退化草原土壤有机质对氮素添加和功能群去除的响应

发布时间：2018-03-11 00:21

本文选题：退化草原　切入点：土壤有机质　出处：《内蒙古大学》2015年硕士论文　论文类型：学位论文

【摘要】：本研究选取锡林郭勒盟白音牧场轻度退化和重度退化典型草原群落,分别进行了氮素添加梯度(0、30、50、80 g/m2 NH4N03)实验和去除功能群(将植物按能量功能群分类：高能值植物、中能值植物和低能值植物功能群,每个处理剪除另外两个功能群,分别保留高、中、低单一功能群)实验,研究不同土层(0-10cm,10-20cm, 20-30cm)土壤有机质含量在不同退化状况下对氮素添加及功能群去除的响应。主要结论如下：(1)两种不同退化程度草原群落比较,轻度退化草原的0-20cm层土壤有机质含量显著高于重度退化草原,20-30cm层二者无显著差异,氮素的添加并没有显著改变这种格局。(2)不同退化程度草原对于氮素添加梯度的响应不同：对于轻度退化草原,30g/m2氮素添加显著提高0-20cm土层的土壤有机质含量,氮素是轻度退化草原主要的限制因子；对于重度退化草原,土壤有机质在氮素添加梯度下各层变化不显著,氮素不是重度退化草原的主要限制因子。(3)草原土壤有机质随着土层深度的下降而显著下降,随着退化程度的加剧而显著下降。功能群去除会显著增加土壤有机质的含量。在影响草原土壤有机质含量的主效应因素中,作用大小依次为：土壤深度退化程度功能群去除(4)在两种不同退化程度的草原,植物能量功能群的去除能明显提高土壤有机质含量,在轻度退化样地,保留单一低能值和高能值功能群对土壤有机质的影响显著,但三种去除处理(即分别保留高能群、中能群和低能群)之间无显著性差异；在重度退化样地,保留单一高能值功能群对土壤有机质的影响显著,除在20-30cm高能值和低能值功能群土壤有机质含量有显著差异,其他功能群去除处理之间无显著性差异。
[Abstract]:In this study, the typical grassland communities with slight degradation and severe degradation were selected from Baiyin pasture of Xilingol League. The experiments of nitrogen supplementation were carried out and the removal of functional groups (classification of plants according to energy functional groups: high energy plants) and removal of functional groups (NH4N03) were carried out respectively. Middle and low energy plant functional groups, each processing cutting off the other two functional groups, respectively, high, middle, low single functional groups) experiment, The responses of soil organic matter contents in different soil layers to nitrogen addition and functional group removal under different degradation conditions were studied. The main conclusions were as follows: 1) the comparison of two grassland communities with different degradation degree, the soil organic matter content in different soil layers was 10 ~ (-20) cm ~ (-1) and 20 ~ (30 cm) soil organic matter content in different degradation conditions. There was no significant difference in soil organic matter content between 0 ~ 20cm layer and 20 ~ 30cm layer of severe degraded grassland, and there was no significant difference between them. Nitrogen addition did not significantly change the pattern. (2) the response of grassland with different degradation degree to nitrogen gradient was different: for mild degraded grassland, nitrogen addition of 30 g / m 2 significantly increased soil organic matter content in 0-20 cm soil layer. Nitrogen is the main limiting factor of the degraded grassland, but for the heavily degraded grassland, the soil organic matter has no significant change under the nitrogen gradient. Nitrogen is not the main limiting factor of heavily degraded steppe.) soil organic matter in steppe decreased significantly with the decrease of soil depth. The removal of functional groups can significantly increase the content of soil organic matter. Among the main effect factors affecting the content of soil organic matter in steppe soil, The order of action was as follows: soil depth degradation degree functional group removal 4) in two different degraded steppe, the removal of plant energy function group could obviously improve soil organic matter content, in the slightly degraded sample land, The effects of single low energy and high energy functional groups on soil organic matter were significant, but there was no significant difference among the three removal treatments (i.e., retention of high energy group, middle energy group and low energy group). Retention of a single high-energy functional group had a significant effect on soil organic matter, except for 20-30cm high energy value and low-energy functional group soil organic matter content, but no significant difference between other functional groups removal treatment.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812.2

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