USE OF NONCONTACTING ELECTROMAGNETIC INDUCTIVE METHOD FOR ESTIMATING SOIL-MOISTURE ACROSS A LANDSCAPE

There is a growing interest in real-time estimation of soil moisture f or site- specific crop management. Non-contacting electromagnetic indu ctive (EMI) methods have potentials to provide real-time estimate of s oil profile water contents. Soil profile water contents were monitored with a neutron probe at selected sites. A Geonics LTD EM-38 terrain m eter was used to record bulk soil electrical conductivity (ECA) readin gs across a soil- landscape in West central Minnesota with variable mo isture regimes. The relationships among EG(A), selected soil and lands cape properties were examined. Bulk soil electrical conductivity (0-1. 0 and 0-0.5 m) was negatively correlated with relative elevation. It w as positively correlated with soil profile (1.0 m) clay content and ne gatively correlated with soil profile coarse fragments (>2 mm) and san d content. There was significant linear relationship between ECA (0-1. 0 and 0-0.5) and soil profile water storage. Soil water storage estima ted from ECA reflected changes in landscape and soil characteristics.