The neutron-probe data present a series of measurements of volumetric water content in the soil profile compiled using the neutron method. These data were collected from throughout the FIFE study area from May 1987 through August 1989. The neutron method of measuring soil water content uses the principle of neutron thermalization. When both hydrogen and oxygen are considered, water has a marked effect on slowing or thermalizing neutrons. Thermal neutron density is easily measured with a detector, if the capture cross-section remains constant then the thermal neutron density may be calibrated against water concentration on a volume basis.