Effect of Nitrogen Rate and Simulated Golf Cart Traffic on Buffalograss Rough Density.

Requiring minimal management, buffalograss [Buchloe dactyloides (Nutt.) Engelm] is increasing in popularity for use in golf course roughs.  Repeated golf cart traffic in turfgrass rough areas, combined with the slow growth rate of buffalograss could potentially reduce canopy density.  The objective of this trial was to determine the influence of nitrogen rate and repeated simulated golf cart traffic on buffalograss density.  Field trials were initiated in July 2014 and 2015 at the Rocky Ford Turfgrass Research Center in Manhattan, KS on ‘Cody’ buffalograss maintained at 7.6 cm. Experiment design was a strip-plot, with a 4×5 factorial treatment structure. Factors were four nitrogen application rates, and five traffic rates. Nitrogen (46-0-0 Urea) rates included 0, 49, 98, and 147 kg N ha^-1. Nitrogen was applied in half rate applications, at trial initiation and eight weeks following. Traffic treatments were applied twice per week to achieve 0, 2, 4, 8, and 16 passes/week, with a 454 kg custom-built golf cart traffic simulator. Light box images were taken biweekly and digital image analysis was conducted using SigmaScan to determine buffalograss cover (0-100%). Analysis of variance was conducted in SAS and means were separated according to Fisher’s Protected LSD at P≤0.05. In 2014, a significant interaction between traffic and nitrogen was not observed for buffalograss density. Significant main effects of traffic and nitrogen rate were observed in 2014. As nitrogen rate increases, regardless of traffic, the density of buffalograss increased. Nitrogen treatments of 0, 49, 98 and 147 kg N ha^-1 resulted in 48, 53, 59, and 67% buffalograss cover, respectively, 84 days after initiation (DAI). As traffic rate increased, regardless of nitrogen rate, buffalograss density decreased. Traffic treatments of 0, 2, 4, 8, and 16 passes/week resulted in 73, 68, 57, 47 and 39% buffalograss cover, respectively, at 84 DAI.  Experiment is currently being repeated in 2015.