Abstract:
Continuing agricultural expansion and urban development in Saudi Arabia, (located in
an arid climate), together with an increased demands for more water supplies, calls for
more efficient irrigation practices, and an increase in Crop Water Productivity (CWP).
Throughout the present study, a deficit irrigation system was investigated for its impact
on soil salinity, crop response factor (Ky), CWP, and a crop, namely cucumber’s (Cucumis
sativus L.) yield. Cucumber seeds were planted in a greenhouse equipped with drip
irrigation system. The crop evapotranspiration (ETc) was assessed through Pan
Evaporation method (PE) and estimation based upon Penman-Monteith equation (PM).
The results revealed good agreement between PE and PM ETc. The irrigation treatments
consisted of four levels of ETc (40, 60, 80, and 100% of ETc) in addition to the traditional
one as practiced by local farmers. At the 60 and 80% ETc treatments, the deficit
irrigation was tested at different growth stages (Initial, developmental, middle, and late
stages of crop growth). Each of the treatments was carried out in three replicates. The
results showed that soil salinity in general increased with decreasing level of applied
water. The crop cucumber could tolerate shortage of water during the middle season
growth stage, when the Ky values ranged between 0.57 and 0.76. The level of water used
up in 100% ETc treatment was much lower than that in the traditional drip irrigation as
practiced by farmers. In other words, the CWP values increased with water consumption
being decreased. The results also indicated that the highest values for CWP were found
for the most stressed treatment of 40% ETc, while on the other hand the overall crop
productivity had decreased.
Keywords: Arid Environment Condition, Cucumber Water Productivity, Low Irrigation
Limit, Water Use Efficiency, Yield Reduction Ratio.
