Tuesday, November 6, 2007 - 9:15 AM
167-2
The Effect of Nitrogen Fertility on Growth, Rooting and Quality of Velvet Bentgrass (Agrostis canina) and Creeping Bentgrass (Agrostis stolonifera).
Recent regulation of turfgrass inputs has created an interest in the golf industry for lower input putting green turf. Velvet bentgrass (Agrostis canina L.) may be a lower input alternative to creeping bentgrass (CBG), however, fertility requirements for velvet bentgrass (VBG) are not extensively documented. A greenhouse study was conducted to determine the effect of varying nitrogen rates on SR7200 VBG and L-93 CBG on 80:20 sand:peat and 100% sand USGA profiles; clipping production, visual turf quality ratings, and root accumulation were examined. The nitrogen rates used in the greenhouse study were 0.012, 0.024, 0.048, 0.096, 0.19, 0.28 kg N/100m2/week, supplied as urea solution. A current field study is also examining the effect of nitrogen level on visual turf quality, normalized difference vegetation index (NDVI), clipping production, and recovery from various stresses, including core aeration and vertical mowing. Nitrogen treatment rates are the same as those used in the greenhouse study using granular microprill urea and foliar applied urea to investigate differences between soil and leaf applied nitrogen. The study is being conducted on two rootzones – an 80:20 sand:peat USGA specification and two native soil areas – all of which have been seeded to 1/3 each of SR7200 VBG, L-93 and Penn A-4 CBG. Treatments are arranged using a randomized complete block factorial design with 4 replications of each nitrogen treatment on each respective turf type. Results from the greenhouse study indicate that growth in both species improved with increased nitrogen rate, but that VBG declined over time at the higher rates. Preliminary field observations indicate that SR7200 rates better than L-93 and A-4 under lower nitrogen on native soil whereas on 80:20 the creeping bentgrass cultivars are performing better at all nitrogen levels than SR7200. More detailed results will follow pending complete statistical analysis.
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