Abstract: Physical and chemical properties of soils at five stages in the process of karst rocky desertification in 2006-2013 were investigated with chronosequence method in karst plateaucanyon region in Guizhou. This work aims to study the spatial and temporal evolution of soil physicochemical properties, and provide a scientific basis for further control of rocky desertification. The results showed that controlling of karst rocky desertification had generally improved the soil physicochemical properties, such as capillary porosity, total porosity, field moisture capacity, capillary moisture capacity, saturated permeability, pH, total potassium content, available potassium content and total phosphorous content. As time went on, change trends of soil physicochemical properties were stable or fluctuant at early stage and became better subsequently, which appeared as a non-linear pattern. These changes illustrated that there was a lag-effect between the improvements of soil physicochemical properties and plant community structure and microclimate, and they were probably affected by the heavy drought in southwest China in 2009-2010. At the spatial scale, soil physicochemical properties in stage of no rocky desertification had the best performance, and there were no significant differences among the other four stages of rocky desertification. This study demonstrated that the differences of soil physicochemical properties among different stages of rocky desertification became indistinct after long-term control, while “space instead of time” method was inapplicable in the current work. The poor performance of soil properties in stages of potential and slight rock desertification suggested that more attention should be paid to these two stages in the future practice.

Key words: net ecosystem exchange, vapor pressure deficit, clearness index, photosynthetic photon flux density, ecosystem respiration.