Maize (Zea mays L.) is a major crop on the Loess Plateau, and calculating the ratio between transpiration to evapotranspiration (T/ET) of maize is important for estimating field water balance. In this study, the sap flow method was adopted to measure transpiration (T) characteristics of maize. In order to calibrate the sap flow gauge, the sap flow rate was compared to the leaf T determined by weighing method. The sap flow value was measured per hour during 3 days and the mean of hourly values in each day was taken as the daily value to avoid the influence of hydraulic capacitance. There was a significant linear relationship between leaf T and sap flow rate. The slope and intercept of linear regression were 0.764 and 4.944, with a R2 of 0.97 (p < 0.01). We also analyzed the T and ET of maize under field conditions. The T/ET of maize was 63.3% from July to September 2012. The T/ET and leaf area index had a good linear relationship. Partitioned ET into soil evaporation (E) and T may have important implications for analyzing crop water use efficiency, evaluating the crop production potential of precipitation and optimizing field water management.
- sap flow method
- sap flow rate
- transpiration rate
- First received 18 April 2016.
- Accepted in revised form 7 June 2016.
- © 2016 The Authors
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