Characteristics of maize transpiration and soil evaporation in Horqin sandland

In Horqin sandland, the maize (Zea mays) leaf transpiration rate, sap flow, and soil evaporation were measured by using Li6400 portable photosynthesis system, heat balance Dynamax packed sap flow measuring system, and microLysismeters, respectively. The results of this study showed that during measuring period, the leaf transpiration rate ranged from 0.9 to 3.6 mm, the sap flow was about 7.3-29.8 g/h, the average soil evaporation occupied 20% of the total water utilization, but could increase up to 30% after irrigation shortly. There was a significant correlation between the amount of sap flow and the leaf transpiration rate. The Pearsons correlation coefficients of the higher, middle and lower layer leaves transpiration rate to the sap flow were 0.667, 0.732 and 0.607 respectively. This implied that the plant water requirement might be reasonably estimated by measuring the leaf transpiration rate. Compared with evapotranspiration calculated by using water balance method, the experiment results showed that sapflow and micLysismeters could be used to measure evapotranspiration of maize.