三峡库区不同植被类型土壤养分特征

Characteristics of soil nutrients of different vegetation types in the Three Gorges reservoir area

通过三峡库区8个植被类型370个样地的群落调查和土壤分析,研究了不同植被类型、土壤类型、海拔对表层土壤有机质及全氮、速效磷、速效钾含量的影响。结果表明:(1)三峡库区不同植被类型土壤有机质、全氮平均含量规律为阔叶林>竹林>针叶林>灌丛>草丛,森林土壤有机质及全氮平均含量丰富;速效磷平均含量表现为草丛>落叶阔叶林>灌丛>暖性针叶林>常绿落叶阔叶混交林>温性针叶林>竹林>常绿阔叶林,草丛与其他植被类型差异显著;速效钾平均含量表现为常绿落叶阔叶混交林>落叶阔叶林>灌丛>针叶林>竹林>草丛>常绿阔叶林,竹林、草丛、常绿阔叶林与常绿落叶阔叶混交林、落叶阔叶林、灌丛、针叶林差异显著。(2)不同土壤类型养分含量差异显著,黄棕壤中有机质、全氮含量高,分别为6.83%、0.44%,紫色土中速效磷含量高,达到54.24mg/kg。(3)随海拔升高,有机质、全氮含量呈明显增加趋势,速效磷、速效钾含量变化趋势不明显。

Through investigating and analyzing soil contents of 8 vegetation types and 370 experimental plots around the Three Gorges reservoir, we studied how different vegetation types, soil types, and altitudes affected the amounts of surface organic matter, total N, available P as well as available K. The results indicate： In general, average amounts of soil organic matter and total N are rich in forest around the Three Gorges reservoir area ; specifically, the average amounts of the organic matter and total N vary in different vegetation types in the following order： broad-leaved forest 〉 bamboo forest 〉 coniferous forest 〉 shrub 〉 grass. The average amounts of available P in the vegetation decrease gradually in the order of： grass 〉 deciduous broad-leaved forest 〉 shrub 〉 warm coniferous forest 〉 deciduous broad-leaved evergreen forest 〉 temperate coniferous forest 〉 bamboo forest 〉 evergreen broad-leaved forest, as the grass differentiates from other types of vegetation dramatically. The average amounts of available K vary in the order of deciduous broad-leaved evergreen forest 〉 deciduous broad-leaved forest 〉 shrub 〉 coniferous forest 〉 bamboo forest 〉 grass 〉 evergreen broad-leaved forest. The amounts of nutrients in different types of soil vary remarkably, as the yellow-brown soil is rich in organic matter and total N, while the purple soil is rich in available P. With increases in altitude, organic and total N increase dramatically; no obvious trend is found as the amount of available P and available K change. The correlation analysis indicates that the content of soil organic matter, total N are significantly positively correlative.