Two field experiments were conducted during 2018/2019 and
2019/2020 seasons at Shandaweel Agriculture Research Station,
Sohag Governorate, to study the effect of different rates of
mineral NPK fertilization under foliar application with Nano
NPK, on vegetative growth, yield and quality of onion. Split
plot design with three replicates was used. Mineral NPK
fertilization rates occupied the main plots (100% NPK, 75%
NPK, 50% NPK and 25% NPK), whereas Nano NPK spraying
rates (control, 2 L/fed, 4 L/fed and 6 L/fed) occupied the sub
plots. The obtained results could be summarized as follow: (i)
Application of 100% NPK gave the highest values of plant
height while, application of 25% of NPK gave the lowest
values, in the two seasons; (ii) Spraying with Nano NPK at rate
of 6 L /fed appeared the highest values of plant height, whilst,
spraying with water (control treatment) appeared the lowest
values; (iii) Application of 100% of mineral NPK gave the
highest values of total yield, while, application of 25% of NPK
gave lowest values in both seasons; (iv) Spraying with Nano
NPK at rate of 6 L /fed appeared the highest values of total
yield/fed, whilst, spraying with water (control treatment)
appeared the lowest values, in the two seasons; (v) The highest
values of total yield/fed were obtained by using 75% mineral
fertilization and spraying with Nano NPK at rate of 6 L/fed, in
both seasons; and (vi) The highest values of exportable bulbs
yield were obtained by using 75% mineral fertilization and
spraying with Nano NPK at rate of 6 L/fed., while, the lowest
values were obtained by application of 25% of mineral NPK
and spraying with water (control treatment), in both seasons.