Creeping Bentgrass Response to a Stabilized Amine Form of Nitrogen Fertilizer.

PiNT+potassium (PiNT+K) is a newly developed amine form of N fertilizer that purportedly stabilizes the N through a reaction with the potassium cation. Stable forms of N offer the possibility of maintaining turfgrass quality with less N fertilizer and less biomass growth, a desirable goal in turfgrass management that would also reduce environmental impact. The influence of PiNT+K and an analog fertilizer (KNO₃ and NH₄NO₃) on the quality of creeping bentgrass were compared at different N rates (0, 25, 37.5 and 50 kg N ha^-1) in 2009 and 2010. At the same N rate, the normalized difference vegetation index (NDVI) of the PiNT+K treatments was 2-3% greater than NDVI from the analog treatment, while the dark green color index (DGCI) was 4-7% greater. Fertilizer burn (osmotic desiccation) was observed on plots treated with the analog fertilizer, but treatments with PiNT+K appeared safe from osmotic desiccation, even at high N rates. The N rate of 37.5 kg N ha^-1 of PiNT+K outperformed the analog fertilizer at 50 kg N ha^-1 when the quality of creeping bentgrass, turfgrass management, and N use efficiency were considered. The PiNT+K treatment provided better turf quality as measured by NDVI and DGCI, yielded similar above-ground biomass, and had less unused N (N application – N uptake) in comparison to the analog fertilizer.