EFFECT OF DROUGHT STRESS ON THE PRODUCTION OF POTATO CROP GROWN UNDER SURFACE AND SUBSURFACE DRIP IRRIGATION SYSTEMS

Increasing water demand and climate change reduced agricultural water resources in arid and semi-arid regions. Field experiments were conducted at Demo Farm, Faculty of Agriculture, Fayoum University. Potato tubers were planted during two seasons (2021 and 2022). Three deficit irrigations (DI): I1 (100% of ETc), I2 (80% of ETc) and I3 (60% of ETc). Two partial root zone drying (PRD) irrigations: (double laterals and single laterals). Three lateral depths: zero cm (surface drip irrigation) and 15 and 30 cm (subsurface drip irrigation, SDI). Some growth parameters and yield of the potato crop were determined. Results indicated that the highest mean values of plant growth and yield of potato plants were recorded with irrigation treatment I1 under PRD and SDI with buried lateral depth of 15 cm. Also, the highest values of physiological parameters were recorded with irrigation treatment I1 under PRD and SDI with buried lateral depth 15 cm. When DI treatments increased from I1 to I2 and I3, the mean values of potato yield decreased. Using PRD treatment led to increasing the values of potato yield at irrigation treatments I1, I2 and I3. It could be recommended when irrigation water is abundant, using the irrigation treatment I1, PRD irrigation under SDI with buried lateral depth at 15 cm to reach the maximum yield of the potato crop. Meanwhile, under water scarcity, using DI treatment I2, PRD irrigation under SDI with buried lateral depth at 15 cm, will save 20% of the IWA with a low decrease in potato yield.