A number of the manure related Conservation Innovation Grants (CIG) have been successful. Several feed management related projects have been major successes under the CIG program. Other successful projects have dealt with such technologies as anaerobic digesters; community digesters; environmental credit trading; lagoon management; manure to energy generation; alternative litter sources, storage, and handling; and pathogen, odor, and emissions mitigation, to name just a few.
The presentation will provide specific numbers of projects and funding per year, and information about actual projects that NRCS considers to have been successful.
What Is the Purpose of the CIG Grant Program?
Glenn Carpenter came to Natural Resources Conservation Service as a Senior Economist in December of 2001 with the Animal Husbandry and Clean Water Division. In May, 2004 he became the agency’s National Leader for Animal Husbandry, with that Division. In 2010 his position was moved to the Ecological Sciences Division. Much of his work with NRCS has been related to the animal waste issue and the agency’s interaction with EPA over the CAFO Rule.
Glenn has three degrees in Poultry Science from Michigan State University. Prior to joining NRCS, Glenn served in Extension Poultry positions at two universities.
The 2002 Farm Bill created a mechanism under the Environmental Quality Incentives Program (EQIP) for a program of Conservation Innovation Grants (CIG). These grants were “…intended to stimulate innovative approaches to leveraging Federal investment in environmental enhancement and protection, in conjunction with agricultural production…” The grants were to provide a mechanism for funding projects to aid in technology development and transfer. The granting program actually began in 2004, and has continued since that time.
What Did We Do?
By statute, the USDA Natural Resources Conservation Service cannot do research. Because of this, and because the interest of NRCS lies in directly assisting farmers and ranchers in the adoption of technologies that will benefit conservation, projects funded under this program must be in the field demonstration or tool application stages. Since the initial grant funding cycle in 2004, NRCS has provided funding through EQIP every year. To date nearly 500 grants have been awarded, with total funding in excess of $180 million.
A large share of these CIGs has been strongly animal, and/or manure related. Almost 25 percent of the total number of grants has been animal related, and these grants have received slightly over 26 percent of the total dollars. About 19 percent of the total grants have been manure related and these have received about 22 percent of the funding. Those animal related grants that are not manure related largely deal with range and pasture systems.
What Have We Learned?
Several feed management related projects have been major successes under the CIG program. Other successful projects have dealt with such technologies as anaerobic digesters; community digesters; environmental credit trading; lagoon management; manure-to-energy generation; alternative litter sources, litter storage, and handling; and pathogen, odor, and emissions mitigation from manure, to name just a few.
The number and variety of funded projects has covered a wide range of geographic areas and technical innovations. A multistate feed management project resulted in training programs, a tech note for NRCS, and many fact sheets and other materials that are available on Livestock and Poultry Environmental Learning Center webpage. Another major grant demonstrated the effectiveness of filter strips and other vegetated treatment areas on mitigating manure runoff from cattle feedlots. Utilizing high pressure injection of manure, a Pennsylvania project demonstrated a decrease in odor and runoff while also preserving nitrogen. Several projects have successfully demonstrated the effects of precision feeding of dairy cattle to show the change in manure nutrients. Projects have demonstrated the effectiveness of different tillage systems and technologies on manure nutrient runoff. Other projects have dealt with innovative waste-to-energy technologies, or waste to value-added-product creation. These are just a few of the number and variety of projects funded through the Conservation Innovation Grants program.
Future Plans
The success of the CIG program since 2004, both in numbers of projects and in innovative technologies and tools applied, demonstrates that the program is important to agriculture in the U.S. NRCS has shown its support by continually funding the program, and by making additional moneys available for special targeted CIGinitiatives.
Authors
Glenn H. Carpenter, National Leader, Animal Husbandry, USDA Natural Resources Conservation Service glenn.carpenter@wdc.usda.gov
United States Department of Agriculture, Natural Resources Conservation Service, Conservation Innovation Grants Program
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
* Presentation slides are available at the bottom of the page.
Ammonia and odor emissions from land application of liquid dairy manure, and costs associated with manure land application methods are serious concerns for dairy owners, regulators, academic, and the general public. Odor and ammonia samples from agricultural fields receiving liquid dairy manure applied by surface broadcast and subsurface injection methods were collected and analyzed. Costs associated with both of the manure application methods were estimated. The test results showed that subsurface injection reduced both the odor and ammonia emissions compared with surface broadcast; therefore, applying liquid dairy manure by subsurface injection could be recommended as one of the best management practices to control ammonia and odor emissions. The estimated costs associated with subsurface injection were higher than surface broadcast. However the higher costs could be partially compensated by the higher nitrogen fertilizer value captured in the soil by the deep injection method.
Why Study Air Emissions from Dairy Farms?
A floating self-propelled mixing pump and a remote controller (yellow)
Agriculture is the single most important economic sector in Idaho. Dairy production currently stands as the single largest agricultural pursuit in Idaho. Currently, Idaho ranks as the third largest milk production state in the US. Idaho has roughly 550 dairy operations with 580,000 milk cows. Over 70% of milk cows are located in the Magic Valley in southern Idaho (Idaho Department of Agriculture-Bureau of Dairying, 1/22/2013). A number of dairies in the Magic Valley use flushing systems resulting in huge amount of lagoon water which is applied to crop lands near the lagoons via irrigation systems during the crop growing seasons. The volatilization of ammonia (NH3) from the irrigated lands and lagoons is not only a loss of valuable nitrogen (N), but also causes air pollution. Concentrated dairy production in a limited area such as the Magic Valley has caused air and water quality concerns. Controlling odor and capturing N in dairy manure are big challenges facing the southern Idaho dairy industry.
Direct injection incorporates manure directly beneath the soil surface and thus minimizes odor and NH3 emissions during application. Injecting manure decreases soluble phosphorus (P) and N in runoff relative to surface application. Some common types of direct injection applications are liquid tankers with injectors and drag-hose systems with injectors. Manure can be successfully injected in both conventional tillage and non-till systems with currently available equipment. The manure direct injection has been proven in other regions, such as the Midwest, to effectively manage odors and manure nutrients. The purpose of this research was to demonstrate, evaluate, and encourage the widespread adoption of the manure direct injection method in southern Idaho for mitigating odors and managing manure nutrients.
Subsurface injection with drag hose system
What Did We Do?
A manure application field day was held on October 31, 2012 on a dairy in Buhl, Idaho, to demonstrate and evaluate dairy manure land application via a drag-hose system and manure mixing equipment. The dairy had approximately 3,500 milking cows managed in a free-stall and open-lot mix set-up, with about 60% of the cows housed in free stalls. Waste is flushed from lanes running under the feeding alleys and from the milking parlor. The wastewater passes through solids removal equipment and basins and then into three lagoons in series. Manure used for this demonstration study was from the last lagoon, which had about 9 million gallons of manure at the beginning of the demonstration field day and its sludge had been not cleaned for 5 years.
Soil after manure subsurface injection
The on-farm manure application trials conducted at two sites were comprised of two manure application methods: surface broadcast and subsurface injection. At each of the sites, a square plot of approximately 3,600 m2 in the western portion of the site was used for surface broadcast and the rest of the land was used for subsurface injection. The western portion of the site was chosen because the prevailing winds were from the north during the test period. The previous crop at the two sites was corn; both sites had been disked after harvest.
The manure lagoon was agitated before and during application with a floating mixing pump. Manure was pumped from the lagoon directly to the application field via drag hoses. The two manure application methods were demonstrated with the same equipment. Subsurface injection placed manure behind the shank in a band approximately 20 cm (8 inches) deep. Surface broadcast was realized by lifting the shanks above ground so manure was applied on the soil surface. Manure was applied from east to west and back again until the site was finished. The equipment shanks were lifted only when the equipment was in the designated 3,600 m2 square plot for surface application. After manure application in the site, three towers, each 1.5 m high, were placed in a north-to-south orientation with approximately 15 m spacing. The middle tower was placed at the center of the manure surface applied plot. Three towers were placed in the manure subsurface injected field parallel to the ones in the manure surface broadcasted plot and approximately 200 m apart to avoid or minimize cross-contamination between the two manure application methods.
Passive NH3 samplers (Ogawa & Co. USA Inc., Pompano Beach, FL) were installed on each tower at a height of 0.5 and 1 m to determine the NH3 concentration at each location. Ammonia samplers were changed approximately every 24 hours over a two-day period after manure application. Right after collection of NH3 samplers in field, samplers were placed into airtight containers and then shipped back to the U-Idaho Twin Falls Waste Management Laboratory where the NH3 sampler filters were carefully removed from the samplers and transferred into 15-mL centrifuge tubes. Five mL of 1 M KCI was added to each of the centrifuge tubes to extract NH3 trapped in the filters. The extractant was transported to the USDA Northwest Irrigation and Soils Research Laboratory (NWISRL) located in Kimberly, Idaho where it was analyzed for NH4-N using a flow-injection analysis system (Quickchem 8500, Lachat Instruments, Milwaukee, WI). Background concentrations of NH3 were determined by placing three towers 50 m upwind (north) of the site following the same procedure described previously. Concentrations from passive samplers are time-average concentrations for the amount of time the sampler was exposed to the air and were calculated with the following equation:
In this, [NH3-N]air is the concentration of NH3-N in the air, [NH4-N]extractant is the concentration of NH4-N in the extractant, and 31.1 cm3/min is a constant used to calculated diffusion to the trap (Roadman et al., 2003; Leytem et al., 2009). Details regarding the design and calculation of NH3 concentrations can be found in Roadman et al. (2003) and Leytem et al. (2009).
Air samples were collected from the first test site right after manure application using Tedlar bags. One air sample was collected at 1 m above ground from each of the three towers located in the surface broadcast plot, subsurface injection, and background, respectively. A total of nine air samples were collected and then sent via UPS over-night service to Iowa State University Olfactometry Laboratory for odor analysis. The nine air samples were analyzed within 24 hours based on ASTM E679-04 (ASTM, 2004).
For each test site, a grab sample (about 1 L) of liquid manure was collected and transported to a commercial lab (Stukenholtz Laboratory, Inc., located in Twin Falls, Idaho) for pH and total nitrogen analysis. The manure pH, total N, and calculated total N application rates are shown in Table 1. The liquid manure application rate was approximately 20,000 gallons per acre on both the test sites.
Table 1. Manure pH and total N concentrations and application rates of total N at the two test sites
Site and Application Method
Manure pH
Manure total N concentration (mg/L)
Manure total N Application Rate (kg/acre)
Site 1
7.4
3433
257
Site 2
7.3
3519
265
A soil temperature probe with data logger (HOBO U23 Pro v2 2x external temperature data logger-U23-003) was placed 3 cm below the soil surface to record soil temperature data in 15-min increments. Wind speed, temperature, and relative humidity data were obtained from local Buhl Airport, located six miles from the test sites, due to failure of the mobile weather station set on the test sites. The ambient weather conditions and soil temperature at the test sites over the test period are shown in Table 2.
Table 2. Ambient weather conditions and soil temperature at the test sites
Site 1
Site 2
Item
Day 1
Day 2
Day 1
Day 2
Average wind speed, m/s
5.0
4.2
4.2
3.1
Air temperature, average(minimum, maximum),˚F
61 (42, 78)
49 (45, 63)
49 (45, 63)
47 (38, 61)
Average relative humidity, %
28
53
53
51
Soil temperature, average(minimum, maximum), ˚F
50.9 (51.1, 56.1)
47.3 (51.1, 51.2)
46.5 (51.5, 52.1)
66.7 (51.6, 69.1)
Cost analysis was carried out for four different manure land application systems as shown in the “What Have We Learned?” section below. Cost calculations are based on 500 hours annual use for the tractor and 200 hours annual use for the injection system. Tractor operator labor is figured at $11.70/hour, diesel is figured at $4.00/gallon. Equipment costs were determined using the MACHCOST program from the University of Idaho’s department of Agricultural Economics and Rural Sociology. The program is available on the AERS web page at https://www.uidaho.edu/cals/idaho-agbiz/resources/tools. Equipment data was provided by John Smith at Smith Equipment Co. Rupert, ID 83350. Some machinery data was taken from “Costs of Owning and Operating Farm Machinery in the Pacific Northwest” PNW 346 available on line at: https://www.extension.uidaho.edu/publishing/pdf/PNW/PNW0346/PNW0346.html.
What Have We Learned?
Odor results from test site 1
T-test for Odor showed there was no significant difference between the background and subsurface injection (P=0.41), there was significant difference between the background and surface broadcast (P=0.03), and P value was 0.08 for the t-test of mean difference between the subsurface injection and surface broadcast. The field day attendees felt there was significant difference in odor perception between the subsurface injection and surface broadcast methods.
Test site 1
First day ammonia sample results from test site 1.
Second day ammonia sample results from test site 1.
The NH3 concentration data from test site 1 showed significant difference between surface broadcast and subsurface injection based on P<0.05. The NH3 concentration data from test site 1 showed 82% and 64% reduction in NH3 concentration for first and second sampling day, respectively when liquid dairy manure was applied by subsurface injection vs. surface broadcast.
Test site 2
First day ammonia sample results from test site 2.
Second day ammonia sample results from test site 2.
The NH3 concentration data from test site 2 showed significant difference between surface broadcast and subsurface injection based on P<0.05. There were 64% and 41% decrease in NH3 concentration for first and second sampling day, respectively when manure was applied by subsurface injection compared with surface broadcast.
The NH3 concentration data from both the test sites showed lower NH3 concentration in the air from the subsurface injected soil vs. surface applied land which means higher nitrogen fertilizer value captured in the soil by the subsurface injection method.
Cost analysis results:
*Fuel and Lubricant Costs are assigned to the Power Unit.
The above fact sheet summarizes probable costs of operation for a 7,400 gallon tank with a 2,000 gpm discharge rate and a 15 foot wide broadcast unit. A 180 PTO HP tractor is needed to pull this unit at an average ground speed of 8 mph. Up to 10 acres per hour can be covered with the unit. The tank is discharged in approximately 4 minutes. Time and equipment to refill the tank is not included in these calculations.
*Fuel and Lubricant Costs are assigned to the Power Unit.
The above fact sheet summarizes probable costs of operation for a 7,400 gallon tank with a 2,000 gpm discharge rate and a 12 foot wide broadcast unit. A 215 PTO HP tractor is needed to pull this unit at an average ground speed of 7 mph. Up to 7 acres per hour can be covered with the unit. The tank is discharged in approximately 4 minutes. Time and equipment to refill the tank is not included in these calculations.
*Fuel and Lubricant Costs are assigned to the Power Unit.
The above fact sheet summarizes probable costs of operation for a 7,400 gallon tank with a 2,000 gpm discharge rate and a 12 foot wide broadcast unit. A 225 PTO HP tractor is needed to pull this unit at an average ground speed of 7 mph. Up to 7 acres per hour can be covered with the unit. The tank is discharged in approximately 4 minutes. Time and equipment to refill the tank is not included in these calculations.
*Fuel and Lubricant Costs are assigned to the Power Unit.
The above fact sheet summarizes probable costs of operation for a system utilizing 5,280 FT of 8 inch hose and 1,320 FT of 5 inch hose. The pump unit capacity is 1,500 gpm to a 16 foot knife injection unit. A 250 PTO HP tractor is needed for the injection unit operating at 75% field efficiency and at an average ground speed of 3.5 mph. The lagoon pump is a 270 HP unit and operating efficiency assumed at 70%. Beyond 2 miles a booster pump would be necessary. Up to 4.75 acres per hour can be covered with the unit. Operation is continuous as no tank refill is needed.
Based on the estimated costs above, the subsurface injection method has higher costs mainly due to the need of larger tractor and lower operating speed. However, we did not include the time and equipment costs associated with refilling the tank for the tank application system. Due to the short time to discharge the tank on the tank broadcast and tank injection systems additional equipment to refill the tank in a timely fashion would be desirable. This would increase the investment in equipment and also would reduce the number of acres that could be covered per hour due to down time while the tank is refilled.
In summary, subsurface injection can reduce both the odor and NH3 emissions compared with surface broadcast; therefore, applying liquid dairy manure by subsurface injection could be recommended as one of the best management practices to control NH3 and odor emissions. The estimated costs associated with subsurface injection were higher than surface broadcast. However, the higher costs could be partially compensated by the higher nitrogen fertilizer value captured in the soil by the subsurface injection method.
Future Plans
We will finish development of educational videos to demonstrate the manure subsurface injection technique and disseminate results from this study to our stakeholders.
Authors
Lide Chen, Waste Management Engineer and Assistant Professor, Biological and Agricultural Engineering Department, University of Idaho lchen@uidaho.edu
Mario de Haro Marti, Extension Educator
Wilson Gray, District Extension Economist and Extension Professor
Howard Neibling, Extension Irrigation and Water Management Specialist and Associate Professor
Mireille Chahine, Extension Dairy Specialist and Associate Professor
Sai Krishna Reddy Yadanaparthi, Graduate student, University of Idaho
Acknowledgements
This project was supported by the USDA Natural Resource Conservation Service through a Conservation Innovation Grant. We would also like to thank Dr. April Leytem and Mr. Myles Miller (USDA Northwest Irrigation and Soils Research Laboratory (NWISRL) located in Kimberly, Idaho) for their help with analysis of ammonia samples.
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Treatment lagoons are one of the most common biological treatment methods used on swine and dairy farms that use recycled supernatant as a means to remove manure from animal housing facilities by flushing. A properly functioning treatment lagoon will provide adequate treatment to allow reuse of the effluent without compromising animal health or generating strong odor.
A typical treatment lagoon system used on swine and dairy farms.
A lagoon should have a minimum biological treatment volume and provide sufficient volume for settling and storage of sludge to provide the needed levels of treatment prior to recycling. This presentation will provide a summary of the benefits of using liquid-solid separation to maintain and potentially reduce the required treatment volume, reduce sludge build-up, increase useful life of an existing lagoon, and to reduce the size of new lagoons based on the ASABE Standard. Information will also be provided concerning desired loading rates and supernatant concentrations for recycling, and impacts of odor production potential.
Components of a treatment lagoon for animal manure.
What Did We Do?
The ASABE Lagoon Standard (ANSI/ASAE EP403.4, ASABE 2011) was used to calculate lagoon treatment volumes for swine and dairy manure using volatile solid loading rates for a variety of climates ranging from a cold climate, such as Southern Minnesota (3 lb VS/1000 ft3-day), to a hot climate, such as Central Florida (6.0 lb VS/1000 ft3-day). Liquid-solid separation methods can provide a reduction in the mass of VS in the liquid fraction by 10% to 80%. The corresponding reduction in treatment volume were also determined for swine and dairy manure over a wide range of climates.
The ASABE Standard also provides a method to estimate sludge storage volume requirments per year for swine and dairy lagoons that is based on the total solids loaded into a lagoon. The impact of implementing solid-liquid separation on the sludge accumulation rate was also destermined for TS removals in the range of 20% to 80%.
What Have We Learned?
The percent reduction in treatment volume of a lagoon was the same as the mass fraction of VS removed by liquid-solid separation. That is, a 30% reduction in VS provided a 30% reduction in treatment volume. The practical result is that implementation of liquid-solid separation system that can remove 30% of the VS would allow pork producers in the Midwest to use similar treatment volumes as pork producers located in South Carolina or Central Georgia.
Liquid-solid separation also reduced sludge build up in lagoons by the same percentage as the TS removal efficiency. Therefore, a 30% reduction in TS will reduce sludge accumulation by30%.
Reduction in TS and VS loading can help to reduce odors from lagoons, reduce the size of the lagoon needed to provide treatment, and can yield better treated surface water for flushing manure from the buildings.
Removal of large portions of the VS (60% to 80% reduction) using high-rate liquid-solid separation methods has the added benefit of greatly reducing the amount of the organic-N loaded. As a result, less organic-N will be converted to ammonium-N in a lagoon where a portion will be lost to the air as ammonia.
Future Plans
This information will be published as part of a new USDA-NRCS technical note or as part of the National Engineering Handbook, Part 651 Agricultural Waste Management Field Handbook.
Authors
Dr. John P. Chastain, Professor and Extension Agricultural Engineer, School of Agricultural, Forestry, and Environmental Sciences, Clemson University jchstn@clemson.edu
Jeffrey P. Porter, P.E. Environmental Engineer Manure Management Team USDA-Natural Resources Conservation Service
Additional Information
Solid-Liquid Separation Alterntives for Manure Handling Treatment, a new USDA-NRCS technical note or as part of the National Engineering Handbook, Part 651 Agricultural Waste Management Field Handbook.
Acknowledgements
Piedmont-South Atlantic Coast Cooperative Ecosystems Studies Unit (CESU). This Cooperative and Joint Venture Agreement allowed for this work to take place.
Manure Management Team USDA-Natural Resources Conservation Service, Greensboro, NC
Additional support was provided by the Confined Animal Manure Managers Program, Clemson Extension, Clemson University, Clemson, SC.
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
A new method was used at the Ag 450 Farm Iowa State University (41.98N, 93.65W) from October 24, 2012 through December 14, 2012 to assess GHG emission from land-applied swine manure on crop land. Gas samples were collected daily from four static flux chambers. Gas method detection limits were 1.99 ppm, 170 ppb, and 20.7 ppb for CO2, CH4 and N2O, respectively. Measured gas concentrations were used to estimate flux using four different models, i.e., (1) linear regression, (2) non-linear regression, (3) non-equilibrium, and (4) revised Hutchinson & Mosier (HMR). Sixteen days of baseline measurements (before manure application) were followed by manure application with deep injection (at 41.2 m3/ha), and thirty seven days of measurements after manure application.
Static flux chamber (pictured) method was developed to measure greenhouse gas emissions from land-applied swine manure from a corn-on-corn system in central Iowa in the Fall of 2012. Gas samples were collected in vials and transported to the Air Quality Laboratory at Iowa State University campus.
Why Study Greenhouse Gases and Land Application of Swine Manure?
Assessment of greenhouse gas (GHG) emissions from land-applied swine manure is needed for improved process-based modeling of nitrogen and carbon cycles in animal-crop production systems.
What Did We Do?
We developed novel method for measurement and estimation of greenhouse gas (CO2, CH4, N2O) flux (mass/area/time) from land-applied swine manure. New method is based on gas emissions collection with static flux chambers (surface coverage area of 0.134 m^2 and a head space volume of 7 L) and gas analysis with a GC-FID-ECD.
Baseline (post tilling) greenhouse gas (GHGs) emissions monitoring was followed with swine manure application in the Fall of 2012 (pictured) and about 10 weeks of post-application monitoring of GHGs.
New method is also applicable to measure fluxes of GHGs from area sources involving crops and soils, agricultural waste management, municipal, and industrial waste. New method was used at the Ag 450 Farm Iowa State Univeristy (41.98 N, 93.65 W) from October 24, 2012 through December 14, 2012 to assess GHG emission from land-applied swine manure on crop (corn on corn) land. Gas samples were collected daily from four static flux chambers. Gas method detection limits were 1.99 ppm, 170 ppb, and 20.7 ppb for CO2, CH4, and N2O, respectively.
What Have We Learned?
Measured gas concentrations were used to estimate flux using four different mathematical models, i.e., (1) linear regression, (2) non-linear regression, (3) non-equilibrium, and (4) revised Hutchinson & Mosier (HMR). Sixteen days of baseline measurements (before manure application) were followed by manure application with deep injection (at 41.2 m3/ha), and thirty seven days of measurements after manure application. Preliminary net cumulative flux estimates ranged from 115,000 to 462,000 g/ha of CO2, -4.65 to 204 g/ha of CH4, and 860 to 2,720 g/ha N2O. These ranges are consistent with those reported in literature for similar climatic conditions and manure application method.
Greenhouse gases (GHGs) were analyzed in the Air Quality Laboratory (ISU) using dedicated GHGs gas chromatograph. The picture above shows an example of gas sample analysis for CO2, GH4 and N2O. Each ‘peak’ represents one of the tagget GHGs. Gas concentrations were used in a mathematical model to estimate GHG flux (mass emitted/area/time).
Future Plans
Spring 2013 measurements of GHG flux from land-applied swine manure are planned. The spring study will follow the protocols developed for the Fall 2012 season. Estimates of the Spring and Fall GHG flux will be used to develop GHG emission factors for emissions from swine manure in Midwestern corn-on-corn systems. Emission factors will be compared with literature data.
Authors
Dr. Jacek Koziel, Associate Professor, Iowa State University Department of Agricultural and Biosystems Engineering koziel@iastate.edu
Devin Maurer, Research Associate, Iowa State University Department of Agricultural and Biosystems Engineering
Kelsey Bruning, Undergraduate Research Assistant, Iowa State University Department of Civil, Construction and Environmental Engineering
Tanner Lewis, Undergraduate Research Assistant, Iowa State University Department of Agricultural and Biosystems Engineering
Danica Tamaye, Undergraduate Research Assistant, University of Hawaii College of Agriculture, Forestry, and Natural Resource Management
William Salas, Applied Geosolutions
Acknowledgements
We would like to thank the National Pork Board for supporting this research.
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
The Anaerobic Digester Workforce Development Project is a project funded by the New York State Energy Research and Development Authority, aimed at developing and delivering high quality educational programs targeted to a range of workforces within the dairy farm-based anaerobic digestion (AD) sector of the clean energy field.
A goal of the project was to form a farmer driven discussion group among existing AD owners and operators. Farmers value and learn from the insights of fellow producers because they trust the experience and knowledge of others who are in situations similar to their own. This is especially true when adopting new technology. The purpose of this discussion group was to allow farmers an opportunity to learn from each other by sharing their real world experiences integrating and operating an anaerobic digester system into their farm business. Realizing that frequent, long-distance travel of all involved was a barrier to continued, dedicated involvement, the group opted to pursue a virtually-based discussion group platform. Farmers from across the state were linked via an online meeting site. This is an efficient method to allow farmers to interact with each other in a meaningful way without leaving their farm. The use of high definition video conferencing enhanced the interaction considerably. There have been many lessons learned from this challenging venture, as well as many successful communication strategies to share.
What Did We Do?
Realizing that frequent, long-distance travel of all involved was a barrier to continued, dedicated involvement, the group opted to pursue a virtually-based discussion group platform. Farmers from across the state were linked via an online meeting site. This is an efficient method to allow farmers to interact with each other in a meaningful way without leaving their farm.
What Have We Learned?
The focus of this presentation is to introduce the topic of forming and facilitating farmer based discussion groups with an emphasis on distance learning. By using online meeting and video conferencing farmers from across geographic areas can meet and engage in meaningful dialogue. This is especially useful when producers are implementing new technology in which they have no or limited experience. The opportunity to have an open dialogue with other farmers that have real world experience with the technology is invaluable. The experience and exchange of knowledge between farmers assists in the implementation and operation of the technology.
Future Plans
The virtual discussion group will continue to meet and develop. As we gain more experience and farmers become more comfortable with this method of interact we expect for the discussions to increase in value and effectiveness.
Authors
Kathryn Barrett, Sr. Extension Associate, Cornell University, ProDairy Program, Director of Dairy Profit Discussion Group Program. kfb3@cornell.edu
Acknowledgements
The Anaerobic Digester Workforce Development Project is a project funded by the New York State Energy Research and Development Authority, aimed at developing and delivering high quality educational programs targeted to a range of workforces within the dairy farm-based anaerobic digestion (AD) sector of the clean energy field.
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Why Be Concerned With Manure Management for Small Farms?
Increased local or regional food marketing opportunities have allowed commercial success in livestock and poultry operations with relatively small herds and flocks. The Census of Agriculture recently reports an increase in the number of small farms, as a proportion of all farms, across much of the U.S. Small animal feeding operations, less than 300 animal units, are a productive component of the animal ag sector. Finally, there continues to an interest in the development of hobby farm and equine related properties. All of these scenarios result in the necessity to manage manure resources, often on small acres, and often in close proximity to a neighbor. Knowledge about, access to, and acquisition of, appropriate manure handling equipment is a requirement to proper manure and nutrient management on all of these types of commercial or hobby farms and ranches.
What Did We Do?
This overview seeks to provide examples of power equipment and manure handling tools appropriate to smaller operations. An emphasis is placed on solid manure handling, small acreage land application, and light duty compost production equipment. Examples of equipment choices and options are based on Internet and literature reviews, as well as personal field experiences.
What Have We Learned?
A balance between size/power, cost, and versatility must be considered when purchasing or leasing equipment for small livestock and poultry operations. Smaller operations often deal only in solid manure. This can simplify equipment choices to small tractors and skidsteer loaders, which can perform a variety of manure management and compost related tasks. Tractor size will limit traditional manure spreader options. However, several manufacturers are now offering light weight, ground drive spreaders, towable by small tractors or even ATVs.
Authors
Thomas M. Bass, Livestock Environment Associate Specialist, Montana State University tmbass@montana.edu
Acknowledgements
Mike Westendorf, Rutgers University and Jean Bonhotal, Cornell University
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Composting is becoming widely accepted as a best management practice for equine facilities. Stable waste is a readily compostable feedstock which generates heat and transforms into a finished compost product in as little as 2 weeks using in-vessel technologies. Composting the stable waste is financially beneficial, turning a liability into an asset, negating disposal fees, offering a decrease in bedding expenses and creating a saleable product. In- vessel composting allows for compliance with increasing environmental regulations associated with manure management.
The primary topic will be the cost analysis of in-vessel vs. open pile composting of stable waste. The author will also compare the value of the product produced, specifically the value added with weed seed kill, reduction of pathogens, and the uniform quality and dryness of end product. The presenter will provide lab data showing compost stability and pathogen reduction using both shavings and pellet bedding. Value of the end product is seen in bedding re-use and/or soil amendment.
Discussion of cost savings will differ for different venues in the industry. Case studies will be shown for the financial analysis of a private 20 horse stable and the 65 horse stable at the US Army base at Fort Myer/Henderson Hall in Washington DC.
In-Vessel Earth Flow system used for manure waste at IOS Ranch, Bainbridge Island, WA
Why Study Composting Stable Waste?
To identify a financially beneficial way to dispose of stable waste for equine facilities.
What Did We Do?
Costs associated with the disposal of stable waste are increasing, taking a larger part of the operating budget for many barns. The increasing costs are largely due to environmental awareness and new and expanded regulations for all segments of the waste stream. Barns can no longer legally pile manure unprotected in the backyard. In many regions, haulers have to be registered and dump sites are forced to put in expensive regulation-specified collection pads. . Farms are less likely to take and store stable waste for land use and not all municipal dump sites have the infrastructure to handle the waste. Barn owners are left searching for affordable solutions.
Composting came to the forefront as a proven method to dispose of stable waste by turning a cost into a revenue stream by eliminating haul off disposal fees and creating a saleable by product with stable soil amendment. Urban locations have the added burden of odor control; also addressed with a composting system, especially with an in-vessel system. With these systems, environmental regulations are met and even exceeded. The resulting composted material can be either sold or used on site as soil amendment or for bedding reuse. If the material is sold, the infrastructure for this sales effort will need to be established.
Existing technology for composting food waste was examined to treat stable waste. The in-vessel composting systems with an automated auger and computer-controlled cycles adapted to stable waste easily. In fact one of the test sites, Joint Base Meyers/Henderson, tested the use of stable waste from the Caisson Stable as the bulking agent for the food waste from their commissary and mess halls. In a second test, the stable waste was used exclusively and proved to be a superior soil amendment that passed all laboratory testing and is currently being used at Arlington National Cemetery.
Private stables are putting in-vessel systems on site as they have small footprints, low energy consumption, low manpower hours, ease of use and comply with regulation. Medium sized barns (over 40 horses) use Site Built flow systems that have many of the same benefits as the in-vessel systems. Larger stables, event centers and high-density equine areas are looking at large scale Aerated Static Pile (ASP) yards. Cost models show these yards to be a lucrative financial investment when cost and difficulty of disposal is present as well as a market for the end product. Even when conservative numbers are used for both number of horses serviced and value of end product, ASP facilities are a good business opportunity. The investment cost for the in-vessel systems, site built systems and ASP sites vary by size and volume. In cases where the expense of haul off of the stable waste exists, the ROI for an in-vessel system illustrates a solid investment.
Easy loading with the front bucket of a tractor.
Horse manure and traditional wood shavings or pellets is an excellent feedstock for composting. As explained by Michael Bryon Brown of Green Mountain Technology, “Horses are not ruminants and therefore do not extract as much nutrient from the grasses they eat. This leaves more energy available for the compost process. Typically, horse manure is collected with bedding material which is saturated in urine which has available urea and ammonia. The wood shavings are also an excellent bulking agent and carbon source for the compost process. The bedded horse manure has a high C:N ratio of 30:1 or higher. However, much of the N is in the form of ammonia which is readily available. The net effect is that if the horse manure balls are blended with the shavings before the ammonia dissipates, it will create the ideal compost matrix.”
In the auger-based systems, the horse manure is shredded and blended with the bedding, bringing the nitrogen in contact with the grass fibers. This blended material generates heat, driving off moisture as vapor. Temperatures rise to 135-155F sterilizing the compost, killing weed seed and drying the mixture. In-vessel composted material is ready to exit the system in 10-14 days; in a site-built system, depending on length of the bay, 15-25 days. The exiting material is void of any manure or ammonia smell and is homogenous in nature. Laboratory testing has shown the compost to be stable and free of pathogens according to EPA regulations. Composting stable waste reduces by up to 50% both water-soluble phosphorous and nitrogen that would be present in rain water runoff from an untreated pile.
Interior auger used to mix and move the stable waste material.
The price for composted material will vary across the country in accordance with the demand for the product. In urban areas outside of Seattle, Washington, compost is selling for as much as $32 a yard at retail and $20 a yard wholesale. Untreated aged horse manure is being sold in Florida for $5 a yard. Historically barns have advertised manure for sale with an ad in the local paper, offering to fill up a pick up for a nominal sum. Initial effort will be spent to set up a network of buyers for the compost material. Once the network is set it should create a steady income stream.
Options other than soil amendment include re-use as bedding for both equine and dairy businesses, lowering another cost of operation if the compost material is priced below new shavings. Regional prices for new shavings vary by up to $8 dollars per yard and availability ranges from scarce to plentiful. Further financial gain can occur with the added health benefits to bedding re-use, long recognized in the dairy industry and recently explored in the equine industry.
We plan to follow development and enforcement of regulations on manure waste, support networking of compost markets, continue research on the health benefits of bedding re-use and continue to develop composting systems that are affordable for the equine industry.
Authors
Mollie Bogardus, MBA in Sustainable Business, Bainbridge Graduate Institute, Equine Specialist, Green Mountain Technologies, Inc. mollie@compostingtechnology.com
Additional Information
Bogardus, Mollie. “Equine Applications – Case Studies.” Green Mountain Technologies, Inc.. N.p., 13 Sept. 2012. Web. 27 Feb. 2013. <http://compostingtechnology.com/equine>.
Brezovec, Paul. “Evaluating Composting for Contingency Bases « « BioCycle BioCycle.” Composting, Renewable Energy & Sustainability | BioCycle.net BioCycle. Version Nov 2012, Vol.53, No. 11, p. 20. Biocycle Magazine, n.d. Web. 27 Feb. 2013. <http://www.biocycle.net/2012/11/evaluating-composting-for-contingency-ba….
“Equine Applications- Media- lab results.” Green Mountain Technologies. Green Mountain Technologies, Inc, n.d. Web. 27 Feb. 2013. <http://compostingtechnology.com/equine>.
Sikora, Lawrence. “Composting Effects on Phosphorous availability in Animal Manures.” SERA-17 Organization to Minimize Phosphorous Losses from Agriculture. SERA-17, n.d. Web. 15 Jan. 2013. <www.sera17.ext.vt.edu/Document/BMP_composting_effects.pdf>.
Wheeler, Eileen. “Cornell Cooperative Extension, Orange County Equine, Saratoga County Equine.” Cornell Cooperative Extension, Orange County Equine, Saratoga County Equine. Penn State, n.d. Web. 27 Feb. 2013. <http://www.cceequine.org>.Zaborski, Ed. “Composting to Reduce Weed Seeds and Plant Pathogens – eXtension.” eXtension – Objective. Research-based. Credible.. University of Illinois at Urbana-Champaign, 22 Oct. 2012. Web. 27 Feb. 2013. <http://www.extension.org/pages/28585/composting-to-reduce-weed-seeds-and….
Acknowledgements
Special thanks to Caitlin Price Youngquist , Farm Planner, Snohomish Conservation District, for her continuing collaboration and dedicated work on this subject.
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. 2013. Title of presentation. Waste to Worth: Spreading Science and Solutions. Denver, CO. April 1-5, 2013. URL of this page. Accessed on: today’s date.
Accumulated manure can cause health, odor, pest, and water quality problems if not properly managed. One option is to collect the waste daily, load it in a spreader, and spread it on cropland, hayland, or pasture (often referred to as a “daily haul” system). This is time consuming and also has to be done regardless of the soil moisture, weather, or time of year. Spreading during rain, on saturated or frozen soils can cause compaction or lead to offsite runoff of manure. Growing crops can also be damaged during spreading.
The alternative to daily spreading is to stockpile or store the manure for a period of time, at which point it may be spread or hauled away and utilized beneficially elsewhere. Even though the number of livestock on your farm may not be large, enough manure will be generated to pose a problem if planning is not done.
Example: A single horse can produce 50 pounds of manure per day which translates to 11 cubic yards and 9 tons annually. The manure and bedding produced by this horse in a year can exceed 25 cubic yards. This would require a storage area of about 12 feet by 12 feet with an accumulated depth of 3 to 5 feet for one year of storage, depending how much decomposition and compaction of the manure takes place.
Regardless of the type or size of manure storage, there are a few basic principles to always follow:
Keep the clean water clean. Any up-slope surface run-on should be diverted around the manure storage or animal lots by creating a small berm. Rooftop water can be directed via gutters, downspouts and possibly underground outlets so that it goes around animal lots and manure storage.
Treat the dirty water. Any rainfall landing on the manure pile or the livestock concentration areas should (preferably) be retained in the structure or settling basin. Over time, the water evaporates, leaving behind the solid materials to be collected and spread on fields. The liquid can also be directed to a treatment area, such as a well vegetated filter strip. The plants will slow the flow, settling solids (filtering the runoff) and utilizing the nutrients as they grow. This option requires regular management as the liquid flow may eventually cut a channel and create an unobstructed path to creeks, streams, ponds or other clean water. The solids from the manure may also accumulate and smother the vegetation. The goal is to direct the drainage over the vegetated area as evenly (like a sheet) as possible and regularly harvest the vegetation as hay or silage to remove prevent build up of nutrients.
Avoid flood-prone areas. Flood waters that can reach a manure storage location will transport manure downstream and cause extensive water quality problems.
Accessibility. Store the manure where it is easily accessible to load and unload. Efficiency is important in order to properly manage the manure facility. Make sure you can access the site in all types of weather conditions. If it is difficult to access the site, you are less likely to regularly manage or maintain it.
Avoid steep slopes when siting your storage location. The steeper the slope, the more difficult it is to manage the storage area, and the greater potential for offsite runoff. It may be necessary to build a small dirt berm (do not use manure for the berm) to prevent storm water from leaving the area and running downslope.
If you spread the stored manure on your own land, do so following a nutrient management plan that establishes the spreading rate per acre to match the nutrients available in the manure to the needs of the crop.
Manure Storage Considerations
Storage can be very simple or quite complex; very inexpensive or quite pricey. The choice depends on a number of factors.
Storage siting
The first thing to decide when contemplating storage is the location. The spot has to be very convenient to the animal housing, but there is more to consider. The storage must be located well outside of any stream floodplain, and should have a slight slope for drainage, but not slope so much that runoff can cause problems. It is important to prevent manure from being washed offsite to streams or lakes. Manure contains potential pollutants when it is not managed correctly. The bacteria, phosphorous, nitrogen, and organic matter pose risks to aquatic organisms and humans.
Odor management is another consideration when siting a storage facility. Look at wind direction as relates to dwellings. The final consideration is aesthetics. If possible, keep the facility out of view of neighbors and passers-by. Sometimes a screen of trees and shrubs can help, and also may reduce odor.
Storage sizing
The sizing of a storage facility depends upon three factors:
How many animals are on the farm, and how much of the manure is collected?
What is the time period the storage will be accumulating manure before emptying?
How much money is available for building the facility?
From the weights and volume cited above for a single horse, it is easy to see how a storage facility can get large quickly, with just a few animals. Also consider that the ideal length of time permanent storage should have capacity for is six months; the minimum should be 3 months. For information on how to calculate the amount of manure produced, visit Manure Production and Characteristics.
Options for Manure Storage
Stockpiling
Cost: Low
Stockpiling of manure is just what it sounds like- simply taking the solid manure and soiled livestock bedding and piling it up in a convenient location. This primitive method can be acceptable for the farm with just 1 or 2 horses or several sheep. However, the spot must be compacted and sealed so that rainfall landing on the pile cannot leach pollutants into the soil and ground water. Sometimes gravel in a packed pad works well, or stone dust is used. The area approaching the pad needs to be firm also to prevent rutting in wet periods. Also, the pile should have a very slight slope (1-3%) to facilitate drainage to a vegetated filter strip.
A stockpile can be covered with a plastic tarp to reduce odors, flies, and leaching concerns. Rainfall will run off to the edges and never penetrate the pile. The tarp will need to be anchored securely all around the edges. A filter strip of vegetation or (preferably) a small dirt berm is still needed on the downslope side.
Dry Stack
Cost: Moderate
This is probably the most common and practical choice for the small livestock operation. A dry stack facility has three walls to contain the manure. The best ones have a poured concrete floor. The floor is slightly sloped for drainage out of the facility, and the drainage runs to an adjacent vegetative filter strip. The walls of a dry stack facility will be a minimum of four feet high. The walls, especially the back one opposing the entry, must be stout since the manure will be exerting outward pressure as the pile grows higher. Also, clean out is usually done with a front-end loader, and pushing will be done as the manure is scooped up. The walls can be poured concrete, cinder block, horizontal timbers, or vertical timbers. Secure anchoring below the frost line is crucial.
Composting
Cost: Moderate to High
The treatment of raw manure through composting is gaining in popularity. The final product is crumbly, low odor and resembles rich topsoil. It is often highly marketable. Composting reduces the amount of available nutrients, kills pathogens, reduces odor, and reduces manure volume. However, it requires management. A pile of manure left alone is not composting- it is decomposing, which is a big difference.
Composting requires a balance of nitrogen, carbon, oxygen, and liquid. When things are running properly, the center of the pile will reach 140 degrees, which kills pathogens and renders a relatively stable product. An untended decomposing pile has a nearly anaerobic core that produces objectionable odors when broken into. Although the center is often hot, it’s not hot enough to sanitize. Composting requires taking the pile’s temperature, and turning of the pile regularly to mix and aerate. Sometimes it will need water; other times it will need to be covered so it does not become saturated and lower the oxygen level to unacceptable levels.
Turning the pile is usually done with a small tractor equipped with a front bucket loader. There are many ways to set up the composting site. It could just be several long windrows, 4 – 6 feet high, on compacted ground or compacted gravel, or concrete. Or, there may be several small dry stack-type bays connected together side by side, and the manure is moved from one bay to the next, and the manure is mixed and aerated in the process. Manure and bedding, when properly mixed, can be transformed into compost in as little as six weeks.
Cost: Highest
Liquid storage is used by many larger dairy or swine farms. The waste is diluted with stall wash water and pumped to a lagoon or other holding location. From there the liquid effluent and the solids are pumped into an injector tank and spread in the field as a slurry, either sprayed on the surface or injected into the soil. Or, the effluent is spray irrigated and the solids are separated and spread in a conventional fashion. This type of storage and management system is usually the most complex and expensive, and is usually not practical for smaller livestock operations.
Sometimes, the best solution is to simply have a dumpster or some other form of semi portable holding structure, and place the manure in there. When needed, a waste management purveyor can pick it up for beneficial re-use on cropland that can use the organic matter and nutrients. Remember to still have a vegetative filter strip to treat the leachate draining from the dumpster as it drains away.
If the amount of manure being generated daily is small enough, a small manure spreader can serve as the storage device. When full, simply hook up the tractor and spread the waste in the cropland or hayland according to a nutrient management plan. Caution, though- if applying to pastureland, it is important to spread the manure about four weeks before a grazing cycle. Smothering of grasses can occur if the manure is applied too heavily. Parasite eggs in raw manure may cause an infestation problem on pastures.
Vegetated Filter Strip
It is crucial to have a vegetated filter strip to treat the runoff water coming from a manure pile or a concentrated livestock area. The combination of grass uptake, soil filtering and adsorption, and biological processes in the top inches of soil significantly reduces pollution potential of manure runoff. The filter should be established in a vigorous, thick stand of grasses adapted to the soil conditions at the site. Animals should be kept off of it, and it should be hayed at least twice a year to remove nutrients and encourage growth. On a flatter slope, the strip should be a minimum of 30 feet wide, wider if slope is steeper. A better option than a vegetative filter strip is a Vegetative Treatment System. See the article on What is a Vegetative Treatment System? or a runoff containment. To see all the runoff control options, see Do I need to control the barnyard or lot runoff on my small farm?
Managing Stockpiled Dry Manure on Small Farms
Flies and odors from stored manure can be reduced if good management is practiced.
Keep the manure as dry as possible.
Remove manure from the farm regularly during fly breeding season.
Try not to use insecticides or larvacides; naturally occurring fly predators- tiny, non-stinging wasps and parasites, are beneficial to the pile. Wasps are active during fly season and their activity is better in dry manure.
When cleaning out the storage, leave a couple of inches of dry manure over the bottom of the storage area to provide a population of fly parasites and predators. Manure removal can be staggered to leave one section per week to supply fly predators and parasites.
Remove a winter’s stockpile of manure during cold weather (<55°F) before fly breeding season.
Barnyard and Corral Management
Manure should not only be removed from stalls and barns, but corrals, barnyard areas, and sacrifice areas should be regularly cleaned to reduce flies, odor, and the potential for mud. A box scraper, skid loader, or tractor and loader can be used to remove manure built up on the surface of these areas. For more information, see the following publication: Sacrifice Areas.
Author: Fred Kelly, USDA Natural Resources Conservation Service, New Jersey
Manure storage and handling systems enable livestock producers to efficiently utilize all the components in their manure management system. A typical manure management system will include some or all of the following components.
Area where manure is produced (ie. feedlot, freestall barn, confinement building).
Manure treatment area (solids separator, digester, aerator).
The purpose of manure collection and handling systems is to efficiently gather and move manure among these components of a manure management system.
Manure Collection and Handling Equipment
The type of equipment and procedures used to collect and handle manure depends primarily upon the consistency or “thickness” of the manure. The term “solids content” or “percent solids” is often used to describe this characteristic in manure. Different species of livestock excrete manure with different percent solids.
As can be seen in Figure 20-1, the percent solids of manure excreted by swine, beef and dairy falls within a rather narrow range (10 to 13 percent solids), while poultry manure is excreted at a considerably higher solids content. The solids content of excreted manure is often changed by such processes as adding bedding, drying manure on a lot surface, adding washwater or dewatering the manure by solids separation.
The terms “solid” (greater than 15% solids), “slurry” (5 to 15% solids) and “liquid” (0 to 5% solids) are typically used within the livestock industry to describe the characteristics of a particular manure. Solid manure will “stack” to some degree with minimal seepage of free water from the pile depending upon moisture content. Slurry manure has fluid characteristics and tends to flow like a thick chocolate malt. Liquid manure has flow characteristics similar to that of water.
The following pages contain additional information related to each manure type.
Slurry manure is typically generated in systems where little or no bedding is added to the excreted manure/urine. Slurry manure is typically between 5% and 15% solids. It is “thicker” than liquid manure, but cannot be stacked or handled the same way as solid manure. Some common system for handling and storage of slurry manure are described in this article.
Collecting Slurry Manure
Slotted Floor
The simplest manure collection arrangement for slurry manure is the slotted or perforated floor over a manure collection tank. In this scenario excreted manure simply falls through openings in the floor on which the animals stand and collects in a tank below.
Slotted floors above a manure tank are a simple means of collecting slurry manure.
Scrapers
Slurry manure can also be collected using scrapers. In this case the manure is usually confined in an alley (dairy freestall barn) or gutter under slats (swine confinement building). A scraper moves along the length of the alley or gutter and deposits the slurry manure in a reception pit or tank at the end.
Mechanical or tractor-mounted tire scrapers can be used to collect slurry manure in a dairy freestall barn.
Vacuum
Another type of slurry manure collection device utilizes a vacuum to “suck” slurry manure from a concrete surface and deposit it into a tank. This approach eliminates the need to pump the slurry manure into a tank or wagon.
Labor is reduced when a suction or vacuum is used to collect slurry manure from a concrete alley.
Slurry Pumps
Slurry manure has fluid properties that allow it to be moved by pumps that are specially designed to handle thick fluids containing solids and stringy material. Slurry manure pumps are designed with open-type impellers and usually have cutting or chopping devices at the inlet to the impeller to minimize plugging problems. Low-pressure/high volume slurry pumps are used to fill tankwagons and move manure in other applications where higher pressures are not required. High-pressure slurry pumps are used to move manure through long pipelines and provide the needed pressure for land application in crop fields.
Slurry pumps have open impellers and cutter/chopper blades designed to handle manure with high solids content.
Low-pressure/high volume slurry manure pumps are used to quickly fill manure tankwagons.
High pressure slurry manure pumps can move manure long distances through pipelines to field application equipment.
Transporting Slurry Manure
Tankwagons
Tankwagons can be used to transport or move slurry manure from one point to another, usually from a manure storage facility to a crop field. Tankwagons are available in a variety of sizes from small (1,000 gallons) to quite large (12,000 gallons). Tankwagons typically serve the dual function of transporting slurry manure to a crop field and spreading or injecting the manure into the soil for crop nutrient uptake.
Large tankwagons allow producers to empty manure storage facilities quickly with less labor.
Pipelines
Since slurry manure has fluid properties it can be pumped through pipelines from storage to crop field as an alternative to hauling with a tankwagon. Pumping is a “continuous flow” process whereas hauling is necessarily a “batch” process. Hence pumping can offer significant advantages over hauling in moving large amounts of manure in shorter lengths of time. Tankwagons are generally used to move manure over longer distances although pipelines have been used for distances up to five miles.
Rigid aluminum irrigation pipe has been used for pumping slurry manure in the past. However the labor advantages of using flexible “layflat” tubing for pumping make this type of pipeline more attractive in many cases. Long lengths of this tubing can be stored on reels and placed overland with much less labor than is required with rigid tubing.
Flexible hose or tubing requires less labor for a manure pipeline than rigid pipe.
Slurry Manure Land Application
Field or land application of slurry manure requires that the application devices place the manure in the proper location and at the proper rate for good nutrient management practices. Devices which inject or incorporate manure into the soil are generally preferred since the following advantages are associated with this practice.
Odor is reduced
More nutrients are retained
Runoff potential is reduced
Injection units place manure into the soil to reduce odor, conserve nutrients and minimize runoff.
Some injection units are designed for sod with minimal surface disturbance.
Authors: Charles Fulhage and Joe Harner
Photos: CC 2.5 Charles Fulhage or Joe Harner
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