Wednesday, June 11, 2014

Creeping Bentgrass Establishment

Eric Chestnut, Thomas Green, and Dr. John N. Rogers, III
Michigan State University

Due to the recent harsh winter and new bentgrass varieties that have come into the market, a study currently underway at the Hancock Turfgrass Research Center at Michigan State University has become quite timely and relevant. Pure Distinction creeping bentgrass was seeded into a bare soil profile last August with the intent of using four factors (nitrogen fertilizer rate, mowing height, PGR use, and verticutting) to discover the fastest way to get a plot of turf capable of withstanding putting green traffic. Although the following observations are preliminary, we hope that those interested may find them useful.
Pure Distinction 5/5/14. 
As of May 29, 2014, only the nitrogen fertilization and mowing height regimens have been implemented  long enough to notice any treatment differences. The most striking contrast is between the fertilizer rates. Rates of 0.05, 0.10, and 0.15 lb N/1000 ft2 are sprayed (initiated Sept. 2013) weekly. The photographs below reveal that the plots receiving 0.10 lb N/1000 ft2 and 0.15 lb N/1000 ft2 of fertilizer are much farther along than the plots receiving 0.05 lb N per week. The differences between the two higher rates are currently harder to differentiate, but the highest (0.15 lb N/1000 ft2) rate did seem to grow in significantly faster initially than either of the other two rates. The warm air and soil temperatures during the past couple of weeks have given most of the 0.10 lb N/1000 ft2 plots a chance to catch up to the highest rate, but the lowest rate plots still have significantly less coverage than the others.
Pure Distinction 5/25/14. Darker green areas are 0.10 & 0.15 lb N/1000 ft2 rates and thin areas are the 0.05 lb N/1000 ftrate.
Mowing was initiated last fall and resumed this year on April 30, 2014 yielded minimal clippings until the second week in May due to cold soil and air temperatures. Half of the plots were originally being mowed at 0.200” and the other half at 0.150”, with each height being reduced by 0.05” each week until a height of 0.125” is reached. Mowing heights are currently at 0.190” and 0.140”. Plots being mowed at the lower height are growing in more densely than areas at the higher cut, even though they look similar from a standing distance due to longer, more lateral growing leaves on the higher cut turf (see Figures 4-7).

Mowing Height Differences. 5/29/14.  Plot on the right (above the 1) is mowed at 0.140” and the plot on the left (above the 2) is mowed at 0.190”. Both plots fertilized at 0.150 lb N/10000 ft2. They look very similar from above, but upon closer inspection the lower mowing height (the plot on the right) has more leaf density than the higher height (plot on the left).
Mowing height 0.190”. 5/30/14. Notice there are quite a few areas where the leaves are sprawling outward instead of standing up.
Mowing height 0.140” 5/30/14. When compared to the higher mowing cuts the grass blades are more upright and less sprawling.
The verticutting regimen was initiated on May 28, 2014. At the time this post was written, the cutting was too new to see any differences between plots. The PGR applications will began  the week of June 1, 2014.

Multiple Factor Photo. 5/26/14. Plots below the number 2’s are mowed at 0.190” and plots below the number 1 (second from the right) are mowed at 0.140”. Fertilizer rates are as follows from left to right: 0.05 lb N/1000 ft2, 0.05 lb N/1000 ft2, 0.15 lb N/1000 ft2, 0.10 lb N/1000 ft2