退化羊草草原生态化学计量动态及其与土壤养分的关系

发布时间：2018-04-06 00:16

  本文选题：生态化学计量学　切入点：土壤养分含量　出处：《内蒙古大学》2017年硕士论文

【摘要】：生态化学计量学通过分析植物与土壤的C、N、P等元素及其比值特征,揭示生态系统过程及其对环境的响应。本文以内蒙古锡林河流域羊草草原为研究对象,通过野外调查与测试分析,利用生态化学计量学理论与方法,在群落、功能群和物种三个水平上探讨不同退化阶段羊草草原植物生态化学计量学特征,分析其对土壤养分环境的响应,阐明植物—土壤养分关系,明晰植物生长的限制因子。主要结论如下:1.利用所观测的69个样地资料,将羊草草原划分为4个不同的退化阶段:Ⅰ羊草+杂类草群落(22个样地)、Ⅱ羊草+针茅群落(18个样地)、Ⅲ羊草+糙隐子草群落(21个样地)和Ⅳ羊草+冷蒿群落(8个样地)。2.研究区域羊草草原土壤养分含量匮乏,土壤肥力处于较低水平。退化导致土壤养分含量逐渐减少,全氮、全磷与速效氮显著降低。3.在群落、功能群以及物种水平,植物氮、磷含量与土壤速效氮、速效磷均多呈极显著正相关,植物C:N比值、C:P比值分别与土壤速效氮、速效磷呈极显著负相关。退化造成的土壤养分含量减少,导致植物养分含量与生态化学计量特征发生了改变。4.在群落、功能群和物种水平,除一、二年生草本植物外,其他植物的C:N比值随着草地退化加剧而减小,植物可能是通过提高生长速率的途径应对变化的环境。5.群落、功能群和物种水平,除一、二年生草本植物的N:P比值随着退化程度的加剧而降低外,其他植物的N:P比值均有所升高,表明植物的生长可能由受到N元素限制转为受到P元素的限制。本项研究进一步明确了草地退化过程中植物生态化学计量动态特征,及其与土壤养分环境的关系,丰富了人们对草地生态系统生态化学计量学的认知,对于促进退化草地生态系统的恢复与保护具有参考价值。
[Abstract]:Eco-chemometrics reveals the ecosystem processes and their responses to the environment by analyzing plant and soil elements such as C ~ (+) N ~ (+) P and their ratios.This paper takes Leymus chinensis grassland in Xilin River Basin of Inner Mongolia as the research object, through field investigation and test analysis, using ecochemometrics theory and method, in community,The ecochemometrics characteristics of Leymus chinensis grassland in different degradation stages were discussed at the three levels of functional group and species. The responses to soil nutrient environment were analyzed. The relationship between plant and soil nutrients was clarified and the limiting factors of plant growth were clarified.The main conclusions are as follows: 1.Using the 69 sample plots observed,The steppe of Leymus chinensis was divided into four different stages: 鈪，

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