气候和区段对昆明蒋家沟流域山地失稳性坡面土壤化学计量特征的影响

The Influence of Climate and Sections on Soil Stoichiometric Characteristics on Unstable Mountain Slopes in Jiangjiagou Watershed, Kunming

根据蒋家沟流域的气候垂直带谱,选取了流域内温带湿润山岭区(TH)、亚热带和暖温带半湿润区(SW)、亚热带干热河谷区(SD)为研究区,分析典型失稳性坡面土壤养分含量、化学计量比的空间分布特征及其与气候和区段的关系。结果表明:研究区土壤C∶N、C∶P和N∶P分别介于10.98~29.43、22.39~38.19和1.74~2.20,TH的C∶N、C∶P显著高于SW、SD,表明良好的水热条件有利于土壤养分积累。土壤C∶N、C∶P与N∶P整体上呈现稳定区>失稳区>堆积区的变化趋势且三者间差异显著,表明区段显著影响土壤C∶N、C∶P与N∶P;气候因子(温度与降水)显著影响蒋家沟流域的土壤碳氮磷化学计量学特征。因此,水热条件良好的温带湿润山岭区土壤化学计量比(C∶N和C∶P)高于其他两个气候区,亚热带和暖温带半湿润区、亚热带干热河谷区的土壤化学计量比受坡面稳定性影响,总体表现出稳定区>失稳区>堆积区的区段显著差异趋势。

According to the vertical climate zone spectrum of Jiangjiagou watershed, the temperate humid mountainous region(TH), subtropical and warm temperate semi-humid region(SW), and subtropical dry hot valley(SD) in the watershed were selected as the research area to study the spatial distribution characteristics of soil nutrient content and stoichiometric ratio of typical unstable slopes and their relationships with climate and section.The results showed that the soil C∶N, C∶P and N∶P in the study area ranged from 10.98 to 29.43, from 22.39 to 38.19, and from 1.74 to 2.20. The C∶N and C∶P in the TH were significantly higher than SW and SD. TH with good hydrothermal conditions was conducive to soil nutrient accumulation. In terms of sections, the soil C∶N, C∶P, and N∶P showed stable area > unstable area > deposition area, indicating the section significantly affected the soil C∶N, C∶P and N∶P. Correlation analysis and variance analysis results showed that climate factors(temperature and precipitation) significantly affected the stoichiometric characteristics of soil carbon, nitrogen, and phosphorus on unstable mountain slopes in Jiangjiagou watershed. In our study, TH with good hydrothermal conditions had significantly higher soil C∶N and C∶P than the other 2 climates, while SW and SD affected by unstable slopes showed significant differences of stable area > unstable area > deposition area in soil stoichiometric ratios.