Many conservation practices are available for animal agriculture producers interested in protecting air and water quality, improving soil health or wildlife habitat, and increasing the productivity of animals, pastures, and crops. This module will especially focus on conservation practices impacting water quality with the goal of keeping clean water clean.
Farmers and ranchers can implement conservation practices on their own. They can also seek technical or financial assistance through agencies such as a local Conservation District or USDA Natural Resources Conservation Service (NRCS).
NRCS has developed approximately 160 conservation practice standards at the national level. States have the option of adopting a standard and using the same or more stringent criteria. Farmers should use state-adopted standards whenever available. To find out whether your state has adopted a certain standard, contact your local NRCS office.
Conservation practices relevant to water quality and animal agriculture can be divided into three categories. Clicking the link will take you to a virtual tour website that describes each practice and includes several photos.
Applying Conservation Practices to Individual Farms
Conservation practices should be implemented on an individual farm basis to ensure they are addressing a natural resource concern and will be effective in the particular farm setting.
Some questions to ask when evaluating whether a conservation practice will be beneficial for an animal agriculture operation:
Is the farm a confinement facility or are animals on pasture (or both)?
Are confined animals kept under a roof or open lots (or both)?
Where are pastured animals housed or fed in the winter?
Does the operation include crop land?
Are there waterbodies such as streams or ponds on the facility or crop land?
How does the farm store or handle manure; as a solid or slurry/liquid?
How much manure does the farm produce and where is it currently stored?
Are there neighbors nearby? How many and where?
Are there environmentally sensitive features on or near the facility? Wells, sinkholes, public parks or public use areas, wildlife, impaired waterbody, or similar features should all be considered.
What are the goals of the farmer or rancher? What is important to them and what do they have interest and capacity to implement and manage?
For example, consider these fictional farms. Both have 200 dairy cows and are interested in developing a manure management system. They are both in the same state with similar soil types.
Farm 1: There is a child in college interested in returning to help manage the farm, so future expansion is a strong possibility. The farm has sufficient cropland to use the manure they currently produce as crop fertilizer.
Farm 2: This farm is considering organic production. They do not have much cropland and must export most of their manure to neighboring crop farmers. This farm also has connections to organic crop farmers as well as the nursery and landscape industry.
While both farms have similar characteristics, they have very different goals. Their conservation plans could be very different. Farm 1 is likely to consider an earthen or concrete slurry manure storage structure with the biggest question being how large to make the structure considering a possible expansion in the near future. They are likely to develop a comprehensive nutrient management plan (CNMP) to ensure the cropland base continues to support any future expansion.
Farm 2 may look at manure collection and storage very differently. The cattle may have access to open lots (manure is handled as a solid) or grazing paddocks. Given the off-farm connections and lack of crop land, composting or other ways to generate value-added products may be an option. Marketing manure or exporting it off-farm will be important to this farm’s manure management plans.
Both farms intend to protect natural resources but need to implement different practices to reach their goals.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the USDA.Natural Resources Conservation Service through an interagency agreement with the U.S. Environmental Protection Agency.
All images on this page, unless otherwise noted, are courtesy of the U.S. Department of Agriculture or USDA NRCS. For questions on this material, contact Jill Heemstra, jheemstra@unl.edu.
This page focuses largely on USDA Natural Resources Conservation Service (NRCS) practice standards and how NRCS works with farmers by providing technical and financial assistance. The next section in this module discusses many of the practices relevant to animal agriculture in greater detail.
Why is conservation important in animal agriculture?
Conservation is key for farmers interested in protecting natural resources while producing food, fuel, and fiber from working lands. There are a variety of conservation practices that can be voluntarily implemented to protect natural resources for surrounding ecosystems, community, and future generations. Conservation practices can have both on-farm and off-farm benefits and can be customized to the unique location, soils, and needs of each farm. Conservation practices are site-specific, not one-size-fits-all. They must be planned and installed with the characteristics of the individual site in mind.
Many conservation practices are voluntary and incentivized through technical and financial assistance. If a farm is subject to regulatory oversight, NRCS practice standards may not meet the requirements of state or federal regulations or permits. Producers should double-check those requirements rather than assuming that they will suffice.
Photo 1. Animal agriculture operations are very different from farm to farm.
Because manure is one of the largest by-products of animal feeding operations, conservation practices are often designed to increase the farmer’s ability to manage manure as a beneficial resource and reduce risk associated with manure application. Nutrients (whether from manure or from inorganic fertilizer) not taken up by crops can run off from fields or leach to groundwater through rain events or irrigation.
Conservation practices can have beneficial impacts on water quality, wildlife habitat, and air quality. Adopting practices that result in manure applications that are well-timed, at agronomic rates, and away from sensitive locations can help farmers make significant positive contributions to water quality. Conservation practices are important in grazing operations to improve soil and vegetation health and to protect water quality and wildlife habitat. For example, restricting livestock access to a stream or creek reduces the chance the animals will deposit manure or urine in the water, break down stream banks and beds, and/or stir up sediment. Rotational grazing can provide important rest and recovery time for vegetation and allow wildlife cover for nesting or raising their young.
Agencies Involved in Implementing Conservation on Farms
There are several public agencies that cooperate to encourage the use of conservation practices on farms:
USDA Natural Resources Conservation Service (NRCS)
Photo 2. A local USDA Service Center
USDA NRCS was established in 1935 to work in close partnerships with farmers and ranchers, local and state governments, and other federal agencies to maintain healthy and productive working landscapes on a voluntary, non-regulatory basis. Originally known as the “Soil Conservation Service,” the name was changed to NRCS in 1994 to better reflect the broad scope of the agency’s mission. Learn more about the history of NRCS.
The National Office is located in Washington, DC, and is where national policy, procedures, and conservation practice standards are developed. State offices adopt these standards, either directly, or with changes that make the standards more stringent. The local or district office (Photo 2) works directly with farmers and ranchers to assist them in protecting natural resources by implementing conservation practices on working land. They provide technical and sometimes financial assistance for conservation practices. Learn more about how NRCS is organized.
Video: How to receive conservation assistance from NRCS
Financial assistance for USDA NRCS conservation practices comes from the Farm Bill, a piece of legislation that is developed about every 5 years by Congress. The Farm Bill is traditionally made up of several programs in the areas of food and nutrition assistance, marketing, commodity support, research, conservation, and more. The conservation programs authorized in the 2014 Farm Bill include:
Environmental Quality Incentives Program (EQIP)
Conservation Stewardship Program (CSP)
Agricultural Management Assistance Program (AMA)
Local NRCS offices will help farmers determine if their conservation needs are a fit for financial assistance. Factors that they will consider include:
Whether the farm is in a watershed or area designated with a high need for conservation practices
Past efforts of the farmer
Legislative priorities, such as bioenergy
The need to encourage beginning, veteran, and minority farmers
Photo 3. This local conservation district office is located in the same building as the local USDA service center.
Conservation districts are local governmental units responsible for protecting and conserving natural resources in their assigned geographic area. They are governed by a locally-elected board. In some states, they may have a different name, such as soil and water conservation district or natural resource conservation district. There are over 3,000 conservation districts, nationwide.
Conservation districts often partner with NRCS (Photo 3) to work with local farmers, ranchers, and other landowners to implement conservation practices that help address issues of local importance. By working together, NRCS and the districts can more efficiently address conservation needs.
US Environmental Protection Agency
EPA’s role in conservation is primarily regulatory but also includes non-regulatory, voluntary, and incentive-based programs such as the Clean Water Act Section 319 funding. This program provides grants to states and tribes to reduce nonpoint source runoff.
EPA also develops partnerships with industry. One such example is the EPA AgSTAR program, which works with farmers on a voluntary basis to encourage the use of anaerobic digesters for manure treatment and renewable energy generation.
Recommended resource: EPA National Agriculture Center includes information on regulations, compliance assistance, and partnerships.
State Environmental/Water Quality Agencies
Photo 4. State environmental agencies are generally tasked with enforcing the Clean Water Act and Clean Air Act.
Many Clean Water Act and other programs that originate with federal statutes are implemented by State, Tribal, and Territorial environmental agencies. Those programs generally work directly with local partners and landowners to develop watershed plans and implement nonpoint source control measures. Those partners often include Conservation Districts for agricultural projects and often utilize resources from multiple agencies and organizations, including USDA. Under Section 319 of the CWA, states, territories, and tribes receive grant money that supports a wide variety of activities to control nonpoint source pollution, including technical assistance, financial assistance, education, training, technology transfer, demonstration projects, and monitoring to assess the success of nonpoint source implementation projects.
Recommended Resource: Nonpoint Source Success Stories features stories about nonpoint source impairments with documented water quality improvements attributable to restoration efforts.
State Agricultural Departments
For the most part State agricultural Departments do not play a direct regulatory role in enforcing the Clean Water Act or Clean Air Act. One major area where state agriculture departments are involved in the implementation of conservation practices are in the case of animal mortality, both routine and catastrophic. Most states have regulations that specify appropriate methods for carcass disposal. State agriculture departments may also develop programs that encourage the use of conservation practices through cost-share, educational outreach, or other methods.
NRCS Conservation Practice Standards
There are over 160 conservation practices for which national standards have been developed. Any that are adopted by a state can be implemented in that state to assist farmers and ranchers with their environmental stewardship efforts. Farmers and ranchers should use the conservation practice adopted by the state, rather than the national standard.
To find your state’s approved practice standards, contact your local NRCS office for assistance.
Photo 5. Many different conservation practices are used on animal agriculture operations.
What are conservation practice standards?
Photo 6. A screenshot of the Anaerobic Digester conservation practice standard. Click here to download the full-size PDF version.
A conservation practice is defined as: “A specific treatment, such as a structural or vegetative measure, or management techniques, commonly used to meet specific needs in planning and implementing conservation, for which standards and specifications have been developed.”
NRCS conservation practice standards provide guidance for applying conservation practices and set the minimum level for acceptable application of the technology. Each standard is given a number. For example, the standard for “Anaerobic Digester” is #366. Practice standards include information (Photo 6), such as:
Purpose: The conservation goal achieved with this practice
Where it applies: The type of farm, land use, or situation where the practice is appropriate
Criteria: Location, safety considerations, permits needed, management, related conservation practices, and other important considerations
Three categories of conservation practices that apply to animal agriculture include:
How are standards for practices developed/updated?
Practice standards may be newly identified or change over time based on new science and technology. They are periodically reviewed and updated, usually every 5 years. Any new or updated practice standard is reviewed by technical experts in pertinent fields and is available for review and comment by the public before it is adopted.
NRCS publishes national conservation practice standards in its National Handbook of Conservation Practices (NHCP). If a practice is adopted by a state, the state has some latitude to develop a more stringent or specific version that fits typical conditions or situations in that state.
Recommended Resource: The first 12-13 minutes of the video “Use of NRCS Conservation Practice Standards and Specifications” describes the process of how a new standard may be identified as well as the process used to validate it and the sections included in a standard. It is presented for NRCS staff, but is useful for others that work with farmers who want more background on how a practice standard is developed and what is required to be in a standard.
What is conservation planning?
Photo 7. Conservation planning needs to consider individual farm goals and current conditions.
A conservation plan is a record of the conservation practices implemented on a farm or ranch. It may include sub-plans such as one for grazing management, comprehensive nutrient management, wildlife management, or others.
Conservation planning starts with a farmer or rancher recognizing a problem area or wanting to improve some aspect of the farm or ranch. The next step is to contact NRCS. NRCS helps the farmer or rancher review and analyze the current conditions for possible solutions. Depending on the preferences of the client, certain practices may be selected to include in the conservation plan.
Conservation plans are voluntary and are developed by NRCS at no cost.
How do farmers access technical or financial assistance for conservation?
Contact your local NRCS office to access technical assistance in implementing conservation practices. If conservation practices are eligible for financial assistance (cost-share), farmers complete and submit an application. If approved for cost-share, a contract is developed that specifies what will be done, when it will be done, and how much assistance will be provided.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the USDA.Natural Resources Conservation Service through an interagency agreement with the U.S. Environmental Protection Agency.
All images on this page, unless otherwise noted, are courtesy of the U.S. Department of Agriculture or USDA NRCS. For questions on this material, contact Jill Heemstra, jheemstra@unl.edu.
A Brief Overview of the Clean Water Act National Pollutant Discharge Elimination System (NPDES) Requirements for Concentrated Animal Feeding Operations
Farms classified as concentrated animal feeding operations (CAFOs) are subject to National Pollutant Discharge Elimination System (NPDES) permitting under the Clean Water Act (CWA) because they are, by definition, “point sources” of pollution. This has been the case since the mid-1970s. Under the CWA, point sources are prohibited from discharging pollutants to the waters of the U.S. except as authorized by an NPDES permit.
To be considered a CAFO, a farm must first meet the definition of an animal feeding operation or AFO. AFOs that meet certain criteria for size and pollution potential are considered to be CAFOs. CAFOs that discharge pollutants into waters of the U.S. must be covered by an NPDES permit. The CAFO regulations are available on the U.S. Environmental Protection Agency (EPA) website in the document “Compiled CAFO Rule“.
The regulations include requirements for CAFO operators to develop a nutrient management plan that includes management measures for both the production area and the land application areas of the operation, as well as record-keeping and reporting requirements.
What Is a Point Source and a Non-Point Source of Pollution?
A point source of pollution, as defined in the Clean Water Act is:
Any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft, from which pollutants are or may be discharged. This term does not include agricultural stormwater discharges and return flows from irrigated agriculture.
The EPA is responsible for administering most elements of the CWA, including the NPDES program. Most states are authorized to issue NPDES permits, including those issued to CAFOs (State NPDES CAFO contacts).
State-specific water quality requirements may also apply to livestock operations. In some cases those measures may be implemented in a “dual purpose” (NPDES + state) permit, or may be implemented solely in state permits. State permits most commonly apply to CAFOs that do not discharge to waters of the U.S. Additional information: The EPA Agriculture Center has compiled information about laws and regulations that apply to animal agriculture and other agricultural activities including cropping, chemical handling, buildings and construction, and fuel as well as requirements for air emissions.
The U.S. Department of Agriculture (USDA) has no regulatory authority for CWA programs but provides technical or financial assistance through the Natural Resources Conservation Service (NRCS) for farms implementing recommended manure management or nutrient planning processes.
In addition to regulations enforced by federal and state agencies, livestock and poultry farms are occasionally subject to rules at the local level such as county zoning. These often address groundwater or wellhead protection as well as odor and nuisance concerns. New farms or those making substantial changes are especially likely to need to check into local zoning requirements before constructing new facilities.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Reviewers: Tetra Tech, Inc.; Paul Goeringer, University of Marlyland; Kent Woodmansey, South Dakota Department of Environment and Natural Resources; Joe Harrison, Washington State University; and Tom Hebert, Bayard Ridge Group
Building on the previous sections in this module, this section focuses on tools and resources for managing manure-related risks and highlights strategies for good stewardship. It highlights assessing risk, siting, planning for emergencies, getting along with neighbors, and keeping records.
“It’s all about sustainability. The more we know, the more we can plan, and the better job we can do. There’s always new information, new knowledge and new technology.”
This module focuses on water quality, but stewardship also includes attention to air quality, odor and nuisance concerns, and aesthetics (appearance).
Location! Location! Location!
Selecting an appropriate site for manure storage, feed storage, open lots, barns, stockpiles, and land application is a critical first step when looking at building new structures or expanding existing ones. Assessments of existing farm sites should identify risk areas to be avoided or where improvements are needed to protect water resources.
Below are potential pollution sources and some of the factors that should be considered when assessing the risks to environmentally sensitive features when siting and designing operations. These lists are not comprehensive but provide some common areas for consideration.
Potential Pollution Sources
Manure storage
Animal lots and barns
Feed storage
Dead animal burial, composting, or pickup site
Open lots or corrals
Land application
Field stockpiles of manure
Pesticide, chemical, fuel storage
Factors Influencing Pollution Potential
Distance
Soil type
Slope
Presence of tiles and other drains, pipes, ditches, culverts or other conveyances
Cross-connections in water supply and/or waste systems
Vegetative cover
Environmental Features of Special Concern
Wells and wellhead protection areas (groundwater)
Rivers, streams, ponds, lakes, wetlands and other water
Sinkholes, karst topography
Neighbors, public spaces
Threatened or endangered species or habitats
Assessing risk is a very site-specific exercise. In one situation, 100 feet between a potential pollutant and a stream may be perfectly acceptable, such as when the buffer has extensive vegetation and little slope. In other situations, even a 100-foot buffer might be inadequate, such as when the buffer is subject to channelized flow due to erosion. There are a variety of tools to help producers assess the risk of particular siting decisions, such as Farm*A*Syst. Figure 1 provides an example of the type of questions asked in such tools to guide producers the best siting choice.
Photo 1. (Above) An example of poor siting that was later corrected. The area roughly outlined in orange was originally an animal pen at this feedlot. The run-on of stormwater from the crop field was not diverted around the pen nor was the subsequent runoff from the pen contained. A combination of water quality concerns and poor cattle performance resulted in the farm owner evaluating different options. They chose to relocate the pen to the other side of the feedlot (not shown; right side of photo). The new pen has no run-on and the manure and runoff are completely contained.
In many cases, specific regulatory requirements prescribe how to assess and address site-specific risk. As a general rule, regulatory standards should be thought of as a starting point for good nutrient management while recognizing that site-specific conditions may require additional controls to adequately protect sensitive features.
Recommended Resources for Site Selection or Assessing Risks Related to Animal Feeding and Manure Management
Do a search for “Farm A Syst” + your state name to find worksheets created to assess water quality risks around farms utilizing state-specific recommendations and considerations. If you cannot locate Farm*A*Syst materials this way, contact your local or state extension service to find out if that or a similar resource exists in your state. These worksheets cover a broad range of topics, including animal lots and manure but also chemicals, fuel, septic systems and more.
Regular monitoring and timely maintenance of manure storage and handling equipment is one of the best ways to prevent accidental spills and releases. Most releases or discharges causing water quality problems are preventable with appropriate management. However, occasionally accidents or emergencies due to unforeseen conditions or events do occur. Having a plan for when things go wrong is essential. A crisis is no time to wonder who to call, look up phone numbers, or figure out the location of needed supplies. Planning for events like catastrophic animal mortalities, an unresponsive person in or around a manure pit, or a manure spill saves time, possibly lives, and can lessen the environmental impact.
Manure spills can occur around the farm site (collection or storage), during transport to fields for land application, or during land application. Emergency plans should consider what to do in each of these scenarios.
An emergency response plan for a manure spill should include several steps:
Stop the leak. Eliminate further spillage. Does everyone know how to shut off the pumps and close valves (or where these items are located)? Notify emergency responders as needed for human safety, traffic control, or other safety matters. Always prioritize matters of human safety first!
Contain the spill. Do you have equipment to build a temporary earthen berm? If not, who does? Are hay bales, stakes, sheets of plastic and plywood or similar items readily available for blocking culverts, tile drains, or ditches?
Assess the spill. How much spilled? How far did the spill flow or spread?
Notify the appropriate agency. There is no national database on the number of manure spills that occur each year. Most spills are reported to state authorities.
Clean up the spill. The equipment needed will depend on whether the spill is solid or liquid/slurry manure. Procedures will also vary depending on if or how much manure reached waterways. See the “Responding to a Manure Spill” section below for case studies.
Make repairs and restore the site. Fix any faulty equipment, hoses, valves, pumps, etc. Ensure roadways are clean, and spilled manure is either land applied appropriately or transferred to a different storage structure. Remove temporary berms and blockages. Reseed the site if necessary.
Train employees and family. Practice the plan. The plan should be reviewed, updated as necessary, and everyone on the farm trained on an annual basis.
Responding To a Manure Spill: Case Studies, Templates and Other Resources
Always check with your state extension service to see if they have templates and resources for spill response and other emergency situations. Templates may be pre-populated with important phone numbers or requirements for notification, and some Extension systems even maintain a list of contractors to assist with cleanup.
Animal Waste Management Field Handbook Chapter 13 “Operation, Maintenance, and Safety” covers preventative management and safety considerations. (USDA Natural Resources Conservation Service)
LPES Lesson 50 “Emergency Action Plans” is a comprehensive resource (48 pages). It includes six case studies (pages 10-13) and recommendations for cleanup procedures and templates (starting on page 33).
The video below presents two case studies of excellent manure spill response efforts. It is excerpted from Kevin Erb’s (University of Wisconsin) presentation in the webinar “Manure Spills and Emergency Planning“. That link will also take you to videos and links for the steps for a spill response, solid manure considerations, and steps/technologies to prevent manure spills.
Photos 2-4 below include critiques of a manure spill response from 2005. These are intended as a learning exercise and should not discourage efforts to clean up manure spills. A less-than-perfect spill response is much better than no response at all. All three photos are courtesy of Kevin Erb, University of Wisconsin.
Photo 2. (Above) Using bales to stop future erosion from the site is a good temporary measure for low grade slopes and unchannelized flow. However, these bales should be staked into the ground to be effective. If sod is disturbed, the area should be reseeded and covered with straw or mulch to suppress weeds.
Photo 3. (Above) Spilled manure was removed from the ditch; however, sod was removed along with the manure. This increases the potential for erosion. It also removes the plants that could use the manure nutrients. The sod removal was done above buried utility lines. This is discouraged, and probably illegal in most locations.
Photo 4. (Above) The areas above and below the culvert were cleaned up post-spill. However, the culvert was not flushed out. Not only did this create a “stinky mess” but could potentially flow downslope with the next rain.
Record Keeping
One common problem encountered when a complaint is made about a farm or an emergency situation is examined, is missing or incomplete records. The most important thing to remember about records is “If you don’t document it, you did not do it!” If there are no records of manure spreader calibration or manure nutrient analysis, the entire nutrient plan can be undermined. While a farmer knows to inspect and maintain equipment, he or she needs to be able to prove that inspection or maintenance in the event of a spill, an inspection or a complaint.
A common way to organize records is by how often they need to be accessed. Some records are permanent, such as farm maps and design schematics of the manure storage. These are not accessed every day and can be filed securely. Records that need to be filled out daily, such as rainfall records, should be in a handy location like a clipboard or a smartphone. One Nebraska farmer bought mailboxes and installed them in several locations where inspections and observations needed to be made often including the manure storage and weather station. Electronic technologies, apps, GPS, and computer software can be used and new features are being introduced regularly in public and privately-developed programs.
Records need to be backed up regularly and protected in case of situations like fire, flood, or electrical surges. Have a plan for backing up important records.
In the following video Christine Blanton with North Carolina Department of Environment and Natural Resources discusses why records are important and how they can be useful in making management decisions. While the emphasis is on records for permitted operations, the information is relevant to all animal feeding operations.
Recommended Resources for Record Keeping
Do an Internet search for “animal feeding operation record keeping templates” + your state name to see if there are checklists and forms already developed for your area. These can always be modified.
Critical Records of Ag Production (C.R.A.P.) is a record keeping app developed at Utah State University for manure transfers, application, equipment inspections and other important operations
Getting Along With Neighbors
“I provide a business card with my number to all of the neighbors and ask them to call me anytime with questions or concerns, allowing them to also give me advance notice if they have a get together or event that our crews should be aware of. I say to call anytime they have a question or concern. I stop by once per year, even to the neighbors who don’t like me.”
Animal feeding operations can be the source of odors, flies, traffic and other nuisance issues for neighbors. Doing as much as possible to minimize nuisances, listen to neighbor concerns, and maintain positive relationships within the community is important not only for animal agriculture, but any business.
A very helpful exercise to define a farm’s stewardship ethic, and be able to communicate it to those outside the farm, is to create an environmental policy statement (EPS). An EPS is a short paragraph that describes the farm and commits to stewardship, regulatory compliance and continual improvement. The policy statement can be used on a farm website, on brochures, posted on the office wall, and should be among the first things given to new employees. It provides a framework for talking about what is important to a farm when talking with neighbors and others in the community.
Coexisting with Neighbors (University of Georgia) Developed for poultry farmers, but relevant to all animal feeding operations
Review, Reassess, and Improve
One common characteristic shared by farms that plan for stewardship is a desire to continually improve upon current efforts. This mindset is very comparable to an environmental management system (EMS) process in which a plan is developed, implemented, monitored, and then reviewed for improvements. The new plan is implemented, and so on. Taking an honest look at mistakes and learning from them is part of continual improvement.
“We cannot stand idle. If we do, the industry will pass us by, and we’ll be out of business. This philosophy of continuous improvement has led the family toward updates that contribute to the operation’s sustainability.”
See part three of this module for recommended resources on nutrient management.
[Recorded webinar] Management of Confined Livestock Systems from a Producer’s Perspective (USDA Natural Resources Conservation Service). This recording features several farmers that made significant changes to their operation. They share experiences with using technical or financial assistance programs, learning from other producers, and challenges.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Reviewers: Tetra Tech, Inc.; Joe Harrison, Washington State University; and Tom Hebert, Bayard Ridge Group
Many of the images and scenarios on this page may be permit violations or may contribute to exceedances of water quality standards; however, additional information beyond what is provided on this educational page is required to make determinations of that nature. The next topic in this module provides additional information on Clean Water Act requirements.
Challenges In Managing Manure Nutrients
Nitrogen (N) and phosphorus (P) are essential for plant growth. When nutrients are applied in excess of what crops need or when they are applied at a risky time, more nutrients can end up in water than might otherwise have been the case. This holds true regardless of the source of nutrients. This module focuses on manure and some of the challenges in managing manure nutrients.
Economics. Manure contains more than nutrients. Organic matter contributes to soil health and crop growth. Manure also contains water. “Dry” solid manure can be 20-40% water and manure pumped from a liquid or slurry storage is about 90% water. Nutrients in manure are less concentrated than in commercial fertilizers. Relatively speaking, that makes manure expensive to haul long distances. As animal agriculture sectors have consolidated, resulting in larger farms, more manure is produced in smaller areas. Because of the transport expense, manure tends to be applied close to where it is produced.
In areas with many livestock or poultry farms exporting manure, it can be challenging to find fields within a reasonable distance for application. Farmers are beginning to do more manure marketing and some are looking at technologies that can add value to manure. These can offset the costs of transporting manure or can transform manure nutrients into a form that is economical to transport. Related: USDA Economic Research Service “Effects of structural change: manure and excess nutrients” (dairy). The referenced chapter is part of a larger report.
Nitrogen:Phosphorus Ratio. Another important point regarding manure is that it contains more P than N relative to what crops need. If manure is applied at rates to meet the crop N needs, more P than the crop can use in a single year is applied. Over time, P in the soil can build up to levels that present a significant risk for transport to water. Managing this, at least in part, includes a process known as nutrient management planning.
Another way to manage this risk is through the use of the phosphorus index (P-index). The P-index is a risk assessment that factors in several inputs to determine if N-based rates of manure can be used or if application needs to be reduced to a P-based rate. In some cases, the index may show a high enough risk to discontinue P application (manure or otherwise) altogether. To learn more about the P-index, do an Internet search with your state name + phosphorus index. Recommended Resource: SERA-17 publications.(a multistate information exchange group focused on P.)
Variable Nutrient Content. Manure is not a standard product. It varies greatly among animal species and even within species due to varying farm management practices. The most accurate estimate of a farm’s manure nutrient content comes from sampling and manure testing. Recommended Viewing: Iowa Learning Farms videos on liquid manure and solid manure sampling procedures.
Nitrogen Availability. Much of the nitrogen in manure is in organic form. This type of nitrogen is not plant-available (more below) and is slowly mineralized by soil microbes into plant-available forms over several years. The rate at which this mineralization happens is dependent on temperature, moisture, and soil microbial activity, all of which cannot be predicted exactly. Extensive research has led to state-specific recommendations for estimating the amount of nitrogen that will be available to plants each year from manure and other organic sources. Most state Extension services have publications available on this topic.
Recommended Reading: Nitrogen Management on U.S. Corn Acres 2001-10 (USDA Economic Research Service). See Table 3 “Share of treated corn acres that did not meet rate, timing, and method criteria by N source” for data illustrating the challenges of nutrient management and manure.
What Happens When Manure Nutrients Reach Surface Water?
Nutrients, including N and P, are necessary for plant and animal life in streams, lakes, and other surface water bodies; however, a large influx of N, P, or both moves the system out of balance. This enrichment is known as eutrophication.
Photo 1. (Above) Algae is beginning to grow in earnest as the water warms up in late spring.
Aquatic plants and algae grow rapidly under eutrophic conditions (Photo 1). When the algae or plants die, the decomposition process depletes oxygen dissolved in the water, a condition known as hypoxia. Without adequate oxygen, fish, shellfish, and other aquatic life die or move to non-hypoxic areas. Another concern is that certain types of algae release toxins that can be harmful to people, pets, or livestock. Excessive algae growth, toxic or not, is referred to as a harmful algal bloom.
Hypoxic zones are an environmental problem, as well as an economic one, as large areas may become unsuitable for commercial fishing, shrimping, and similar activities. The sources responsible for nutrient releases into water vary for each watershed, but usually include agriculture as well as municipal wastewater treatment, urban stormwater, residential areas, and others.
Manure Nutrients in Groundwater
Groundwater is the primary source of drinking water in many parts of the country. The U.S. Environmental Protection Agency (EPA) has set 10 parts per million (ppm) of nitrate (NO3–) as the maximum level considered safe for drinking water.
High nitrates occur in surface water as well as groundwater, but are most often discussed as a risk for groundwater because of the large number of private, rural groundwater wells used for drinking water. Municipalities that use surface or ground water for drinking are required to test for nitrates and take corrective action if levels are above allowable limits.
How Do Nutrients Reach Water?
Nutrients are mobile. They cycle and transform in the environment. Even perfectly managed manure handling systems cannot expect to contain 100% of the N and P. Losses can be held to acceptable levels through management and conservation practices. Nutrients from crop fields reach water sources in one of two ways, runoff or leaching. Nutrient runoff occurs when nutrients dissolve in water that flows over the soil surface or when water carries particles of soil containing nutrients to a stream, river, lake, ocean or other surface water. Nutrient leaching occurs when nutrients dissolve in water that is flowing downward through the soil profile.
Nitrogen
Manure N is mostly in organic form with a lesser amount of inorganic ammonia. The amount of each varies greatly depending on the animal species and manure collection and storage practices. Once applied to a crop field, a complex network of chemical and biological processes, referred to as the nitrogen cycle, takes over. Organic N from sources like manure or crop residue is mineralized to ammonium (NH4+) and eventually nitrate (NO3–).
Organic N and NH4+ are more likely to be associated with soil particles or soil aggregates and may be carried with eroded soil in runoff to surface water bodies. High ammonia levels in surface water are detrimental to aquatic organisms.
Nitrate is soluble and can be carried with runoff or leach downward through the soil profile. When NO3– is carried down below the root zone, it can no longer be captured by plants and used for crop or grass growth. This puts groundwater resources at risk for contamination. Ammonium (NH4+) or organic N are not generally viewed as a risk for leaching.
Phosphorus
Phosphorus also cycles through organic and inorganic forms and all, or nearly all, P applied through manure is considered available to plants. Unlike NO3–, P binds tightly to soil particles. Rain events capable of eroding soil particles are likely to carry P along with the runoff. To a much lesser extent, P can be soluble (dissolved in water) and carried in runoff, especially when soil P builds up to very high levels. Most P is carried to surface water bodies along with soil.
Phosphorus is not generally a significant leaching risk because of its tight bond to soil particles. There are a few situations, such as soils that are saturated with P or where subsurface (tile) drainage is used, where the risk of P leaching may be substantial.
What Are the Risks Associated with Manure and Water Quality?
When it comes to manure nutrients and land application, proper management is critical.
Farm Site Risks
Around the farm site, manure collection and storage as well as uncontained runoff from open lots are the primary risk areas for manure releases or discharges to water (Photos 2 and 4, below). Many states have rules that require minimum distances between manure storage structures and water, wells, sinkholes, or other environmentally sensitive areas. These distances are called setbacks. The closer that manure is stored near these features, the greater the risk of contamination.
Photo 2. (Above) Uncontrolled feedlot runoff is a risk to water quality. Photo courtesy of U.S. Department of Agriculture Natural Resources Conservation Service (USDA NRCS). Containment systems like those shown in Photos 3 and 5 (below) should be used.
Photo 3. (Above) An example of an open lot feeding operation that not only contains runoff in sediment basins and holding ponds, but also installed a diversion to prevent clean water from entering the feedlot. Photo courtesy of USDA NRCS.
Photo 4. (Above) Water is draining uncontrolled from this lot into the adjacent natural drainage area. Runoff should be managed with appropriate best management practices such as clean water diversions, settling basins, or holding ponds like those shown in Photo 3 (above) or Photo 5 (below).
Photo 5. (Above) This open lot includes a settling basin (or sediment basin) in the foreground. The animal pens are behind the photographer. When solids have settled out, the liquid is allowed to flow through the pipe into the liquid manure storage in the background. The settling basin is designed for easy access for regular removal of the solids. This two-part system increases the storage life of the manure storage structure in the background by preventing a large portion of solids from entering the structure.
Manure storage structures require careful attention to engineering, construction, operation, and maintenance. If any of these aspects are deficient (Photo 6, below), the structure is at risk for failure. Most problems can be prevented by regular inspection and maintenance. Iowa State University analyzed 58 manure incidents in 2007 and “human error” was identified as the most common cause (13 incidents). They cited things like “leaving pumps unattended” and “failure to close valves” as the type of human errors that occur.
Photo 6. (Above) An overflowing manure storage. Photo courtesy of USDA NRCS. Regular inspections and timely removal of manure for land application could have prevented this situation. In some areas, covered manure storage structure structures are recommended to prevent rainfall and snowmelt from contacting the manure.
Photo 7. (Above) A poultry litter storage facility that is covered. The roof keeps the litter dry and helps prevent the problem seen in Photo 6. The structure is nearing full capacity and the photo was taken on the day it was emptied and the litter hauled to fields for land application. Photo courtesy of Josh Payne, Oklahoma State University.
In addition to manure storage structure failures, manure discharges or spills can be caused by the failure of pumps, hoses or pipes, valves and other handling equipment. The area where manure is loaded into spreaders or tankers is a common area for spills to occur. These spills should be cleaned up quickly to avoid the potential for runoff and to keep the farm site neat.
Transportation Risks for Manure Spills
Moving manure from the farm to the field on public roadways includes the inherent risks that come with traffic. Collisions and overturned tankers or spreaders can result in manure being released onto roads and into ditches.
Photo 8. (Above) An overturned manure tanker on a public roadway. Photo courtesy Kevin Erb, University of Wisconsin.
Land Application Manure Loss Risks
During manure application, the risks for manure/nutrient losses include:
Overapplication
Not observing setbacks
Poor timing (weather)
Overapplication. Applying too much manure can be the result of incorrect calculations, incorrect settings on the application equipment, or improperly calibrated equipment. Equipment failures can also lead to too much manure being applied to a field or small area of a field. Overapplication also occurs when there is too little available land for the manure that must be applied.
Setbacks. Many states have setbacks that require minimum distances between land application and water, wells, sinkholes, or other environmentally sensitive areas. The closer that manure is applied near these features, the greater the risk of contamination. This is especially true in locations with karst topography. Sinkholes or fractured bedrock provide a direct path for manure to reach groundwater.
Timing. Weather is an especially important factor in application risk. Applying manure to saturated soils or when drainage tile is flowing increases the risk for both surface-applied and injected manure. Field operations under those conditions also leads to soil compaction which is bad for crop yields and can increase the future risk of runoff.
Frozen or snow covered soils prevent manure from contacting the soil or infiltrating into the soil and also limit or prevent incorporation which is necessary to help stabilize applied manure as part of the soil structure thereby reducing runoff potential. As plants are generally not growing in frozen or snow-covered soils, no agronomic uptake of manure nutrients is occurring either. Applying on frozen or snow covered ground is not advisable and, in many cases, not allowed according to state requirements.
Manure application should be avoided if significant rain is predicted, especially for surface-applied manure that will not be incorporated, and should not begin until soil conditions are favorable.
Photo 9. (Above) Manure application immediately preceding a significant rain event is a high pollution risk and should be avoided. Spreading on this field occurred on the same day as a rainfall and manure was carried by runoff to the base of this field. This photo was taken after another rain event approximately two weeks later, showing more runoff with the potential to further carry manure and nutrients offsite. Making a high-risk application was the first mistake. The second mistake was in not cleaning up the solids as soon as field conditions allowed and re-spreading them when rainfall was not expected.
Photo 10. (Above) This was taken the same day as Photo 9 on a field three miles away. The biggest difference is that the manure application (also solid beef feedlot manure) to this field occurred under dry conditions and the manure was lightly incorporated. In the photo, runoff from the rainfall that occurred two weeks after manure application does not appear to be carrying manure from the field; this shows how well the manure was integrated into the soil structure. The manure nutrient runoff risks from this field are much lower than the field in Photo 9.
Photo 11. (Above) Manure application to frozen or snow-covered soil should be avoided. Some states prohibit manure application during winter months. Managing manure storage levels so that adequate capacity is available to retain manure during extended periods of high-risk conditions (such as winter) is an important management practice.
Other Potential Water Quality Concerns
This page focuses on nutrients and water quality but there are additional manure-related topics of which you should be aware. The following sections very briefly introduce three of these: pathogens, pharmaceuticals, and organic matter.
An example of a watershed impacted by waterborne pathogens, including those associated with manure, is Samish Bay in Washington. The presence of fecal coliforms at high levels in the bay have made the water unsuitable for shellfish production and recreation. Research is being done on the effects of manure treatment, especially composting and anaerobic digestion, on pathogens in manure. Recommended Viewing: Two webcast presentations “Pathogens 101” and “Microbes: From Farm to Public Risk“.
Biochemical Oxygen Demand (BOD)
We previously discussed the ability of manure nutrients to stimulate plant growth in aquatic systems. Once the “bloom” is over and the plant material begins to decay, oxygen is rapidly removed from water and can lead to fish kills or can lead to long-term hypoxic zones. In addition to nutrients, the large amount of organic matter in manure also depletes water of dissolved oxygen if a significant amount of manure reaches the water body. Runoff from silage or feed piles on livestock farms is another waste stream that has a high BOD and should be contained or controlled just like runoff from manure storage or open lots. Recommended reading: Oklahoma State University developed a comprehensive explanation on organic matter in manure and other wastewater and how it interacts with the environment.
Recommended Resources
The video below was produced by the U.S. Poultry and Egg Association in cooperation with the Livestock and Poultry Environmental Learning Center and U.S. EPA. It covers several water quality topics as well as some air quality concerns. Even though the video references poultry production, it is applicable to other species.
[Archived webinar] “Manure Spills and Emergency Planning” includes sections on spill causes and case studies, solid manure considerations, and technology to prevent spills.
[Archived webinar] Nitrates In Groundwater includes research from several states and a presentation on N losses from tile drainage
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Reviewers: Tetra Tech, Inc.; Joe Harrison, Washington State University; Tom Hebert, Bayard Ridge Group; and Mark Risse, University of Georgia
Farms collect and store manure in different ways. For the most part, manure is handled and stored as either solid, slurry, or liquid. The biggest differences are between systems designed for solid manure and those designed for liquid or slurry manure.
Solid Manure
Solid manure is approximately 80% (or less) moisture and 20% (or more) solids. It can be stacked into piles and handled with equipment like front-end loaders and box scrapers. Semi-solid manure (around 15% solids) is handled and stored the same as solid manure.
Common examples where farms handle manure as a solid:
Beef feedlots and dairy farms scrape manure from open earthen lots (Photo 1)
Broiler (meat chicken) litter is a mix of manure, feathers, and bedding (Photo 2)
Layer (egg-producing chicken) manure contains feathers but no bedding (Photo 3)
Less common examples where farms handle manure as a solid:
Bedded pack barns or hoop buildings for beef cattle or pigs
Photo 1. (Above) Two examples of open earthen lots with beef cattle on the left and dairy cattle on the right.
Photo 2: (Above) Broiler litter being cleaned out of a house (left) and what a similar house looks like when populated with chickens (right). Photos courtesy of Josh Payne, Oklahoma State University.
Photo 3: (Above) Most layer hen houses built recently use belt systems to remove manure. Several cages are stacked on top of each other and a belt in between each tier catches the manure. The belts convey manure to a collection point; manure is taken from the collection point to a separate storage area. Photo courtesy of Robb Meinen, Pennsylvania State University.
Solid Manure Storage
Solid manure is typically stacked or piled in storage areas that may be covered (Photos 4 and 6, below) or uncovered (Photo 5, below) depending on the amount of rainfall or snowmelt an area receives. Farms in arid areas are more likely to manage solid manure storage areas without a roof or cover.
Roofs or covers prevent rain or snowmelt from entering the storage area, but are more expensive to build. If precipitation causes runoff from uncovered solid manure storage areas, the runoff needs to be captured and contained to prevent it from reaching streams, lakes, or other surface water.
Photo 4. (Above) Solid layer hen manure is stored on the ground level of this high-rise layer house. The hens are housed in the upper level and manure falls through slats in the floor. High-rise houses used to be the most common system for layer hens but are gradually being replaced by manure belt systems. Image courtesy of the United Egg Producers.
Photo 5. (Above) The solid manure storage area and handling equipment for a beef feedlot.
Photo 6. (Above) A covered manure storage structure on a poultry farm. Photo courtesy of David Schmidt, University of Minnesota.
Slurry Manure
Slurry manure is approximately 10-15% solids. It is a very thick liquid that requires pumps for collection and handling. Equipment and structures for handling slurry manure need to be engineered for materials of this consistency.
Common examples where farm collect and handle manure as a slurry:
Pig manure in deep pit barns
Dairy manure in scrape (Photo 8, below) or vacuum systems in free stall barns
Less common examples where farms collect and handle manure as a slurry:
Layer hen farms with scrape systems
Slatted floor beef buildings with a manure pit
Photo 7. (Above) A slatted floor in a small-scale swine research barn. Slatted floors are part of both slurry and liquid manure collection systems, especially on pig farms. If a deep pit for long-term storage is beneath this floor, the farm handles manure as a slurry. If manure is flushed from beneath the slats to an external storage structure, the farm likely handles manure as a liquid. Photo courtesy of Rick Ulrich, University of Arkansas.
Photo 8: (Above) An automated scraper collecting slurry manure in a freestall dairy barn. Slurry manure can also be collected from barns or feed pads using vacuum tankers. Photo courtesy of Karl Vandevender, University of Arkansas.
Liquid Manure
Liquid manure has only a small amount of solids (less than 5%). It is very dilute in terms of nutrient content and cannot be hauled long distances because of the cost of hauling large amounts of water. Liquid manure is collected and handled with gravity flow or pumps and is stored in structures called ponds or lagoons.
Common examples where farms handle manure as a liquid:
Runoff holding ponds for open earthen lots (beef or dairy)
Pull-plug or flush systems in pig barns
Flush systems in dairy barns
Less common examples where farms handle manure as a liquid:
Layer hen farms with flush systems
Slurry and Liquid Manure Storage
Slurry and liquid manure can be stored in earthen pits (Photo 9, below), holding ponds, or treatment lagoons. They can also be stored in above-ground tanks (Photo 10, below) or in concrete structures (Photo 11, below).
Photo 9. (Above) An earthen liquid manure storage structure on a pig farm. Photo courtesy of USDA NRCS.
Photo 10. (Above) The orange arrow points to an above-ground steel manure storage tank.
Photo 11. (Above) The manure storage structure on this dairy farm includes a concrete wall near the barn and ramp for access when removing manure. Photo courtesy of David Schmidt, University of Minnesota.
The video below, produced by the University of Wisconsin, introduces systems for handling and storing liquid and slurry manure. It also discusses safety precautions for these systems and structure. The final section covers the importance of agitation, or mixing, when preparing manure for land application.
Process Wastewater
Process wastewater is water used by farms, often for cleaning, which comes in contact with animals, manure, or feed. It may also contain chemicals for sanitizing or cleaning a product or surface. This is not considered to be manure, but must be captured and contained and can be stored in the liquid manure storage structure or a separate structure.
Common types of process wastewater generated on animal farms:
Egg wash water
Milking center wash water
Covered Manure Storage
In recent years, the use of covers on manure storage structures has increased. This is especially true for pig farms. Covers are primarily used to address odor concerns, but can also be part of an anaerobic digestion system. Photo 12, below, shows a covered manure storage structure.
Photo 12: (Above) A very small earthen manure storage structure with a cover installed. Most covered manure storage structures are larger than this but look very similar.
Is There Enough Manure Storage Capacity?
The main purpose of manure storage is to contain manure, process wastewater, and contaminated runoff until it can be safely and appropriately applied to crop fields or be used in an alternative manner. Good stewardship of manure storage involves two important steps:
Designing the facility so it has enough capacity to store manure and process wastewater generated by the farm plus precipitation plus freeboard (margin of safety) during time periods when land application is not possible or appropriate.
Operating and maintaining the manure storage or treatment facility so that problems can be identified and prevented or corrected before they cause overflows or failures.
There are several considerations when calculating the amount of capacity needed in the manure storage or treatment structure and planning for its operation and maintenance.
Regulatory requirements. For some farms, the minimum amount of storage capacity and freeboard as well as frequency of inspections is prescribed by regulation. Keeping records on design and construction, inspections and findings, maintenance activities, corrections made, and amount of manure or process wastewater in the storage structure is essential to prove the requirements are met.
Cropping system. Manure is not usually applied to fields between planting and harvest for cultivated crops. The amount of time fields are unavailable during the growing season should be factored into the planning for manure storage structures. Hay or pasture fields add some flexibility because manure can be applied more often. But, as with cultivated crops, hay or pasture fields should not have more manure nutrients applied than is agronomically indicated in the nutrient management plan. Farmers who rely on off-site manure transfers to neighboring farms or for other uses should also consider the cropping system or other timing needs of manure recipients and plan their storage period appropriately.
Climate. The design capacity of manure storage will be influenced by the amount of time that manure must be stored during extended time periods that are undesirable for land application. Those include times when soils are frozen, snow-covered, or saturated. Design capacity for uncovered manure storage structures also needs to consider how much rain or snow melt may add to manure levels.
Photo 13. (Above) This collage shows two depth markers in manure storage structures. The concrete structure on the left includes a simple rope (see orange arrow) marked at regular intervals as a way to monitor manure levels. The marker on the right is more elaborate and includes (recommended) a “start pumping” mark (yellow bar extending to the left). The especially important levels a farm manager should know are “start pumping” when the level reaches design capacity and, for some structures, “stop pumping” when it reaches a lower limit. It is also important to know the level to which manure should be pumped/emptied before entering a season where land application is not possible. If a state bans manure application from December 15 until April 1 for example, a farm should know which mark manure levels should be below to ensure enough storage capacity going into that season. Concrete structure image courtesy of Robb Meinen, Pennsylvania State University and metal depth marker image courtesy of Leslie Johnson, University of Nebraska.
Future plans. What are the chances a farm will add more animals in the future? Expanding to 1,500 animals when the manure storage is designed for 1,000 means the structure will fill up faster than originally intended, making unlawful spills or inappropriate land application practices more likely.
Figure 1. A schematic of the different categories of waste and the related volumes that the storage design must accommodate. More than just manure, process wastewater, or open lot runoff needs to be factored into the designed capacity. Anaerobic lagoons require a minimum volume at all times so that the bacteria treating the manure remain present and active. Some minimum storage level also helps keep the bottom sealed by preventing drying and cracking. Storage or treatment structures that do not have a roof or cover also need to hold typical rainfall or snowmelt for the area. Every storage structure storage should be designed and managed to maintain a margin of safety, or freeboard, so that it is never filled to the top. Figure courtesy of University of Missouri Extension via Dr. Charles Fulhage.
Photo 14. (Above) A manure storage structure about to overflow due to recent rainfall. This problem is most common when long winters or extended wet periods in the fall or spring make manure land application difficult or impossible. Managing this risk requires planning ahead as much as possible to prevent it. In this photo, the farm is agitating the manure and getting ready to apply it to a field to lower the manure level in the storage structure. Favorable weather conditions allowed application when field soil conditions were acceptable, or no longer saturated.
Consistency of Manure/Water Mixtures factsheet by Doug Hamilton (Oklahoma State University) explains the differences between solid, slurry, and liquid manure.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Reviewers: Tetra Tech, Inc.; Joe Harrison, Washington State University; Rick Koelsch, University of Nebraska; and Tom Hebert, Bayard Ridge Group
The animal agriculture industry is widespread across the U.S. with some areas having more of certain types of farms than others. The sectors highlighted in this module include dairy, beef cattle, layer chickens (eggs), meat chickens (broilers), and pigs.
The images below shows where each of the five highlighted sectors are located in the U.S. The darker colors on each map indicate more animals in that area. These maps are based on the most recent (2012) Census of Agriculture, which is conducted every five years by the USDA National Agriculture Statistics Service.
Trends In Animal Agriculture
The graphs below show data from the USDA Census of Agriculture from 1987 until the most recent one (2012).
For dairy and beef cattle, you can see clear trends showing that the number of animals is declining slightly but the number of farms is declining drastically. This means that the average farm with cattle in 2012 had many more animals than the average cattle farm in 1987. In each graph, the orange line represents the number of animals and the blue line represents the number of farms.
For pigs, the number of animals has increased slightly and the number of farms has decreased a lot. Like with cattle, this means that the average pig farm in 2012 had many more animals than the average farm in 1987. Chickens show a different trend in that the number of birds in the U.S. has increased but the number of farms has also increased.
How Much Manure Do Animals Produce?
The amount of manure animals produce varies greatly based on species; a dairy cow will produce much more manure than a chicken, for example. Two cows can excrete very different amounts of manure based on the feed they eat, their size, and age. The same is true of chickens and pigs.
The U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) estimates that for every 1000 pounds of body weight, most common farm animals will excrete between 60 and 80 pounds of manure per day (source). Based on those numbers a 1400 pound dairy cow will excrete 112 pounds of manure and a layer hen will excrete around 1/3 of a pound of manure per day.
The American Society of Agricultural and Biological Engineers (ASABE) released standard D384.2 “Manure Production and Characteristics” in 2005. Table 1 and Table 2 of that standard provide numbers that are similar to the NRCS manure production estimates. The ASABE standard estimates that a layer hen will excrete 0.19 pounds of manure per day and a dairy cow (weight not specified) will excrete 150 pounds per day.
The amount of manure an animal excretes is not necessarily the same amount that farms collect or store. For animals housed in open lots, manure dries considerably as it lays on the surface of the pen. For example, a feedlot steer may excrete 80 or 90 pounds of manure per day, but after that manure has dried on the pen surface, the farm may only end up with 8 or 9 pounds of manure to collect. The same goes for layer hen manure on manure belts or in storage structures.
For animals housed in barns with flush systems, the total volume will include animal manure, wasted feed and water, and water used for the flush system.
How Has Manure Management Changed?
In decades past, most farms handled manure as a solid* material, often mixed with bedding, and hauled the manure and bedding out to a field regularly, referred to as “daily haul”. Photos 1 and 2 (below) show what a daily haul system looks like.
Photo 1. (Above) A spreader being loaded with manure directly from the barn.
Photo 2. (Above) Spreading manure in a recently harvested field. Photos 1 and 2 are courtesy of Anne Cumbie Randle.
As farms have grown larger, and technologies improve, more manure is being handled as a slurry or liquid* — especially on dairy and pig farms. Beef cattle feedlots, and layer chicken and broiler farms mostly handle manure as a solid.
The volume of manure generated on many modern animal feeding operations necessitates storing manure in engineered structures. Manure storage has become a more visible feature on farms compared to past decades.
The primary purpose of storage systems is to provide a place to contain manure so that farmers can apply manure to fields at times when nutrients can best be utilized by crops and thereby avoid applying it to fields at inappropriate times such as when soils are frozen, snow-covered or saturated. Avoiding these times reduces the risk of runoff to water and soil compaction. Also, while not yet common, manure treatment systems that generate renewable energy or process manure for other value-added products start with storage.
* Solid manure is generally at least 20% solids and 80% or less moisture but can be stacked and piled. Liquid manure is usually 5% solids and 95% or more moisture. Slurry manure is in between. Both slurry and liquid manure are moved via pumps. (See Figure 1 on page 11 of LPES Lesson 20).
The Basics of Manure Management
The components of a manure management system include:
Collection. How much manure is produced by the animals on the farm? How will the farm gather manure for storage?
Storage. How will the manure be contained until it can be used or treated? Photos 1-3 below show some examples of manure storage.
Treatment. Not all systems are designed to include manure treatment. Treatment systems tend to be very expensive, but they can lead to new uses for manure or new revenue streams for the farm. Anaerobic or aerobic lagoons, composting, anaerobic digestion, vermicomposting, and thermal technologies are examples of manure treatment.
Transport. How will the manure be moved from the storage structure to the field or to its intended use?
Utilization. Manure has many beneficial uses. The most common use (by far) is land application as a plant fertilizer.
Photo 1. (Above) An earthen liquid manure storage structure. Ideally, this type of manure storage would have a marker installed that indicates when the liquid level reaches the maximum design limit (a depth that provides enough capacity to store the expected volume of wastewater plus a margin of safety in case of a large rainfall or prolonged period of bad weather that prevents pumping out to a field). Photo courtesy of Tetra Tech.
Photo 2. (Above) A storage area for solid manure. It is important that any runoff from this area is captured and contained. Photo courtesy of Saqib Mukhtar, University of Florida.
Photo 3. (Above) A concrete storage structure for slurry manure on a dairy farm. The ramp in the foreground allows access to remove accumulated solids.
A Look at Five Different Types of Animal Agriculture
Click on a photo to start a short virtual tour showing the outside, inside, and basic manure handling and storage practices on layer, beef, pig, dairy, and broiler farms. These tours discuss typical manure collection intervals and practices along with typical storage facilities and management. Links to additional resources are provided throughout the text and at the end of each tour.
For the fun activity below, use the scroll bar at the right of the frame to move down and show the “continue” or “submit” buttons if they do not appear.
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Reviewers: Tetra Tech, Inc.; Mark Risse, University of Georgia; Leslie Johnson, University of Nebraska; Bill Couser, Couser Cattle; Tom Hebert, Bayard Ridge Group; Glenn Carpenter, USDA NRCS; Joe Harrison, Washington State University; and Jace Thornton, National Cattlemen’s Beef Association
This module is an overview of animal agriculture in the U.S. and how industry trends have affected manure management. Because the primary use of manure is land application as a plant fertilizer, the module addresses nutrient management and surface water quality impacts. The module also covers regulatory requirements and efforts to manage and reduce risks of manure nutrients reaching water.
Economic pressures and consumer demands have driven a trend toward consolidation in the animal agriculture industry. This has changed the way manure is collected and stored. Virtual tours of layer hen, pig, beef, dairy, and broiler sectors are included.
Animal feeding operations collect and store manure in several ways with the largest differences being between those that handle manure as a “solid” and those that handle manure as a “slurry” or “liquid”.
Land application of manure requires specialized equipment and technologies that continue to evolve. This equipment and technology must be combined with nutrient management planning to ensure manure applications are from the right source, at the right rate and time, using the right methods, and in the right place.
Improperly managed manure can negatively impact water quality. This section focuses primarily on surface water and nutrients but other topics are briefly introduced.
Some animal feeding operations are regulated under the National Pollutant Discharge Elimination Program (NPDES). The NPDES program is part of the Clean Water Act.
As new information, tools, and resources become available, farmers have opportunities to continually improve environmental stewardship and manage risks related to manure and water quality.
This section highlights manure management, land and pasture management, and mortality management practices available for animal ag producers to practice conservation on their farm.
Acknowledgements Part I
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) with funding from the U.S. Environmental Protection Agency and with input from the Natural Resources Conservation Service, National Cattlemen’s Beef Association, National Milk Producers Federation, National Pork Board, United Egg Producers, and U.S. Poultry and Egg Association.
Many people contributed time, expertise, video, or images for the production of the three videos produced in this module.
Animal agriculture trends and manure management – Tetra Tech, Inc.; Mark Risse, University of Georgia; Leslie Johnson, University of Nebraska; Tom Hebert, Bayard Ridge Group; Bill Couser, Couser Cattle.
Manure nutrient management – Tom Hebert, Bayard Ridge Group; Tetra Tech, Inc.; Mary Berg, North Dakota State University; Mario de Haro Marti, University of Idaho; Mark Risse, University of Georgia; Leslie Johnson and Rick Koelsch, University of Nebraska; Bill Couser, Couser Cattle.
Managing manure to protect water quality – Tetra Tech, Inc.; Mark Risse, University of Georgia; Leslie Johnson, University of Nebraska; Tom Hebert, Bayard Ridge Group; Bill Couser, Couser Cattle.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise, were provided by Jill.
Acknowledgements Part II
These materials were developed by the Livestock and Poultry Environmental Learning Center (LPELC) and Eastern Research Group, Inc. with funding from the USDA Natural Resources Conservation Service through an interagency agreement with the U.S. Environmental Protection Agency.
For questions on these materials, contact Jill Heemstra, jheemstra@unl.edu. All images in this module, unless indicated otherwise are courtesy USDA NRCS.
A source of organic matter that improves soil quality and reduces soil erosion and runoff? OR A source of pathogens that limit the beneficial uses of surface water?
A means of recycling essential nutrients for crop production and reducing use of energy intensive fertilizers? OR A source of nutrients polluting surface and ground water?
A means of recycling and sequestering carbon in the soil? OR A source of gaseous emissions creating nuisance and air quality concerns?
Manure Benefits and Risks Depend on Location, Amount, and Timing
These above statements can all be true. Manure is a desirable plant fertilizer and has positive impacts on soil and soil health, but management decisions during land application influence the relative environmental benefit or risk resulting from manure. Timing, location, and amount of manure applied all must be carefully considered.
Manure application at amounts that match the nutrient requirements of harvested crops is the foundation of protecting water quality.
Preferred timing must balance multiple factors including timing of crop uptake of nutrients and probability of rainfall events following manure application.
Location must consider site specific field characteristics that influence environmental risks. Related Information: LPES Curriculum Lesson 33 and Lesson 34 include details on site selection.
Nutrient Management Plans
A nutrient management plan (NMP) is a document that spells out rate, timing, location, and other manure and fertilizer application factors. The two nutrients that are watched most closely, relative to water quality, are phosphorus and nitrogen.
An NMP for any farm generally follows the same outline. Regulated or permitted operations will have the most specific requirements. In some states, even small farms are required to develop NMPs. There is a great deal of technical assistance available for developing NMPs from extension, agencies, and private consultants. In some areas, cost-share assistance may be available. There are also many software tools available; one example is the Manure Management Planner Software. Since every state is different, it is recommended to look for state-specific resources and requirement before developing your NMP.
Amount of Manure to Apply
One of the first steps in developing an NMP is to estimate the amount of manure produced on a farm. Some other important pieces of information include: nutrient content as determined by a manure test (Related information: Sampling Manure) and the availability of nitrogen from that manure (consult your state extension service to obtain calculations on nitrogen availability appropriate for your area). Last, but not least, it is important to calibrate manure application equipment to ensure that you know how much manure was actually applied to each field.
Location, Location, Location
Manure application should be set back from wells, streams, lakes, sinkholes, or other environmentally sensitive features. Most states have rules dictating exactly how farm this setback should be.
Tile-drained fields should also receive special consideration with regard to manure application. If manure is applied while soils are saturated or right before a rainfall event, the manure may preferentially flow through tile drainage to water bodies.
Manure application in spring, shortly before crops are planted, is generally recommended as it allows a short window where nutrients are prone to leaching or runoff. When manure is applied to fruit or vegetable crops, this recommendation may differ.
Manure application during crop growth will closely match nutrient needs, but can be destructive to the growing crop. One way to avoid crop damage is to apply liquid effluent through irrigation systems. (Also see Ohio research on top-dressing liquid swine manure to wheat and side-dressing on corn).
Applying manure in the fall, after the main crop is harvested, is a common practice and helps ensure manure storage structures are emptied before winter–reducing the chances of a overflow. Given the high price of fertilizer and the increased awareness of water quality, more farmers are following fall manure application with a cover crop.
Winter manure application is a controversial topic in many areas. Manure applied to snow-covered or frozen soils may be more likely to runoff under some conditions. Winter applications should only be made in order to prevent a manure storage overflow and should be done in low-risk areas with little slope or potential for runoff to water.
Evaluating if Nutrient Management Is Working
Whole Farm Nutrient Balance (WFNB) is a way to evaluate if the farm is currently accumulating more nutrients than are being exported from the farm. If this analysis is repeated from time to time, the trend can tell if a farm’s efforts are working or not. This website includes a dairy example and a swine example of WFNB.
Page Manager: Becky Larson, University of Wisconsin ralarson2@wisc.edu and Nichole Embertson, Whatcom Conservation District nembertson@whatcom.com
Reviewers: Rick Koelsch, University of Nebraska, Doug Beegle, Pennsylvania State University, Ron Wiedreholdt, North Dakota State University.
Photo: CC 2.5 Rick Koelsch
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Photo 3. This local conservation district office is located in the same building as the local USDA service center.
