贵州贞丰—关岭花江喀斯特石漠化过程中岩土体化学元素含量与石漠化差异性关系研究

摘要

The Zhenfeng-Guanling-Huajiang rock desertification demonstration area is a typical karst canyon in Guizhou,where the water and soil losses are serious and many places have suffered from intense rocky desertification.In order to study the intensity and diversity of rocky desertification in the area,11rock and soil samples from the 11 quadrats in the demonstration were collected and their chemical compositions were analysed.The results show that,(1) When the ratio of CaO/MgO in rock is larger and ratio of Rb/Sr is lower,the level of rocky desertification is higher.It means the strength of rocky desertification increases with the ratio of CaO/MgO increasing,and reduces with the ratio of Rb/Sr increases.(2) In the process of carbonate rock dissolution and weathering into the soil,Ca and Mg ions in rocks are taken away.As a result,their contentsin the rock are accordingly reduces,while the content of Mg ion in soil increases in intense rocky desertification areas.(3) The degree of chemical element loss and concentration has slightly differences in different rocky desertification areas.Generally the content instrong and potential rocky desertification area are higher than the mild and moderate rocky desertification area.(4) The ratio of Rb/Sr in the soil is higher,the degree of rocky desertification is more intense,that is the ratio of Rb/Sr increases with the intensity of growing rocky desertification.According to the different chemical elements in different rock desertification areas,this work studies the mechanism of water and soil loss in this area,which provides theoretical and practical basis for research of the water and soil loss and rocky desertification control in the demonstration area.%不同等级石漠化地区岩体和土体中化学元素有较大的差异,表现在石漠化演化过程中不断被改变,化学元素的差异性对石漠化等级差异性的形成有着内在的关联性.文章以贵州贞丰—关岭花江石漠化治理示范区为研究区,选取11处样地的岩石样和土样,对其进行室内实验分析,以了解该地区岩石和土壤的化学元素含量,从而研究其含量的差异性与石漠化等级之间的关系.结果显示:①岩体中CaO/ MgO)的值越大,Rb/Sr值越低,石漠化等级越高.②在碳酸盐母岩逐渐溶蚀和风化成土的过程中,岩体中Ca、Mg离子被带走,导致成土后土体中Ca、Mg离子含量降低,但强度石漠化地区的土体中Mg离子含量却增加.(③不同等级石漠化地区的样品化学元素流失和富集的程度略有差异,一般强度和潜在石漠化地区(离子)含量要高于轻度和中度石漠化地区.④土体中Rb/Sr值越大,石漠化等级越强.该研究可以为示范区的水土流失及石漠化治理提供理论和实践依据.