林型和地形因子对太岳山森林地表凋落物矿质元素含量的影响

森林地表凋落物是树木生长所需矿质养分的重要储库,探索森林凋落物矿质元素对环境因子变化的响应,有 助于进一步了解植物-凋落物-土壤的反馈机制.本研究选择涵盖整个太岳山的9个不同海拔梯度,采样收集森林地表 凋落物并同时记录环境因子特征,经实验室分析测定样品中的6种重要矿质元素,包括磷(P)、硫(S)、钾(K)、钙(Ca)、镁 (Mg)、铁(Fe)的质量分数,并分析林型和地形因子(海拔、坡度和坡向)对凋落物矿质元素的影响.结果表明,坡向是凋落 物S质量分数的主要影响因子,并单独解释了S质量分数变异的40%;凋落物P和Ca质量分数变异主要是由林型、海 拔和二者的交互作用造成的;然而,林型和地形因子对凋落物中K、Mg、Fe没有显著影响.这些差别反映了矿质元素受植 物生理调节及其在凋落物中固持能力的差异性.研究结果可为森林生态系统矿质养分循环建模提供借鉴. 

Influence of forest type and topographical factors on mineral elemental concentration of forest floor in the Taiyue Mountain

Forest floor decomposition by fungi and bacteria is an essential part of carbon and nutrient cycling.These nutrient elements in turn can directly influence growth and reproduction of trees and microbes,and regulate the relevant biochemical processes.A better understanding of mineral element concentration in the forest floor is critical to the development of a holistic perspective on the ecology of biogeochemical cycling,as well as on plant-soil interactions.Six replicate forest floor samples were collected at different altitudes with an elevation interval of 100 m from 1 377-2 185 m in the Taiyue Mountain.Concentrations of phosphorus (P),sulphur (S),potassium (K),calcium (Ca),magnesium (Mg),and iron (Fe) in collected samples were determined.Differentiation patterns of element concentration in the whole study area were examined,with a view to explore the influence of forest types and topographical factors on element concentration.Significant variations in element concentrations in forest floor were found.S was mainly driven by the slope variabale,accounting for 40％ of the variation.P and Ca were driven by the elevation variabale,forest type and their interactions.No significant influence was found on K,Mg and Fe in the forest floor by forest type or topographical factors.These variations may reflect differences in physiological regulations of mineral elements and their capability of fixation in forest floor.These results may be conducive to understand and construct models of nutrient cycling for forest ecosystems.