bentgrass

This is a difficult problem—pitch mark scars—and the only long term solution I know of is firmer surfaces. I was reminded of that this week when I saw balls bouncing on the greens at a tournament in Japan (see videos below).

I was passing through Corvallis and stopped to meet Tom Cook, who maintains his primarily bentgrass lawn with the greatest of care. Or is it neglect? He has not applied fertilizer to the lawn in 15 years, irrigates during the summer dry period only enough to keep the grass green, mows weekly, hand pulls the most egregious weeds, interseeds with white clover, and even keeps an unirrigated strip of turf in which one can find rat’s-tail fescue (Vulpia myuros).

There’s a short video about greenkeeper Mamoru Shoji and course maintenance at Kasumigaseki CC on YouTube. I especially like the view from the drone just after the 3 minute mark, showing the greens nestled among the carefully trimmed pine trees.

When I think about disturbance, I think primarily of verticutting and hollow-tine coring and sand topdressing and then brushing that sand in. Such an approach—one with disturbance—requires a faster growth rate too, and higher nutrient inputs, in order to recover from the disturbance.

Bentgrass grows more—or at least it produces more clippings for a while—when temperatures are higher than optimum for net photosynthesis. This means that you’ll typically see more clippings when the temperature is above the optimum for cool-season grass, even though the growth potential (GP) goes down at those high temperatures.

Perspective. It’s funny how that works. When I first read this research report in 2011, I skimmed over some parts, and cherry-picked what I was looking for — that 15 to 20% surface area removal was required every year in order to keep soil organic matter under control.

There’s a new column on the Nichino Ryokka website. It’s a collaboration between ATC and Nichino Ryokka, with some selected content from the ATC site published in Japanese. The first column is here, and the topic is a 12 point checklist for dealing with creeping bentgrass heat stress (the original list is here).

A late July solid-tine spiking treatment of a creeping bentgrass green in Hokkaido, Japan. How’s this for a lede? “Hollow-tine coring and solid-tine spiking practices may not alleviate creeping bentgrass summer decline.

Last November I saw a creeping bentgrass nursery in Japan. The nursery had been fumigated to kill seeds in the soil before the bentgrass seeds were planted. I was surprised to see, scattered across the nursery, plants with big leaves that clearly were not creeping bentgrass.

The MLSN guideline for phosphorus (P) is 21 ppm. I usually recommend enough P fertilizer to keep soil P, as measured by the Mehlich 3 extractant, from dropping below 21 ppm.