东祁连山灌-草群落交错带土壤呼吸动态及影响因子分析  

Soil respiration dynamics and impact factor analysis of a shrubland- grassland ecotone in the Eastern Qilian Mountains

作　　者：魏巍[1,2] 周娟娟[1,2] 曹文侠[2] 徐长林[2] 

机构地区：[1]西藏自治区农牧科学院草业科学研究所,西藏拉萨590000 [2]甘肃农业大学草业学院,甘肃兰州730070

出　　处：《草业学报》2015年第12期1-9,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金(31360569);现代农业产业技术体系(CARS-35)资助

摘　　要：为探究高寒灌-草交错带土壤呼吸动态及影响因素,应用LI-8100A 土壤呼吸自动测定系统,对东祁连山典型灌丛-草地交错带土壤呼吸动态及土壤因子进行测定,分析呼吸速率与土壤因子的相互关系.结果表明,整个交错带内土壤呼吸速率的均值介于2.3～7.2μmol/（m2·s）,各样地间土壤呼吸速率大小顺序为珠芽蓼草甸中心（S1）〉草甸-金露梅灌丛交错区（MSC1）〉金露梅灌丛中心（S2）〉 金露梅- 杜鹃灌丛交错区（MSC2）〉 杜鹃灌丛中心（S3）,S1 和MSC1 样地的土壤呼吸日变化呈单峰型,峰值出现在14：00,S2、MSC2、S3 样地峰型不明显,且日变幅较小,仅为0.3～1.1μmol/（m2·s）;交错带内土壤物理性质和养分储量呈明显的垂直分异规律,土壤呼吸速率与土壤温度、全磷储量呈极显著的正相关（P〈0.01）,与土壤含水量极显著负相关（P〈0.01）,与0～20cm 土壤有机碳储量呈显著负相关（P〈0.05）;拟合分析显示,土壤温度、含水量和全磷储量是土壤呼吸速率的主要限制因子,土壤呼吸与土壤温度拟合系数最高,可解释土壤呼吸空间变异的79.9%.This research explored the factors influencing soil respiration dynamics of an alpine Shrubland -Grassland ecotone.The soil respiration dynamics were measured using a LI-8100A automated soil CO2 flux system,and relationship between soil respiration and soil factors was analysed for an eastern Qilian Mountain typical Shrubland-Grassland ecotone.The mean soil respiration rate was 2.3 -7.2 μmol CO2/(m2 ·s).The rankings of soil respiration rate at different sampling points were:Polygonum viviparum meadow center (S1 )>Polygonum viviparum meadow - Potentilla fruticosa shrub ecotone (MSC1 )> Potentilla fruticosa shrub center (S2 )>Potentilla fruticosa -Rhododendron shrub ecotone (MSC2 )>Rhododendron shrub center (S3 ).The diurnal variation of soil respiration of S1 and MSC1 had a unimodal pattern,with the peak at 14:00. For S2 ,MSC2 and S3 respiration rates were only 0.3-1.1 μmol CO2/(m2 ·s)and the peak was not obvious. Soil physical properties showed a significant vertical gradation within ecotones.Soil respiration rate was signifi-cantly and positively correlated with soil temperature and total phosphorus (P <0.01),significantly negatively correlated with soil moisture (P <0.01),and significantly positively correlated with soil organic carbon in the 0-20 cm soil layer (P <0.05).Analysis of the relationship between soil respiration and soil temperature,soil moisture,total phosphorus,and organic carbon showed that soil temperature,soil moisture and total phos-phorus were the main limiting factors for soil respiration rate.The highest fitted coefficient was soil tempera-ture,which explained 79.9% of the spatial variability in soil respiration.

关 键 词：高寒草地 群落交错区 碳通量 土壤呼吸 

分 类 号：S812.2[农业科学—草业科学]