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.
A recent PACE Turf update mentioned this research project by Jackie Guevara and Kevin Frank: Effects of different soil testing interpretation philosophies on creeping bentgrass and annual bluegrass putting greens.
This post takes a few minutes to read because it covers this topic in a bit of detail. The summary is, I make use of two types of soil organic matter tests for turfgrass, these tests measure two different things, both important, and I recommend turfgrass managers measure both of these, ideally once a year.
These are the predicted distributions and percentiles of total organic matter in the surface 2 cm (0.8 inches) of warm-season grass putting greens.
I include a plot for predicted organic matter of a random green of an unknown species.