Manure management practices for the Minnesota pork industry
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Manure is an inevitable by-product of pork production. Pigs in Minnesota generate approximately 11 million tons (on a wet basis) of manure every year. From a nutrient standpoint, this annual manure production contains 73,000 tons of nitrogen, 55,000 tons of phosphorus equivalent fertilizer and 58,000 tons of potassium equivalent fertilizer. Manure management plays a crucial role in determining how these nutrients impact the environment. Because of this, manure management is becoming a major factor in local, state, national, and international pork production.
In response to this concern, a project entitled "The Future of Waste Management: Strategies and Practices for the Minnesota Pork Industry" began in July of 1992. The project's mission was to help the Minnesota pork industry take a proactive approach toward environmental issues surrounding swine waste management practices. The primary goal of the project was to identify waste management practices for the pork industry that were economically feasible, technically viable, and environmentally sound. Secondly, these management practices would be promoted throughout the industry and to the general public.
The concern over manure management in the pork industry has occurred because recent advances in science have clarified the connection between manure and pollution. In some situations, declining water quality has been linked to poor manure management. Another important factor is the increasing environmental concern by the general public. Unfortunately, for much of the public the words manure and pollution have become synonymous. Because of this actual or perceived problem with manure, the public is demanding producer accountability in regard to manure handling. This accountability is being delegated by new regulations, lawsuits, and negative media coverage.
Environmental management practices
It is imperative to identify and implement proper manure management techniques if the pork or other livestock industries are to thrive in Minnesota. Handling manure and other farm waste in the most efficient and environmentally sound means possible is referred to as environmental management practices (EMPs). Most of these practices involve managing manure from the source (the pig) to the end use (typically utilization by crops). However, there are other farm wastes that must also be handled properly, such as needles, bottles, bags, paper, and pesticides. Proper disposal, re-use, and recycling of these wastes is also necessary to avoid pollution problems.
Producers must recognize the value of implementing "EMPs" in their pork production systems. Manure is often seen only as a liability, with substantial costs involved in the removal of the "waste." However, some of these costs can be recovered by recognizing and handling manure as a "resource." Therefore, from a long-term perspective, utilizing manure as the valuable resource that it is, to recover nutrients primarily for crop production, can be economically beneficial.
Unfortunately, manure can also be a liability if improperly managed. Proper management practices will eliminate or significantly reduce the liability to producers. Most pork producers want to "do the right thing" and manage manure properly so it does not adversely affect the health of their family or community or the general public.
Manure can be a tremendous benefit as a soil amendment and as a source of plant nutrients. Manure can also be a significant polluter of Minnesota's air and water (figure 1). Proper manure management is essential for gaining maximum benefit from manure and reducing the liability or pollution potential. Producers must take a systems approach to manure management (figure 2) so that all aspects of manure production and handling can be fully utilized. The five main manure management categories can be broken down into the following components:
- site selection
- manure production
- collection and storage
Desirable practices include:
- Locate so runoff from open lots or manure storages is contained.
- Minimize production site's visibility from public roads and neighbors.
- Be aware of both distance and direction to neighbors and communities.
- Locate facility to accommodate land application of manure.
- Keep facilities well maintained.
- Provide public education and information about plans for expansion.
- Comply with applicable local, state, and federal environmental regulations and zoning laws.
- Evaluate current or proposed farm sites for potential environmental hazards.
- Take some kind of action on all complaints.
To reduce manure production:
- Control water wastage.
- Control feed wastage.
- Improve efficiency of feed utilization.
- Formulate diets to reduce manure production.
Collection and storage
During the collection and storage of manure, adverse environmental effects can occur from both potential water pollution and odors. The following recommendations are suggested to reduce those potential pollution and safety hazards.
- Use collection systems that eliminate manure "ponding" on solid surfaces.
- Provide adequate storage capacities.
- Keep rainwater out of storage areas.
- Cover storage systems whenever economically possible.
- Manage deep pit systems to minimize gas concentrations inside the barn.
- Stockpile manure on a concrete or clay pad.
- Locate storage systems to avoid pollution potential.
- Locate storage systems where manure and nutrients are needed.
- Have contingency plans for accidents or overflows.
The treatment of manure is not common on Minnesota pig farms, but in some special cases, the following practices can reduce the environmental impact:
- liquid-solid separation systems
- anaerobic lagoons
- anaerobic digesters
- oxidation ditches and aerated lagoons
- filter strips, grass waterways and constructed wetlands
The final application of manure on cropland is another factor in environmentally sound manure management. The following practices will help ensure the full utilization of manure nutrients for crop production and will decrease the pollution potential:
- Develop a manure management plan.
- Agitate the storage until, before, and during application.
- Keep adequate records of manure application on cropland.
- Calibrate application equipment.
- Time manure application to fit crop needs.
- Avoid spreading manure near surface waters or waterways.
- Incorporate or inject manure into the soil.
- Consider neighbors when applying manure and remember its potential odor.
Manure management will always be a part of pork production. Management practices will have a significant impact on the environment regardless of the size of the operation. Producers who make wise manure management decisions help to maintain a healthy environment now and for generations to come. To reduce the risk of air or water quality damage from manure:
- Understand how manure impacts air and water quality.
- Keep the public in mind when locating, expanding, or maintaining a facility.
- Reduce the amount of material entering the waste stream.
- Collect and store manure to preserve nutrients and minimize gas and odor emissions.
- Apply manure to fields in a way that most fully utilizes the available nutrients.
More detailed information on these environmentally sound management practices, or EMP, is available in a 32-page report available from the Department of Agricultural Engineering or the Minnesota Pork Producers Association. By adapting environmental management practices, producers can continue to protect the environment without sacrificing farm profitability. Both farm profitability and environmental protection are essential elements for maintaining a viable pork industry in the state.