During the winter and spring of 2016, specialists at Purdue University and the USDA-Natural Resources Conservation Service (USDA-NRCS) received numerous reports that roots were clogging tile drains. Other agricultural advisers were hearing similar stories and many were posting and reading about these reports online.
The issue is not common. There are many long-term no-tillers who use cover crops that do not have plugged tile. Farmers who are experiencing this are not seeing it in every tile, so it appears to be site-specific and tied to other factors besides simply no-till with cover crops.