毛乌素沙地花棒茎干液流规律研究

Research on Stem Sap Flow Dynamics of Hedysarum scoparium Fisch. et Mey in Mu Us Sandy Area

利用热平衡包裹式探头茎流测量系统和自动气象站监测了花棒生长季的茎干液流以及周围气象因子。结果表明:(1)花棒白天液流速率大,晚上液流速率较小,具有明显的昼夜节律性。5,6月份由于水分条件有限,且花棒处于生长初期,液流速率较小;7,8月份进入雨季土壤水分充足,生长旺盛期液流速率大;9,10月份液流速率又降至较低水平,整个生长季日平均液流量为0.39～0.87L/(cm-2.d-1)。(2)晴天液流速率较大,变化幅度也大;阴雨天液流速率变化幅度较小但波动剧烈。(3)花棒液流速率变化趋势与环境因子变化趋势基本吻合。相关性分析表明,影响花棒茎干液流变化的环境主要因子为太阳总辐射、风速、空气相对湿度和空气温度。

Heat-balance Packaged Stem Sap Flow Measuring System and Automatic Weather Station System were used to simultaneously measure and monitor the sap flow velocity and related environmental factors of the Hedysarum scoparium Fisch.et Mey in Mu Us Sandy.The results showed that： （1） There was a higher sap flow rate of H.scoparium during the day,and a lower rate at night.It had an obvious diurnal distribution.In the May and June,because of the limited water,during the early growth period,there was a lower sap flow rate.In the July and August,due to the adequate soil moisture,there was a higher rate at vigorous growth period.In the September and October,the flow rate had dropped to a lower level.During the growing season the average daily sap flow flux was 0.39-0.87 L/（cm^-2.d^-1）.（2） The diurnal changes of sap flow under different weather conditions are different markedly,and sap flow will be lower and its changing curve is completely irregular and fluctuant,during rainy and cloudy days.（3）The flow rate of H.scoparium was positively correlated with some surrounding environmental factors.Correlation analysis showed that the order of their coefficient from correlation analysis was solar radiationwind speedair temperatureair elative humidity.