围栏封育对天山北坡草甸草原土壤呼吸的影响  

Effects of fencing on soil respiration rates in the meadow steppes in the northern slope of the Tianshan Mountains

作　　者：胡毅[1,2] 朱新萍[1,2] 韩东亮[1,2] 贾宏涛[1,2] 胡保安[1,2] 李典鹏[1] 

机构地区：[1]新疆农业大学草业与环境科学学院,乌鲁木齐830052 [2]新疆土壤与植物生态过程实验室,乌鲁木齐830052

出　　处：《生态学报》2016年第20期6379-6386,共8页Acta Ecologica Sinica

基　　金：中国科学院战略性先导科技专项(XDA05050405);国家自然科学基金(31560171);新疆维吾尔自治区研究生教育创新计划(XJGRI2014084)

摘　　要：对新疆天山北坡草甸草原围封9a的样地和围栏外的放牧样地进行比较,采用LI-8100土壤呼吸监测系统对草甸草原围栏内外土壤呼吸进行监测,分析围栏内外土壤呼吸的日变化、季节变化及其与环境因子的关系。结果表明:围栏内外土壤呼吸速率存在明显的日变化和月变化规律,均呈单峰曲线,且在植物生长季峰形比较明显,围栏内和围栏外土壤呼吸速率最高值出现在6月份17:00,分别为5.87、4.41μmol m^(-2)s^(-1),围栏内土壤呼吸速率比围栏外高出33.1%。最低值出现在10月份8:00,分别是0.26、0.29μmol m^(-2)s^(-1)。土壤CO_2日排放量与日均气温和地温的变化特征一致,与日均土壤含水量的变化特征相反,围栏内的土壤呼吸明显高于围栏外。土壤呼吸速率与气温和5 cm地温呈显著正相关,与其它深度的地温相关性不显著;与土壤湿度相关性不显著。cycling in respiration is an important indicator in evaluating soil surface carbon dioxide （CO2 ） flux, and carbon grassland ecosystems is strongly affected by grassland management and implementation. Fencing and grazing are two important grassland management tools in the meadow steppe of the Tianshan Mountains ; however, there is limited knowledge of how fencing may influence soil respiration in the arid and semi-arid areas of meadow steppes. In our study, we compared short-term （9-year fencing） fenced meadow steppes with grazed meadow steppes along the northern slopes of arid and semi-arid areas of the Tianshan Mountains of China. We evaluated daily and seasonal soil respiration dynamics and the correlation between soil respiration rate and environmental factors in both fenced and grazed meadow steppes using a Li- 8100 automated soil CO2 flux system （LI-COR, Lincoln, Nebraska, USA）. Significant variations of daily and seasonal soil respiration rate were found as a one-peaked curve at the evaluated fenced and grazing meadow steppe in Tianshan Mountains, and the single peak in the growing season was especially obvious. In June, daily soil respiration rates peaked at 17：00 h for both areas, but soil respiration rates were 33.1% higher in fenced （5.87 μmol m-2 s-1） than grazed （4.41 μmol m-2 s-1） meadow steppes. In October, daily soil respiration rates were lowest at 08：00 h for both fenced （0.26 p, mol m-2 s-1） and grazed （0.29 μmol m-2 s-1） meadow steppes. Annual CO2 flux is highest in summer, and the contribution of CO2 flux in June and July to the total annual CO2 flux was highest during our sampling period. Furthermore, CO2 flux was 37% higher at fenced than at grazing sites, suggesting that fencing had a more positive effect on CO2 flux than grazing in arid and semiarid areas of the meadow steppes. Our results are mainly due to the decrease in belowground biomass and root secretion, which reduces root and microbe respiration. The dynamics of soil CO2 flux were consistent wit

关 键 词：围栏封育 土壤呼吸 地温 土壤含水量 草甸草原 

分 类 号：S812.2[农业科学—草业科学]