Abstract: The Karst rock desertification (KRD) in Southwest China is characterized by a large number of rocks cropping out from the ground. To understand the responses of soil moisture to the bare rocks, a monitoring was made on the dynamic changes of soil moisture in a KRD region during an extreme drought period from September 2009 to February 2010. During this drought period, the soil moisture content on the north side of the rocks was significantly higher than that on the east, west, and south sides (P<0.01), and the surface soil moisture content increased with the protruding height of the rocks. There existed significant correlations between the sizes of the bare rocks and the soil moisture content on the west and north sides (P<0.01) and on the east side (P<0.05) of the rocks. Sharper rocks were associated with lower soil moisture content on the east, west, and north sides of the rocks. With the increasing distance from the rocks, the soil moisture content decreased after an initial increase on the north, east, and west sides, but showed an increasing trend on the south side. The soil moisture content around the rocks increased with soil depth. During the drought period, bare rocks presented shading effect, resulting in higher soil moisture content on the north side of the rocks, as compared to the other three sides. The location at 15 cm north of the rocks had the highest soil moisture content, being a favorable site for the vegetation restoration under stressful environmental conditions in the KRD area. These research findings would have significance in the vegetation restoration of the ecosystems damaged by the KRD process.

Key words: insecticide, greenhouse gas., application dosage, herbicide, fungicide, active ingredient, biological pesticide