Spatial variability occurs when a quantity that is measured at different spatial locations exhibits values that differ across the locations.
Let us suppose that the Rev' z(x) is perfectly known at any point x within the field under study.
Uncertainty is closely related to the amount of spatial variability, but it is also strongly dependent upon sampling.
[1] Geostatistical analyses have been strictly performed to study the spatial variability of pesticide sorption[2][3][4] and degradation[5] in the field.
Webster and Oliver[6] provided a description of geostatistical techniques.