基于典范对应分析的喀斯特峰丛洼地土壤-环境关系研究

Relationships Between Soil and Environment in Peak-Cluster Depression Areas of Karst Region Based on Canonical Correspondence Analysis

喀斯特地区是典型的生态脆弱区,环境容量小,抗干扰能力低,不同的土地利用方式、海拔、地貌地形特征等环境因子对土壤性质的空间变异有重要影响,峰丛洼地地貌景观异常破碎,石漠化严重,土壤性质对其环境的变化更加敏感.在野外调查取样、实验室分析的基础上,采用典范对应分析(CCA)研究土壤-环境关系.结果表明,不同的环境条件下土壤性质的空间变异有很大差异,全氮、碱解氮、有机碳、速效磷、速效钾、碳氮比的空间变异要比全磷、全钾和pH值的空间变异大,其中全氮、碱解氮和有机碳的空间变异趋势相似;不同的土壤性质与不同的环境因子之间的关联性不同,土壤有机碳、全氮和碱解氮与裸岩率和坡度有很好的关联性,速效钾主要受植被类型的影响,碳氮比与土壤厚度有很好的相关性,而全钾、全磷和pH值受环境的影响相对较小;不同的环境因子对土壤性质的影响程度大小依次为:土地利用方式>植被类型>裸岩率>坡向>土壤厚度>坡度>海拔高度.除全钾和pH值以外,不同的土地利用方式对土壤性质有显著影响.

Karst region is a typical ecological fragile zone, with small environmental and anti-interference capability. Many environment factors, such as different land use, elevation and topographic relief, have significant influence on spatial variability of soil properties, resulting in abnormal fragments of landscape and severe rocky desertification. The method of canonical correspondence analysis（CCA） was employed to reveal the relationships between soil and environment in peak-cluster depression areas of karst region, using the samples from field survey in Guzhou. Results show that spatial variability of TN, AN, SOC, AP, AK and C/N are greater than TP, TK, and pH, with the similar trend among TN, AN and SOC. Furthermore, CCA shows that SOC, TN and AN have high correlation with bare rock rate and grade, AK and vegetation type, together with the significant correlation between C/N and soil depth, while the environment has little effect on TK, TP and pH. Environmental factors that affect soil properties are listed as the following order： land use 〉 vegetation type 〉 bare rock rate 〉 aspect 〉 soil depth 〉 elevation. Except TK and pH, soil properties are significantly affected by different land-use types.