Economic and Environmental Impacts of Alternative Practices on Dairy Farms in an Agricultural Watershed

ABSTRACT:

Nutrient losses from agricultural nonpoint sources are a key component of surface water impairment across the United States. Nitrogen is clearly the primary pollutant problem in many agricultural areas. However, development of management practices that reduce phosphorus loadings is becoming more important in many watersheds because phosphorus is often the limiting nutrient for fresh water eutrophication. This study presents the results of computer simulations performed to assess the impacts of various management practices on phosphorus losses from dairy farms in a watershed in north central Texas. The results show that moving from nitrogen to phosphorus-based waste application rates could significantly reduce phosphorus losses at moderate cost to producers. Composting solid manure for end uses outside the impacted watersheds provides even greater phosphorus load reductions and requires less land, but results in significantly higher cost to producers. The choice for each watershed depends on such key factors as available land area and the load reduction sought.