Caring for Our Environment
Environment
FAQs
Q. What happens with the manure produced in a hog production operation?
A. Hog manure is generally used by the farmer to increase the productivity of his crop or grass land. It's an excellent source of nitrogen, phosphorous and potassium, and improves soil quality. Properly applied, it can replace or reduce a farmer's use of commercial fertilizers and since it's a by-product of the hog operation, manure use can make a big difference in the economic viability of a farm. There are strict environmental regulations requiring the farmer to properly land apply hog manure based upon the nutrient needs and water holding capacity of the soil.
Q. How is the hog waste applied to farmland?
A. The contents of most lagoons are applied most economically to land by means of irrigation. Solids-free liquid from a lagoon is applied through sprinkler nozzles. In solid or semi-solid form, manure is spread on the land and incorporated or injected into the soil. Soil incorporation is a mechanical process that mixes the soil with the manure. Soil injection is a mechanical process that places manure directly under the soil surface, so the nutrients can be better used by crops or grass. Injecting and incorporating manure are effective ways to reduce odor. The use and operation of the proper land application systems are important to protecting surface water, groundwater, and air quality. Changes to feed rations, manure-solids separation, and biological digestion are becoming increasingly important steps in the manure-handling and treatment process prior to land application.
Q. Is hog waste considered a hazardous substance?
A. No. Properly managed manure presents little risk to the public or to the environment. Organic compounds in hog manure -- like the compounds in a compost pile -- are easily broken down into various nutrient sources for crops and grass. Because hog manure contains only low concentrations of these compounds and nutrients, the products of decomposition are not known to be present at levels that are hazardous to plants, wildlife or humans.
Q. I've heard on the news about hog operations being fined by regulatory agencies. Is this a big problem?
A. While these incidents sometimes create news stories, they are extremely rare. Let's use the nation's largest hog production state as an example. In 2002, the Iowa Department of Natural Resources reported 14 enforcement actions against all livestock operations. In 2003, 11 were reported. This equates to about 1 violation for every 8,000 livestock enterprises in the state.
Q. How is the land application of hog manure regulated?
A. The pork industry is subject to federal, state and local regulations. Typically, permits are required at state and local levels for construction of animal housing units and manure storage systems. Operating permits for manure handling may also be required. As in other industries, pork producers must meet or exceed all local, state, and federal worker health and safety requirements. In brief, pork producers are faced with regulations at all levels of government. Producers monitor these steps to ensure proper land application of manure:
- Monitor manure volumes throughout the year
- Sample manure for lab analysis of nutrient content
- Calibrate manure spreader
- Monitor weather and field conditions prior to manure application
- Calculate the appropriate rate of application based on crop uptake and soil fertility
- Keep detailed manure application records
- Inspect the field during and after application
Q. Are hog production operations negatively impacting drinking water sources?
A. Livestock production is one, but not the largest, source of nutrients such as nitrogen and phosphate introduced into the environment. Human sewage, commercial fertilizer, private septic systems, the atmosphere and residential fertilizer all contribute to excess nutrients in surface and groundwater.
Q. Do hog production facilities pose a threat to wildlife?
A. Modern pork operations do not threaten wildlife or their habitats. Agricultural production methods -- including those used on pork operations -- increase food yield while using less space, allowing greater areas of natural habitat to be protected. In fact, farm fields provide some of the last remaining large open areas for wildlife habitat and feeding. That includes areas for threatened and endangered species. Proposed operations that might affect a particular endangered species habitat would not receive a permit for construction or operation. Modern farming operations typically provide valuable resources for all types of wildlife.
Q. Why is there odor associated with hog production facilities?
A. Compounds produced from manure handling or storage systems on pork operations can cause odor. The odor is caused by gases generated during microbial decomposition. In general, odors from manure operations are generated by three sources - barns, manure storage/treatment facilities and land application. Lagoon treatment systems typically generate more odors during the initial start-up year because microbial activity has not yet reached its optimum efficiency. With time, these biological processes stabilize and treatment lagoons generate negligible odors. Most potential odor is generated by the lower, most anaerobic layers of a lagoon. If lower layers are allowed to decompose undisturbed, odors are minimized. The upper layers of a lagoon, where there's more water, generate significantly less odor. Odorous compounds vary with location, production practices, season, temperature, humidity, time of day and wind speed and direction. All compounds, however, represent elements and nutrients that occur naturally in the environment. For example, throughout the world, naturally occurring wetlands produce more methane than all agricultural land combined. Natural wetlands also produce hydrogen sulfide and other gases typical of anaerobic treatment processes used in pork production.
Q. Can odor be controlled?
A. The best way to control odor is to properly manage production facilities and to take measures to avoid problems. At a facility that is isolated and screened from roads and a proper distance from neighbors -- odor is rarely an issue. Barns equipped with clean, well-maintained ventilation systems to move fresh air, help disperse odors. Exhaust from the barn should be directed away from sensitive outside areas like homes. Maintaining lagoons and other manure storage facilities properly and using land application methods such as soil injection are effective ways producers significantly reduce odor levels from their farms. Producers recognize it is in their best interest to keep odors at a minimum.
Q. Is odor subject to regulation?
A. Odor related to pork production is not regulated under the federal Clean Air Act. Livestock-related odor is unregulated because methods to scientifically define offensive odor, substantiate it and measure it have not yet been developed. What is offensive to one person may not be to another. As a result of the difficulty in establishing objective federal standards to measure odor, most states have not imposed odor regulations. Some states are regulating odor along with other specific odorous gases.
Q. Is it true a large swine operation has a potential waste output greater than a large metropolitan area?
A. Population equivalents are sometimes used to characterize the potential for animal production systems to create water pollution problems. This is incorrect since modern manure handling systems are designed, operated and required to prevent discharge into water bodies. A typical finishing pig produces an average of 1.2 gallons of manure each day, a total of 438 gallons of manure each year. At an average rate of 0.05 pounds of nitrogen per gallon, that's only about 21 pounds of nitrogen produced annually per pig space. A city of a half million people produces nearly 50 million pounds of nitrogen in its waste stream. That's almost 100 pounds of nitrogen per person -- enough nitrogen to fertilize more than a quarter of million acres of corn at 150 bushels per acre.