花江小流域石漠化过程中的土壤有机碳氮的变化

以花江峡谷区1.2 km2小流域为研究对象,通过设置不同喀斯特石漠化强度的样地,研究不同等级石漠化样地的土壤有机碳、全氮含量在石漠化过程中的变化。结果表明,喀斯特生境中土壤具有高度异质性,人为干扰方式对土壤有机碳、全氮含量变异性的影响很大;樵采石漠化样地小生境土壤有机碳、全氮含量维持在较高水平,开垦石漠化样地小生境土壤有机碳、全氮含量较低;随着石漠化程度的加剧,樵采和开垦系列样地土壤有机碳、全氮含量呈现不断降低的趋势,这在一定程度上体现了石漠化过程的土壤退化本质。小流域内石漠化成因类型的划分对揭示石漠化过程中的土壤退化是必须的。

CHANGES IN SOIL ORGANIC CARBON AND TOTAL NITROGEN IN THE PROCESS OF ROCK DESERTIFICATION IN HUAJIANG WATERSHED

The Huajiang area is a typical gorge area with medium-serious karst rock desertification;the research area is a 1.2 square kilometer watershed,where the major lithosphere is successive limestone.The research object is changes in soil organic carbon and total nitrogen contents in rock desertification plots of different grades.The results showed that the soil of karst habitants had high variability,the anthropogenic disturbing ways evidently influenced the SOC and total nitrogen contents and variabilities.The SOC and total nitrogen contents of microhabitat were high in the wood chopping rock desertification plots,while the SOC and total nitrogen contents of microhabitat remained low in the reclamation rock desertification plots.The SOC and total nitrogen contents of SOC and total nitrogen in the areas of wood chopping rock desertifications are evidently higher than those in the areas of reclamation rock desertifications;and the vertical distributions of SOC and total nitrogen contents in different plots could also embody the influence of wood chopping and reclamation disturbing ways.As for the process of rock desertification,the decrease of SOC and total nitrogen contents and the increase of wood chopping rock desertification grades proceeded in the same direction,so did the reclamation rock desertification process.To some extent,this result could embody the essence of soil degradation along with the process of rock desertification.In order to reveal the relationship between the process of rock desertification and soil degradation,it is necessary to classify rock desertification genetic types in the watershed studied.