Recent work conducted as part of the CRC for Spatial Information’s ‘Biomass Business’ project has confirmed that buried aluminium access tubes, typical of those used for neutron soil moisture probes are found to significantly alter the readings of EM38 soil surveys when they are collected within 50 cm of the tube location. Neither the empty access holes used to insert the access tubes, nor the widely-used Polyurethane nor PVC tubes used for capacitance-type soil moisture probes were found to alter the EM38 readings. Work is continuing linking EM38 response with soil moisture.