Implementation of Adaptive Nutrient Management for Nitrogen – Case Studies From Pennsylvania Farms.

Nitrogen management has been challenging because N cycling in agricultural soils is an extremely complex biological process and the process is further complicated by the uncertainty of weather and estimation of nutrient availability from applied animal manures. Newer technologies such as the presidedress soil nitrate test (PSNT), the corn stalk nitrate test (CSNT), and aerial images collected shortly after tasseling have been shown to improve the efficiency of N management but the adoption of the technologies by farmers has been extremely low. One of the reasons for low adoption maybe the fact that the newer technologies provide an evaluation of a farmer’s N management during the season or at the end of the season, and many farmers and agricultural consultants are not familiar with how to use information from evaluations of N practices made at the end of the season. Adaptive management is a process to make effective use of evaluations of agricultural practices like N management that have much uncertainty. We describe here three case studies of farms that participated in a six-year program to use adaptive management to improve N use efficiency. These farms were part of a larger program to improve N management with 105 farmers in Pennsylvania. The adaptive management process significantly changed fertilizer nitrogen use and resulted in better nitrogen use efficiency. We will demonstrate how the adaptive management program affected the farmers’ N management practices and show how the farmers changed their practices based on the evaluations of their N management.