Use of Biosolids to Enhance Tomato Growth and Tolerance to Fusarium Oxysporum f. sp. Radicis-Lycopersici

Abstract Aims: A biosolid made from municipal sludge, acting as an organic fertilizer that enhanced plant growth and crop productivity, was evaluated for its effect on tomato growth and tolerance enhancement against the phytopathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici (Forl). Methods: Peat and/or two soil types were amended with mixtures of this biosolid (0, 80 and 160 tn/ha) in order to study the growth of tomato plants and their response to Forl, either under controlled conditions or outdoors in a net protected area. Results: The results showed that biosolid addition increased tolerance of tomato plants against the disease. There was also an increase of tomato fresh weight, root weight, stem height and leaf number compared to the Forl-inoculated control soils. Forl, at 5 weeks after tomato transplanting, caused higher disease index on plants grown outdoors in biosolid plus clay soil than in biosolid plus sandy soil, while the opposite occurred under laboratory conditions where higher disease index was recorded on plants grown in peat plus sandy soil than in peat plus clay soil. Conclusions: The findings strongly support the evidence that this biosolid may act as an organic fertilizer and as a possible stimulant of tomato tolerance against Forl. Therefore, this type of biosolid, previously proven to be minimal ecotoxicological impact, should be considered for its possible use in agriculture according to the principles of circular economy and waste minimization.