Comparison of different fertilization rates on yield, evapotranspiration, and water use efficiency of sweet corn under drought-salinity stresses

The present study investigated the effects of three fertilization (N-P2O5-K2O) rates (F1: 240-100-120 kg ha-1, F2: 192-80-96 kg ha-1, F3: 154-64-77 kg ha-1) coupled with four irrigation practices (Control: C, irrigated at the 100% field capacity, Drought: D, irrigated 60% of C, Saline: S, irrigated at the 100% field capacity, Drought and saline: D+S, irrigated 60% of S) on sweet corn yield, evapotranspiration (ET), water use efficiency (WUE), and shoot fresh-dry weights. The obtained results depicted that the grain yield at D, S, and D+S treatments decreased by 24.2%, 46.6%, and 62.0%, respectively, relative to the C treatment. Moreover, grain yield at the F3 condition was reduced by 45.3% compared to the F1 condition. Additionally, the highest ET (330.7 mm) and yield (74.0 g) was achieved with F1×C treatment. The F2 and F3 treatments reduced WUE by 17.9% and 31.5%, respectively, compared to the F1 treatment. The highest reduction in yield, ET, WUE, and shoot fresh-dry weights was found at D+S irrigation treatment under all fertilization conditions. The tallest plants were observed in the F1×C treatment, being 24.0%, 33.5%, and 43.2% taller than plants in the F1×(D+S), F2×(D+S), and F3×(D+S) treatments, respectively. Under F3 conditions, exposing sweet corn plants to single or combined salinity and drought stress remarkably degraded the growth ability of the plants, and therefore, it is not economical and sustainable cultivation for agriculture. Finally, cultivation of sweet corn plants under individual or combined drought-salinity stress is not recommended due to the high reduction in grain yield.