Soil organic matter/material "high" values

Dr. Robert Carrow recommended a maximum soil organic matter content of 4% by mass in the top 2 inches of sand-based putting green rootzones. That's with the verdure removed, and I expect that would be equivalent to about 4.25% with the verdure on.

The NZSTI and the STRI recommend total organic material be kept at less than 6% by mass in the top 2 cm of putting green rootzones. This is also with verdure removed. The number would be a…