Seasonal changes in the soil moisture distribution around bare rock outcrops within a karst rocky desertification area (Fuyuan County, Yunnan Province, China)

Sheng Li,Jun Chang,Xiaohua Yao,Huadong Ren,Liang Xue,Steffen Birk

doi:10.1007/s12665-016-6290-1

Sheng Li, Jun Chang + Show 4 more

Open Access

https://doi.org/10.1007/s12665-016-6290-1

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Abstract

The spatial and temporal soil moisture distribution is an important control on surface ecological processes in areas with rock outcrops resulting from karst rocky desertification (KRD). To explore the local effects of bare rocks within different seasons, soil moisture was measured in a KRD region (Fuyuan County, Yunnan Province, southwest China) at different depths and in different directions and distances from rock outcrops in both the dry and the wet seasons. The soil moisture north and east of the rocks was higher compared to the other directions and to the control plot. This effect is attributed to the shading by the rocks. The shading effect is evident in all seasons but more pronounced in the dry season. In the wet season, the directional dependency is restricted to the surface layer and the increase in soil moisture with depth is more pronounced around the rocks than at the control plot. This is attributed to precipitation-induced runoff from the rock outcrops infiltrating into the deeper layers at the rock–soil interface. These findings suggest the redistribution of water in the wet season and the spatial variation of evapotranspiration in the dry season are factors controlling the local soil moisture pattern around the rock outcrops.

Highlights

The moisture of the surface soil layer plays a significant role in the microenvironment and is a key parameter in soil surface modeling (Peters-Lidard et al 2001; Song et al 2009)
These findings suggest the redistribution of water in the wet season and the spatial variation of evapotranspiration in the dry season are factors controlling the local soil moisture pattern around the rock outcrops
This work examined the seasonal changes in the small-scale soil moisture distribution within the microenvironment close to bare rock outcrops on a slope in this type of setting

Summary

Introduction

The moisture of the surface soil layer plays a significant role in the microenvironment and is a key parameter in soil surface modeling (Peters-Lidard et al 2001; Song et al 2009). Soil moisture and its spatial variation are closely related to vegetation (Ferreira et al 2007; Vivoni et al 2008). The variability and pattern of soil surface moisture has received increasing attention from local to continental scales (Qiu et al 2001; Koster et al 2004; Feng et al 2004; Parent et al 2006). The assessment and interpretation of observed soil moisture patterns is complicated by the spatial scaling of soil moisture. The apparent variance in soil moisture data was found to be unaffected from spacing, but to decrease with decreasing extent and increasing support (Western and Bloschl 1999; Rodriguez-Iturbe et al 1995; Famiglietti et al 2008)

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