Thatch and mat at the top of turfgrass rootzones are removed from soils prior to testing for soil organic matter. Total organic material (OM246) testing is designed to measure the soil organic matter plus the thatch and mat.The blog post discussed is https://www.asianturfgrass.com/post/organic-matter-and-screens/Read more about all kinds of turfgrass topics at https://www.asianturfgrass.com/Find a suite of decision-making tools at https://www.paceturf.org/Get free ATC newsletters at https://www.asianturfgrass.com/newsletter/ Find out more about soil tests with ATC at https://www.asianturfgrass.com/project/soil-tests/