Crop evapotranspiration in the Nile Delta under different irrigation methods

ABSTRACTEddy correlation measurements within the Nile Delta allowed the determination of evapotranspiration (E) for seven crops (rice, maize, cotton, sugar beet, berseem, wheat and fava beans) using basin irrigation (BI), furrow irrigation (FI), BI with increased intervals (BIi), FI with increased intervals (FIi), strip irrigation (SI) and drip irrigation (DI). Total E values over the cropping season for rice (BI, BIi) were the highest (>600 mm), while those for sugar beet (DI), maize (SI and DI) and berseem (BIi) were the lowest (<250 mm). The differences were due to a combination of atmospheric demand, soil moisture, the presence of surface standing water, root depth, and the length and timing of the cropping season. The DI and SI methods had the advantage for water saving, while the FIi and BIi methods were effective for crops with shallow root lengths. Estimated annual E was 566–828 mm/year (water-saving irrigation) and 875–1225 mm/year (conventional irrigation).