Spatial heterogeneity of soil water content on surface land following
reforestation in a semi-arid region
Abstract
The spatial pattern of soil water content (SWC) determines the success
of vegetation restoration in semi- and arid regions. The Qilian
Mountains in China are in a semi-arid area where decades of
environmental degradation prompted large-scale restoration efforts with
a native constructive species Picea crassifolia. However, the
relationships between SWC and landcover are not clear in this area,
hindering woodland restoration. In this study, we determined spatial
distribution and characteristics of SWC in the Qilian Mountains in four
main types of landcover. Our results revealed that 1. SWC decreased in
the order of natural forest, brushland, grassland, planted forest, and
mixed forest, but it was significantly different only in natural forest
(p<0.05); 2. planted forest exhibited a lower SWC at young
ages (less than 50 a) than natural forest, brushland or grassland, and
the ecohydrological effect of afforestation exhibited hysteresis at long
time scales; 3. a variogram analysis and Kriging interception of the
spatial pattern of SWC showed that shrubland and grassland exhibited
superior adaptability to local SWC compared with afforestation. The
differences in SWC among various landcover types indicated that
strengthening the maintenance and protection of natural forests is more
important for restoration efforts than afforestation; furthermore, in
semi-arid regions, shrubs and grasses are more suitable for use in
ecological restoration than forest plantations.