Our Office Hour (actually 2.5 hours) discussion, summarized
Chris Tritabaugh and I met to review the OM246 test results from samples collected in October 2021 at Hazeltine National Golf Club. We did this as a livestream episode of ATC Office Hours, which is available for watching or listening at your leisure.
And leisure is an apt word, because this “office hour” conversation ended up stretching to 2.5 hours, as we reviewed the test results and talked about a number of related matters.
Fortunately, YouTube and podcast players have settings to listen at increased speed, which works great for native English speakers who want to get through such a long episode more quickly. But this approach doesn’t work if you don’t understand English so well.
We discussed the total organic matter by depth report (OM246) for samples collected in October 2021. Chris and I looked at the charts in the report that showed how the total organic material had gone from 4.7% to 4.9% to 4.9% in samples collected in October 2019, October 2020, and October 2021. This is the total organic material measured by mass loss on ignition—by burning the sample in a muffle furnace at 440 °C—in the top 2 cm of the rootzone.
We talked mostly about the top 2 cm, because that’s where there is the highest level of organic material, because that’s where topdressing sand applied to the surface ends up, and because that’s where water hits the surface and foot traffic hits the surface and mowers roll across the surface and balls bounce on the surface.
I think it is fascinating to find that even with a relatively low amount of sand applied, the organic material stayed at 4.9% from October 2020 to October 2021. In the past, I would have recommended from 12 to 15 mm of sand be applied in one year, and I would have recommended from 15 to 20% of the putting greens’ surface area should be removed by hollow-tine cultivation (coring) or scarification. Maybe I would have said those were the goals, but realistically perhaps 10% surface area removal would be ok, and perhaps sand at about 8 or 10 mm would be a bare minimum.
But from October 2020 to October 2021, there was no scarification, no hollow-tine cultivation, and only 5.3 mm of sand applied to the greens during that interval.
We both expressed surprise, if I recall correctly, that in the past we would have thought it necessary to do a lot more disruptive work to the putting surfaces, to prevent organic matter from accumulating in excessive amounts. And we find this OM246 testing, together with regular assessment of playing performance through stimpmeter measurements and the bobble test, quite effective in allowing the putting surfaces to be optimized for golf play during the greatest possible number of days in the golfing season. What we mean by that is a count of the days during which the greens have a speed at or above a level desired by the membership, and the greens on those days have no scars from cultivation or loose sand on the greens that could affect the ball roll.
Much of the discussion was about the playability of the surfaces, and how this can be accomplished while still managing the organic matter at a suitable level. We recommended, I think, that a way to accomplish the desired playability at any facility using this type of approach might include measurement of the quantity of sand applied, measurement of the OM246 values over time, so that the effectiveness of the sand topdressing can be evaluated, and measurement of ball roll (and possibly ball bounce, or surface firmness); knowledge of these things allows the turf manager to optimize work that will produce the maximum possible days of excellent putting surfaces.
That’s what I recall.