不同林龄灰木莲人工林土壤微量养分特征

Characteristics of Soil Micronutrients in Different Ages of Manglietia conifera Plantation

以广西高峰林场的10、12、18和51 a灰木莲人工林为研究对象,对比分析土壤中微量元素Fe、Mn、Cu、Zn、B、Al在不同林龄林分中的含量差异及其与土壤有机质、pH值及物理性质之间的相关性,为评价灰木莲人工林的土壤改良效果及养分管理提供依据。结果显示:(1)林龄变化对土壤微量元素含量特征存在显著影响(P<0.05),其中土壤微量元素Fe、Mn、Cu、Zn含量均随着林分年龄的增加而显著增加,有效B含量无显著变化,交换性Al含量显著降低。(2)各微量元素有效性指数从大到小依次为Fe、Cu、Mn、Zn、B、Al,除Al(0.57)外,其余元素的有效性指数均大于1,且随林龄增加而增大。不同林龄间微量元素有效性综合指数从大到小依次为51、18、10、12 a,整体呈现出随林龄增加而增大的趋势。(3)土壤有效态微量元素与土壤有机质、容重、持水量及总孔隙度之间相关性显著,其中有机质对土壤有效态微量元素含量变异的解释度最高(55.7%)。研究结果表明:灰木莲人工林土壤微量元素含量受林龄变化的影响,并且土壤有机质是引起不同林龄人工林土壤微量元素含量变化的关键因子;灰木莲的长期经营提高了土壤微量元素的有效性和土壤有机质的含量,有利于改良土壤肥力。

In this study,to provide the basis for evaluating the soil improvement effect and nutrient management of the plantation,the contents of Fe,Mn,Cu,Zn,B,Al in soil and their correlations with soil organic matter,soil acidity and physical properties were compared and analyzed in 10,12,18 and 51a Manglietia conifera plantation in Guangxi Gaofeng Forest Farm.The results showed that with the increase of stand age,the contents of available microelements Fe,Mn,Cu and Zn in the soil of M.conifera plantations showed an overall increasing trend,while no significant change occurred in the content of available B,and the downward trend was found in the content of exchangeable Al.In terms of availability index of each element,except for exchangeable Al(0.57),the availability indices of soil microelements Fe,Cu,Mn,Zn,and B were all greater than 1 and increased overall with the increase of stand age.In general,the comprehensive availability index of microelements increased with the increase of stand age,i.e.51a>18a>10a>12a.Pearson correlation analysis and RDA analysis showed that soil available trace elements were significantly correlated with soil organic matter,bulk density,water holding capacity and total porosity.Organic matter had the highest explanation for the variation of soil available microelements(55.7%).In conclusion,soil organic matter was the key factors affecting the content of soil available microelements in plantations with different forest ages.The long-term management of M.conifera increased the availability of soil microelements and the content of soil organic matter,which was beneficial to the improvement of soil fertility to some extent.