FIELD SCALE TEMPORAL AND SPATIAL STABILITY OF SOIL
MOISTURE
Abstract
Spatial patterns of soil moisture across a field seem to exhibit some degree of temporal
stability. However, how these patterns and locations might be predicted from invariant
attributes like topography is not well understood. The goal of this project is to determine
how topography relate to underlying stable and consistent moisture pattern s and to
examine the spatial scale over which those relationships are exerted. In this study, we got
the soil moisture data which was collected across a working 25-acrea field just southeast
of Ames, IA, during the late spring and early summer of 2004 and 2005.
Spatial
characteristics of the soil moisture patterns will be analyzed with variogram analysis in
order to determine the scale within which the spatial dependence of moisture exists, as
well as to investigate the relationships between moisture patterns and topographic index
such as elevation in this case. Taking the finer elevation data as a covariate, Universal
Kriging will be used as a tool to predict the moisture distribution based upon the linear or
2nd polynomial regression in the whole field. All the spatial analysis of soil moisture data
will be used to reveal if the spatial characteristics of the soil moisture patterns are similar
from one date to another or not, based upon which, therefore, the temporal stability of the
soil moisture patterns will be determined.