Temporal stability of estimated soil water flux patterns across agricultural fields

When a field or a small watershed is repeatedly surveyed for soil water content, sites often can be spotted where soil is consistently wetter or consistently dryer than average across the study area. This phenomenon has been called time stability, temporal stability, temporal persistence, or rank stability in spatial patterns of soil water content or in soil water contents. The temporal stability presents significant interest for upscaling observed soil water contents to obtain average values across the observation area, improving soil water monitoring strategies, and correcting the monitoring results for missing data. The objective of this work was to research the temporal stability in estimated soil water fluxes using extremely frequent multi-depth measurements of soil water content with multisensor capacitance probes installed in soil in multi-year corn production. Data on water contents at 10, 30, 50, and 80 cm depths were collected every 10 min for 20 months of continuous observations from May 2001 to December 2002. Temporal stability was well pronounced for soil water fluxes estimated from soil water balance for the depth of 60 m. Soil water fluxes can be upscaled and efficiently monitored using the temporal stability of soil water patterns.