Throughout history, people who raise livestock and poultry have used manure as a fertilizer, soil amendment, energy source, even construction material. Manure contains many useful, recyclable components, including nutrients, organic matter, solids, energy, and fiber. With today’s technology, manure can be used more efficiently and in more ways than ever, which should mitigate many of the environmental impacts that result when manure is treated as a waste.
If you want to learn more, please visit our website.
Farmers, gardeners, landscapers, and others commonly use livestock manure as a fertilizer to provide nutrients needed for crop production. Manure nutrients have real value as fertilizer. Manure’s fertilizer value will increase as the price of commercial fertilizers increase.
Like commercial fertilizer, manure must be managed properly to avoid environmental impacts. Manure has fertilizer value in its raw form; however, processing manure through digestion, composting, or other means can yield materials that are more portable and whose nutrients are more available to plants, more balanced to crop needs, or less prone to environmental losses.
Using fresh manure as a fertilizer to raise crops that will be fed back to the livestock, either directly or as a by-product of further processing, is an excellent way to recycle nutrients. Ideally, fresh manure would be used on the farm where the manure is generated or on a neighboring farm, because fresh manure is expensive to haul even short distances.
Livestock manure is commonly land-applied as a semi-solid or liquid. Farmers can incorporate manure into the soil or inject it under the soil surface to reduce the risk of runoff losses and odor problems. Sometimes manure solids are separated from the liquid. Following liquid/solid manure separation, the remaining manure liquids still contain about half of the original nutrients. The solids can be used for bedding or for other uses and the liquids can be land applied to both water and fertilize crops.
Farmers are the most common users of fresh manure for fertilizer, but home gardeners and landscapers also sometimes fertilize with fresh manure.
Composting livestock manure reduces odors, kills disease-causing agents (pathogens), reduces bulk, and stabilizes the manure for easier handling. A properly constructed and managed manure composting operation can also process mortalities (dead animals) from livestock operations. In some parts of the country, composting operations must be intensively managed to guarantee pathogen-free compost that meets requirements of both health regulations and public perception.
Compost can be applied more evenly and with better control than manure. The nitrogen in compost is not as readily available to plants as the nitrogen in fresh manure, but the availability of phosphorus, potassium and other nutrients from compost is similar to, or higher than, the availability of those nutrients from fresh manure.
Farmers and ranchers can use composted manure at their own operations as fertilizer or bedding. Sales of compost can remove excess nutrients from farms and ranches that cannot use all of their manure nutrients for their own needs.
Compost is less expensive to transport than fresh manure due to its lower moisture content, and more profitable to transport because of its higher market value. This means that compost has more potential for use in areas farther from the farm. Manure compost can be used for many purposes in non-agricultural areas, including site restoration, erosion control, soil remediation, and wetland restoration.
Compost users include gardeners, landscapers, vegetable farmers, turf growers, golf course managers, ornamental crop growers, and homeowners. More information about manure composting is available from numerous sources, for example:Pelletizing compacts fresh manure at high temperature and pressure to convert it into a dry finished product. Pellets are useful as a soil amendment or fertilizer. Because the pellets take up a smaller volume, they can be more easily stored and transported than manure. In some cases, processing can result in a product with a consistent and predictable nutrient content, making it more convenient for crop production and other uses. The pelletizing process is mainly used for poultry litter but could be applied to separated solids from other manures.
Nutrient extraction technologies, or manure nutrient recovery technologies, can remove nutrients from manure for fertilizer products. Nutrient extraction removes elemental nutrients from raw manure, separated liquids, or residuals of anaerobic digestion by chemical precipitation or coagulation. Examples of fertilizer products that can be generated with nutrient extraction systems are ammonium sulfate, calcium phosphate, and magnesium ammonium sulfate (struvite) crystals.
Bioconversion involves growing organisms on manure or manure nutrients and then harvesting them to use as components of animal feed, fertilizer, or soil amendments.
Algae grown on nutrients from dairy wastewater can be harvested to produce a product used in plant fertilizers
and high-protein animal feed supplements. Black soldier fly larvae eat manure, killing disease-causing agents (pathogens) and transferring the manure nutrients to their bodies. The nutrient-rich larvae are a value-added product that can be exported off the farm. High protein feeds made with products like these can be worth up to $500 per ton. The manure left over after the larvae are harvested is useful as a soil amendment or fertilizer similar to compost.
Vermicomposting uses worms to digest manure, creating pathogen-free, nutrient-rich products that can be sold and
exported off the farm. Worms produce nutrient-rich castings. The castings, along with the manure used to grow the worms, are useful as a fertilizer or soil amendment. This vermicompost is said to contain more available plant nutrients than conventional compost. In addition to the revenue from selling the vermicompost, the worms can be sold as fishing bait or processed for supplemental feed for poultry or fish operations.
Farmers, gardeners, and others use livestock manure as a soil amendment to improve soil quality. In addition to providing nutrients for plant growth, applying fresh or composted livestock manure to cropland improves soil organic matter and tilth (the physical conditions that make a soil suitable for growing crops). Applying livestock manure to cropland increases the amount of organic matter in the soil which improves the soil structure and can increase the soil’s ability to hold water.
Increasing soil organic matter also helps keep carbon in the soil (“carbon sequestration”) and out of the atmosphere where it can form the greenhouse gas carbon dioxide. Manure provides these benefits when it is applied in raw form or when solids are applied after solid-liquid separation, pelletizing, digestion, or composting.
Some dairy farms use sawdust, wood shavings, straw, sand, or other purchased materials as animal bedding. Bedding can be expensive—on the order of $40 to $50/cow/year. In recent decades, traditional bedding materials like sawdust or sand have become more expensive. Solid material can be recovered from manure (through solid-liquid separation, composting, or anaerobic digestion) and used as bedding, replacing materials purchased from off the farm.
Dried manure solids can be used for bedding without adversely affecting herd health.Biogas recovered from anaerobic digesters is useful for generating heat or electricity to use on the farm or sell to the local power grid. Biogas production usually uses dairy or swine manure because of their relatively high methane producing potential. However, some digesters in the U.S. use beef manure or poultry litter as feedstocks.
Gas from anaerobic digestion is about 60 to 80 percent methane and has a heating value of 600 – 800 BTU/ft3. (As a comparison, natural gas generally contains more than 85 percent methane and has a heating value of about 950 – BTU/ft3). Most equipment that uses natural gas, butane, or propane as fuel can be modified to use biogas. This includes boilers, space heaters, and electrical generators.
Because digesters capture methane and other air pollutants, they reduce harmful air emissions from manure and provide superior odor control. Using biogas from digesters also offsets fuel consumption and emissions from non-renewable fossil fuels.
Anaerobic digestion to produce biogas (as well as other types of energy products and technologies) usually needs to operate on a large scale to be economically feasible. Anaerobic digestion can be technically complex and can be too expensive, especially for small operations. The process can be more affordable if manure is co-digested with off-farm wastes (such as green waste and food waste).Liquid bio-oil fuels can be produced from manure by thermochemical processes like pyrolysis and gasification. Bioconversion, such as growing algae with manure nutrients, is another process that can produce bio-oil.
Bio-oils are physically different from petroleum-based fuel oil. For example, bio-oils have a lower energy content per gallon and higher acidity than petroleum-based fuel oil. However, tests indicate that bio-oil could be used for applications such as heating or generating electricity.
Commercial experience with biodiesel has been very promising. Biodiesel performs as well as petroleum diesel, while reducing air emissions of particulate matter, carbon monoxide, hydrocarbons and sulfur oxides.
Most production of biodiesel from thermochemical processes involves poultry litter because it is already dry and does not require additional energy inputs for drying wet manure.Gasification can covert manure (at present mainly poultry litter) into a synthetic gas fuel composed of a mixture of water vapor, tars, hydrogen gas, carbon monoxide, carbon dioxide, nitrogen gas, and hydrocarbon gases. Some of the gas condenses to form a combustible bio-oil. The remaining gas can fuel a variety of power systems including reciprocating engines, gas turbines, and fuel cells.
It is possible to produce specialty value-added products from livestock manure for marketing to consumers based on the fiber content of the manure. For the most part, the examples given below are either experimental or done on a boutique scale. Most involve extracting and using the solid fiber from manure.
Sifeng supply professional and honest service.
Good manure management starts with recognizing and understanding the value of manure as a resource that contains nutrients for crop production as well as the potential negative impacts manure can have on air, water, and soil. This publication outlines the general guidelines about managing livestock and poultry manure and provides a list of resources with detailed information on specific topics of good practices for manure management and use.
Manure is commonly used as a fertilizer and as an amendment to improve the quality of the soil. When manure is applied and managed properly according to the agronomic needs of crops, manure will improve crop productivity and reduce the demand for commercial fertilizer (see Phosphorus, Agriculture & the Environment, Virginia Cooperative Extension [VCE] publication 424-029; and Impact of Changing From Nitrogen- to Phosphorus-Based Manure Nutrient Management Plans, VCE publication 442-310). Managing manure to provide balanced nutrients that can be used as fertilizer may require that some nutrients be removed, conserved, or concentrated. For example, if the nitrogen (N) to phosphorus (P) ratio in the manure is one-to-one (1:1) and the agronomic requirement for these nutrients by a crop is four-to-one (4:1), meeting the agronomic needs of the crop using manure may require that some phosphorus be removed. Also, knowing that nitrogen can be lost from manure through volatilization of ammonia, it may be necessary to use management practices that will conserve nitrogen in the manure. If manure must be transported for long distances, it may be important to concentrate the nutrients to reduce the volume of water that has to be transported with manure in order to reduce transportation costs.
Nutrients can be recovered, conserved, or concentrated in manure through one or a combination of physical, chemical, or biological methods (see Selecting a Treatment Technology for Manure Management, VCE publication 442-306). Crops usually need more nitrogen than phosphorus; therefore, it would be beneficial to concentrate the nitrogen and remove the excess phosphorus from the manure to get the full benefits of manure using nutrient-recovery technologies that involve chemical, biological – or a combination of both – methods and a manure-separation system.
If handled properly, manure can be used to produce biogas that can be used as an alternative energy source (see Biomethane Technology, VCE publication 442-881). The biogas can then be used to produce electricity, hot water, steam, and/or transportation fuels. The quantity and quality of gas produced will depend on the digester design, operating temperature, and the type and quality of manure fed to the digester. Animal manure can also be subjected to the process of pyrolysis to produce char, oils, and gas. The oils and chars can be used for fuel or further processed to produce value-added products, such as plastics. Other considerations are to burn dried or solid manure in combustors or gasifiers to produce heat.
Animal manure can also be used for yeast and algae production, which can then be used to produce animal and fish feed and biofuel (see Microalgae as a Feedstock for Biofuel Production, VCE publication 442-886). Manures can also be used in the production of mushrooms or composted to produce a weed- and pathogen-free, high-quality soil amendment.
Water quality is everyone’s concern and it is important to remember that poor nutrient management can lead to water quality problems. The EPA reports that manure from animal agriculture is one of the major sources of contamination of our water supply. Manure contains nitrogen, phosphorus, organic matter, and pathogens that are considered four primary contaminants that affect water quality. These pollutants may enter water resources by runoff, leaching, and deposition from the atmosphere. Nutrients from the atmosphere may be deposited on land through precipitation (rain and snow fall) or dry deposition. These contaminants may increase the cost of treating the water for domestic and industrial uses.
Nitrogen is one of the basic components of proteins, which is a part of all living things. Nitrogen is usually provided to animals via feed. Animals use only part of the nitrogen in their feed to produce meat, milk, or eggs and for body growth and maintenance. The remaining protein is excreted.
Nitrogen in manure exists in two forms that can be described as inorganic or organic. The inorganic forms include ammonia, nitrate, and nitrite. The organic forms include urea, undigested proteins in manure and feed, and other animal waste products such as hair and feathers. The inorganic forms readily cause pollution when compared to the organic forms. However, when the organic forms of nitrogen decompose, ammonia is produced. Ammonia can be transformed into nitrates and nitrites when oxygen is provided to the manure. Ammonia can easily be lost to the atmosphere from the manure by volatilization. Different forms of nitrogen present different risks to water quality. Ammonia concentration exceeding 2 parts per million (ppm) can lead to fish kills. Nitrates above 10 ppm in drinking water may cause blue baby syndrome when consumed by infants. Excess nitrogen can cause eutrophication of surface-water resources.
Phosphorus is an essential nutrient to plant growth and development. Animals require it for bone development and optimum production. Animal manure that is land-applied to supply nutrients for crop growth typically does not match the nitrogen-to-phosphorus (N:P) ratio required by crops. Consequently, if manure is applied to satisfy the nitrogen requirements of a crop, phosphorus is over-applied and the soil phosphorus levels can increase (see Soil Test Note No. 5: Fertilizing with Manures, VCE publication 452-705; and Phosphorus, Agriculture & the Environment, VCE publication 424-029). When soils become saturated with phosphorus, the potential for losing it in runoff water increases. Phosphorus typically moves with water runoff and soil erosion. It can be attached to minerals containing iron, aluminum, and calcium or to organic matter such as crop residue, bacteria in the soil or manure, or decaying organic matter.
Pathogens include microorganisms such as viruses, bacteria, and protozoa that cause infection or disease. Disease-causing microorganisms may be present in manure. Therefore, it is important to maintain adequate separation between the potential source of pollutants and water sources. Pathogens are most likely transported to water with surface runoff and erosion or by direct animal access to surface water. Streams and lakes used for drinking water and recreational purposes provide the greatest opportunities for transmitting these pathogens. Human beings may be infected if they consume crops irrigated with untreated manure that contains pathogens.
Organic matter in manure can be a valuable environmental resource if managed properly; however, if manure reaches a water body or moves off-site by water runoff, organic matter can become a harmful pollutant. Organic matter can come from manure, silage leachate, and milking center wastewater. Organic matter degrades rapidly in water and may result in oxygen depletion in bodies of water. Organic matter is transported into water by surface runoff. Rarely does organic matter leach through the soil.
Manure handling, storage, and utilization in livestock and poultry production results in a wide range of air emissions, which may create air quality concerns. The airborne emissions from livestock and animal production systems include hazardous gases, (e.g., ammonia [NH3] and hydrogen sulfide [H2S]), odor, dust, and greenhouse gases (e.g., methane [CH4], nitrous oxide [N2O] and carbon dioxide [CO2]). Dust is generated from regular farm traffic, land preparation, and other crop production activities, as well as from livestock and poultry barns with ventilation exhaust air. The concerns from these emissions include odor, atmospheric visibility, and respiratory health issues (see Ammonia Emissions and Animal Agriculture, VCE publication 442-110).
Odorous compounds are commonly considered to be unpleasant or nuisance experiences by neighbors. Neighbors sometimes relate or determine odor nuisance by a number of factors, including frequency and duration of occurrence; intensity of the odor experience; social factors, such as past experience with agriculture and relationship with the producer; and appearance of the production facility. Some neighbors may have strong emotional reactions and possible health-related issues to livestock- and poultry animal-related odor. Their concerns should be taken seriously. Ammonia released into the atmosphere is a loss of fertilizer value of the manure nitrogen. It may also result in formation of particulate matter that contributes to haze in the atmosphere. If the particulate matter is deposited back on land or on surface water, it may lead to area nitrogen enrichment and cause pollution. Livestock production is a source of greenhouse gases, and greenhouse gases contribute to global warming.
According to the EPA, “Environmental stewardship is the responsibility for environmental quality shared by all those whose actions affect the environment.” Some good manure management and environmental stewardship principles that may be of benefit to livestock and poultry producers are summarized below.
Familiarize yourself with your operation’s potential environmental impacts by conducting an evaluation to determine the highest-risk situations or practices on your farm. Develop plans and invest resource to address the high-risk situations, e.g., handling manure emergency spills and manure storage failures. Your local Extension office, the soil and water conservation district office, and the National Resources Conservation Service may provide you with information on how to perform this task.
Animal producers should set a goal to balance nutrients on their farm and also manage soils in ways to minimize nutrient losses. Nutrient balance should consider what is coming into the farm as purchased feed and fertilizer and the nutrients leaving as managed products, such as crops, animals, or animal products. An example of nutrient flow in a farm is provided in figure 1.
If the nutrients coming into the farm are more than what leaves, this will result in an accumulation of those nutrients on the farm. To correct the nutrient concentration, consider a whole-farm approach rather than focusing on a small part of the production, such as nutrients in manure and their losses to the environment. Understand the big picture by identifying the underlying cause of nutrient concentration and develop effective solutions to address the critical areas for better utilization and management of nutrients on your farm.
Recycle nutrients between livestock and crop components within the boundaries of the farm. Manure nutrients are recycled as fertilizer for crop production. Crops are then cycled as feed to livestock or poultry. Nutrients leave the farm as products, i.e., animals or crops products such as milk and eggs and manure sold or given away for use outside the farm. These nutrients are sometimes referred to as “managed outputs.” Some nutrients will leave the farm as environmental losses, e.g., nitrogen lost to the atmosphere as ammonia, nitrates to groundwater, and nitrogen and phosphorus in surface-water runoff.
Use manure according to a nutrient management plan. The nutrient management plan should maintain a balance between nutrient application and crop use and the needs of that nutrient. Test manure to know its nutrient content. Test soils to establish existing soil fertility levels to know what is needed for the different crops you grow (see Soil Test Note No. 1: Explanation of Soil Tests, VCE publication 452-701; Soil Test Note No. 2: Field Crops, VCE publication 452-702; Soil Test Note No. 3: Forage Crops, VCE publication 452-703; and Soil Test Note No. 4: Trace Elements, VCE publication 452-704).
Apply manure at uniform rates based on crop nutrient needs while avoiding soil contamination, crop damage, and runoff (see Soil Test Note No. 5: Fertilizing with Manure, VCE publication 452-705). Adjust the rate of supplemental fertilizer to compensate for the nutrients applied in the manure. Keep records of all your activities.
Use of manure and fertilizer as nutrient sources for crop production must be managed properly to ensure that they do not contaminate groundwater or surface water. Check soil moisture before applying manure and adjust application rates to avoid runoff. Limit the volume of water applied to an amount that brings the soil to field-moisture capacity. Do not apply manure to saturated soils. Incorporate raw or untreated manure to reduce odors and nitrogen losses. Calibrate application equipment to obtain the desired application rate.
Animal production creates several potential nuisances, including odors, flies, noise, and dust. You need to be fully aware of these nuisances and your neighbors’ possible concerns. The demographics of rural areas (where farming has traditionally occurred) are changing and what used to be exclusively rural areas are becoming urbanized. Public awareness of environmental issues is changing. As a result, farm-neighbor conflicts are increasing around the country. Nonfarm communities complain that farming activities near their homes affect their quality of life. Increasingly, farmers are being forced to consider social as well as air-quality concerns in developing manure management plans. Following are some reminders of good practice as part of your manure management strategy:
We have numerous and diverse neighbors. Some are long-term residents who farmed in the area and are now retired. Some are the result of urban sprawl. Some live in communities within the city limits but next to agricultural land. Schools, churches, hospitals, and golf courses are also some of your neighbors. It is interesting to note that some nonfarm community members are buying former farms and moving into the country, seeking “fresh” air. The bottom line is that urbanization of rural areas and consolidation of livestock farms often lead to tense relationships between farmers and nonfarming neighbors. It is important to recognize this fact and to proactively pursue ways to deal with it. How you handle business on your farm may impact how you resolve conflicts related to your farm.
Large numbers of animals concentrated near nonagricultural residents will produce odor and visual issues related to confined-animal feeding operations. With the changing demographics, rural roads may start experiencing aggressive drivers who do not appreciate or recognize the slower farm traffic. With the hectic pace of life there may be little, if any, communication between the farmer and neighbors. This can create situations for misunderstanding and a greater likelihood that conflicts will occur. Sometimes common ground and mutual agreement is not realized until later. Do not let issues concerning your manure management get out of con- trol. Be proactive in talking to your neighbors. Implement responsible farm management practices while conducting activities that promote the benefits of the farm to neighbors and the community.
There are a variety of outreach efforts you may want to consider to enhance the perception of the farm among neighbors and the larger community. Accept visitors to your farm as your schedule will allow and within the bounds of biosecurity. Tell visitors what you do and why you do it. Visitors should include all ages and groups. If possible, provide neighbors with sample farm products, assist with or volunteer to mow brush in the summer, plow snow in the winter, and consider allowing access to areas of the farm for recreational activities. Let your neighbors know about your farming operations and activities. This should include the manure application schedule. If neighbors have special events occurring at their homes on certain dates that may be impacted by a farming operation, such as land application of manure, work with them to reschedule that operation. Note: Outreach to community, open houses, and neighborly assistance can help cultivate open communication and understanding between the farming and nonfarming communities.
Before embarking on new projects or expanding existing enterprises on the farm, arrange to meet with the local authority boards to show them your plans and solicit questions and comments. After finishing the project, hold a neighborhood barbecue and tour to meet the neighbors; show them what you do and why. It is more difficult to carry a disagreement with someone you know and are friendly with or who has made a first move to get to know you.
When planning farm operations that will impact people in the area (e.g., spraying liquid manure next to a school, church, or golf course), communicate and explain the operation ahead of time. Plan the operation at a time that causes the least disruptions to the other parties. Remember, people are much more accommodating if issues are addressed ahead of time, even if it is something they do not particularly like. In most cases, people will give you more latitude with something they do not like if you make a good faith effort to deal with their concerns about your farming operation.
Many times people tend to smell with their eyes more than their noses. It is therefore extremely important to have a neat facility, clean animals, well-tended crops and buildings, and machinery in good repair. Yards around barns and along the road and ditches should be mowed. It is not always possible to prevent all farm odors, but if people are presented with the picture of a clean, orderly, well-managed farm, they will tolerate more actual odor than from a farm that looks untidy (figures 2 and 3).
For more Manure Handling Systeminformation, please contact us. We will provide professional answers.