Why Adaptive Management Is Needed for Nutrient Management.

The purpose of nutrient management plans (NMPs) is to improve nutrient management on livestock farms. The underlying assumption is that implementation of BMPs recommended by Land Grant universities will minimize loss of nutrients and loss in yield. This assumption may be the reason evaluation of NMPs is not typically completed. To know if NMPs are effective, two types of evaluation should be completed: objective evaluation of whether farmers implemented the NMP, and evaluation of whether the BMPs were accurate for individual fields. Current software used for NMPs, such as the Manure Management Planner (MMP), do not have the capability to evaluate NMPs. There is strong evidence that the farmers’ implementation of NMPs is inconsistent, and the accuracy of Land Grant BMPs for individual fields is poor. Farmers do not fully implement NMPs for many reasons at strategic, tactical, and operational levels. The best example of the poor accuracy of BMPs is N recommendations for corn. The N Rate Calculator, which is the only publicly available N recommendation system based on a large number of N yield response trials, shows that N recommendations for individual fields are predicted with only 25-30% accuracy. NMPs at the University of Connecticut were designed to evaluate the effectiveness of the NMPs. A Probit model evaluating the reasons for nonimplementation of the NMPs shows that hauling distance and transport machinery are the primary reasons for nonimplementation. NMPs and BMPs need improvement if nutrient loss is to be minimized.