春小麦蒸腾测定中茎流计的标定及其应用

Application and calibration of sap flow gauge in spring wheat transpiration

通过人工气候生长室盆栽试验,在对不同珍珠岩覆盖量下的土壤蒸发特征进行分析的基础上,采用由热平衡原理设计的茎流计对三个水分处理(高85%～75%、中65%～55%、低45%～35%)下的盆栽春小麦蒸腾特征进行研究并依据称重法结果加以标定,结果表明:(1)珍珠岩覆盖量为0.11 g/cm2时能够达到较好效果,并据此换算出测定时段春小麦实际蒸腾量占总蒸散量的比值为83.04%;(2)单株小麦茎流速率与蒸腾速率的回归分析得出相关系数r=0.92,方程斜率与截距值分别为0.4463和8.3391,以小时(h)为单位的回归分析结果与以天(d)为单位的类似;(3)以2012年10月31日为例,标定后单株小麦蒸腾速率分别为:高26.51 g/d、中17.13 g/d、低12.71g/d。采用茎流计法测定田间作物蒸腾时对测定结果加以标定是非常必要的。

This study aimed at evaluating the transpiration characteristics of potted spring wheat using a sap flow method designed by a heat balance technique under three different water treatments （high 85 % - 75 %, middle 65 % 55 % and low 45 % - 35 % ） calibrated using a weighing method. The results showed that ： （ 1 ） the treatment with the perlite cover of 0.11 g/cm2 is better than the others. Under this condition, the spring wheat transpiration accounts for 83.04% of the total evapotranspiration; （2） the single wheat sap flow rate was strongly correlated with the transpiration rate at the daily scale with the correlation coefficient of 0.92, and slope and intercept of 0.4463 and 8. 3391, respectively. Similarly regressive results were also obtained at the hourly scale. （3） Taking Oct. 31st, 2012 as an example, the calibrated single plant transpiration rate were 26.51 g/d, 17.13 g/d and 12.71 g/d, respectively, under three water conditions ranked from high to low. Overall, this study indicates, while determining the transpiration of field crops, it was necessary to calibrate the transpiration rate by sap flow method.