Determination of Water Requirement and Crop Coefficient for Basil (Ocimum basilicum L.) under Controlled Greenhouse

The development of agricultural crop cultivation in greenhouse is one of the main strategies for managing water scarcity. Awareness of the crop water requirement and accurate estimation of crop coefficient is one of the most important component in irrigation scheduling and improving water use efficiency. The objective of this research was to determine water requirement and crop coefficient of basil in controlled greenhouse condition. For this purpose, a study was carried out in a research greenhouse of the College of Agriculture and Natural Resources, University of Tehran during a growth period using micro-lysimeter. Micro-lysimeters are useful tools for accurate determination of the crop evapotranspiration under standard conditions (ETc), or the actual crop evapotranspiration (ETa). In this study, the evapotranspiration of the reference crop and the Basil water requirement were estimated using the soil water balance equation. According to the results, average reference and basil crop evapotranspiration during the growth stage were equal to 8.23 and 5.13 mm per day, respectively. Then the crop coefficient was calculated based on the ratio of basil crop and reference evapotranspiration. The average basil crop coefficients for the initial, mid and end growth stages were obtained to be 0.30, 0.86 and 0.76, respectively.