chapter  10
28 Pages

Soil Spatial Variability

One of the parameters of soil ecosystems are soil processes (Gregorich et al., 2001). Process is based on the Latin word “procedere-to proceed, to advance, to go on.” Each individual stage of a process depends on the previous stage in either a causal (deterministic) manner or a probabilistic (stochastic) manner. A soil process can be considered in space and time. A spatial soil process is the change of a variable or a state vector consisting of several variables across a spatial domain caused by underlying e¦ects. ¤e spatial process of soil water content considered across a landscape can be in¥uenced by spatial changes in soil type, topography, vegetation, rainfall, evapotranspiration, management, etc. Similarly, a temporal process is the change of a soil variable or state vector observed at the same location over time caused by underlying e¦ects. ¤e temporal process of soil water content is in¥uenced by temporal occurrences of precipitation, evapotranspiration, drainage, capillary rise, etc. Hence, subsequent stages in either space or time do not vary randomly but depend on each other. If in fact subsequent stages of a process do not depend on each other but rather vary randomly, the monitoring of a sequence of stages would not allow us to derive any causal or statistical relationships between various ongoing changes. In other words, the spacing or time increments between observations would be inappropriate to identify the process.