The Effect of Timely Meteorological Data of Greenhouse Environment on The Calculation of Reference Evapotranspiration

In recent years, the development of greenhouse cultivation has been recommended to use water resources optimally. Due to the significant differences in the microclimate of the greenhouse with the open air and its effect on the parameters affecting the reference evapotranspiration, special study is needed to use the reference evapotranspiration estimation relationships. The aim of this study was to investigate the reference evapotranspiration difference calculated using timely meteorological data inside the greenhouse and outdoors and long-term outdoor meteorological data for 6 months in Aliabad area of Jiroft city in a greenhouse with tomato cultivation. Reference evapotranspiration inside the greenhouse and outdoors for timely and long-term data in the study period were 342.7, 508.6 and 636.4 mm, respectively. The net solar radiation was 58% lower inside as compared to outside of greenhouse. The percentage difference of reference evapotranspiration inside the greenhouse and outdoors based on timely data was vary for different month of year, as average this difference was 39% during the study. Therefore, notice to actual evapotranspiration in greenhouse is very important for accurate irrigation management.