湘东大围山垂直带表层土壤肥力质量分析

为了解山地土壤肥力质量的垂直地带性分异规律,选取中亚热带典型花岗岩中山(湘东大围山)土壤垂直带,沿海拔梯度采集21个调查样地的表层土壤样品,室内分析14项土壤物理、化学指标(砂粒含量、粉粒含量、黏粒含量、容重、pH值、有机质含量、全氮含量、全磷含量、全钾含量、碱解氮含量、有效磷含量、速效钾含量、阳离子交换量和盐基饱和度),基于主成分分析法构建土壤肥力质量评价的最小数据集,探索土壤肥力质量指数、土壤理化性质与海拔的关系。结果表明,土壤肥力质量评价最小数据集包括黏粒含量、阳离子交换量、有机质含量、有效磷含量和速效钾含量5项指标。土壤有机质、全氮含量和阳离子交换量均随海拔升高呈先减少后增加的趋势,土壤全磷和有效磷含量与海拔呈显著正相关。土壤类型(亚类)也显著影响土壤有机质、有效磷含量和阳离子交换量,均以灌丛草甸土最多,红壤最少。土壤肥力质量综合指数随海拔升高呈先降低后升高的趋势,按指数大小由高到低划分为4个等级,52%的调查样地处于中等偏上水平。中亚热带大围山花岗岩中山土壤肥力质量总体中等偏上,土壤肥力质量指数具有明显的高度带现象,山地土壤保育与开发中应重视土壤质量的垂直地带性分异规律。

Topsoil fertility quality evaluation along an elevation gradient of Dawei Mountain in eastern Hunan Province

Soil quality conservation and improvement are essential for the promotion of ecosystem service functions.In this study,to understand the vertical zonal differentiation of soil fertility quality in mountainous areas,an elevation gradient along the granite Dawei Mountain in eastern Hunan Province was selected.Topsoil samples from the 21 surveyed plots were collected for the investigation,and 14 indices of soil physiochemical properties were analyzed(sand content,silt content,clay content,bulk density,pH value,organic matter content,total nitrogen content,total phosphorus content,total potassium content,alkali-hydrolyzable nitrogen content,available phosphorus content,available potassium content,cation exchange capacity and base saturation).Subsequently principal component analysis was employed to construct a minimum data set of soil fertility quality evaluation,and the relationships among soil fertility quality index,soil physiochemical properties,and altitude were explored.The results showed that the minimum data set of soil fertility quality evaluation included five indices:clay content,cation exchange capacity,soil organic matter content,available phosphorus content,and available potassium content.The contents of soil organic matter,total nitrogen and cation exchange capacity first decreased and then increased with the increase in altitude.Soil total phosphorus and available phosphorus were significantly positively correlated with altitude.Soil type(subgroup)significantly affects soil organic matter,available phosphorus contents and cation exchange capacity,with the highest values observed for shrub meadow soils and the lowest for red soils.The soil integrated fertility index first decreased and then increased with the increase in altitude.The soil quality was classified into four grades,and 52%of the surveyed plots were above the average level.This study therefore indicates that the soil quality possesses a zonal differentiation along the elevation gradient of granite Dawei Mountain in subtropical China.