Onion Crop Response to Regulated Deficit Irrigation under Mulching in Dry Mediterranean Region

Enhancing water productivity for sustainable crop production and water savings represents a major challenge for agricultural water management. Pot experiments under open field conditions were conducted for two years, 2016 and 2017, to assess the effects of regulated deficit irrigation under mulch on onion crop production, following a 2 × 3 factorial experiment with two soil cover systems (wheat straw mulch and no-mulch) and three irrigation levels (100%, 80%, and 60% of crop evapotranspiration), with six replications.The results indicated that onion plants were responsive to straw mulching. Bulb diameter, total yield, dry matter, and water productivity were significantly enhanced under mulch whatever the irrigation level used. The seasonal crop water requirements also considerably decreased (about 33%). The results also showed the sensitivity of onion to water stress. Yield, dry matter, and water productivity were higher under full irrigation compared to the deficit irrigation. However, when mulch was used, regulated deficit irrigation highly significantly improved water productivity and onion crop quality and quantity; and this approach could be a promising management practice to meet water shortage consequences in the dry Mediterranean region.