and unload ends of the vessel. Each subsequent lab analysis shows the weekly change in N or P as the manure turns into compost as shown below (Fig. 6 – 8).

Figure 6. Nitrogen levels of dry pack manure before and after composting.

Figure 7. P2O5 levels of dry pack manure before and after composting.

Figure 8. Water extractable phosphorus levels before and after composting.

Winter 2017

The nutrient levels showed no clear trend of diminishment during the 3 weeks of monitoring as shown in Table 1. The average N actually increased which seems highly unlikely given ammonia losses typically experienced during composting. The good news is that it has reasonable fertilizer value when compared to typical composts. The average P₂O₅ levels were unchanged during the 3-week sampling also. The water extractable P showed a slight downward trend but once again the data was scattered. The only conclusion we can make from the data is that more P was liberated during the thermophilic phase of composting than was bound up by bacterial bodies. In retrospect, additional water extractable samples should have been performed on the cured compost to see how much water extractable P is in the product immediately before the compost is applied to fields or gardens.

Table 1. Lab Analysis of Bedded Horse Manure Before and After Three Weeks of Composting
Average results for Compost Feedstock Loaded into the Earth Flow unit at Days End Farm in December 2015			Average results for Compost Unloaded from Earth Flow unit at Days End Farm in December 2015
TEST	Dec 2015 Summary (%)	Average result-Dec 2015 (mg/Kg)	TEST^α	Dec 2015 Summary (%)	Average result-Dec 2015 (mg/Kg)
	As Received	Dry basis
Nitrogen, N %	0.39	0.95
Ammonical-N %	0.07	0.16	Total Kjeldahl Nitrogen	1.12	11200.00
Phosphorus, P %	0.10	0.23	Total Phosphorus	0.33	3346.67
Potassium, K %	0.36	0.87	Total Potassium	1.10	11033.33
Sulfur, S %	0.06	0.14	Total Sulfur	0.19	1923.33*
Magnesium, Mg %	0.13	0.32	Total Magnesium	0.38	3760.00*
Calcium, Ca %	1.76	4.53	Total Calcium	2.35	23466.67*
Sodium, Na ppm	602.00	1480.00	Total Sodium	0.18	1773.33*
Iron, Fe ppm	889.00	2173.33	Total Iron		4310.00*
Aluminum, Al ppm	368.33	873.00	Total Aluminum		3500.00*
Manganese, Mn ppm	93.07	230.00	Total Manganese		278.67*
Copper, Cu ppm	8.05	19.77	Total Copper		26.33*
Zinc, Zn ppm	33.60	82.93	Total Zinc		91.33*
Boron, B ppm	2.50	6.12	Total Volatile Solids	78.14	781400.00
Test	Result	Result
Moisture %	59.5		Moisture †	31.46	Moisture †
Solid %	40.5		Total Solids †	68.54	685366.67
Additional Tests	Result
P₂O₅ (as received) , %	16.41		C/N RATIO †	40.67
K₂O (as received) , %	0.428		Carbon (TOC) †	45.43	454333.33
^αAll values are on a dry weight basis, except as noted by†; Detection limit on all N series is on a wet basis. ^*Within normal range, Analyses by Waypoint Laboratories, Richmond, VA

Figure 9. Nitrogen levels of dry pack manure before and after composting.

Figure 10. P2O5 levels of dry pack manure before and after composting.

Figure 11. Water extractable phosphorus levels before and after composting.

Spring 2017

Unlike the last sampling event over the winter, the nutrient levels showed a clear trend of diminishment during the 3 weeks of monitoring as shown in Fig. 9-11. The average N reduced by 30% or more during the three weeks of composting. The average P₂O₅ levels showed a downward trend on the unload and unchanged on the load end which is expected given that P is not lost in the compost process. The water extractable P had a clear downward trend for both the load and unload ends of the vessel with an average 42% reduction over the 3 weeks. Water extractable P is more important than a reduction in the P₂O₅ levels as it indicates the amount of P available for leaching. In general, the lab data supported the trends that are typical of composting. It is not clear if the change over the winter results were seasonal or if the sampling methods were inconsistent. One possibility is the change in feed type that the heifers receive in the summer vs winter. In retrospect, additional water extractable samples should have been performed on the cured compost to see how much water extractable P is in the product immediately before the compost is applied to fields or gardens. This sampling would have provided a more complete picture of the entire compost process for nutrient management.

Next Steps

There is no doubt that P chemistry and bioavailability are complicated subjects. Based on this work and studies done by Larry Sikora at USDA and John Spargo there needs to be a more comprehensive study performed with greater control of variables to demonstrate what might actually happen in the field with P availability and losses in compost. The other effort GMT is involved in is the development of a compost feedstock recipe calculator that includes values for different feedstock P concentrations and also performs C/P ratio calculations (Fig. 12). The calculator has an interactive dial format that immediately shows the user how the volumes of different feedstocks changes not only C/N but C/P ratios as shown below. The hope is that the software will raise awareness about P and help to make compost products with balanced nutrient ratios.

Figure 12. User interface for Compost Calc recipe calculating software.

Authors

Michael Bryan-Brown, Green Mountain Technologies, mbb@compostingtechnology.com

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

March 5, 2019March 20, 2019

Composting of Dairy Manure with the Addition of Zeolites to Reduce Ammonia Emissions

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Purpose

The purpose of this project was to demonstrate the effects of adding natural clinoptilolite zeolites to a dairy manure compost mix at the moment of initiating the composting process on ammonia emissions, nitrogen retention, composting performance, and characteristics of the final compost product. A typical dairy cow in the U.S. produces approximately 148 lb of manure daily (feces and urine, not counting bedding; Lorimor et al., 2000). This amounts to millions of tons of monthly manure production. On-farm composting of manure is one of the most-used practices to manage dairy manure in Idaho. Composting reduces manure volume between 35 and 50%, which allows the material to be significantly more affordable to transport than fresh, wet manure. Composting converts the nitrogen (N) present in the raw manure into a more stable form, which is released slowly over a period of years and thereby not totally lost to the environment. Composting contributes to alleviating problems associated with ground and surface water contamination and also reduces odor complaints (Rink et al., 1992; Fabian et al., 1993). During the manure handling and composting process, between 50 and 70% of the nitrogen can be lost as ammonia if additional techniques are not used to increase nitrogen retention. In most cases, manures from dairies and other livestock operations don’t have the proper carbon to nitrogen (C:N) ratio to be composted efficiently without added carbon (usual straw bedding has a C:N of 60 to 90). Dairy cow manure is rich in nitrogen (C:N ratios below 18:1), causing a great proportion of the available nitrogen to be lost as ammonia due to the lack of carbon to balance the composting process. The loss of nitrogen from manures as ammonia reduces the nutrient value of the manure, produces an inefficient composting process, and generates local and regional pollution. Lack of carbon also results in a lower-grade compost that can carry elevated concentrations of salts, potassium and phosphorous. In many arid zones there are not enough sources of carbon to balance the nitrogen present in the manure.

Zeolite is a mineral defined as a crystalline, hydrated aluminosilicate of alkali and alkaline earth cations having an infinite, open, three-dimensional structure. Zeolites are able to further lose or gain water reversibly and to exchange cations with and without crystal structure (Mumpton, 1999). Zeolites are mined in several western U.S. states where dairy production also is concentrated. This paper showcases a project that explored the effects of adding natural zeolites to dairy manure at the time of composting as a tool to reduce ammonia emissions and retain nitrogen in the final composted product.

What did we do?

This on-farm research and demonstration study was conducted at an open-lot dairy in southern Idaho with 100 milking Jersey cows. Manure stockpiled during the winter and piled after the corral’s cleaning was mixed with freshly collected manure from daily operations and straw from bedding and old straw bales, in similar proportions for each windrow. The compost mixture was calculated using a compost spreadsheet calculator (WSU-Puyallup Compost Mixture Calculator, version 1.1.; Puyallup, WA). Moisture was adjusted by adding well water to reach approximately 50% to 60% moisture on the initial mix. Windrows were mixed and mechanically turned using a tractor bucket. Three replications were made on control and treatment. The control consisted of the manure and straw mix as described. The treatment consisted of the same mix as the control, plus the addition of 8% of clinoptilolite zeolite by weight during the initial mix. Windrows were actively composted for four months or more. Ammonia emissions were measured using passive samplers (Ogawa & Co., Kobe, Japan) for the first five to seven days after building each windrow (called turn 1 in Figure 1) and after the two subsequent turns. Ammonia emissions per measurement period and per turn were obtained. Three periods of one to three days at the time of building each windrow and after the first turn were measured. After the second turn, two measurement periods of three to four days were made. Values of mg NH3-N/m3 are time-corrected by minutes of sampling (Figure 1). Complete initial manure (compost feedstock mix) and final screened compost nutrient lab analyses were performed for each windrow. Analyses of variance (ANOVA) on lab data and on ammonia samples were performed using SAS 9.4 (SAS Institute, Cary, NC).

What have we learned?

The addition of 8% w/w natural zeolites to the dairy manure compost mix on a mechanically turned system using a tractor bucket reduced cumulative ammonia emissions by 11% during the first three turns (Figure 2) and showed a significant reduction trend in ammonia emissions. Figure 1 shows the differences and trend line in ammonia emissions per monitoring period and per turn. Treated windrows’ cumulative emissions were significantly lower (P<0.05) at 2.76 mg NH3-N/m3 from control windrows at 3.09 mg NH3-N/m3. Nitrates (NO3) on the composted treatment (702 ppm) were 3 times greater (p=0.05) than the control (223 ppm) (Figure 3). These results demonstrate that the addition of natural zeolites has a positive effect on reducing ammonia emissions during the composting process and increasing the conversion to nitrates, retaining nitrogen in the compost in a form that is more available to crops.

Future Plans

Field days and journal publications about this project are expected to occur within the next year.

Corresponding author, title, and affiliation

M. E. de Haro-Martí. Extension Educator. University of Idaho Extension, Gooding County, Gooding, Idaho.

Corresponding author email

mdeharo@uidaho.edu

Other authors

M. Chahine. Extension Dairy Specialist. University of Idaho Extension, Twin Falls R&E Center, Twin Falls, Idaho. H. Neibling. Extension Irrigation Engineer. University of Idaho Extension, Kimberly R&E Center, Kimberly, Idaho. L. Chen. Extension Waste Management Specialist,

Additional information

References:

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

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

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

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

Acknowledgements

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

March 5, 2019March 20, 2019

PA Finishing Swine Barn Experience: Changing from Mortality Burial to a Michigan Style Composting Barn

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Purpose

In the spring of 2014, the farmer with a 2020 finishing pig barn, wanted to change from burial of mortality to composting the mortality. We will document the change and the use of the composting barn from July 2014 to Dec 2016.

What did we do?

This 2020 finish pig barn space has about 3% mortality and expects about 250 deaths per year to compost. We discussed building a PA Michigan single wall compost barn design. The farmer built a 24×40 compost barn, with a 3 feet center dividing wall. The barn was completed in the summer of 2014 and we will track the pig barn turns and compost barn mortality loadings from July 2014 to December 2016. The barn has used about 56 cubic yards of woodchips/ bark mulch the first year and then replaced with about 40 cubic yards of sawdust for the second year.

The compost temperatures have reached 130 Degrees F and the farmer is very pleased with how the barn works and how he can mix and turn the compost. The presentation will cover barn costs, barn design and sawdust mortality loading and turning.

Field with windmills and barn
PA Michigan compost barn built at the end of the hog barn

Compost heap under shelter
Excellent example of free flowing air into the compost piles while
having a center push up wall to help turn the piles

What have we learned?

We have documented the farmers use of the barn, the mortality rates, compost sawdust and woodchip use, and mixing schedules. We have also documented the mortality cost rates for this farm.

Future Plans

We will highlight this PA Michigan compost barn type to other pig barns and document the use of them in Pennsylvania.

Corresponding author, title, and affiliation

J Craig Williams

Corresponding author email

Jcw17@psu.edu

Additional information

http://extension.psu.edu/animals/health/composting

http://msue.anr.msu.edu/program/info/managing_animal_mortalities

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

March 5, 2019March 6, 2019

Elimination of Equine Streptococci from Soiled Equine Bedding

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Purpose

Streptococcus equi subspecies equi (S. equi), causes the potentially fatal respiratory disease in horses known as “strangles”, while the closely related Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) causes potentially fatal infections in humans. A study was undertaken to determine the survival of these 2 organisms in compost and soiled bedding.

What did we do?

Dacron bags were filled with a feedstock mixture of soiled equine bedding and feed waste at ratios of 3:1 (C:N ratio 40.6), 1:1 (C:N ratio 31.9), and 1:4 (C:N ratio 25.4). The Dacron bags were inoculated with S. zooepidemicus, and placed in 3 compost windrows of the same 3 feedstock ratios 24 h later. Streptococci were quantified at different time points. Next, S. equi was inoculated into Dacron bags then placed into a compost windrow of the same feedstock ratio. Streptococci were quantified. To rule out killing of both Streptococcal species by microflora during the 24 h storage period, samples of soiled equine bedding, both autoclaved and non-autoclaved, were inoculated with S. zooepidemicus and periodically sampled. A repeated study was conducted with S. equi. To determine the role of moisture on the killing of S. equi in equine waste, soiled equine bedding was dried at 37 °C for 48 h and sterile water then added to dried bedding.

What have we learned?

Microbes in soiled equine bedding may eliminate Streptococci, indicating that normal compost microflora may provide sustainable methods for the control of human and animal pathogens.

Future Plans

Future studies could assess the role of individual bacterial species in the abatement of Streptococci, and possible additives to a compost pile which might increase numbers of streptocidal organisms. In addition, compost could be examined to discover novel antibiotics or bacteriophages which may be used for disease control.

Corresponding author, title, and affiliation

Alexandria Garcia, Graduate Student, University of Maine

Corresponding author email

Alexandria.poulin@gmail.com

Other authors

Dr. Robert Causey, Associate Professor at University of Maine, Scott Mitchell, Student, Kathleen Harvey, Student, Ashley Myer, Student, Mark Hutchison, Extension Professor, and Martin Stokes, Professor

Additional information

Garcia, Alexandria, “Abatement of Streptococcus equi in Equine Compost” (2016). Electronic Theses and Dissertations. 2435.

http://digitalcommons.library.umaine.edu/etd/2435

Acknowledgements

Maine Agricultural Center, Dr. M. Susan Erich, Mark Hutchinson

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, 2019September 4, 2020

Composted Horse Manure and Stall Bedding Pilot Project

Why Study Compost as Bedding for Horses?

The purpose of this project was to study and promote the use of compost as an alternative horse stall bedding and encourage horse owners and managers to think more creatively about manure management. Our objective was to reduce bedding use, and improve manure management practices at equine facilities in Snohomish County, Washington State.

Recreational and professional horse owners contribute to maintaining agricultural open space and supporting the agricultural infrastructure and local economy. Horse owners have historically been overlooked as contributors to animal agriculture, and as a result many horse owners lack a basic knowledge about manure and nutrient management. They are not aware of their impact on water and soil quality. Disposal of used stall bedding is costly for horse owners in northwestern Washington State, and has a potentially large impact on water quality. Disposal practices often include filling in low spots and ravines, or building massive piles. Composting manure at high temperatures eliminates pathogens and parasites, stabilizes nutrients, and reduces odors and vector attraction.

What did we do?

The Snohomish Conservation District (SCD) worked with ten commercial and two private equine facilities to test the use of compost as an alternative horse stall bedding material. Facilities ranged in size from 5 to >20 stalls. The primary system used for composting and reusing bedding involved a micro-bin composter (O2 Compost, Snohomish, WA) and a Stall Sh*fter® (Brockwood Farm, Nashville, IN). Micro-bins were assembled on-site and filled with used stall bedding (Fig.1-2).

Figure 1. Assemble compost micro-bin on site and fill with manure and bedding Figure 2. Turn on blower to provide aeration and monitor temperature

After 30 days of composting, the bin was emptied and the manure was separated from the bedding (Fig. 3). The composted bedding was then used in a stall (Fig. 4). Equine facility managers provided feedback on the effectiveness, perception, and impacts of using the compost as stall bedding. Results varied between trial sites based on type and quantity of bedding used, season, and stall management practices.

Figure 3. After 30 days of composting, empty the bin and sort the composted manure from the bedding using the Stall Sh*fter (registered trademark)

Figure 4. Use composted bedding in the stall and composted manure in the garden.

What have we learned?

Composted stall waste makes a soft absorbent bedding for horses or other livestock. Composted bedding is less dusty than shavings or wood pellets, darker in color, and has a pleasant earthy odor. There were no reports of composted bedding increasing stall odors or flies, or negatively impacting horse health. The best results were reported when mixing the composted bedding with un-composted bedding in equal proportions or two parts compost to one part bedding. There were some reports of horses with skin and respiratory conditions improving during the time they were on composted bedding, including thrush in the feet, hives and “rain rot” on the body, and “scratches” on the legs.

When separating the composted manure from the bedding, the amount and type of bedding determines the effectiveness of a bedding re-use system. Concern about appearances was more prevalent than concern about disease or parasite transfer. Even though barn managers were not entirely ready to make the switch to composted bedding, this project helped start many conversations (in person, through publications, and social media) about manure management and resource conservation. It was a great opportunity to help horse owners make the mental leap from “waste” to “resource”.

Future Plans

This project demonstrated that compost is a safe and effective horse stall bedding. Future work should be focused in three areas:

1. Developing systems for making composted bedding that are practical on a large scale and provide an economic incentive for large equine facilities to recycle their waste.

2. Outreach and education programs directed at horse owners who board their animals at commercial facilities. Would some horse owners be willing to pay a premium to board their horses at a facility that is managed in an environmentally sustainable manner?

3. Clinical trials to examine the effects of composted bedding on skin and respiratory conditions.

Author

Caitlin Price Youngquist, Agriculture Extension Educator, University of Wyoming Extension cyoungqu@uwyo.edu

Additional information

Visit http://BetterGround.org, a project of the Snohomish Conservation District.

The full report, including photographs of trial sites, is available on the Western SARE website: https://projects.sare.org/sare_project/ow11-315/

Acknowledgements

I would like to thank all of the farm owners and managers who very graciously participated in this project and were willing to try something new. The contribution of time and energy is very much appreciated.

Thanks also to the staff at O2 Compost for their efforts, ideas, and creativity. This would not have been possible without them.

And Mollie Bogardus for helping take this project to the next level, and explore all the possibilities.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

March 5, 2019July 13, 2020

Relative Mineralization Rates of Manure and Effect on Corn Grain Yield and N Uptake

Why Is It Important to Study Availability of Manure Nitrogen?

Application of fresh and composted manure as a fertilizer source in corn production has long been a useful practice in many sustainable crop production systems especially when phosphorus, and not nitrogen (N), is the primary nutrient of interest. But when manure is applied as the primary source of N, despite several agronomic advantages associated with manure use, there is a high risk of ground water pollution, and often times, would produce lower yields and grain protein than inorganic fertilizers. Nitrogen mineralization and availability from manure is difficult to predict. Therefore estimating the amount of crop N uptake that may be attributed to manure applied in the same year or to its residual impact, can be a useful approach towards quantifying a supplementary quantity of inorganic N fertilizer with the manure.

What did we do?

yield response to manure This study measured in situ relative soil N mineralization rates (flux) during three growing seasons of continuous no-till (2013 and 2014) corn in Carrington, ND. We applied fresh (FM) and composted beef feedlot manure (CM) only once in spring 2012 at N rates of 90, 180, and 240lbs/A as FM, and 90 and 180lbs as CM. These rates were applied based on the calculation that 50% of N from FM and 25% of N from CM, would be available the first year. Other treatments were urea at 90, 150, 180, and 240lbs N/A, plus a check at 0lbs/A. In 2013 and 2014 urea was applied to respective plots, based on soil test, to raise the N levels to the respective 2012 N levels. We used the randomized complete block design with four replicates. Three replicates were used to measure soil N (NO3- + NH4+) mineralization rates bi-monthly with Plant Root Simulator probes (PRS™), from the urea fertilized and manured plots at the 0, 90 and 180lb levels at 4-6 leaf growth stage. Four pairs of PRS™ probes were buried in the top 6 inches near corn roots and replaced every two weeks for four sampling dates. We measured yields, protein content, and N uptake.

What have we learned?

N mineralized near corn roots, 2014 Yields were generally low in all three years of this study, well below the average for this region. Bi-monthly N mineralization was significantly higher as N increases with urea as N source during the early sampling dates (Figures 2 and 3) and subsequently declined to similar levels as the manure treatments. It is therefore possible that the plants benefited from higher early uptake of N from urea up to the early stages of peak corn N uptake but not enough to produce significantly higher yields than the manure treatments. Analysis of variance showed no significant treatment effects for yields in 2012 (α = 0.05) but grain protein differences were significant. These differences were observed only between the check and 180 lbs N in 2012. The highest mean grain yield was recorded with the 90 lbs N treatment where, the residual soil N at planting was just 33 lbs. The protein level was also significantly higher than the check and CM plot that received 180 lbs N in 2012, and with a soil residual N prior to 2013 planting, at 35 lbs. Each year, grain yields responded positively to N rates (applied as urea) and residual N levels from FM but not with CM. Since corn was grown for three continuous years, unsurprisingly yields declined with years of production since N was not applied to the FM and CM treatments after first application in year one. Similarly, yield decline was observed with urea over the three years but not as steep as the FM and CM treatments. The FM at 240 lbs N, and urea at 180 and 240 lbs treatments produced significantly higher grain protein than the check in 2012 (data not shown). Lower N mineralization and very likely, lower N availability was observed with the CM treatments especially at 180 lbs N, which consistently scored the lowest mean yield and protein in 2013 and 2014. Grain yields were consistently higher at 90 lbs N than 180 lbs N with the CM treatment. N mineralized near corn roots, 2014 Summer droughts of 2012 and 2013 at this site and possibly, factors associated with continuous corn production (e.g. disease, temporal N immobilization) compounded the effects of urea treatments even though N uptake was consistently higher with urea. Total N taken up in corn grains from the FM and CM treatments increased with N rates but decreased with time (Table 1). From this study, corn grains took up more N from the plots treated with FM than the CM over the three-year period of the study. Subsequent changes in soil conditions such as moisture, N leaching, temperature, can sometimes limit the efficiency of inorganic fertilizer uses, and favoring low cost alternative uses such as manure especially if the prevailing conditions enhance N mineralization from manure or soil organic matter. Based on N input plus soil N status at the beginning of planting every year, corn N uptake efficiency was in the order: Check>FM>CM>Urea, with efficiency decreasing at higher N rates. The minimum proportion of grain N uptake by any treatment to the single highest N uptake for any urea-N treatment (considered as a reference) in a given year, was 42% for the check in 2013.

soil nitrogen at planting and mean yearly uptake in corn grain

Future Plans

Relative contribution of nitrogen from the fresh and composted manure treatments and residual N will be used to estimate the percentage of N coming from these treatments over a three-year period. This will be used to establish new studies to assess different levels of fertilizer N to apply with manure to improve on the grain protein content and yields.

Authors

Jasper M Teboh, Soil Scientist, Carrington Research Extension Center, North Dakota State University Jasper.Teboh@ndsu.edu

Szilvia Zilahi-Sebess, and Ezra Aberle

Additional information

More detailed results from 2013 can be found in the North Dakota Corn Growers 2013 Annual Report at: www.ndcorn.org/uploads/useruploads/annual_report.pdf

Acknowledgements

North Dakota Corn Growers Association, Western Ag Innovations, Mr. Ron Wiederholt, Mr. Blaine G Schatz (Director, CREC)

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

March 5, 2019March 6, 2019

Composting Swine Slurry to Reduce Indicators and Antibiotic Resistance Genes

Purpose

Over the last twenty years there have been considerable increases in the incidence of human infections with bacteria that are resistant to commonly used antibiotics. This has precipitated concerns about the use of antibiotics in livestock production. Composting of swine manure has several advantages, liquid slurries are converted to solid, the total volume of material is reduced and the stabilized product is more easily transported off-site. The goal of this study was to determine if composting can also be used to reduce the concentration of indicators and bacteria containing genes for antibiotic resistance (AR) in swine manure.

What did we do?

Sample Analysis:

Compost trials were conducted in either fall (FT) or spring (ST) and piles were turned once, three times or upon reaching 65 ºC. Microbial indicators and populations with AR genes for tetracycline, erythromycin and sulfonamide resistance were quantified by culture and/or quantitative, real-time (qPCR) analysis.

Compost materials and conditions:

Decomposed materials (a mixture of swine slurry and woodchips) were obtained on two separate occasions from swine high-rise finishing facilities (HRFF) located in western Kentucky. The HRFF houses between 4,000 and 4,800 swine which are placed in the facility at 18 to 20 kg and are removed after three months (weighing about 105 kg). The high-rise floor raises the living area 3.7 m above the ground. Manure, excess feed, water and wastewater drop through slatted floors into 2.5 cm screened woodchips (average size 1.9 ± 0.9 cm). The slurry-woodchip material was turned up to three times per week while under the HRFF. When the material was visibly moist, reducing its ability to absorb additional waste materials, it was removed from the facility for finishing in windrows. In fall 2011 (FT) and Spring 2012 (ST), HRFF slurry-woodchip mix (approximately 60 m3 weighing 48.4 Mg) was brought by semi-trailer trucks to the Western Kentucky University Agricultural complex where ma terials were divided into three or four windrow piles. In the FT, swine slurry-woodchip mixes having a bulk density of 849.6 kg m-3 and consisting of around 19.6 m3 of material were formed into three piles of approximately 10.4 m x 2.1 m x 0.9 m (L x W x H). In the ST, swine slurry-woodchip mixes having a bulk density of 778.4 kg m-3 and consisting of around 18.8 m3 of material were formed into three piles of approximately 5.8 m x 2.7 m x 1.2 m (L x W x H) and a fourth batch (unturned) was left piled at the side (0X; 3.6 m3). In each study, piles were turned using a windrow compost turner either once per week (1X), three times per week (3X) or upon the internal compost temperature reaching 65 ºC (@65). Compost for the FT @65 treatment heated to 65 ºC by day 14 and was turned 11 times over the course of the trial. However, during the ST, the @65 pile did not heat for the first 63 days (mean temperature 27 ± 8 ºC) therefore weekly turning was initiated at that time. Samples were taken on days 0 and three and then weekly for the first 12 weeks and bi-weekly until composting was stopped at day 112 for the FT and day 142 for the ST.

What have we learned?

In the FT, concentrations of enterococci decreased below culturable detection within 21 days, corresponding with a 99% decrease in detection by qPCR (Fig. 1). Similar decreases in qPCR detection in the ST took longer (day 49 or day 77 of composting). Changes in the concentration of bacteria with AR genes varied by antibiotic type (erythromycin (36% – 97%), tetracycline (94% to 99%) and sulfonamide (53% to 84%) and compost season (greater decreases in ST). There were few differences based on turning regime. Even the unturned compost pile had 90%, 98% and 56% reduction in bacteria resistant to erythromycin, tetracycline and sulfonamide, respectively.

Results suggest that composting effectively decreases the concentration of indicators and AR genes in swine manure. As concerns over antibiotic resistance and pathogens increase, composting provides a valuable manure management tool for decreasing contaminants and improving the value of this material as a soil conditioner.

Future Plans

Volume reduction, low moisture and low readily degradable organic matter suggest that the finished compost would have lower transportation costs and should provide value as a soil conditioner. Studies are warranted to evaluate its agronomic value as an alternative source of plant nutrients. Future studies will be conducted to evaluate the nutrient value this compost as an organic fertilizer for row crop production.

Authors

Kimberly Cook, Research Microbiologist, USDA ARS kim.cook@ars.usda.gov

Carl Bolster, USDA ARS; Karamat Sistani, USDA ARS

Additional information

http://www.ars.usda.gov/main/site_main.htm?modecode=50-40-05-00

Acknowledgements

This research was conducted as part of USDA-ARS National Program 214: Agricultural and Industrial By-products: CRIS 6445-12630-004-00D. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA.

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The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.