Turf quality ratings

Today, I discussed the intricacies of rating plots for turf quality with Dr. Richardson. This is a subjective rating and all raters would rate differently based on the individuals criteria. Since we are working on a bentgrass putting green situation, density and uniformity will be the crucial criteria within turf quality ratings. We also believe that these two characteristics will be the ones that are altered with our treatments.

Just wanted to write out some of the basic rules/thoughts that will help my rating skills.

1. Best to rate plots on cloudy days whenever possible. If I have to rate plots on a sunny day, be sure to stand with the sun to my back (cast shadow toward plots being rated).
2. Don't wear sunglasses when rating plots
3. Go with an initial thought and rating at first glance; Don't over think it!
4. If rating for color it is best to rate this from a distance.

At this point, there are few differences in the treatments because temperatures have not began creeping upward that would help differentiate treatments. We did see some potential differences in plots that were rolled 6 days a week. They appeared slightly less dense when comparing to other rolling treatments. This was a consistent observations in many of the plots. Also, the higher mowing height appeared more "splotchy" due to the increased leaf area. This observation compared to the lower mowing height where turf was relatively tight with higher density and finer leaf texture.

To help better separate plots color, digital images were obtained using the light box. Two images were collected in each plot and data will be averaged for the two images. Once plots are split and traffic treatments are being applied, a single image of each plot will most likely be obtained.

Root analysis

A preliminary root analysis was performed on my research plots around the end of May or first of June. Twelve samples were collected from randomly selected plots. The samples were washed to remove sand and organic matter from the samples. For analysis, two centimeters of turf and thatch material was removed from the top of the sample. The remaining organic matter was removed in a bucket of water. The root samples were separated in a clear dish prior to putting them in the WinRhizo root scanner. Data was obtained from this analysis.

Further root sampling of all plots was performed on June 10 and 11, 2010. Two samples were obtained from each plot using a profile sampler to a depth of 10 cm. Only one sample was obtained from plots previously analyzed in the preliminary sampling. Prior to washing samples a thatch depth measurement was recorded for each sample because the thatch layer is extremely thick. This data may be more useful for the ball mark analysis. Sand and organic matter were removed from each sample by placing the samples in the clipping collection device with an metal mesh to allow sand and organic matter to pass through. All samples were washed on June 11, 2010 requiring approximately 6 hours to wash 96 samples.

Root analysis was performed using the WinRhizo once again. This was a laborious process, but I was able to finish analyzing all samples in approximately 12 hours. Once root material was analyzed, the two samples from each plot were combined and placed in a drying oven for 24 hours at 100 degrees C. Dry weights of roots will be obtained following the drying period.

I will have to work with the data from the txt file in excel to determine what each cell in the Excel file refers to. I feel that overall root length will be the best data. The fine roots of creeping bentgrass were difficult to separate fully, so if multiple roots were stacked on top of each other or in a group, the software believed this was a larger diameter root when it may not have actually been. A second problem was the small amounts of organic matter that were not able to be washed off the roots. These larger particles were analyzed as roots as well. Each sample was similar though, so data should be sufficient for this information.

I believe these roots should be the largest and highest quanity I will be analyzing. I believe that later in the summer, roots will begin diminishing and dying off. Future measurements may result in less root material that may separate more easily.

Ball mark analysis

A preliminary study to determine methods for analyzing ball mark volume and recovery was performed on the NTEP bentgrass putting green. Two ball marks were created in each plot with the golf ball launcher at 40 psi. A red golf ball was placed in each ball mark and digital images were obtained using the newly developed ball lie device. One image was taken in the direction of the balls impact, and a second image was obtained from the opposite side. These images were analyzed to determine the percentage of ball above the canopy. These two values were averaged to determine the percentage of ball above the turf canopy. A single TDR measurement was also recorded for each plot to see if moisture levels affect ball mark size.

Ball marks were not repaired for 3 to 4 hours to allow turf within the ball mark to become injured. Ball marks were repaired with a standard ball mark tool. To determine recovery of ball marks, digital images were obtained with a light box of ball marks 2, 5, and 8 days after creating ball marks. These images will be analyzed using SigmaScan software to determine the time required for ball marks to recover.

Following 8 days of recovery, some of the ball marks appeared to be completely healed, so images will no longer be collected on the test area.

Corrections that should be made for future studies. To ease the time it takes to collect digital images for recovery, I should mark two corders of the shield, so I know exactly where ball marks are and where to place the shield. If dollar spot symptoms are evident, it becomes difficult to distinguish dollar spot symptoms and ball marks. However, ball marks appeared to have darker color in most cultivars compared to dollar spot symptoms.