干旱区制种玉米农田蒸散研究

Evapotranspiration of Seed Maize Field in Arid Region

在黑河流域中游的张掖绿洲区建立了大田环境下的制种玉米农田蒸散研究观测点,以气象观测资料为基础,采用波文比能量平衡法(BREB)和参考作物蒸散量作物系数法(ET0Kc)对制种玉米的蒸散进行了计算。结果表明,在一个完整的生长期内,利用波文比能量平衡法得到的蒸散量为513.2 mm,日均3.2 mm/d,用参考作物蒸散量作物系数法得到的作物蒸散量为486.2 mm,日均3.1 mm/d,2种计算方法得到的蒸散量总值差别小。利用波文比能量平衡法所得结果的分析表明,试验地在不同生长阶段,ET变化剧烈,生长初期、发育期、中期、末期分别为2.3、2.9、4.1和3.0 mm/d,其蒸散量分别约占全年蒸散总量的13%、22%、50%和16%。ET月变化显示,4月和5月维持在一个较低水平,平均为2.1-2.3 mm/d;6月剧烈增加到3.6 mm/d;7月达到最大,平均为4.6mm/d;8月蒸散有所降低,为3.3 mm/d;9月,随着作物进入生长末期,蒸散急剧减小到2.8 mm/d。

Data of a field experiment carried out at Zhangye Oasis, an arid region of northwest China, were used to evaluate the evapotranspiration during the growing seasons of a field of maize for seed. The evapotranspiration was obtained by two methods： Bowen-Ratio Energy Balance（BREB） and Reference Crop E- vapotranspiration-Crop Coefficient （ETo-K,） method. The analysis results show that in a whole growing period, the total ET is 513.2 mm and a daily mean 3.2 mm/d by BREB, while a total of 486.2 mm and a daily mean 3.1 mm/d by ETo-Kc. Using the results of BREB, some conclusions were drawn as follows. The ET varied with growing stages. In initial growing stage, developmental growing stage, middle growing stage and the late growing stage, the ET were 2.3,2.9,4. land 3.0 mm/d ,and with a percentage of total ET of 13%,22%,50% and 16%, respectively. In April and May, ET maintained in a lower level about 2.1-2.3 mm/d. ET increased sharply to 3.6 mm/d in June and got the maximal value of 4.6 mm/d in July. After that, it decreased lightly in August. With the coming of late growing stage, the ET decreased rapidly to 2.8 mm/d in September.