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Exploring the variation in soil saturated hydraulic conductivity under a tropical rainforest using the wavelet transform
Author(s) -
Hassler S. K.,
Lark R. M.,
Milne A. E.,
Elsenbeer H.
Publication year - 2011
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2011.01400.x
Subject(s) - soil science , environmental science , soil water , wavelet , spatial variability , geology , mathematics , statistics , artificial intelligence , computer science
Saturated hydraulic conductivity ( K s ) of the soil is a key variable in the water cycle. For the humid tropics, information about spatial scales of K s and their relation to soil types deduced from soil map units is of interest, as soil maps are often the only available data source for modelling. We examined the influence of soil map units on the mean and variation in K s along a transect in a tropical rainforest using undisturbed soil cores at 0–6 and 6–12 cm depth. The K s means were estimated with a linear mixed model fitted by residual maximum likelihood (REML), and the spatial variation in K s was investigated with the maximum overlap discrete wavelet packet transform (MODWPT). The mean values of K s did not differ between soil map units. The best wavelet packet basis for K s at 0–6 cm showed stationarity at high frequencies, suggesting uniform small‐scale influences such as bioturbation. There were substantial contributions to wavelet packet variance over the range of spatial frequencies and a pronounced low frequency peak corresponding approximately to the scale of soil map units. However, in the relevant frequency intervals no significant changes in wavelet packet variance were detected. We conclude that near‐surface K s is not dominated by static, soil‐inherent properties for the examined range of soils. Several indicators from the wavelet packet analysis hint at the more dominant dynamic influence of biotic processes, which should be kept in mind when modelling soil hydraulic properties on the basis of soil maps.