Development of the crop coefficient for vertically trained cucumber vines grown in soilless media under naturally ventilated greenhouse conditions

Abstract

In the wake of climate change and water scarcity issues, protected cultivation combined with precise irrigation management allows effective water resource utilization. This research was intended to find the actual crop evapotranspiration (ETc) of vertically trained cucumber vines in a soilless medium and develop crop coefficients (Kc) under greenhouse conditions. Experiments were performed in three micro-lysimeters (volume 0.015 m3) placed inside a naturally ventilated greenhouse from April to June 2018 (season I) and September to December 2019 (season II) with a planting density of 0.32 m2/plant. The FAO-56 Penman–Monteith equation was used to calculate reference evapotranspiration (ETo), and lysimeters were used to calculate the actual ETc. The average actual ETc of cucumber vines in season II (147.81 mm) was almost half of the ETc in season I (275.24 mm). The higher ETc in season I was due to a higher ETo of 493 mm during season I compared to 150 mm in season II inside the greenhouse. Kc values for season I were 0.3, 0.74, 1.11 and 0.68 compared to 0.3, 0.77, 1.38 and 0.79 in season II during the initial development, mid and end stages of cucumber vines, respectively, under greenhouse conditions.