Ten Years of the New York Phosphorus Index: Nutrient Management Planners' Feedback.

The phosphorus index (PI) is a state-specific tool that estimates the relative risk of generating P runoff from agricultural fields. In 2009, NRCS requested evaluation of PIs due to inconsistent P management recommendations and lack of water quality improvement in some states. A survey was conducted among 37 active certified nutrient management planners in NY to evaluate their perspectives on what is working in the current NY PI and which changes should be considered in a revised version. Survey results showed that all factors included in the current NY PI are considered important by the planners. In their opinion, water quality violations are mainly driven by manure applications just before snow melt of rainfall events and by spreading manure too close to streams. Most planners (56%) indicated the PI should encourage manure incorporation, proper timing (44%), cover crops (39%), setbacks and buffer areas (36%), manure application to fields with little connectivity to streams (28%), and practices to reduce erosion (22%). Planners indicated the PI should discourage manure applications to saturated soils (61%) and to fields close to streams (44%), manure spreading without incorporation (36%), manure application to fields with steep slopes (20%), and leaving bare soils in winter (17%). A complete change of the PI was not advised, but 53% of the planners suggested updating the weighing factors in the NY PI, especially for timing of application. Sixty-four percent of the planners did not support including a screening tool in the revised PI. In turn, 47% supported a physiographic-based PI (NY plus Northern PA) compared to 35% who preferred to continue with the NY-based PI. Finally, 75% of the planners did not want to have different PIs for different watersheds within NY. The planners’ feedback identified management practices that can be evaluated in a revised version of the NY PI.