Efficacy of agro-industrial wastes on the weed control, nutrient uptake, growth, and yield of onion crop (Allium cepa L.)

Purpose Two field experiments were conducted to examine the efficacy of orange peel waste (ORPW), olive oil processing waste (OLPW), and mango leaf waste (MLW) as aqueous extracts or soil mulches on growth, yield, and bulb quality response; nutrient uptake; and weed control. Methods The treatments were aqueous extracts (ORPW20%, OLPW30%, and MLW30%) alone or mixed with half a dose of oxyfluorfen herbicide (938 ml ha(-1), 1/2OXYF, the recommended dose is 1875 ml ha(-1)), soil mulching with orange peel waste, mango leaves, olive oil waste, and rice straw (ORPWM, OLPWM, MLW, and RSM, respectively) at 10 tons ha(-1), hoeing, oxyfluorfen herbicide (at 938 and 1875 ml ha(-1)), and unweeded control treatment. Results The highest weed control efficacy, at 100 days after transplanting, was found in the ORPW20% + 1/2OXYF (89%), hoeing (88.3%), and ORPWM (88%) treatments. The ORPW20% + 1/2OXYF and hoeing treatments also showed the highest ability in saving N, P, K, Zn, Mn, and Fe nutrients, without significant differences from the MLW30% + 1/2OXYF and ORPWM treatments. The ORPW20% + 1/2OXYF, ORPWM, MLWM, and MLW30% + 1/2OXYF treatments significantly increased marketable onion bulb yield by 100.6%, 93.9%, 92.1%, and 89%, respectively, without significant difference from hoeing treatment (102.3%). Conversely, the increase of marketable bulb yield in the RSM, OLPWM, and OLPW30% + 1/2OXYF treatments was 85.4%, 83.5%, and 78.7%, respectively, statistically equaled that obtained from OXYF treatment (79.3%). Conclusion It was concluded that ORPW and MLW as aqueous extracts mixed with 1/2OXYF herbicide or as soil mulches could be used in controlling weeds and increasing onion crop yield and bulb quality.