滇中亚高山森林植物叶-凋落叶-土壤生态化学计量特征

C,N and P stoichiometric characteristics of leaf,litter and soil for subalpine forests in central Yunnan,China

为了深入认识滇中亚高山区域5种典型森林生态系统养分循环规律和系统稳定机质,通过测定植物叶、凋落叶和土壤C、N、P含量,掌握该区域典型森林植物叶-凋落叶-土壤生态化学计量特征。结果显示:(1)5种森林类型C、N、P含量差异显著,其中各林型植物叶和凋落叶C、N、P含量均高于土壤。(2)5种森林类型植物N、P再吸收率均为华山松林>云南松林>常绿阔叶林>高山栎林>滇油杉林;5种森林类型的再吸收率均为P(均值为61.20%)高于N(均值为36.48%),表明了该区域土壤P的相对匮乏。(3)5种森林类型C/N、C/P、N/P均表现为凋落叶>植物叶>土壤;各林型植物叶N/P范围为10.17—15.31。(4)5种森林类型植物叶与凋落叶C、N、P含量、C/N和C/P均呈极显著或显著正相关;凋落叶与土壤的C、N含量及N/P呈显著正相关;5种森林类型植物叶N与P含量呈显著正相关关系;土壤N与P含量呈显著负相关关系。本文探究养分元素在"植物叶-凋落叶-土壤"之间的化学计量特征,为了解该区域森林生态系统的养分状况和揭示生物地球化学循环过程提供了理论数据。

In order to understand the nutrient cycling and system stability mechanism of five typical forest ecosystems in subalpine of central Yunnan province,the characteristics of the typical forest leaf-litter-soil ecological stoichiometry were studied by measuring the contents of leaf,litter and soil C,N and P.The results showed that:(1)C,N and P contents of five forests were significantly different,among which the contents of C,N and P of leaf and litter were all higher than soil in each forest type.(2)The N and P resorption rates of five forest types were ranked as Pinus armandii forest>Pinus yunnanensis forest>Evergreen broad-leaf forest>Quercus semicarpifolia forest>Keteleeria evelyniana forest.The P(mean value of 61.20%)resorption rates of all forest types were higher than N(mean value of 36.48%),indicating the relative shortage of soil P in this region.(3)The C/N,C/P and N/P of five forest types presented in the order of litter>leaf>soil,and the N/P were ranged from 10.17 to 15.31.(4)The contents of C,N,P,C/N and C/P in the leaf of five forest types were significantly positively correlated with that of litter.There was a significantly positively correlation between litter and soil C,N contents and N/P.The contents of leaf N and P were significantly positively correlated,but the contents of soil N and P were significantly negatively correlated.This study explored the stoichiometric characteristics of nutrient elements between"leaf-litter-soil",which provided theoretical data for understanding the nutrient status of forest ecosystem in this region and revealing the biogeochemical cycling.