地形对麻栎人工林土壤肥力质量的影响

Effects of topography on the soil fertility quality in Quercus acutissima plantation

【目的】探究麻栎(Quercus acutissima)人工林土壤肥力质量在不同地形下的差异,综合评价地形对麻栎人工林土壤肥力的影响,为合理利用林地资源、提高人工林质量提供依据。【方法】以麻栎人工纯林为研究对象,将地形划分为平缓坡地、阳坡凹地、阳坡凸地、阴坡凹地和阴坡凸地5个类型,分别测定了5种地形下土壤理化性质和酶活性等15个指标,运用主成分分析和相关系数法筛选并建立了土壤质量评价最小数据集,采用加权求和指数法对不同地形下的土壤肥力水平进行综合评价。【结果】5种地形中,阳坡凹地土壤有机质、全氮和全钾含量最高,阴坡凹地pH、土壤全磷和有效磷含量最高,阴坡凸地土壤容重最小。阴坡凹地土壤微生物生物量氮含量最高,且脲酶和酸性磷酸酶活性最强。主成分分析和相关性分析结果表明,有机质、pH、容重、脲酶活性、蔗糖酶活性构成了土壤质量评价的最小数据集。不同地形中,土壤质量指数大小依次为阳坡凹地(0.533)>平缓坡地(0.511)>阴坡凹地(0.510)>阴坡凸地(0.495)>阳坡凸地(0.482)。【结论】在本试验地,地形通过改变土壤pH、有机质、土壤容重、脲酶活性和蔗糖酶活性等5个关键指标,影响了麻栎人工林的土壤肥力质量。其中,阳坡凹地土壤质量最高,有利于土壤养分的积累。

【Objective】 Quercus acutissima is among the main tree species in warm temperate and subtropical forests of China.This study aims to investigate the effects of topography on the soil fertility quality of Q.acutissima plantation,in purpose of providing theoretical bases for rational utilization of forest resources.【Method】In this study,we analyzed 15 soil indexes of five types of topographies(gentle slope,concave sunny slope,convex sunny slope,concave shady slope and convex shady slope) in Q.acutissima plantation.Then,the minimum data set of soil quality evaluation by combining principal component analysis and correlation analysis.The soil quality of Q.acutissima plantation was also comprehensively evaluated using the weighted additive index.【Result】Among the five types of topography,concave sunny slope had the highest levels of pH,soil organic matter,total nitrogen content,and total potassium content;concave shady slope had the highest levels of soil total phosphorus content,available phosphorus content,soil microbial nitrogen content,urease activity and acid phosphatase activity;and convex shady slope had the lowest level of soil bulk density.The results of principal component analysis and correlation analysis suggested that the smallest data set for soil fertility quality evaluation should include soil organic matter,pH,bulk density,urease activity,and invertase activity.In different topographies,the rank of soil fertility quality index in different topographies was concave sunny slope(0.533) > gentle slope(0.511) > concave shady slope(0.510) > convex shady slope(0.495) > convex sunny slope(0.482).【Conclusion】In this studied Q.acutissima plantation,the topography significantly influenced the soil fertility quality via its effects on five key indicators,i.e.,soil pH,organic matter,soil bulk density,urease activity and invertase activity.The concave sunny slope facilitated the accumulation of soil nutrients,leading to the highest level of soil fertility quality among different topographic types.