Abstract Information of crop evapotranspiration (ETc) and crop coefficient (Kc) is essential for improving water use and optimizing irrigation scheduling. Here, a three-year (2015, 2016 and 2019) experiment was conducted for tomato grown in a solar greenhouse under full and deficit drip irrigation to investigate the variation of ETc measured by sap flow system plus micro-lysimeter in 2015 and by weighing lysimeter in 2016 and 2019. The controlling meteorological factors on ETc in two irrigation treatments were analyzed by using path analysis method. A single crop coefficient model considering leaf senescence, soil water stress and fraction of canopy cover was proposed under two irrigation levels. The results showed that total seasonal ETc over the whole growth stage under full irrigation was 310−350 mm, which was 16–23 % higher than that under deficit irrigation. The maximum hourly ETc rate in each month during the three-years experiment varied from 0.15 to 0.89, and from 0.15 to 1.88 mm h−1, respectively, under deficit and full irrigation. Path analysis showed that the net radiation was the dominant meteorological factor aff ;ecting ETc through the direct eff ;ect, followed by the vapor pressure deficit, mainly through an indirect action on ETc. The Kc values at different growth stages estimated by the proposed single crop coefficient model under full and deficit irrigation agreed well with the measured ones, and the water stress coefficient, Ks, under deficit irrigation varied from 0.5 to 1.0. The proposed single crop coefficient model also estimate daily ETc of drip irrigated tomato reasonably in the solar greenhouse with regression coefficient of 0.93−0.99, determination of coefficient of 0.78−0.95 and root mean square root of 0.35−0.52 mm d−1.

中文翻译：

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全灌溉和亏缺灌溉条件下日光温室番茄蒸腾量和作物系数

摘要 作物蒸散量 (ETc) 和作物系数 (Kc) 信息对于改善用水和优化灌溉调度至关重要。在此，对日光温室种植的番茄进行了为期三年（2015年、2016年和2019年）的全滴灌和亏缺滴灌试验，研究了2015年液流系统加微渗漏仪和渗渗仪称重测得的ETc变化。 2016年和2019年，采用通径分析法分析了2个灌溉处理中ETc的控制气象因素。提出了两种灌溉水平下考虑叶片衰老、土壤水分胁迫和冠层覆盖率的单一作物系数模型。结果表明，全灌条件下整个生育期的总季节性ETc为310～350 mm，比亏缺灌溉高 16-23%。三年试验期间每个月的最大每小时 ETc 率分别为 0.15 至 0.89 和 0.15 至 1.88 mm h-1，在亏缺灌溉和充分灌溉下。通径分析表明，净辐射是通过直接作用影响ETc的主要气象因素，其次是蒸气压亏缺，主要通过对ETc的间接作用。充分灌溉和亏缺灌溉下所提出的单一作物系数模型估计的不同生长阶段的Kc值与实测值吻合良好，亏缺灌溉下的水分胁迫系数Ks在0.5至1.0之间变化。