地形因子与人工林土壤有机碳密度的关系——以晋西黄土丘陵区为例

摘要

Four typical plantations were selected to explore the nature of soil organic carbon (SOC) density under different plantations of the Loess Hilly Region,in Western Shanxi Province,China.SOC densities in upper layer (0-20 cm) and lower layer (20-40 cm) were measured and compared to analyze the distribution of SOC density accordingly.By ordinary least squares (OLS),the quantitative relationship between the topographic factors and SOC density was analyzed.The result shows that there are positive correlations between SOC density and total N,and available N at 0.01 level.SOC density under four plantations is ranked as:mixed wood＞coniferous plantation＞artificial broad-leaved forests＞shrubs.There is SOC density difference,accounting for 18.4％ of the differences in SOC density,in different topographic conditions.SOC density decreases with the increasing of slope.As aspects changes from sunny to shady,its distribution characteristics of different slope position is as slope top＜slope surface＜slope base.%为了探究晋西黄土丘陵区不同人工林下土壤有机碳密度的性质,在该区选取了4种典型人工林配置模式,对其土壤上层(0 ～20 cm)和下层(20 ～40 cm)的有机碳密度进行了测定和比较,分析了不同人工林下土壤有机碳密度分布的特性.借助普通最小二乘法(OLS),对地形因子与土壤有机碳密度之间的量化关系进行了分析.结果表明:土壤碳密度与全N、水解性N均在0.01水平上显著正相关.林下的土壤碳密度排序为针阔混交林＞人工针叶林＞人工阔叶林＞灌木林.土壤碳密度在不同地形条件下存在差异,但地形差异只能解释土壤碳密度差异的18.4％.土壤碳密度随着坡度的增大而减少,从阳坡到阴坡不断增加,坡面位置的分布特征则为坡顶＜坡面＜坡脚.