An Evaluation of Growth, Yield and Water Use Efficiency of Greenhouse Cucumber Production at Different Soil Moisture Circumstances using Tensiometer as Moisture Measuring Instrument

High yield of top quality crop is a prerequisite for profitable production of greenhouse produced cucumber. On the other hand, because of water deficit in Iran it is necessary to economize in this scarce and valuable input. An experiment was carried out in the experimental greenhouse of University College of Agriculture and Natural Resources, University of Tehran to optimize water use in soil culture of greenhouse cucumber, applying drip irrigation as a irrigating system and tensiometer as the moisture measuring instrument. The aim of this research was to determine a suitable starting point of soil water potential at which irrigation pumps would start to operate and while growth and yield of greenhouse cucumber would be at its optimal state. Three water potentials for starting the irrigation system (-25, -45, and -65 centibar) were compared. Results showed the volume of applied water was 1.24 times higher in the -25 centibar treatment than in the -45 one and 2.03 times higher than that in -65 centibar treatment. The treatments had significant effect on water use efficiency. Decrease in volume of applied water resulted in increase of water use efficiency. Water use efficiency was 48 percent higher in -65 centibar treatment in comparison with -25 centibar and 46 percent higher in the -65 centibar as compared with -45 centibar treatment. Increase in soil water enhanced the vegetative growth. Yield quality was acceptable and not seriously affected by different soil moisture levels. Because of better water use efficiency of -65 centibar treatment as compared with the other ones and no serious change in fruit quality and quantity parameters, it can be concluded that a pump starting point of -65 centibars is recommendable for soil based greenhouse cucumber irrigation.