Onion is the most widely-used flavoring vegetable in the world. And it is an important export crop in Egypt about 17%  529.631Tt., from total annually production. Scarcity of water resources in Egypt (arid and sigemi-arid regions) threatening food security. As well as, it is a limiting factor in agriculture expansion. So, maximizing irrigation water productivity by right combination of water and nutrients, and the method of fertilizer application through field water management practices (modern irrigation techniques, and fertigation) in irrigated crops, are a pre requisite for higher yields and good quality production. On the other hand it is very important to overcome water shortage and encourage environment preservation, particularly in sandy soils.
Field experiment was conducted during 2016 /2017 season in private farm at Alexandria Cairo desert road, El-Behiara governorate. To study the effect of fertigation technique on some onion yield (quantity) i.e., bulb diameter “d1 and d2" (cm)., bulb mass “Bm" (g), bulb actual volume “Bv" (cm3), moisture content “MC" (%), and bulb yield “BY" (Mg fed-1)., through three emitters type, i.e., on line OT4 (I1), built in drip line GR 16 (I2) and built in drip line antiroots (I3), to obtain maximum irrigation water productivity, highest fertilizer effective, promoting yield quantity and quality and preservating environment of hyper mismanagement of water and fertilizer.
Generally, results showed that using (I3) treatment recorded higher values compared with (I1) and (I2) treatments. Where, results indicated that, bulb yield “BY" (Mg fed-1) values increased about 8.32 and 2.77%., by using (I3), compared with (I1), and (I2). Also, using (I3) lead to increased irrigation water productivity “IWP" (kg m-3) about 66.1 and 33.2%., compared with using (I1), and (I2). In addition, it could be seen that bulb mass “Bm" (g), was increased by 60.77 and 14.39 %, when using (I3) compared with (I1) and (I2)