Publication Date:
2011-12-24
Description:
There are various factors governing the spatial and temporal variability of soil water storage including soil properties, topography, and vegetation. Some factors act locally, while others act non-locally, which means that a factor measured at one location has effect on soil water storage at another location. The objective of this study was to examine the effects of local and nonlocal controls of soil water storage in a hummocky landscape using cyclical correlation analysis. Soil water storage, soil properties, and terrain indices were measured along a 128-point transect of 576 m long from the semi-arid, hummocky, prairie pothole region of North America. There are large coefficients of determination ( r 2 ) between soil water storage and sand content ( r 2 = 0.32 to 0.53), organic carbon content ( r 2 = 0.22 to 0.56), depth to carbonate layer ( r 2 = 0.13 to 0.63), wetness index ( r 2 = 0.25 to 0.45), and other variables at the measurement scale at different times, indicating strong local effects from these variables. The correlation coefficients were also calculated by physically shifting the spatial series of soil water storage with respect to that of controlling factors. The shifting improves the correlation between the spatial series and the length of shifting indicated the difference in the response of soil water to its controlling factors. For example, the value of r 2 increased over eight folds ( r 2 = 0.47 to 0.64) after shifting the spatial series of soil water storage by 54 m, almost equal to the average length of existing slope, compared to the very weak correlation ( r 2 = 0.02 to 0.08) at the measurement scale. This indicated the nonlocal effect from the relative elevation. Identification of nonlocal effects from factors improves the prediction of soil water storage. Copyright © 2011 John Wiley & Sons, Ltd.
Print ISSN:
0885-6087
Electronic ISSN:
1099-1085
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
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