辽西农林复合系统中杨树水分耗散规律

以辽西杨树-烟草复合系统为研究对象,采用Granier热扩散探针法,对杨树-烟草复合系统的杨树树干液流进行连续观测,并对环境因子(空气温度、空气湿度、净辐射、风速、土壤温度和土壤湿度)进行同步观测。结果表明:杨树液流速率具有明显的早晚低、中午高的单峰型日变化特征,并具有从6月到9月逐渐降低的季节性变化规律,6月液流速率月平均的日变化峰值为5.77×10-3cm/s,9月下降至2.34×10-3cm/s。相关分析表明:净辐射、空气温度、空气湿度是杨树液流速率的主要影响因子,风速和土壤温度次之,土壤湿度影响最小,并建立了依据环境因子估算液流速率的逐步回归模型。树干液流与环境因子之间的数量关系能很好地预测杨树的蒸腾耗水量。

Water consumption of poplar in agroforestry system in western Liaoning,northeastern China

Sap flow velocity of poplar in agroforestry system was continuously measured with Granier’s thermal dissipation probe. As well, we measured environmental factors, such as air temperature, air humidity, net radiation, wind speed, soil temperature and soil moisture content. The results showed that the diurnal variation of sap flow velocity presented an unimodal curve. From June to September, the sap flow velocity decreased gradually, from a mean monthly value of 5.77×10-3 cm/s in June to 2.34×10-3 cm/s in September. Correlation analysis showed that the sap flow was mainly affected by net radiation, air temperature and air humidity, followed by wind speed and soil temperature, and finally by soil moisture content. A stepwise regression model for predicting sap flow velocity from environmental factors was also constructed. The relationship between sap flow velocity and environmental factors can be a good predictor to forecast transpiration of poplar trees.