Real-time 2D visualization of soil fertilizer dynamics in potatoes using a multi-sensor capacitance probe array

Abstract

The use of intensive soil water monitoring with multiple-depth sensor arrays in representative soil volumes can indicate plant water usage rates in the broader scale. Multiple Sentek TriSCAN soil moisture monitoring probes were installed in a cross-hair arrangement adjacent to potatoes ('Ruby Lou') irrigated with a centre pivot. Volumetric soil water content (VWC - site-specifically calibrated) and volumetric ion content (VIC) data was collected for the full growth season on a near-continuous basis simultaneously across the probe array. This was analysed using IrriMAX™ 2D Viewer and VIC Filter software to visualise the water and salt distribution within the soil in 2 dimensions. This software uses automated cubic spline interpolation techniques to generate contour maps and video animations of the water and salt dynamics. The parameter scales are obtained from the whole dataset and planar views (transects) are painted with false colours to visualise the dynamics of the water and salt movements throughout the soil profile. When this is interpreted with known fertilizer input records, this method allows the visualisation of the spatial distribution of nutrients within the soil and the duration of time over which such a distribution persists. This gave insights into the plant usage and soil drainage characteristics that were then applied over the larger area, thus helping the operator to optimize fertilizer and irrigation inputs to best suit plant requirements. Of particular benefit was the routine timed application of irrigation waters to control salt build-up within the soil.