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### 河南省冬小麦农田蒸散和作物系数

1. 1中国气象局河南省农业气象保障与应用技术重点实验室/河南省气象科学研究所， 郑州 450003；2郑州市气象局， 郑州 450005； 3国家气候中心， 北京 100081）
• 出版日期:2020-09-10 发布日期:2021-03-10

### Evapotranspiration and crop coefficient of winter wheat cropland in Henan Province.

HU Cheng-da1, FANG Wen-song1*, WANG Hong-zhen2, DUAN Ju-qi3

1. (1China Meteorological Administration/Key Laboratory of Agrometeorological Safeguard and Applied Technique in Henan Province/Henan Institute of Meteorological Science, Zhengzhou 450003, China; 2Zhengzhou Meteorological Bureau, Zhengzhou 450005, China; 3National Climate Center, Beijing 100081, China).
• Online:2020-09-10 Published:2021-03-10

Abstract: Evapotranspiration is the main pathway for water consumption in croplands and thus must be considered in cropland management and planning. We estimated the reference crop evapotranspiration of winter wheat in 2017 and 2018 in Zhengzhou agricultural meteorological experimental station from overwintering to maturity period by the PenmanMonteith formula. The actual evapotranspiration in the winter wheat cropland under the conditions of full irrigation (T2) and natural precipitation (T1) were measured using a largescale weighing lysimeter. The crop coefficients of winter wheat under both conditions were calculated. We analyzed the changes and their correlations with meteorological factors. The results showed that under different water conditions, the evapotranspiration of winter wheat showed a hump pattern. The evapotranspiration and fluctuation amplitude of T2 treatment were significantly higher than those of T1 treatment. The average total evapotranspiration of T2 and T1 treatments in the two years were 535.8 and 256.4 mm, respectively, while the average daily evapotranspiration in the corresponding period were 3.7 and 1.7 mm, respectively. Under the two water conditions, the average daily evapotranspiration was the highest at booting and heading stages and the lowest at overwintering stage. The crop coefficient of winter wheat under full irrigation conditions was significantly higher than the actual crop coefficient under drought stress. They generally showed a trend of decreasing, increasing and decreasing. In T1 treatment, the actual crop coefficient had the best correlation with air humidity, and the poorest correlation with average air temperature, while in T2 treatment, the crop coefficient had a good correlation with average temperature, total radiation, and wind speed, but a poor correlation with air humidity.