Effects of Behind Center Distance on Creeping bentgrass (Agrostis stolonifera L.) Putting Greens.

Increasing green mower aggressiveness via behind center distance (BCD) adjustment has been proposed to produce a smoother cut resulting in improved ball roll distance (green speed).  Limited research has been conducted to quantify if these improvements indeed exist; therefore, the purpose of this study was to examine the effects that changing BCD will have on green speed, turf quality, clipping yield, and topdressing sand removed by mowing.  This study was performed at the University of Tennessee, Knoxville and Michigan State University, East Lansing on creeping bentgrass putting greens.  Six BCD treatments were arranged in a randomized complete block design, and all data were subject to mixed model analysis of variance in SAS v9.4 (SAS Institute, Cary, NC).  Significant differences (P<.05) were found among total clipping collection and total sand collection; however, no significant differences were detected for green speed or overall turf quality.  The most aggressive BCD setting collected significantly more (P=0.0279) clippings (1.42g m^-2) per plot than the other treatments, which ranged from 0.93 to 1.07 g m^-2.  Topdressing sand collection analysis revealed that the most aggressive BCD setting collected significantly more (P<0.0001) sand (8.83g m^-2) than the control and the least aggressive BCD settings (2.75 and 2.12 g m^-2, respectively).  The amount of clippings and/or sand collected was greater in more aggressive treatments; however, this did not effectively translate into faster green speeds or changes in turf quality.  Based on our observations, BCD can be decreased without compromising green speeds while minimizing the amount of topdressing sand collected. This could result in increased reel longevity due to the reduction of abrasive wear on the cutting components.