Response of onion crop to bulb set size and planting date under mulching in dry Mediterranean environment

The present pot experiment under open field conditions was conducted to evaluate the response of onion crop to bulb set size and planting date using mulching. Two different sizes of onion sets at planting (large (6-10 g) and small (2-6 g)) and three different planting dates (February, March, and April) with two soil coverings (with and without straw mulching) were tested. Treatments were replicated three times. Onion was not exposed to any drought stress during the course of the experiment. Results indicated that the larger bulb sets which were planted earlier under mulching, maximised the total bulb yield (Yield, 44.0 t ha -1 ), water use efficiency (WUE, 8.37 kg m -3 ), and irrigation water use efficiency (IWUE, 9.57 kg m -3 ). Moreover, findings revealed that onion crop appreciably respond to smaller bulb sets when they were planted earlier under mulching. Onion bulb responses were predicted to be linearly increased with the earliness in planting date, with an obvious better preference under mulching and heavier bulb sets. Hence, adopting early planting date with mulching is suggested for sustainable crop production and for enhancing water use efficiency in dry Mediterranean area.