Composting Livestock ManureThis guide gets into some of the technical details you need to understand when composting larger volumes of organic waste.
MAKING AND MAINTAINING A COMPOST PILE
ABOUT THESE GUIDELINES
These guidelines apply generally to any composting effort, but are specifically adapted here to assist owners of horses in the management of horse manure/bedding material waste. Horse owners are fortunate in that horse manure is an ideal composting material. Horse manure has a C:N ratio that is almost perfectly balanced to the needs of the micro-organisms which perform composting action.
If you maintain the structure and moisture level of the compost pile in accordance with the guidelines given below, three things will be accomplished:
An efficient compost process will stabilize the breakdown and loss of valuable nutrients in the manure. The stabilized nutrients can then be made available for future plant growth. Fresh manure tends to lose its' valuable nutrients into the air and water when the C:N ratio is out of balance or when the pile is exposed to uncontrolled amounts of rain water. Leaching nitrogen compounds can have a negative impact on nearby bodies of water and produce nuisance odors. Sound waste management is "Waste Reduction" at its best.
The information provided here is adapted from guidelines developed by the Northeast Regional Agricultural Engineering Service Cooperative Extension. This adaptation is a cooperative effort of Klickitat County Solid Waste and the Washington State Department of Ecology.
You can add other materials to your manure compost pile. Almost all natural, organic material will compost, but not everything belongs in the compost pile. Some wastes attract pests, others contain pathogens that can survive the compost process, even if the pile gets hot.
As shown in the table above, fatty food wastes, such as meat or bones, should be avoided. They attract rodents, raccoons, dogs, cats, flies, and other pests; and they can cause odors. Cat and dog manures can contain harmful pathogens that are not always killed by the heat of the compost pile. Manures also attract cats and dogs to the pile.
Plants harboring diseases, or suffering severe insect infestations, should not be added to the compost pile. Certain pernicious weeds, including morning glories, buttercups, and grasses (such as quack grass) with rhizomatous root systems, may not be killed if the pile does not heat up. Piles containing these types of weeds must be turned to encourage the high pile temperatures that will kill them.
Another consideration in choosing materials to go into the compost pile is the time they need to break down. Woody materials, such as wood chips, branches, and twigs can take up to two years to break down unless they are finely chipped or shredded. Their high C:N ratios indicate that they require a lot of nitrogen to decompose, so they may slow the decomposition of other materials. Other materials that break down slowly include: corn cobs, husks, and stalks; sawdust; straw; apple pomace; and some nut shells. These materials should be cut into small pieces to increase their surface areas and mixed with high-nitrogen materials, such as manure or fresh grass clippings.
Materials that break down slowly should be mixed with easily decomposed materials to allow the pile to get hot. If a high nitrogen source is not available, high-carbon wastes should be used as mulches. While materials such as wood chips and straw break down slowly, they also are bulking agents that improve the pile structure, allowing air circulation. If composting dense, high-nitrogen materials, such as manure, the addition of a bulking agent may be required to facilitate the process.
The art of composting is discovering the mix of materials that will provide the best environment for the compost process. Mixing materials of different sizes and textures helps to provide a structurally stable and well drained compost pile. Diverse material also helps maintain the right C:N ratio and an efficient process. For help determining a compost mix try our Compost Mix Calculator.
For livestock manure waste it is crucial to select a suitable storage and composting site because the large volume of material generated can have a negative impact on your health and the environment. Avoid low areas where surface water will flow or collect. Don't put your manure storage or compost pile under the eves of the stable or barn either, because when it rains it will pour clean water directly into the manure and contaminated water will flow out. Avoid areas that provide little or no obstacle for runoff from your storage or compost site to enter directly into surface or ground waters. The best storage and compost site is under a cover where moisture can be controlled. A tarp over the manure will eliminate most water runoff related problems.
The table below relates to processing larger volumes of livestock manure rather than the smaller volumes of a single family home without livestock wastes. In either case the following sensitive areas should be considered when choosing a location for your compost pile. The table below suggests minimum distances between a compost pile and a sensitive area.
A good location is helpful for a successful compost pile. Direct sunlight in the summer dries the pile. Exposure to high winds can dry and cool the pile, slowing the decomposition process. The pile location should not interfere with lawn and garden activities. Water should be readily available. There should also be enough space for temporary storage of organic wastes. Good drainage is important; otherwise, standing water could impede the decomposition process. The compost pile should not be located against wooden buildings or trees; wood in contact with compost may decay.
A pile should be large enough to hold heat and small enough to admit air to its center. As a rule of thumb, the minimum dimensions of a pile should be 3 feet x 3 feet x 3 feet (1 cubic yard) to hold heat. The maximum dimension to allow air to the center of the pile is 5 feet x 5 feet x any length.
If space is a limiting factor, the pile sides should be insulated so that higher temperatures can be maintained in a much smaller volume. Smaller, commercially available units can be insulated with foam board. Piles larger than 5 feet tall and wide may need to be turned to prevent their centers from becoming anaerobic. As the material decomposes, the pile will become smaller.
Compost piles can be constructed by adding stockpiled material in batches or by placing materials in the piles as they become available. The batch method accelerates the composting process if the combined materials have the right C:N ratio and if the materials are mixed properly.
Maintenance of the compost pile involves turning the pile and adding water to maintain conditions conducive to the composting process. If the pile is not turned, decomposition will occur, but at a slower rate. The following maintenance procedure will yield compost in the shortest time.
Turning a compost pile weekly can yield compost in one to two months with the right combination of materials and moisture content. Without turning, decomposition takes six months to two years. Excellent quality compost can be made either way. When selecting a composting method, consider economy, neatness, permanence, need for finished compost, and time available for maintenance.
In a pile constructed according to the method described here, the pile temperature will increase rapidly and soon reach about 110'F. After about a week, the pile should be opened to the air and any compacted material should be loosened. Then the pile should be reconstructed; material previously on the top and sides of the pile should be moved to the center.
At the second turning (after about another week), the material should be a uniform coffee-brown color and moist. The relatively un-decomposed outer layer can be scraped off and turned back in to the center of the pile. The center material should be spread over the outer layer of the reconstructed pile. By the third turning, the original materials should not be recognizable. At each turning, the moisture content should be checked using the squeeze test. Squeezing a handful of compost you should be able to make some water droplets appear around the edges. If you can't squeeze some water out of the compost it is too dry. However, if more than four drops appear it is too wet. Water or moisture absorbing materials should be added, as indicated.
During the first few weeks of composting, the pile should reach a peak temperature of about 140'F. If temperatures surpass 140'F, the pile should be turned to cool it off. Extremely high temperatures can kill many beneficial organisms. If the pile does not reach at least 120'F, more nitrogen or water may be needed. Cold weather can also prevent the pile from heating. Piles that give off strong ammonia smells contain too much nitrogen, and may need more high-carbon ingredients.
Simple carbohydrates and proteins provide most of the energy for the initial, rapid stages of decomposition. When the more resistant materials, such as woody fibers and cellulose, become the main food sources, the activity in the pile will slow down. Less heat will be produced, and the temperature will begin to fall to about 100'F. Even after the temperature falls, the compost will continue to stabilize slowly.
The compost will be finished when the pile cools off and decreases to about 1/3 of its original volume (depending on the original ingredients). It will be dark, crumbly, and have an earthy odor. The C:N ratio will be less than 15:1, approaching the value of humus in soil, and the temperature usually will be within 10F of ambient air temperature. Unfinished compost can be toxic to plants, especially to seedlings and newly established plants. Therefore, compost must be allowed to decompose thoroughly before use.
Given a comfortable, or even nourishing, environment, rodents and other animals may be attracted. Rats are probably the most undesirable pests. In a hospitable environment with plenty of food, they can multiply very quickly and become disease transmitters. So it is crucial to keep high-protein and fatty food wastes out of compost piles in areas where pests may be a problem. Meat and fish scraps, bones, cheeses, butter, and other dairy products should be excluded if pests are a problem. Bread and other high carbohydrate or high-sugar wastes can also attract pests.
Many flies, including houseflies, can spend their larval phase as maggots in compost piles. To control their numbers, compost piles with food in them must be turned frequently to encourage heating (larvae die at high temperatures). To prevent flies piles can be covered with finished compost or dry, high carbon material, like straw. Food waste can be incorporated into the center of a compost pile, rather than on the surface, to avoid pest problems. Pest proof sides, bottoms, and covers may also be installed on compost units to help control pests. Bins built with side and cover openings less than 2 inches will discourage raccoons, skunks, and other large animals. Where rats are a problem, use hardware cloth with openings 1/2 inch or less to enclose sides, cover, and bottom.
The table below gives some desired characteristics you should strive to achieve in order to create an environment which will promote growth of beneficial organisms and rapid composting.
The table below gives some useful characteristics of common livestock manures. C:N ratio indicate the degree to which you might need to add high-carbon materials. Moisture content may influence the type of high-carbon materials you might choose to add.
The following information can be used to estimate the volumes of livestock waste generated at your site. From this you can estimate the need for high-carbon materials to mix and the approximate size of the area needed for processing.
Date of Source Material: 12/19/2005
Source: Klickitat County Solid Waste
Link to Source:
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