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Agricultural
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Arbor Day
Dale Bumpers College
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Improving Management of Animal Production WastesAnimal Waste Management • Location of storage and treatment facilities • Transfer of animal waste from storage to utilization • Location of land application areas • Waste Application Rates & Regulations • Calibration of waste application equipment • Animal liquid waste regulations • Combining dairy wastes • Storage facilities • Land application • Milking center wastewater • Livestock yards and holding areas • Silage storage • Dead animal disposal The benefits of properly managing wastes from animal production are both economic and environmental:
If improperly managed, wastes generated from animal production can:
1. Animal waste management plans An animal waste management plan (AWMP) is designed to effectively use animal waste in an environmentally safe manner. Any situation where the waste is not effectively managed gives rise to potential pollution from animal waste. Livestock waste can be a source of nitrates and fecal bacteria in groundwater. Runoff of phosphorus can cause excessive aquatic growth in surface water. Not only should animal waste and proper disposal be a concern, but other practices associated with animal production should also be considered, such as silage storage and handling of milking center wastewater. A sound animal waste management plan begins with the kind and number of animals in the farm operation and includes every aspect of waste handling. Between the time waste is produced and the time when it is finally utilized, there are several important steps:
Animal wastes are either solid, semi-solid, slurry, or liquid in physical consistency. The specific method by which any of the above management steps is carried out depends partly on the type of animal operation and the physical consistency of the materials handled. For example, liquid wastes from dairies and swine operations will generally be stored in lagoons, and at least some of the waste transfer will be accomplished by pumps or by gravity flow. A good AWMP will include:
For more information and assistance in developing your waste management plan, contact your county Natural Resources Conservation Service (NRCS). 2. Location of storage and treatment facilities The location of a new facility in relation to existing water supplies is an extremely important factor in protecting the safety of your drinking water. If it is possible, locate new animal confinement facilities with plenty of separation between your wellhead and potential contamination sources. There are specific regulations for minimum separation of waste storage and treatment facilities from wells, surface waters, sinkholes, property lines, and dwellings. Try to exceed these minimum standards whenever possible, and always try to install new facilities downslope from any water supplies. 3. Transfer of animal waste from storage to utilization Waste collection and transfer are necessary even when wastes are not stored or treated on the farm. Repeated spills are potential sources of water contamination. Farm animal wastes are valuable because of their high concentrations of nitrogen, phosphorus, and potassium and because these nutrients are readily available for plant use. For the same reasons, unprotected or spilled wastes during collection and transfer threaten ground and surface waters in the same way that unprotected or spilled fertilizers do. Even relatively small amounts of spilled wastes can threaten your water supply if repeated spills occur in areas above shallow, porous soils or if they occur upslope from the wellhead. Similar pollution hazards exist from storage or treatment lagoon overflows. Leaks from improperly designed or poorly connected irrigation lines have to be avoided. Care must be taken to prevent spillage of animal waste materials when traveling down public roads. Keep litter trucks covered with a tarp during transfer, and avoid leaks and spills from manure spreaders onto road areas. 4. Location of land application areas The AWMP specifically identifies the areas where treatment or storage facilities, such as lagoons, stacking sheds, or compost facilities, will be located. The plan also identifies the locations, acreage, and crops to which any animal wastes are to be applied. Land application areas should have less than 15 percent slopes, and applications should not be made within 25 feet of rock outcrops. There should be at least a 100 foot wide buffer zone between the application area and the nearest pond, stream, or waterway. Waste materials should not be applied within 100 feet of the wellhead unless care is taken to ensure that application rates do not exceed the plant nutrient requirements in this area. Applications on frozen or saturated soils should also be avoided. The application areas and crops must be able to accommodate the nutrient loads of the applied wastes with minimal contamination of local ground and surface waters. The amount of waste applied and the timing of application are both important to realize maximum fertilizer value and to avoid water contamination. An owner may have plenty of land for application of animal wastes, but some of it may be located a great distance from the beef, dairy, swine, or poultry confinement facilities. The practice of spreading animal manures on only the nearest field can result in excessive nutrient loading rates to the soil and possibly cause water quality problems. At this writing, there are no regulations limiting dry manure (poultry litter) land application. However, it is strongly recommended that no more than 2.5 tons per acre be applied per application and that the total not exceed 5 tons per acre per year. The best application rate depends on the crop and on the nutrient content of the soil before the application is made, as well as on the nutrient content of the waste material. Soil testing and manure nutrient analysis are recommended procedures for best determining animal waste application amounts. Garden areas are often a potential threat to water sources when they receive almost yearly applications of manure. Garden soils should be tested and receive manure according to soil test recommendations to avoid becoming a source of water pollution due to over-application of manure or commercial fertilizer. The groundwater recharge areas for many Arkansas farm wells include both on-farm and neighboring farm fields. Excessive application of animal manures to croplands may threaten your neighbor's water supply, even if it doesn't affect your own. 6. Calibration of waste application equipment Calibration of waste-spreading equipment, such as irrigation systems for liquid wastes and mechanical spreaders for solid wastes, is needed to ensure safe and efficient distribution of waste materials. For more information about calibration of waste-spreading equipment, contact your county Extension office. 7. Animal liquid waste regulations Manure and other wastes from swine, dairy, and poultry layer operations are often handled as liquids. These materials are collected in storage ponds until they can be efficiently used as fertilizers. Some operations have lagoons that biologically treat the wastes before they are utilized as fertilizers. In some facilities, the treated wastewater is recycled to the confinement house and used in the manure flush system as washwater. Settling ponds may be used to separate out much of the suspended solids before water enters a storage facility, lagoon, or holding pond. This liquid handling system results in large volumes of nutrient-rich liquids being held on farmsteads throughout much of the year. These nutrients can be very valuable to the farmstead if properly managed. The safety of the farmstead water sources depends on the design, operation, and maintenance of these liquid waste handling facilities. Leaks, overflows, or any other uncontrolled discharge from these facilities can possibly pollute the farmstead water sources. The holding pond or lagoon drawdown schedule and the land application plans for liquid storage facilities are critical to the success of these waste management systems and to the protection of ground and surface waters. Arkansas liquid animal waste facilities and management systems are under the jurisdiction of the Arkansas Department of Pollution Control and Ecology (ADPC&E) through their Regulation No. 5, "Liquid Animal Waste Management Systems." Both the facility design and the overall plan for pumping and utilizing liquid wastes must be approved by the ADPC&E before an operating permit can be obtained. These permits are approved upon certification of adequate construction by the Natural Resources Conservation Service (NRCS). The general areas of Regulation No. 5 are as follows:
Besides the areas listed above, there are additional regulations that address:
Dairy operations that handle the manure in a slurry form may consider combining milking center wastes with the manure. This has the advantage of allowing a common storage location for both types of waste. A liquid manure storage facility, properly constructed and sized, provides the flexibility of storing wastes until they can be applied at a desirable time to the correct sites. Applying milking center wastes with manure to fields at rates that do not exceed crop needs for nitrogen does not increase the risk for water contamination. Care must be taken, however, to keep soil phosphorus levels from accumulating to levels that will harm crops. These precautions also apply to land applications of swine and poultry liquid wastes. This is best accomplished by routine soil testing. Ponds and lagoons provide storage and biological treatment and prevent ground and surface water contamination when they are properly designed, constructed, and maintained. The stored wastes can be applied to croplands and pastures by portable irrigation equipment or a liquid manure spreader (honey wagon). Agitation prior to hauling is recommended to get a uniform consistency and nutrient concentration over land application areas. Groundwater contamination can occur if a liquid storage or treatment facility allows waste materials to seep into the soil. A threat to surface water exists if pits are not emptied frequently enough, allowing wastes to flow over the top of the structure. Liquid storage systems require the use of pumps and pipes for moving wastes. These must be carefully installed and maintained to ensure that they do not leak. After a period of years, freezing and thawing, as well as wetting and drying, may cause the sidewalls of earthen basins to crack and erode, allowing wastes to seep into the underlying soil and possibly into the groundwater. While seepage from in-ground waste storage facilities is not always easy to recognize, there are some tell-tale signs: A properly designed structure has the capacity to handle wastes from a specific number of animals for a known number of days. If a pit designed for 180 days' storage is receiving designated waste amounts but has not needed pumping for a year, the pit is almost certainly leaking. Evaporation from liquid storage pits is minimal, particularly with manure from dairy cattle, which forms a crust when it is stored. If additional liquids have to be added before the pits can be agitated and pumped, they may be leaking. If any problems with deterioration or leakage of storage facilities are suspected, the Natural Resources Conservation Service (NRCS) office should be contacted for assistance on correcting the situation. Storage facilities are going to stink, but frequent occurrences of very foul odors from a pond or lagoon are an indication that the treatment process is not working properly. Temporary foulness can result from a change in the rate wastes are being delivered to the pond or lagoon, but persistent foulness should be investigated. Unfortunately, there is not enough knowledge available on odor control, but a system that is being managed according to a waste management plan should have fewer problems. At this writing, there is no recommended additive or chemical for controlling odors. 10. Land application The two common methods for land application of liquid animal wastes are: (1) liquid manure spreaders honey wagons and (2) sprinkler irrigation systems. Honey wagons are relatively inexpensive, but they can require several trips to the field since they generally carry only 1,000 to 2,000 gallons. This can cause problems in keeping up with pumpout schedules and achieving most efficient use of the nutrients. Sprinkler irrigation systems have several variations (hand-move system, towed big gun sprinkler, traveling big gun, etc.), but each includes a pump, pipe, and sprinkler(s). These systems can be relatively expensive, but they usually require less time and labor than a honey wagon. If field application areas are long distances from the storage facility, then a significant amount of pipe will be required. Applications from either of these systems are generally more uniform in material consistency and nutrient concentration if the material is agitated before hauling or during sprinkler pumping. There are many different sprinkler and agitation options to consider, and each operation has a little different situation that makes it impossible to adequately cover the options in this writing. Assistance on sprinkler irrigation systems can be obtained through the county NRCS and Extension offices and through irrigation equipment dealers. Regardless of the application system used (honey wagon, sprinkler, custom applicator), there needs to be some method of calibration and record keeping to determine the amount of material applied to an area. Also, the best recommendation for odor control during application is to practice the "good neighbor policy." Try to avoid application during windy conditions and take note of the wind direction and who it might affect by carrying odors. Avoid applications near dwellings and try to schedule when neighbors may be gone. The county NRCS and Extension offices can provide more information on calibration and may be able to make other recommendations related to odor control. Dairy operations with 50 milking cows will produce 100 to 1000 gallons of milking center wastewater per day. This wastewater volume contains approximately 150 pounds of nitrogen per year. Improper disposal of wastewater may cause groundwater or surface water contamination. Dairy wastewater can be combined with liquid manure in a liquid manure storage facility for later application to the land using irrigation equipment or a liquid manure spreader. If the manure is handled dry, rather than in a liquid handling system, then the milking center wastewater is usually handled separately. A common method is to use a septic tank and soil absorption field (drainfield) for disposal of the milking center wastewater. Any septic tank system should be properly designed and installed according to Arkansas Department of Health Regulations. See Fact Sheet #6, "Household Wastewater Treatment." 12. Livestock yards and holding areas Livestock may spend from just a few hours to all day in a livestock yard or holding area. The amount of animal waste accumulation in an area is determined by the amount of time the animals are present. The animal waste produced in these areas has the potential to cause groundwater or surface water pollution by leaching or runoff. In addition to the water pollution potential, "pollution of the air" may also occur from odors associated with the livestock waste. Proper management of livestock yards, confinement facilities, and holding areas will help reduce potential water quality and odor problems. Surface water diversion A primary concern with livestock yards and holding areas is controlling the movement of nutrients off the lot. Excess water, such as water from barn roofs, paved surfaces, and runoff from surrounding farmstead areas, needs to be either collected or diverted away from the livestock yard. Water from roof areas surrounding the livestock yard could be collected by gutters and diverted away from accumulated or stored wastes. Runoff water from surrounding areas should be diverted away from the livestock yard with berms, dikes, grassed waterways, or ditches. Runoff water from the livestock yard should not be allowed to run directly into streams, lakes, or ponds. The runoff water should be collected and applied to cropland areas or directed to vegetative filter strip areas. Paved areas Manure on paved areas should be removed as often as possible and properly applied to the land in an effective nutrient management program. Frequent cleaning and land disposal of animal wastes will help conserve nutrients in the manure. Frequent cleaning will also help reduce odors and flies. Unpaved areas Manure on unpaved areas doesn't need to be scraped as frequently. Infiltration into the soil and leaching through the soil will be reduced due to the compaction of the manure and soil by the animals on the yard. When manure is scraped from an unpaved lot, the manure should be removed down to within a few inches of the soil. The remaining manure layer is usually compacted and serves as a barrier to water moving through the manure pack and into the soil. If possible, the runoff should be collected for disposal on cropland or a vegetative filter strip. Manure stacks Many farmers will scrape manure into piles in the livestock yard rather than haul it during bad weather or busy work periods. This practice is not recommended because of herd health problems and the potential for water pollution. The severity of these problems depends on characteristics of the livestock yard area where manure is stacked and the area to which runoff flows. Similar problems are possible with unprotected stacks or windrows of poultry litter and compost residues. If a temporary solid manure or litter stack cannot be avoided, it should be protected with a 6-mil plastic cover and located at least 100 feet from the wellhead. The stack should be protected from surface water by an upslope surface water diversion (ditch, dike, grassed waterway, etc.), and any downslope stream or pond should be guarded by a grass filter strip area. 13. Silage storage Although animal waste is the primary area of concern when dealing with nutrient loss and water pollution, other areas related to animal production also pose areas of concern. Significant amounts of material may leach from silos causing potential groundwater contamination. Silage leachate contains high amounts of nitrates. Harvesting silage at the correct moisture content and proper storage will reduce the volume of leachate from the silo. Other management techniques to reduce the volume of leachate coming from silos includes lining or sealing the bottom of earthen silos or trenches. Horizontal trench silos should have compacted clay bottoms or should be lined with cement. The silage should be covered with plastic to prevent excess water from running through the silage. Not only will this reduce the amount of leachate, it will improve the quality of the silage. In some cases, it is possible to collect the leachate from the silo and apply it to the land as a source of crop nutrients. Because silo leachate can burn crops, care should be taken in the amount of leachate applied to the field. Silos and trenches should be located as far as practical from a wellhead, but at least a minimum of 100 feet, and preferably downslope. Trench silos should include some type of upslope diversion (berm, dike, grassed waterway, ditch, etc.) to prevent surface runoff water from entering the silage. A vegetated area should be maintained between the trench and any downslope pond, stream, or other surface water source. The Arkansas Livestock and Poultry Commission (ALPC) is responsible for regulations on the disposal of dead animal carcasses. The following are currently approved disposal methods:
Permits are required for some of the disposal methods. A permit for cooking and feeding must be obtained from the Veterinarian Services Section of the Animal and Plant Health Inspection Service (APHIS) in Little Rock (501-224-9515). Permits for disposal methods that require transporting carcasses off your property must be obtained from the ALPC in Little Rock (501-225-5138). A permit from the ALPC is also required for a one-time burial of a large volume of poultry carcasses due to a catastrophic die-off occurring on a farm. Composting of poultry carcasses is showing real promise, and there is indication that it may also work well for swine carcass disposal. The Extension and NRCS county offices and the ALPC can provide information on composting as well as information on other disposal methods. |
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University of Arkansas • Division of Agriculture |
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