Livestock and poultry manure applied to farmland provides a valuable source of organic nutrients, but nitrogen and phosphorus from manure in excess of the farm's crop requirements can compromise water quality, according to USDA.

Many confined animal operations are unable to utilize all manure nutrients produced on the farm--i.e., apply the animal waste to crops on land under their control. For example, some locations in the Southeast, where poultry production is a dominant agricultural industry, have high levels of excess nitrogen because poultry manure has a high nitrogen content and because land available for spreading is limited.

For areas with excess manure, initiatives to encourage land application on other farms or to provide incentives for alternative manure treatment strategies may be necessary.

USDA's Environmental Quality Incentives Program (EQIP) provides technical, educational, and financial assistance to farmers and ranchers for adopting practices that protect or enhance environmental quality.

Increasing concentration of hog production and manure waste in certain geographic areas of the U.S. has heightened interest in the potential links between stringency of environmental regulation and location of animal production.

Policies regulating environmental pollution from confined animal farming may vary geographically, partly because federal water policy laws allow states to have authority and flexibility to design and implement their own environmental laws. Costs associated with environmental regulation compliance may be a consideration in choosing a business location. Producers may respond to existing or impending costs of regulation by exiting the industry or changing the scale and/or location of production.

Hog production has expanded in recent years in areas in the South and in nontraditional areas of the West, prompting speculation that large operations moved to those areas because of possibly less stringent environmental regulations.