Response of Washington Navel Orange Trees to Magnetized Irrigation Water and Different Levels of NPK Fertilization

A field experiment was conducted to study the effect of two types of irrigation water i.e., saline water (EC=3.58 dSm) and magnetized water, under three NPK fertilization levels (100, 80 and 60% of recommended dose), on the growth characteristics, nutritional status and productivity of Washington navel orange trees during the 2019 and 2020 seasons. Six treatments were arranged in a randomized complete block design as factorial experiment. Each treatment was replicated three times with three trees per replicate. Irrigation with magnetized water enhanced trees growth in terms of number of shoots per branch, shoot length, leaf area, canopy volume, root dry weight, overall nutritional status, yield, and fruit quality. Tree growth, leaf content of chlorophyll, total carbohydrates, and N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, as well as fruit set, yield and fruit quality were significantly improved with increased levels of NPK fertilization, whereas Na, Cl, fruit drop were decreased but leaf proline content was not affected. The interaction effect of magnetic water and NPK fertilization significantly increased all the studied parameters, particularly at 80% NPK. This treatment improves tree growth, root growth, nutritional status, yield, and fruit quality. It could be recommended that the combined application of magnetized water and NPK fertilization (80%) effectively alleviates the adverse effects of saline water stress and improve tree growth, yield and fruit quality under sandy soil and drip irrigation conditions, in addition to saving about 20% of NPK fertilizers.