喀斯特小流域土壤厚度的影响因素

Influencing Factors of Soil Thickness in Karst Small Watershed

在贵州普定县后寨河小流域75 km^2面积内,采用150 m×150 m的网格布点方式,挖设2 755个土壤剖面,研究了土壤厚度在小流域内的分布及其影响因素,并对喀斯特小流域土壤概念进行了探讨,结果表明从流域尺度来看,当前研究的热点问题中存在的一个新词汇即喀斯特土壤,需要定义为由喀斯特岩石发育形成的土壤,而不应该理解为分布在喀斯特区域内的土壤,否则极易导致理解差异而形成误解。流域尺度下土壤的分布特征表现为8度以下坡度条件下多分布厚度大的土层,而随着坡度的增加土层厚度减小;喀斯特与非喀斯特的土壤厚度存在差别,海拔条件下的土壤厚度与地貌特征关联度较大;而人为作用则由于主动选择的结果,人为影响大的土壤厚度较大;小流域内土壤厚度的影响因素主要与水动力条件相关,表现在坡度、坡位的主要影响方面,因此小流域土壤的利用需要考虑到土壤厚度的分布特征,即土壤厚度大的区域可以进行利用,但土层薄的区域则需要加强保护,尤其是坡度较大的区域;而石漠化区域则需要进行治理并加强保护。

2755 profiles were dug according grid of 150m＆#215;150m 75km2 area of small watershed of Houzhaihe,Puding,Guizhou province.Influencing factors of soil thickness distribution were studied,and the concept of karst soil was discussed,the results showed as follow,currently,karst soil,a new word of extremely used,is difficult to understand for the meanings＆#39; confusion,which needed to be defined exactly to be developed from the karst rocks and to be distinguished from the soil distributed in karst area.Soil was thicker when slope was lower than 8 degree,but thinner as the slope increased.The thickness of karst soil thinner than non-karst soil,soil thickness was increased with the decrease of altitude about sea level in the small watershed.Soil was thicker owing to the selection of human.From about,soil thickness was controlled by hydrodynamic force such as degree of slope and position of slope.It is needed to consider soil thickness while utilizing of soil in the small watershed,which means soil can be used while soil thickness is larger,but need to be protected while soil thickness is thinner,especially area of larger slope degree.The area of karst rocky desertification is needed to be managed and strengthened protection.