衡阳紫色土丘陵坡地不同恢复阶段土壤理化特征

以衡阳紫色土丘陵坡地不同恢复阶段的典型植被为研究对象，采用空间代替时间序列方法，选用立地条件基本一致、植被恢复阶段迥异的裸荒地、草地、灌木林和森林，通过调查取样和实验分析，探讨了衡阳紫色土丘陵坡地不同恢复阶段及同一恢复阶段不同土层土壤理化特征的时空变化；分析了不同植被恢复阶段的植被类型和土壤理化特性变化的内在联系及其互作效应。结果表明:随着植被恢复演替的进行，土壤黏粒含量总体增加，其中表层增加较多，亚表层、下层增加不明显；土壤容重逐渐减小，表层土壤容重小于亚表层与下层；土壤有机质逐渐增加，但随土层深度的增加而递减，表现出明显的表聚性；土壤全氮、速效磷和速效钾含量均呈上升趋势，由于植物根系及枯落物数量的差异，各营养成分的垂直分布各异。这将丰富该地区植物生态学与恢复生态学的内容，为衡阳紫色土丘陵坡地生态系统的恢复与重建提供了重要依据。

Soil Physiochemical Characteristics in Different Restoration Stages on Sloping-land with Purple Soils in Hengyang

By using the space series to replace time courses, four typical sample plots: the bare land, herbaceous community, shrubby community and arboreal community in similar sites in the sloping land with purple soil in Hengyang, standing for four different restoration stages, were selected as the study sites to explore the relationship and interaction effects of plant communities with the soil physiochemical characteristics in different restoration stages. The spatial change of soil physiochemical characteristics was studied in different restoration stages and different soil layers at the same restoration stages. The results showed that the soil clay contents increased in general, which increased considerably in surface layers but increased very little in sub-surface and lower surface layers; the soil bulk density decreased with the succession of different restoration stages, and the bulk density in surface soil was lower than that in sub-surface and lower surface; the soil organic matter(SOM) increased with the succession of different restoration stages in general, but the SOM declined with the increase of soil depth, which showed a clear concentration of SOM in the topsoil; the soil TN, AP and AK increased with the successions of different restoration stages; the differences of plant root and litter amount distributions resulted in the differences in profile distributions of each soil nutrient. This study could enriched and broadened the research field of vegetation ecology and restoration ecology in this area to some extent and provided an important theoretical basis for ecosystem restoration and reconstruction in sloping-land with purple soil in Hengyang.