الفهرس 
Response of onion plants to some weed control methods
CONTENTSOnly 14 pages are availabe for public view
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Abstract
Laboratory and plastic house experiments were conducted at Botany Department, National Research Centre, Dokki, Egypt, in October 2018 and 2019, to evaluate the allelopathic effect of the aqueous extracts of orange peel waste (OPPW), mango leaves waste (MLW) and olive oil processing waste (OOPW), at successive concentrations, on germination and growth of two weed species, i. e., Phalaris minor Retz. and Malva parviflora L., in petri dishes and pots trials. In addition, the phenolic compounds, in OPPW, OOPW and MLW extracts, were extracted, then identified and determined, as allelopathic substances, by HPLC. The aqueous extracts of OPPW recorded the highest concentration of phenolic compounds and were the most effective in the inhibition of germination and growth of both weed species followed by MLW and OOPW in the petri dishes and pots trails. The main detected phenolic compounds in OPPW 20% extract were ferulic, chrysin, sinapic, p-hydroxybenzoic, quercetin and rosmarinic. The extract of MLW 30% contained high amounts of p-hydroxybenzoic, vanillic, cateachin, rutin, protocatechuic and gallic acid. Some phenolic compounds were detected in OOPW 30% extract such as gallic, p-coumaric, protocatechuic, p-hydroxybenzoic, vanillic and ferulic acid. Also, two field experiments were carried out at the Agricultural Production and Research Station of the National Research Centre, El-Nubaria, Beheira, Egypt, during the two successive winter seasons of 2018/2019 and 2019/2020 to examine the efficacy of OPPW, OOPW, and MLW as aqueous extracts or as soil mulches on growth, yield, and bulb quality response; nutrient uptake; and weed control of onion crop (Allium cepa L.) cv. Giza Red. The treatments consisted of the aqueous extracts (OPPW 20%, MLW 30%and OOPW 30%) alone or mixed with half a dose of oxyfluorfen herbicide (½oxyf, 375 ml/fed), soil mulches (OPPW, MLW, OOPW, and rice straw), hoeing, oxyfluorfen herbicide (at 375 and 750 ml/fed), and an unweeded control treatment. The lowest values of total number, fresh and dry weight of weeds/m2 were recorded in OPPW 20%+ ½oxyf treatment, without significant difference from hoeing treatment in both seasons. The highest values of vegetative parameters and total and marketable yields of onion plants were also found in OPPW 20% + ½oxyf and hoeing treatments. Also, storage experiments were carried out at the laboratory of Vegetable Crops Department, Faculty of Agriculture, Cairo University, Giza to evaluate the effect of the abovementioned weed control treatments on quality attributes and storability of onion bulbs during a six-month storage at room temperature in corrugated paper boxes. OPPW mulch and hoeing treatments were the most effective treatments in improving storability and maintaining onion bulb quality attributes during a six-months storage at room temperature. It was concluded that using OPPW and MLW as aqueous extracts mixed with ½oxyf herbicide or as soil mulches could be used in controlling weeds and increasing onion crop yield, bulb quality and storability.