Quantifying Nitrogen Requirement for Creeping Bentgrass Putting‐Green Cultivars

Nitrogen is perhaps the most important nutrient for turfgrasses because it improves color, density, and recuperative ability when applied at adequate rates. Although numerous unique traits, such as dark genetic color and improved stress tolerance have been identified, there is a lack of published data comparing creeping bentgrass cultivar N use. Therefore, a field study was initiated in 2009 and 2010 to identify creeping bentgrass ( Agrostis stolonifera L.) putting‐green cultivars that required the least amount of N to maintain acceptable color while maintaining desirable agronomic traits and good overall playability. Eighteen creeping bentgrass cultivars were planted on 2 July 2006 and maintained at a 3.2‐mm mowing height. Nitrogen, liquid urea, was applied at 49, 147, or 294 kg ha −1 yr −1 . Nitrogen applications were applied every 2 wk from April to October. Data collection included turfgrass color, relative chlorophyll index (RCI), clipping yield, lateral regrowth, ball‐roll distance, and thatch accumulation. Increasing N rates resulted in higher RCI, more top growth, faster lateral regrowth, and shorter ball‐roll distances. Regarding thatch accumulation, no significant differences were detected between cultivars. Overall, the creeping bentgrass cultivars that maintained acceptable color with the least amount of N input included ‘007’, ‘Authority’, ‘Penn A‐4’, ‘Shark’, and ‘T‐1’. These cultivars also maintained desirable agronomic traits, such as high RCI, reduced clipping yield, increased lateral regrowth, and adequate ball‐roll distance. This research indicates creeping bentgrass cultivar is an important selection criterion if a reduction in N use is a relevant consideration.