广西不同林龄桉树人工林叶—凋落物—土壤C、N、P生态化学计量特征  

Ecological stoichiometric characteristics of C,N,and P of leaves,litter and soil in Eucalyptus plantations at different stand ages in Guangxi

作　　者：朱育锋[1,2,3] 吴玲 彭晚霞 杜虎[2,3] 刘永贤[4] 兰秀[4] 宋敏 ZHU Yufeng;WU Ling;PENG Wanxia;DU Hu;LIU Yongxian;LAN Xiu;SONG Min(College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, Hunan, China;Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, Hunan, China;Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang 547100, Guangxi, China;Institute of Agricultural Resources and Environment, Guangxi Academy of Agricultural Sciences, Nanning 530007, Guangxi, China)

机构地区：[1]湖南农业大学生物科学技术学院,湖南长沙410128 [2]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,湖南长沙410125 [3]中国科学院环江喀斯特生态系统观测研究站,广西环江547100 [4]广西农业科学院农业资源与环境研究所,广西南宁530007

出　　处：《中南林业科技大学学报》2019年第6期92-98,106,共8页Journal of Central South University of Forestry & Technology

基　　金：国家重点研发计划项目(2016YFC0502405);国家自然科学基金项目(31770495、31660141);广西重点研发计划(桂科AB16380255)

摘　　要：C、N、P元素的养分循环过程是影响森林生态系统结构与功能的关键因素。以广西不同林龄桉树人工林为研究对象,分析桉树幼龄林(1a)、中龄林(2a)、近熟林(3a)、成熟林(5a)、过熟林(8a)叶—凋落物—土壤的C、N、P化学计量特征及其内在联系,探讨林龄对桉树人工林生态化学计量的影响,为桉树人工林可持续经营提供参考。结果表明:1)桉树人工林叶、土壤呈现高C低N、P的元素格局,凋落物呈现高C、P低N的元素格局;叶的C、N、P含量从幼龄林到近熟林呈先增后减趋势,反映桉树人工林早期对养分需求旺盛,随年龄增大需求减小。2)不同林龄叶C、N、P差异显著(P<0.05),凋落物与土壤的N、P、C∶N、C∶P、N∶P均差异显著(P<0.05),凋落物C∶P与叶N∶P、C∶P显著正相关(P<0.05),凋落物N∶P与叶的C∶P、N∶P之间呈极显著正相关(P<0.01),说明凋落物养分源自叶,土壤与叶的C、N、P均不相关。3)与叶相比,凋落物中N、P含量偏低,C∶N、C∶P偏高;土壤C∶P、N∶P偏低,说明土壤P素分解较快,可适时施以磷肥来弥补土壤速效磷的不足;土壤C∶N偏高表明土壤有机质具有较慢的矿化作用。中龄林、近熟林和成熟林叶N∶P<14,生长过程受N限制;中龄林、近熟林和成熟林凋落物分解的主要限制性元素是N,而幼龄林凋落物分解的主要限制性元素是P。The cycling process of elements C, N, and P is an important factor affecting the function of forest ecosystem. Based on five stand ages of Eucalyptus plantations in Guangxi Province (i.e., young stand (1 a), half-mature stand (2 a), near mature stand (3 a), mature stand (5 a) and over mature stand (8 a), we analyzed C, N, and P stoichiometric characteristics and the relationships between leaves, litter, and soil in Eucalyptus plantations. In addition, we discussed the impact of stand age on eucalyptus plantation ecological stoichiometry, which would provide some references for sustainable management of Eucalyptus plantations. The results showed as following: 1) leaves and soil in Eucalyptus plantations presented an element pattern with high C, low N and P, while litter presented an element pattern with high C and P, low N. From young stand to near mature stand, the content of C, N, and P in the leaves showed a trend of increasing first and then decreasing, which reflected that the early Eucalyptus plantations had a strong demand for nutrients, and then the demand decreased with age. 2) C, N, P in leaf were significantly affected by stand age (P<0.05), and N, P, and ratios of C:N, C:P, and N:P in litter and soil were all significantly affected by stand age (P < 0.05). Ratio of C:P in litter was significantly and positively correlated with those of C:P and N:P in leaves (P < 0.05), and ratio of N:P in litter were also significantly and positively correlated with those of C:P and N:P in leaves (P < 0.01). This proved that litter nutrients were derived from leaves. However, the contents of C, N, and P in soil were not correlated with those in leaf, respectively. 3) compared with leaves, the content of N and P in litters was lower, while C:N and C:P ratios were higher. Low C:P and N:P ratios in soil indicated that P in soil were depleted rapidly and phosphatic fertilizer should be applied timely to offset the deficiency of soil available phosphorus. High C:N raio in soil suggested that soil organic matter have slow mi

关 键 词：叶 凋落物 土壤 化学计量学 桉树 

分 类 号：S792.39[农业科学—林木遗传育种]