Soil Biogeochemical Characteristics In The Process Of Karst Rocky Desertification

The problem of karst rocky desertification in Guizhou province has been attached more and more importance in recent years. The harness of rocky desertification has become the national focus and got much sustains from concerned ministries and commissions. However, the austere facts are the overtaking of ecology construction and the lagging of basic researches. As a basic theory, it is of great importance to study soil biogeochemical characteristics in the process of karst rocky desertification, hence lay a precondition and theoretic base for laying out rocky desertification district, mapping out rock desertification regulation step and ecosystem restoring. This research selected a limestone-continuously-distributed catchment in Huajiang gorge area, to study the soil biogeochemical characteristics with reclamation and wood chopping disturbing ways and different disturbing extent in the process of rocky desertification. The following conclusions are drawn from the analysis.1. Karst ecosystem has high degree micro-habitat heterogeneity, and which kind of soil samples can represent the plot still needs further investigation. After studying the SOC content and environment factors of typical plot in Maolan karst virgin forest, the results elucidated that the soil variability of karst ecosystem was much higher than that of non-karst ecosystem, and the visibilities existed in the same micro-habitats, the same type of micro-habitats, and different types of micro-habitats. The variability resulted from the high heterogeneity of environment factors such as micro-habitat soil area, soil depth and litter depth etc.. This conclusion was also proofed by the results of 17 plots in Huajiang area, in which the variations of soil area and soil depth were higher than those of SOC and total nitrogen. In order to get comparative data among soil degradation researches of karst ecosystem, the author suggested a method for sampling representative soil as following ways. Firstly, micro-habitat types which the soil area was almost 95% the total soil area in the plot should be selected. Then, several sub samples from the same micro-habitat should be mixed and homogenized to represent it. Thirdly, the soil samples that represent a micro-habitat type should be...