Efficacy of irrigation intervals and chemical weed control on optimizing bulb yield and quality of onion (Allium cepa L.)

Two field experiments were carried out at the village ten, Abu Humus, El-Beheira Governorate, Egypt, during two successive seasons 2016/2017 and 2017/2018, to evaluate effect of three types herbicide irrigation intervals on productivity quality onion cultivar (Giza Red). The designed as split plot in randomized complete block design with replications. Irrigation – (I1) 20 days, (I2) 30 (I3) 40 days assigned main plots. Herbicides treatments (H1) Control, (H2) Fluazifop-p, (H3) Oxyfluorfen, (H4) Clethodium distributed randomly sub-plots. results revealed that interaction between had significant effects Red) both seasons. Maximum bulbs yield (14.06 14.29 ton/fed) was recorded (I3 H3) first second seasons, respectively. (I2 led increase harvest index values. highest value carbohydrates percentage total soluble solids (TSS) obtained {I3 H2}. residues dry onions under all found well below maximum residue limit set by World Health Organization (WHO)/Food Agriculture (FAO) (0.05 mg/kg). In conclusion, Oxyfluorfen interval could be used improve fresh bulb (ton/fed) cultivar, water use efficiency (WUE). treatment (40 days) H2 (Fluazifop-p)} enhance diameter (cm) after harvest, TSS carbohydrates.