Installation of neutron probe access tubes in stony and bouldery forest soils

A method for implanting neutron probe access tubes in inaccessible stony and bouldery soils is described. The method employs a steel rod to displace the soil after which an access tube is dropped into place. Use of a displacing device rather than a pneumatic drill appears to improve contact between access tubes and soil. This method is not preferable to removal of soil with a sampling tube-like device where possible. (U.S.)