OM246

We provide soil testing services for clients around the world through Brookside Labs, and have an active research program in the area of turfgrass nutrition, soil and plant analysis, and sampling methods.

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

TL;DR: 1) Know the standard sand rate recommendations, which range from 6 to 11 mm per year at present 2) Measure the amount of sand you apply 3) Don’t apply the standard amount!

I’ve looked at soil organic matter (SOM) and OM246 test results for putting greens of different species. In the top 5 cm (that’s about 2 inches), there will be some SOM and there will also be undecomposed material.

A set of OM246 total organic material samples inadvertently got a grinding and sieving process just like normal soil samples.1 As you probably know, a key distinction of OM246 testing is that soil samples are tested at the lab as is, with no subsampling or screening of the sample.

February 3: Harmonizing Turf Growth, Soil Organic Material, and Surface Performance, warm-season edition Download warm-season slides, 3.1 MB pdf file Reference guide (translation table) between species Download guide, 5 page pdf February 4: Harmonizing Turf Growth, Soil Organic Material, and Surface Performance, cool-season edition Download cool-season slides, 3.

I’ve been following the total organic material (OM246) test results from the creeping bentgrass greens at Hazeltine National Golf Club with particular interest. Course superintendent Chris Tritabaugh has been measuring the sand application rate, the N application rate, and the aboveground growth (clipping volume).

These are the slides shown in the four presentations I made at the 2025 Danish Greenkeepers Conference. I’ve also included links to articles, calculators, and information discussed during the event.

A friend is in charge of a type of grass he hasn’t grown before. We went to look at the grass, and on the way to the golf course, he told me that someone had told him the grass didn’t need much sand topdressing.

Remember, the OM246 test measures the total organic material, living and dead. A 4 cm diameter core of fine-bladed manilagrass with extensive living plant material below the surface. If the grass has a more extensive root system, or a more extensive rhizome system, the OM value measured on an OM246 test will go up simply from there being more total organic material in the sample.