Gadolinium in soils and its effect on the count rate of the neutron moisture meter

Abstract

Concentrations of gadolinium up to 36 ppm were found in some Tasmanian soils, particularly deep in the profile. The addition of 10 ppm gadolinium to a soil lowered the slope of the calibration line of a neutron moisture meter. Thus gadolinium needs to be added to the list of elements likely to occur in sufficient amount in soil to affect seriously the count rates of neutron moisture meters.