广东鹤山两种人工林土壤阳离子交换量的特征及影响因素

Characteristics of Soil Cation Exchange Capacity of Two Plantations in Heshan,Guangdong Province

【目的】弄清广东省鹤山市尾叶桉(Eucalyptus urophylla)与厚荚相思(Acacia crassicarpa)造林后的土壤阳离子交换量(CEC)特征及其影响因子。【方法】对鹤山市共和镇造林15年的尾叶桉和厚荚相思人工纯林的土壤CEC和生态化学计量特征进行测定,分析两种树种造林后土壤CEC和其他指标特征及两者间相关关系,利用主成分分析法综合评价两树种造林后对土壤CEC的影响。【结果】厚荚相思林土壤CEC、交换性盐基总量(TEB)和盐基饱和度(BS)均显著大于尾叶桉林。厚荚相思林土壤交换性Ca^(2+)含量显著高于尾叶桉林,而两种林分土壤交换性K+、Na^(+)和Mg^(2+)含量无显著差异。Ca^(2+)/Mg^(2+)、Ca^(2+)/K+和(Ca^(2+)+Mg^(2+))/K+表现为厚荚相思林显著大于尾叶桉林。相关性分析显示,尾叶桉林土壤CEC与土壤自然含水量(SWC)、总有机碳(TOC)、总氮(TN)呈极显著正相关;厚荚相思林土壤CEC与TN、C/N呈极显著正相关,与C/P、C/N/P显著正相关。主成分分析表明,土壤TEB、总磷(TP)、Na^(+)、BS、Ca^(2+)、Mg^(2+)和pH是影响该区域土壤CEC的重要因素。【结论】在鹤山共和样地,与尾叶桉造林相比,厚荚相思造林显著提高了土壤CEC、TEB和BS,说明其土壤保肥和供肥能力更具优势。

Objective The aims was to understand the effects of Eucalyptus urophylla and Acacia crassicarpa plantations on soil cation exchange capacity(CEC)and its impact factors in Heshan,Guangdong Province.Methods The soil CEC and ecological stoichiometric characteristics in E.urophylla and A.crassicarpa plantations after 15-year afforestation were determined in Gonghe Town of Heshan,and the characteristics and correlation of soil CEC and other indices of two plantations were analyzed,and the key factors affecting the soil CEC in afforestation of two plantations were comprehensively evaluated by principal component analysis(PCA)method.Results The results showed that the total amounts of CEC,total exchangeable base(TEB),base saturation(BS)in the soil of A.crassicarpa plantation were significantly higher than those of E.urophylla plantation.The content of exchangeable Ca^(2+)of A.crassicarpa was significantly higher than that of E.urophylla,but the contents of exchangeable K+,Na^(+)and Mg^(2+)were not significantly different between the two stands.The ratios of Ca^(2+)/Mg^(2+),Ca^(2+)/Mg^(2+),Ca^(2+)/K+and(Ca^(2+)+Mg^(2+))/K+were found to be significantly higher in A.crassicarpa than those in E.urophylla.Correlation analysis showed that soil CEC was positively correlated with SWC,TOC and TN in E.urophylla plantations.Soil CEC was positively correlated with TN and C/N,and was positively correlated with C/P and C/N/P in A.crassicarpa plantation.The PCA showed that soil TEB,TP,Na^(+),BS,Ca^(2+),Mg^(2+)and soil pH were the key factors affecting soil CEC in this region.Conclusion In Gonghe sample site of Heshan,A.crassicarpa plantation significantly increased soil CEC,TEB and BS compared to E.urophylla plantation,suggesting that A.crassicarpa plantation has more advantages in maintaining soil fertility.