母质对南方丘陵区水耕人为土理化性质演变的影响

基于时间序列系统分析了我国南方丘陵区三种母质起源的水耕人为土理化性质的演变,结果表明:成土母质可以决定黏粒与土壤有机碳(SOC)对人为水耕成土过程的敏感性,明显影响其演变特征。游离铁(Fed)对人为水耕的成土过程非常敏感,其迁移与转化主要受人为水耕成土过程影响,受成土母质影响很小;硅酸盐铁(Fet-Fed)对人为水耕的成土过程不敏感,但全铁(Fet)含量的分布主要受Fed的影响。黏粒的淋失会对土壤中元素的迁移与分布产生重要影响,造成SiO2相对富集和Al2O3相对亏损,在利用由Al和Si两种元素计算所得到的一些指标指示丘陵区水耕人为土的发育程度时一定要慎重;而TiO2在水耕人为土发育过程中相对稳定,可以作为稳定元素来指示水耕人为土演变过程中其他元素的迁移率。

Influence of parent material on evolution of physico-chemical properties of Hydragric Anthrosols in hilly regions of South China

Chronosequence analysis done of three Hydragric Anthrosols derived from purple sand shale, quaternary red clays and red sandstone, respectively, in hilly regions of South China to explore evolutions of their basic physico-chemical properties. Results show that parent material was the major factor determining sensitivity of clay and SOC to forming processes of the soils and hence apparently evolution of their soil properties. Free ion (Fed) was very sensitive to the soil forming processes, and its translocation and transformation was mainly affected by the latter, rather than soil parent material. However silicate iron (Fet-Fed) was not so sensitive to soil forming processes, and the distribution of total ion (Fet) was affected mainly by Fed. Loss of clay had some important effects on migration and distribution of soil elements, causing enrichment of SiO2 and loss of Al2O3 in the soils. It must, therefore, be careful in working out some indices to indicate development stages of Hydragric Anthrosols by using the two elements, Al and Si. TiO2 was relatively stable throughout the soil forming processes and hence could be used to indicate migration rates of other major elements in the paddy soils.