عنوان مقاله [English]
In managing greenhouse irrigation system, the knowledge of water requirement and crop coefficient tends to be extremely essential at different growth steps. The present study set out to explore the amount of water used in evapotranspiration and to determine crop coefficient in Ocimum Basilicum L. in an hourly manner. To this end, the project was implemented in a greenhouse in Urmia University. More specifically, the evapotranspiration level of Ocimum Basilicum L. and Lawn (as the reference plant) were measured hourly and daily using lysimetric method. The results revealed that an average 45-day evapotranspiration was 4.12 mm /day in Ocimum Basilicum L. whose total water consumption was found to be 188.45 mm. Besides, in case of the reference plant, water consumption was determined to be 338.5 mm during this period. The length of growth stages in Ocimum Basilicum L. including the initial, developmental, middle, and final steps were found to be 10, 20, 10, and 5, respectively. The highest crop coefficient in Ocimum Basilicum L. occurred on the 39th day after planting in the middle phase. As the evapotranspiration of the reference plant showed, the average crop coefficients of the initial, developmental, middle, and final phases in Ocimum Basilicum L. were calculated to be 0.14, 0.52, 0.93, and 0.83, respectively. Furthermore, the highest hourly evapotranspiration process was conducted in the interval of 15-16 hours, which was calculated to be 0.13, 0.41, 0.70, and 0.71 at the initial, developmental, middle, and final stages in Ocimum Basilicum L., respectively.