科尔沁沙地玉米叶面蒸腾与棵间蒸发特性

Characteristics of maize transpiration and soil evaporation in Horqin sandland

利用Dynamax包裹式茎流测量系统、小型蒸渗仪和LI-6400光合作用系统分别测定了科尔沁沙地玉米(Zeamays)的茎秆液流、棵间土面蒸发和叶面蒸腾速率。结果表明,拔节至成熟期间,科尔沁沙地玉米的逐日平均茎秆液流量为7.3～29.8 g/h,叶面蒸腾量为0.9～3.6 mm,棵间蒸发量约占同期总蒸散量的20%,但灌溉后的蒸发比例在30%以上。上、中、下三层叶片的蒸腾速率均与茎秆液流的日变化趋势显著正相关(P<0.05),表明叶片的瞬时蒸腾速率测定可以代表玉米茎秆液流的动态变化特征。同时与水量平衡法对比验证了茎流计间接法可以较好地测定作物蒸散量。

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 20M 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 Pearson＇s 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.