organic matter

Measure exact topdressing effect, and requirement, by checking total organic matter by depth.

I got to see a lot of beautiful and interesting turfgrass around the world in 2022. I looked through my photos from the year and chose these as my favorites.

I’ve tried to explain the value of total organic material testing by comparing it to the soil organic matter. In the timelines shown below, the total organic material in the top 2 cm (0.

This topic—carbon in turfgrass soils—was the subject of a Frankly Speaking podcast episode. One of the topics host Frank Rossi spoke about with guests Drs. Claire Phillips and Alec Kowalewski was the nitrogen mineralized from soil organic matter.

First some background information. I had shared this post that showed a number of different scenarios of organic matter change with hollow-tine cultivation (coring) and solid-tine cultivation, including examples with and without sand topdressing.

An interesting phenomenon happens when grass is planted on a golf course putting green. There’s typically not much organic material in the soil when the green is first planted. The organic material increases rapidly, to about 4% organic material in the top inch (2.

I’ve been thinking about this one a lot. It seems obvious that a sward supplied with more nitrogen fertilizer will tend to produce more organic material in the soil. It also seems obvious that a sward on which hollow-tine cultivation, or scarification, or sand topdressing, have been conducted, will need to receive more nitrogen in order to produce a surface compared with an adjacent sward that didn’t receive any of that work.

Daniel Hahn asked an interesting question about organic matter. Talking about “variability between greens at the same site,” he wondered, “could you explain what your opinion is about the statement, if you think greens vary a lot in OM or if you see minor difference?

I’ve been making estimates of N mineralization from soil organic matter for the past few years using the method described by Gilmour and Mauromoustakos in Nitrogen mineralization from soil organic matter: a sequential model.

Turfgrass creates a lot of soil organic matter (SOM), also called humus, and the quantities of carbon (C) in that organic matter might surprise you. I made this chart to summarize the amount of C in the top 10 cm (4 inches) of a turfgrass rootzone.