There is growing concern about the negative effects to the environment and human health from application of excess nutrients to crop land. Dairy farms in Connecticut have voluntarily participated since 1997 in Nutrient Management Plans (NMPs) funded by the Environmental Quality Incentives Program at the United State Department of Agriculture Natural Resources Conservation Service to minimize the negative effects of land application of manure. It is critical to document improvements in nutrient management by farmers after they have implemented a NMP. It is important to address the factors that affect farmers' decisions during the implementing of NMPs. We selected four dairy farms in Connecticut that had five to seven years of field-by-field nutrient management records. The results indicate that NMPs had a dramatic effect on farmers' decisions about management of fertilizer N and P. But the farmers did not significantly improve their management of manure. The results of a Probit model indicates that the distance farmers have to transport manure is the most important factor preventing farmers from distributing the manure as recommended. Other factors such as field size, land tenure, crop, nutrient needs by crops, fertilizer applications, and the result of soil test phosphorus also had a significant effect on the farmers' decision about manure distribution. NMPs in Connecticut require the use of objective tests such as the Pre-sidedress Soil Nitrate-nitrogen Test (PSNT) and the End-of-season Cornstalk Nitrate-nitrogen Test (CSNT) to document improvements in nutrient management after implement of a NMP. The results from our four farms show that year-to-year variations in rainfall and residual nitrogen from previous manure applications makes it difficult to document improvements in nutrient until there are at least three years of records for a field.

The results of partial budgeting analysis suggest that implementation of NMPs substantially increased the cost of manure management, but the benefit of implementation of NMPs varies. Therefore, farmers could receive negative or positive net benefit from implementation of NMPs. The results of analysis of NMPs developed based on different phosphorus-based nutrient management strategies indicate that implementing NMPs required farmers export substantial amount of manure off the farms, and it could be cost prohibitive for farmers. The results of the research provide advisory information for scientists, extension specialists, farm communities, and policy makers.