Due to the water scarcity in the recent period in dry areas, as is the case in Egypt, so some means have to be used to save water as the use of irrigation systems under water stress, the use of low-quality water, as well as plants that tolerate these conditions. Two field experiments were conducted on a clayey soil with low quality (3.1 dSm-1) in southern Nile Delta of Egypt for evaluating the influence of low quality soil and water on quinoa productivity (initial experiment) and the effects of surface drip (SDI) and subsurface drip (SSDI) irrigation methods with three irrigation regimes (100%, 80% and 60% of irrigation requirements) and humic acid (0 and 50 mgl-1) on soil moisture and salinity, yield and water use efficiency of quinoa (main experiment). The initial experiment was done on pots to measure the effect of water quality (fresh water (0.45 dSm-1), ground water (2.8 dSm-1) and saline water (5 and 7 dSm-1)) on productivity. Regarding to results, the yield was significantly decreased by using saline water (5 and 7 dSm-1), while there were no differences between fresh and ground water. The results of the main experiment indicate that using ground water to irrigate quinoa with SSDI, 80% water stress and 50 mgl-1 humic acid improved soil salinity, pH and moisture content. These favorable conditions of the improved soil reflected on the vegetative growth parameters of quinoa and showed significant increases in seed yield (4.17 Mg ha-1) and water productivity (3.78 kg m-3). |
