I received this email from Zachary LaPorte, and I share it here for two reasons.
First, he’s expressed a number of things related to the measurement of #ClipVol that I have heard from many turfgrass managers who’ve implemented this technique. These observations are of general interest and he’s expressed them especially well.
Second, he asks a question that I can’t answer completely, and I hope someone who reads this may be able to provide more information.
From LaPorte’s email:
“After seeing you speak at the Spanish greenkeepers event in November, I started to investigate more into the measuring of clippings as a tool. I finally started to do this at the beginning of March and measure daily every green. And I can say without any hesitation that this has opened my eyes and my mind to whole another way of maintaining the greens. Without a doubt I have been missing out on so many details of greens maintenance. Both myself and my mechanic are enjoying this method. Well maybe me a bit more than him, haha.
I was the typical superintendent that would ask the guys how much they were taking off the green and somehow judge what to do next. I have always been a firm believer in [GDD] and primo maxx/foliar feeding. But now I am using both volume and [GDD] to fine tune things with great results.
I also discovered many things that were shocking me at first like how much a green can change in growth from one day to another or how the guys mowing the greens at different speed drastically affected the amount of clippings. We are getting better and the greens are more consistent than ever and this is reflected by the positive comments from the players which is really what counts.
I am writing you not only to tell you my experience but also for your help. We have noticed that our JD manual greens mowers are taking off different amounts of grass from one another. I use the mL/m2 method you recommended and the differences are extreme. We have been banging our heads against the wall for a good month trying to figure this out and I was hoping that you might be able to shed some light on the issue.
All machines are set up identically HOC, attack angles etc. We have a bench HOC of 3.5 mm and with the prism on the greens we have a height of 2.5mm. We have found that our #3 machine is cutting 2-3x more. We split a green between two mowers to double check and still the same results. The set up of the machine is at an aggressive attack angle and I had an idea that maybe the size of the reel is to blame for this difference. The diameter of the reel on the #3 machine is 11.618cm #4 is 11.363cm the others are closer to the #4 machine. My question is the following, would this difference of diameter of 2.5mm or radius of 1.25mm influence the amount of clippings being removed? Would that explain the difference? Could it be because we are using such an extreme attack angle that being a bigger reel it is entering more into the turf canopy therefore removing more grass?
I replied with this:
I don’t know the answer for the big difference in volume. My experience with reel diameter is roughly this. At Keya GC in Japan, the club got machines on loan from the distributor for a tournament. The exact model as the club had. Mechanic set them all up the same. The machines on loan from the distributor were getting about 2x the clipping volume as were the club’s own machines. The difference was the reel diameter, which changed the effective angle of attack or behind center distance (these machine setup things are not my specialty), because the loan machines had brand new reels spin ground 1x, and the club’s machines had reels that had been ground more. I don’t know the magnitude of the difference in the reel diameter, but everyone thought the machine setups were identical until the clipvol difference was noticed.
Has anyone else noticed something like this, or can help to explain a possible answer to the observed difference in volume between machines?