CONICET | Buscador de Institutos y Recursos Humanos

The production of onion waste derived mainly from bulbs affected by fungal diseases,during onion classification and storage presents an important agro-environmental issuein onion production regions. Composting is an environmentally friendly strategy torecycle agricultural-waste and produce organic fertilizers. Modifications of the microbialcommunity in soil can affect the ability of pathogen propagules to survive, germinate,and infect plant roots. Hence, the main objective of this work was to exploring themechanisms involved on the presence of three soil-borne phytopathogenic fungi duringthe composting process of onion waste under the hypothesis if that the resultingcompost effectively prevents or minimize the dispersion of phytopathogenic fungi. Tothis end, three composting piles of 60 tonnes each were built by layering onion wasteaffected by phytopathogenic fungi and cow dung at 1:1 ratio. Temperature, moisture,pH, electrical conductivity (EC) and Aspergillus niger, Penicillium sp. and Fusarium sp.growth were monitored for 100 days. During the first 28 days of composting thepresence of phytopathogenic fungi increased significantly showing thereafter adownward trend. Final estimations of fungal populations densities indicated apredominance of A. niger and an effective reduction in the abundance of Fusarium sp.This pilot-scale work demonstrates the feasibility of composting onion wastecontaminated with phytopathogenic fungi and highlights the positive environmentalimpact associated with this practice. Therefore, the composting of onion waste andcow dung is a feasible and sustainable procedure to recycle onion waste and topromote circular economy in onion production regions.