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The marketing of livestock and livestock products generates about $3.24 billion dollars in sales, or 57 percent of all of Arkansas’ farm sales each year. The state’s cattle, poultry, swine and dairy industries also produce about 3.4 million dry tons of manure each year. While the livestock industry is a vital part of Arkansas’ economy, there are concerns regarding the amount of manure being produced and utilized by the industry.
In Arkansas, almost all of the swine and poultry are raised in production houses with the feed being imported onto the farm. Most of the dairy operations are pasture-based systems in which a portion of the feed is imported. The manures collected on Arkansas farms are typically land applied on pasture and hay land.
With this type of system, the manure is a by-product of animal production. This manure can be either a valuable resource to be used to increase farm profits or a waste product to be disposed of. Whether manure is a valuable resource or a waste product depends on how it is managed and utilized.
Manure is a source of nitrogen, phosphorus and potassium. When applied at agronomic rates, it is an excellent source of plant nutrients. The availability of these nutrients without having to purchase commercial inorganic fertilizers has, over time, significantly increased soil fertility on Arkansas farmlands. This has not only resulted in greater hay and beef production, but has also reduced soil erosion.
However, increasing the size of animal production farms to meet production and economic needs has resulted in a growing concern about potential negative environmental impacts. Many of these concerns revolve around the greater volume of manure available for land application and the greater potential for over application of manure-based nutrients. These concerns are resulting in an increase in environmental activism, proposed regulations and modified farm production practices.
The primary environmental effects of proper manure management deal with maintaining the quality of surface and ground water. Manure contains nutrients and organic matter that normally benefit the environment, but, if improperly managed, can reduce water quality.
One source of potential problems is the nitrogen and phosphorus in the manure. Excess nutrients can increase the fertility of water resources which, in turn, increases the amount of algae and aquatic plants in surface water. Minor increases in vegetative growth can cause the plant and animal species in the water to change. Increased algal growth can also cause an “off flavor,” which raises treatment costs for human consumption. Increases in algae and aquatic plants can also change the appearance and curtail the recreational use of streams and rivers. It is also possible for decaying organic matter from either the manure or the increased vegetative growth to reduce the amount of available oxygen. If the available oxygen is reduced enough, fish kills may occur.
Ground water quality can be reduced if contaminated by nutrients, primarily nitrates, from manures, which leach to ground water supplies. This access is possible if manure storage facilities are not properly sealed or manure is applied too closely to sinkholes or rock outcroppings. High nitrate levels in drinking water may lead to health problems such as methemoglobinemia (“blue baby”), especially in young infants.
Animal manures can also cause health problems due to the variety of microorganisms found in manure. A class of microorganisms commonly used as an indicator of manure contamination is fecal coliforms. These bacteria are found in the digestive
tract of all warm-blooded animals, including humans. They are not normally a problem except in high concentrations. Exposure to high concentrations can occur by direct contact with manure or water that has a high concentration of fecal coliforms. It should be noted that a high concentration of fecal coliforms in a body of water might be caused by animal production facilities, human septic systems or even natural sources, such as wild animals and birds.
• Animal production generates about $3.24 billion dollars (57 percent) of agricultural income and is an important part of Arkansas’ economy.
• Manure is the on-farm by-product of animal- based food production.
• Whether manure is a “waste” that may damage the environment or a “resource” that helps farm production depends on how it is managed.
• The long term sustainability of agriculture depends on:
• Production – farmers must have product to sell.
• Profitability – farmers must be able to make a living.
• Perception and Environmental Protection – farmers’ production practices must protect the environment and be acceptable to the public or they will be subjected to regulations to force acceptable practices.
• Since manure can have a negative impact on public perceptions, the environment, production and profitability, careful attention must be paid to its proper management.
Agricultural Waste Management Field Handbook, USDA-Natural Resources Conservation Service, Washington, D.C.
Arkansas Agricultural Statistics for 1997, Arkansas Agricultural Statistics Service, Little Rock, Arkansas
Biomass Resources in Arkansas. 1995. Jim Wimberly. Winrock International, Morrilton, Arkansas
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More information on phosphorus, a primary nutrient of concern, is available in various fact sheets published by the Cooperative Extension Service, Univeristy of Arkansas. |
Author:
Karl VanDevender, Extension Agricultural Engineer
Dr. Karl VanDevender is an Extension agricultural engineer, Cooperative Extension Service, University of Arkansas, Little Rock.
FSA1037-PD-5-01N
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