基于能量平衡的喷灌作物冠层净截留损失估算

为了定量评价喷灌作物冠层截留损失，以地面灌为对照，利用热平衡茎流计对喷灌冬小麦和夏玉米冠层截留水量蒸发产生的蒸腾抑制效应进行了连续两年的田间观测，结果表明：各次灌水，喷灌冠层截留水量的蒸发明显影响田间小气候进而抑制作物蒸腾。喷灌冬小麦和夏玉米蒸腾抑制量变化范围分别为1.65～4.09 mm和0.50～2.75 mm。在此基础上，基于能量平衡原理，结合波文比能量平衡系统,计算出的冬小麦冠层净截留损失不足0.1 mm；夏玉米净截留损失变化范围在1～2 mm之间，占灌水量的4.3%～6.5%。

Estimation of net interception loss by crop canopy under sprinkler irrigation based on energy balance

Transpiration suppression by evaporation of canopy intercepted water was measured using heat balance sap flow during two growing seasons of winter wheat and summer corn to evaluate the canopy interception loss under sprinkler irrigation, compared with surface irrigation. The experimental results demonstrated that crop transpiration was obviously suppressed by microclimate modification resulted from sprinkler irrigation. For one irrigation event, the amounts of transpiration suppression caused by evaporation of the canopy intercepted water were 1.65~4.09 mm and 0.50~2.75 mm from the beginning of spraying to the vanishing of transpiration suppression for winter wheat and summer corn, respectively. Based on energy balance, net canopy interception loss for sprinkler irrigation was determined with Bowen-ratio energy balance technique under sprinkler irrigation. The amount of net interception loss by winter wheat canopy was less than 0.1mm, and the loss intercepted by summer corn canopy varied from 1 to 2 mm, accounting for 4.3%~6.5% of sprinkler irrigation amounts.