Gao Xiang, Zhou Yu, Meng Ping, Pei Song-Yi, Zhang Jin-Song
Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
Ying Yong Sheng Tai Xue Bao. 2022 May;33(5):1183-1190. doi: 10.13287/j.1001-9332.202205.001.
var. is one of the important tree species for afforestation in Three-North Regions of China. Investigating net ecosystem exchange (NEE) and its influencing factors is of significance in understanding carbon balance of var. plantation . We used the eddy covariance system and its supporting instruments to measure NEE and environmental factors of var. plantation in the western Liaoning Province in 2020. The results showed that, at the half-hour scale, plantation emitted carbon during nighttime and sequestrated carbon over daytime. Carbon sequestration was inhibited by drought stress in the afternoon from May to August. At the daily scale, seasonal dynamics of nighttime NEE were mainly controlled by soil temperature and moisture, while that of daytime NEE were mainly controlled by soil moisture and vapor pressure deficit due to drought stress. When soil was dry, precipitation promoted nighttime and daytime NEE and improved photosynthetic and respiration parameters. At the month scale, there was significant negative linear relationship of daytime NEE with ecosystem apparent quantum yield and ecosystem maximum photosynthetic capacity. When air temperature was lower than 5 ℃, ecosystem respiration rate at 10 ℃ and temperature sensitivity of ecosystem respiration increased linearly with decreasing air temperature. The cumulative NEE of var. plantation was -145.17 g C·m, indicating a weak carbon sink in 2020.
变种是中国三北地区重要的造林树种之一。研究净生态系统交换（NEE）及其影响因素对于理解变种人工林的碳平衡具有重要意义。我们于2020年利用涡度相关系统及其配套仪器测量了辽宁省西部变种人工林的NEE和环境因子。结果表明，在半小时尺度上，人工林在夜间排放碳，在白天固碳。5月至8月下午的干旱胁迫抑制了碳固存。在日尺度上，夜间NEE的季节动态主要受土壤温度和湿度控制，而白天NEE的季节动态主要受干旱胁迫导致的土壤湿度和水汽压差控制。当土壤干燥时，降水促进夜间和白天的NEE，并改善光合和呼吸参数。在月尺度上，白天NEE与生态系统表观量子产额和生态系统最大光合能力呈显著负线性关系。当气温低于5℃时，10℃时的生态系统呼吸速率和生态系统呼吸的温度敏感性随气温降低呈线性增加。变种人工林的累积NEE为-145.17 g C·m，表明2020年其碳汇较弱。
