Interactive effect of soil mulching and irrigation regime on yield, irrigation water use efficiency and left-to-right markweeds of trickle-irrigated onion

Reducing the water loss sources, i.e. soil evaporation and weeds presence, is an essential act for keeping well soil moisture to crop growth, especially under drought conditions. Therefore, two-year field trials were conducted for seeking the best compatible practice between irrigation regime and weed control method in onion onion. Three irrigation water regimes (60%, 80% and 100% of the crop water requirements, CWR) and seven weed control practices (rice, wheat and peanut straws as soil mulches as well as oxadiargyl, oxyfluorfen, weeding, and unweeded) were applied. Findings revealed that the application of 60% of CWR either with peanut straw mulch or weeding recorded the maximum reduction in weed biomass. In plots mulched by peanut straw irrigation with 80% of CWR produced acceptable marketable bulb yield, NPK contents, flavonoids content and economic returns closing irrigation by 100% of CWR. In conclusion, the rate of water loss from soil surface through evaporation was much lower in case of mulch treatment than non-mulched one. Thus, mulch not only keeps weeds out but also maintains soil moisture. This allows the opportunity to reduce irrigation water by 20% (80% of CWR) with gaining acceptable yield, saving water and raising benefit/cost ratio.