Effects of drain depth on crop yields and salinity in subsurface drainage in Nile Delta of Egypt

Abstract

The subsurface drainage system is the vast majority of Egypt's Nile Delta agricultural land to drain excess water from the soil, improve crop productivity, and guarantee the irrigated agriculture sustainability. This research aims to propose and assess drain depths that unequivocally connect the drainage system's structure to crop yields, water preservation, and soil salinity. For achieving this study's objective; three experiment sites in the Nile Delta in Zanklon, Tokh, and Hosh Essa were setup and a numerical model (DRAINMOD) was applied to simulate the hydrology, crop yield, and salinity. The tested drain depths were 140, 120, and 100 cm. The results were introduced for different crops and lateral spacing. The study concludes that a 28.5% decrease in drainage depth leads to conservation in the irrigation water by 15%, with a reduction in crop yield varying between 1.2% and 5.8% according to the cultivated crop and the sustaining soil salinity.