阿克苏市灰枣园净生态系统碳交换特征及其对气象因子的响应

为了解枣园与大气之间净生态系统碳交换(NEE)特征,运用涡度相关系统、小型自动气象站及HemiView冠层分析系统分别对2017年阿克苏市郊区灰枣园CO2通量、气象因子及叶面积指数进行观测,研究了枣园NEE变化特征、NEE和叶面积指数及气象因子之间的日动态相关性。结果表明:NEE日动态为“U”形曲线。白天NEE为负值,表现为碳吸收,夜间NEE为正值,表现为碳排放。枣园各生育期的晴天与阴天NEE变化特征基本一致。枣园各生育期按照NEE及阶段NEE强度由高到低排序依次为果实发育期、果实成熟期、花期、萌芽期。枣园全生育期叶面积指数和气象因子按照与枣园NEE的相关性由高到低排序依次为叶面积指数、相对湿度、空气温度、光合有效辐射、饱和水汽压差。果实发育期碳交换速率和NEE最大,因此在枣树果实发育期应保证水分和无机盐的供应,对枣园NEE影响最大的因素是叶面积指数。

Net ecosystem carbon exchange characteristics and its response to meteorological factors in Grey Jujube orchard of Aksu City

In order to understand characteristics of net ecosystem exchange (NEE) between jujube orchard and atmosphere, CO2 flux, meteorological factors and leaf area index in Grey Jujube orchard at a Aksu suburb were observed and determined by using eddy correlation system, small-scale automatic weather station and HemiView canopy analysis system in 2017, and NEE characteristics and diurnal dynamic correlation between NEE, leaf area index and meteorological factors in jujube orchard. The results showed that diurnal dynamic of NEE was U-shape curve, NEE was negative at daytime, which showed carbon uptake, and NEE was positive at night, which showed carbon emission. Change characteristics of NEE in sunny and cloudy days were basically consistent during each growth stages in jujube orchard. Based on NEE and stage NEE intensity from high to low, order of each growth stage of jujube orchard was fruit development stage, fruit mature stage, flowering stage, germination stage. Based on correlation with NEE from high to low, order of leaf area index and meteorological factors during whole growth stage of jujube orchard was leaf area index, relative humidity, air temperature, photosynthetic effective radiation, saturated vapor pressure difference. Rate of carbon exchange rate and NEE during fruit development stage were the largest, so leaf area index was the most important factor to ensure water and inorganic salt supply during fruit development stage.