Spatio-Temporal Soil Water Processes at the Field Scale.

Spatial variability structure of field soil water status changes depending on the average level of soil water content. The associated variance behavior affects the quality of soil water content predictions and related processes. In order to design field experiments related to soil water, the spatial and temporal covariance behavior must be known and adequately represented in process equations. For soil water conditions close to “field capacity”, spatial variance of soil water content and fluxes reaches a minimum whereas variance increases towards wet and dry conditions because of soil structural and soil textural heterogeneity, respectively. An approach is presented in which spatial and temporal development of soil water and its prediction variance are calculated based on a set of equations that combines spatial covariance and a physically-based part for the temporal domain.