不同林龄阶段秃杉人工林养分元素分布及其生物循环特征  

Nutrient Distribution and Biological Cycling in Different Aged Stands of Taiwania flousiana Plantations in Northwestern Guangxi

作　　者：南雅薇 何斌[1] 黄光友 韦家国 吴庆标[1] 黄振格 Nan Yawei;He Bin;Huang Guangyou;Wei Jiaguo;Wu Qingbiao;Huang Zhenge(Guangxi University,Nanning 530004,P.R.China;Shankou Forest Farm of Nandan County)

机构地区：[1]广西大学,南宁530004 [2]广西南丹县山口林场

出　　处：《东北林业大学学报》2023年第4期7-14,共8页Journal of Northeast Forestry University

基　　金：广西重点研发计划项目(桂科AB1729008);广西重大林业科技项目(桂林科字[2010]第7号);广西科学研究与技术开发计划项目(桂科能159832-38);国家自然科学基金项目(31760201、31560205)。

摘　　要：2018年3—4月份,在广西南丹县地理位置毗邻、立地条件相似的区域,以9、17、25、37年生秃杉(Taiwania flousiana)林为研究对象,在不同林龄的秃杉人工林中分别设置3个样地(20 m×30 m),测定样地林冠郁闭度、林分密度,林木胸径、树高、冠幅、枝下高等;在每个林龄阶段样地外选择3株平均木并伐倒,分别测定树叶、树枝、干皮、干材、根系鲜质量,并按灌木层、草本层、凋落物层测定生物量鲜质量,计算林分各结构层次生物量;在每个样地内随机设置5个1 m×1 m木框架尼龙网收集器,按凋落叶、凋落枝、杂物等组分分别测定年凋落物归还量;选取不同结构层次植物各组分样品,分别测定N、P、K、Ca、Mg质量分数;以养分贮存量与分配、养分年净积累量、养分利用系数、养分循环系数、养分周转期为评价指标,采用单因素方差分析法(ANOVA)、邓肯(Duncan)多重比较法,分析不同林龄阶段秃杉人工林养分积累、分布及其生物循环特征。结果表明:①林木各器官5种养分元素质量分数均以树叶最高,其次是干皮、树枝和树根,干材最低;各器官中不同养分元素质量分数,由大到小依次为N、Ca、K、P、Mg。②乔木层中,各器官养分元素积累量占总累积量比例随林龄的增长发生变化,树叶养分元素占总累积量比例随林龄增加而逐渐下降,干材和树皮养分元素占总累积量比例表现出相反的变化趋势。③9、17、25、37年生秃杉人工林养分元素总贮存量,分别为775.91、1120.41、1320.50、1570.39 kg·hm^(-2);其中,乔木层养分元素贮存量,分别占总贮存量的89.30%、86.66%、83.62%、82.04%,随林龄增加而下降;灌草层养分元素贮存量,分别占总贮存量的5.01%、5.93%、6.55%6.43%、5.69%;凋落物层养分元素贮存量,分别占总贮存量的5.69%、7.42%、9.83、11.53%,均随林龄的增加而增加。④9、17、25、37年生秃杉人工林,养分元素年积累量分�In order to reveal the biological cycle characteristics of nutrient elements in the growth process of Taiwania flousiana plantation,the five nutrient elements(N,P,K,Ca,and Mg)accumulation,distribution,and biological cycles in Nandan County of Guangxi were studied by plot survey and laboratory analysis methods.The results showed that:(1)the nutrient contents of different organs of the same stand age were in the descending order of leaf,bark,branch,root and stem.The content of different nutrient elements in each organ was highest in N,followed by Ca or K,P,and Mg.(2)The total nutrients storage at 9,17,25 and 37 years old of T.flousiana plantations were 775.91,1120.41,1320.50 and 1570.39 kg·ha^(-1),respectively,which increased with the biomass accumulation in the process of stand growth.Of the total storage of nutrients,82.04%-89.30%was distributed in tree layer,5.01%-6.55%at shrub and herb layer,and 5.69%-11.53%at ground litter layer.(3)The distribution ratio of nutrients accumulation in various organs in the arbor layer changed with the growth of the stand age.The proportion of leaves gradually decreases with the increase of stand age,and the ratio of stem and bark showed an opposite trend.(4)Nutrients annual accumulations in four age stages of T.flousiana plantations were 76.99,57.10,44.18 and 33.90 kg·hm^(-2)·a^(-1),respectively.The annual net accumulation of different nutrient elements was highest in N,followed by K,Ca,P,and Mg.(5)The annual absorption of nutrients in four stand ages plantations were 114.5,135.39,142.66 and 118.67 kg·hm^(-2)·a^(-1),respectively.The annual nutrients return equaled to 37.58,78.29,98.48 and 85.52 kg·hm^(-2)·a^(-1),respectively.The nutrients utilization coefficients were 0.17,0.14,0.13 and 0.09,respectively.The cycling coefficient were 0.34,0.58,0.69 and 0.72,respectively.The recycling periods were 18.44,12.40,11.21 and 15.20 a,respectively.It could be seen that the nutrient accumulation rates of T.flousiana plantations in the early growth period(before 9 years old)was faste

关 键 词：秃杉人工林 林龄 营养元素 养分积累 养分分布 养分生物循环 

分 类 号：S718.5[农业科学—林学]