南亚热带不同植被下丘陵赤红壤结构特征比较研究

Comparative study on structure characteristics of hilly latored soils under different vegetation in south subtropics.

比较研究了南亚热带几种植被下丘陵赤红壤结构特征．结果表明，丘陵赤红壤的结构随着植被的演退而退化．表现在表土砂化，即砂粒含量相对增加，粘粒含量相对减少；土壤结构稳定性下降，主要体现在较大粒径水稳性团聚体减少；土壤孔隙性变差，主要体现在容重增加和较大孔径的孔隙减少．自然赤红壤容重增加、较大孔隙减少更为明显；耕型赤红壤结构稳定性下降，表土砂化更为突出．研究结果揭示，由植被演退引起的土壤有机质减少，是丘陵赤红壤结构退化的主要内在因素．

The study shows that with the backward succession of vegetation, the latored soils suffered structural degradation, which was characterized by the sandification of surface layer with relatively increasing content of sand grains and decreasing content of clay grains, the lowering aggregate stability with decreasing water stable aggregates and the deteriorating soil porosity with increasing bulk density and lowering large pore content. For natural latored soil, the increasing bulk density and the decreasing large pore content were more obvious, but for cultivated one, the lowering structural stability and sandification of surface layer were more serious. It is also indicated that the decrease of soil organic matter content caused by vegetation deterioration was the main interior factor causing the structural degradation of latored soils.