若尔盖高寒湿地土壤有机碳储量时空变化研究

发布时间：2018-05-23 07:27

本文选题：湿地 + 碳储量　；参考：《北京林业大学》2016年博士论文

【摘要】：近年来,由于不合理利用和区域气候暖干化,湿地生态系统已经发生了严重的退化,湿地面积不断减少,质量和功能持续下降,严重影响了我国的生态安全。通过文献研究,本研究在探明我国沼泽湿地0-1 m土层中土壤有机碳储量空间分布特征的基础上,选择若尔盖高寒湿地(若尔盖县和红原县)作为研究区域,重点选取湿地土壤有机碳储存这一生态系统服务功能,探讨全球变化背景下若尔盖高寒湿地土壤有机碳储量的时空变化。通过野外调研、室内分析、模型模拟、统计分析等多种方法,开展若尔盖高寒湿地土壤有机碳储量时空变化分析。揭示了若尔盖高寒湿地土壤有机碳储量空间分布特征,定量评价了历史时期挖沟排水和放牧强度改变对湿地土壤有机碳储量的影响,预测了未来研究区内湿地土壤有机碳储量在不同情景下的变化趋势。通过系统研究得出以下主要结果和结论：(1)研究区内湿地土壤有机碳密度远高于全国平均值,在0-1 m土层中,若尔盖县和红原县湿地土壤有机碳平均密度为69.5 kg C m-3,是全国湿地土壤有机碳平均密度的3倍,全国土壤有机碳平均密度的6倍。垂直分布上,研究区内湿地土壤有机碳含量和有机碳密度具有垂直分异现象,呈现出随土壤深度增加而下降的趋势,较高值出现在0-0.3 m土层中,且显著高于0.3-1 m土层。水平分布上,土壤有机碳含量和土壤有机碳密度具有较强的空间异质性。在0-1 m土层中,研究区内湿地土壤有机碳总储量约为514 TgC,占全国湿地0-1 m土层中土壤有机碳总储量的8.3%-10.2%,在全国碳循环中占有重要地位。(2)在1980-2010年间,尽管湿地处于退化状态,研究区内湿地生态系统仍表现为净碳汇,在0-1 m土层中土壤有机碳年均净碳汇量约为0.25 t C ha-1 yr-1。但是湿地退化导致土壤潜在碳汇能力降低,研究结果表明,在1980-2010年间由挖沟排水引起的土地利用变化导致研究区内湿地0-1 m土层中土壤潜在碳汇能力降低了0.49-4.051 C ha-1。尽管短期内较高的放牧强度对土壤有机碳储量具有微弱的促进作用,但是增加放牧强度是该地区进行挖沟排水的驱动因素,综合考虑增加放牧强度和挖沟排水对湿地土壤有机碳储量的影响,增加放牧强度短期内所带来的增汇量被挖沟排水的负面影响所抵消。(3)在未来情景下,若尔盖县和红原县湿地0-1 m土层中土壤有机碳储量呈现出增加的趋势。较2010年而言,到21世纪末,研究区内湿地0-1 m土壤有机碳储量将增加15.80 (±7.43) Tg C,其平均土壤有机碳累计强度将增加21.38(±10.15)t Cha-1。与未进行湿地修复的情景比较,湿地修复能够显著提高湿地0-1 m土层中土壤有机碳储量,其固碳潜力约提高0.19(±0.01)t C ha-1 yr-1。考虑到湿地巨大的固碳潜力,在全球变化背景下,在保护现有湿地的基础上,应加大对退化湿地的修复力度,实施湿地生态恢复工程,合理控制畜牧业发展,逐步恢复该地区湿地面积和功能,有效提高湿地固碳潜力,以期在缓解气候变化中发挥湿地应有的重要作用。
[Abstract]:In recent years, due to irrational utilization and regional climate warming, the wetland ecosystem has been seriously degraded, the area of wetland is decreasing, the quality and function of the wetland have been declining, and the ecological safety of China is seriously affected. Through the literature study, the spatial distribution of soil organic carbon reserves in the 0-1 m soil layer of China's marsh wetland is explored. On the basis of the characteristics, the Ruoergai alpine wetland (Ruoergai county and Hongyuan county) is selected as the research area, and the ecosystem service function of the organic carbon storage of the wetland soil is selected, and the spatial and temporal changes of the soil organic carbon reserves in the alpine wetland of Ruoergai under the background of global change are discussed. The spatial and temporal variation of organic carbon reserves in Ruoergai alpine wetland soil was analyzed. The spatial distribution characteristics of organic carbon reserves in the soil of Ruoergai alpine wetland were revealed. The effects of drainage and grazing intensity on the organic carbon reserves in the wetland soil were quantitatively evaluated in the historical period, and the wetland soil in the future study area was predicted. The following main results and conclusions are obtained through systematic study: (1) the organic carbon density of wetland soil in the study area is far higher than the national average. In the 0-1 m soil layer, the average density of organic carbon of wetland soil in Ruoergai and Hongyuan county is 69.5 kg C M-3, which is the average of the national wetland soil organic carbon. 3 times the density, 6 times the average density of soil organic carbon in the country. Vertical distribution, the vertical distribution of organic carbon content and organic carbon density in the wetland soil in the study area showed a tendency to decrease with the increase of soil depth. The higher value appeared in the 0-0.3 m soil layer and was significantly higher than that of the 0.3-1 m soil layer. The content and soil organic carbon density have strong spatial heterogeneity. In the 0-1 m soil layer, the total organic carbon reserves of the wetland soil in the study area are about 514 TgC, accounting for 8.3%-10.2% of the total organic carbon reserves in the 0-1 m soil layer of the national wetland, and occupies an important position in the national carbon cycle. (2) in 1980-2010 years, although the wetland was in a degraded state, The wetland ecosystem in the study area is still a net carbon sink. The annual net carbon sink of soil organic carbon in the 0-1 m soil layer is about 0.25 t C HA-1 yr-1., but the wetland degradation leads to the decrease of the potential carbon sequestration capacity of the soil. The results show that the land use change caused by the ditch drainage in 1980-2010 years leads to the 0-1 m soil layer of the wetland in the study area. The potential carbon sequestration capacity of soil decreased 0.49-4.051 C ha-1., although higher grazing intensity in the short term has a weak promotion effect on soil organic carbon reserves, but increasing grazing intensity is the driving factor of drainage drainage in this area. The effect of increasing grazing intensity and ditch drainage on the organic carbon reserves of wetland soil is considered. In the future scenario, the soil organic carbon reserves in the 0-1 m soil layers in Ruoergai and Hongyuan counties showed an increasing trend. Compared with 2010, the soil organic carbon reserves of 0-1 m m in the study area would increase by 15.80 (+ 7.43) Tg C than in 2010. The average accumulative intensity of soil organic carbon will increase by 21.38 (+ 10.15) t Cha-1. compared with the situation of non wetland restoration. The wetland restoration can significantly increase the soil organic carbon reserves in the 0-1 m soil layer of the wetland, and its carbon sequestration potential is about 0.19 (+ 0.01) t C HA-1 yr-1., considering the huge carbon sequestration potential of the wet ground, under the global change, under the global change On the basis of protecting the existing wetland, we should strengthen the restoration of degraded wetland, implement the ecological restoration project of wetland, rationally control the development of animal husbandry, gradually restore the area and function of the wetland in this area, and effectively improve the carbon sequestration potential of the wetland, so as to play the important role of wetland in alleviating the climate change.
【学位授予单位】：北京林业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S153.6

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