Most dairy farms in Wisconsin continue to produce most of their feed and have sufficient land for recycling manure nutrients through crops. However, to remain economically viable, many dairy farms are increasing herd size and importing more feed. The increased importation of nutrients in the form of feed and fertilizer has resulted in excessive soil nutrient accumulation (Bundy, 1998; Proost, 1999), and has increased the risk of nutrient transfer through surface and subsurface runoff and air pollution.

Federal legislation aimed at controlling farmer practices that potentially pollute surface and ground waters is becoming strict (USDA and USEPA, 1999). The survival of many livestock operations in the U.S, including dairy farms in Wisconsin, will increasingly depend on farmers’ ability to comply with environmental standards, especially those associated with the application of manure to cropland. Clearly, alternative manure management strategies are needed if we are to arrest soil nutrient accumulation and loss from dairy farms.