南水北调工程对湖泊湿地土壤呼吸速率及碳排放的影响研究

Analysis on effects of South-to-North Water Transfer Project on soil respiration rate and carbon emission in lacustrine wetlands

湿地是地球三大生态系统之一,其碳汇功能对应对全球气候变化具有举足轻重的作用。为了阐明湖泊湿地土地利用变化条件下不同植物群落土壤呼吸速率变化及其与相关环境因子的关系,运用LI-8100A开路式土壤碳通量测量系统,测定了东平湖湿地典型植物群落(香蒲、芦苇、杨树林)以及应季作物的春季、夏季土壤呼吸速率,并对大气温度、大气相对湿度、光照强度、土壤温度以及土壤水分等环境因子进行了监测。结果表明:东平湖湿地不同植物群落春夏土壤呼吸速率有明显不同,夏季呼吸速率高于春季;不同群落之间土壤呼吸速率也有较大差异,应季作物土壤呼吸速率均值最大,其次是香蒲群落和芦苇群落,杨树林群落最小。从整体看,南水北调东线工程的实施,扩大了芦苇、香蒲群落和杨树林群落的面积,减少了农作物的面积,对减少碳排放起到了积极作用。为增强湖泊湿地的碳汇功能,减少温室气体的排放,应进一步增加湿地植物中木本植物的面积,减少农作物种植面积;不同土层温度对不同群落土壤呼吸速率的影响不同,香蒲群落土壤呼吸速率与0—5 cm土层温度呈正相关,芦苇群落土壤呼吸速率与0—5 cm,5—10 cm土层温度呈正相关,杨树林群落土壤呼吸速率与0—5 cm,20—25 cm土层温度呈正相关关系。

Wetland is one of the three major ecosystems on the Earth,and its carbon sink function plays an important role in global climate change.In order to clarify the change of soil respiration rate of different plant communities in the wetland of lake and its relationship with related environmental factors,the LI-8100A open-circuit soil carbon flux measurement system was used to determine typical plant communities(Phragmites australis,Typha orientalis and Populus)in the wetland of Dongping Lake.And the environmental factors were monitored ad collected.The results indicated that the soil respiration rates of different plant communities were significantly different in spring and summer,and higher in summer than in spring.There were also significant differences in soil respiration rates among different communities.The mean values of soil respiration rates of crops in season were the highest,followed by Typha orientalis and Phragmites australis communities,and the lowest in Populus communities.Overall,the implementation of the East Route Project of South-to-North Water Transfer has expanded the area of Typha orientalis,Phragmites australis and Populus communities,and reduced the area of crops,playing a positive role in reducing carbon emissions.In order to enhance the carbon sink function of lake wetlands and reduce greenhouse gas emissions,the area of woody plants in wetlands should be further increased and crop planting area should be reduced.Temperature exerted different effects on soil respiration rate of different communities.Soil respiration rate of Typha orientalis community was positively correlated with soil temperature of 0-5 cm layer,and that of Phragmites australis community was positively correlated with soil temperature of both 0-5 cm and 5-10 cm layer,and that of Populus community was positively correlated with the temperature of 0-5 cm and 20-25 cm layer.