Effect of irrigation quota on estimation accuracy of evapotranspiration in growth middle stage of spring maize
ZHOU Shiwei, HU Xiaotao*, WANG Wen′e, RAN Hui, ZHANG Yajun
Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education, Northwest A & F University, Yangling, Shaanxi 712100, China
Abstract：In order to improve estimation accuracy of evapotranspiration(ET)of crops in arid areas, the ET of spring maize in Shiyang River Basin in growth middle stage was estimated with FAO-56 in the paper. The effect of irrigation quota on estimation accuracy of ET was identified by comparing calculated values with measured ones. The estimation error was discussed by analyzing the spatial distribution of soil moisture and its change rule under different irrigation treatments. It was proposed that the average water moisture in the entire root zone rather than in the partial root zone should be used in the calculation of soil water stress coefficient. The results show that the FAO-56 can estimate ET accurately under low irrigation quota treatment, however, its estimation accuracy decreass with increasing irrigation quota. As a result, the estimation error in ET is as poor as -14.13% under high irrigation quota. The soil water stress coefficient is calculated with the average soil moisture in the soil moisture slowly changing layer and above. This method can improve estimation accuracy of ET of crops in arid areas under high irrigation quota treatment effectively.
周始威, 胡笑涛*, 王文娥, 冉辉, 张亚军. 春玉米生长中期灌水量差异对其蒸发蒸腾量估算精度的影响[J]. 排灌机械工程学报, 2018, 36(9): 790-795.
ZHOU Shiwei, HU Xiaotao*, WANG Wen′e, RAN Hui, ZHANG Yajun. Effect of irrigation quota on estimation accuracy of evapotranspiration in growth middle stage of spring maize. Journal of Drainage and Irrigation Machinery Engin, 2018, 36(9): 790-795.
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