Vermicompost leachate as a supplement to increase tomato fruit quality

Due to low yields, organic agriculture cannot satisfy the global demand for food, although it can provide products of higher nutraceutical quality. The objective of this research was to incorporate vermicompost leachates (VCLs) into an irrigation system during tomato (Solanum lycopersicum cv. Rafaello) cultivation to evaluate their effects on the lycopene, beta-carotene, and phenolic content of tomatoes and on the physical and chemical soil variables. To evaluate the effects of VCLs, three types of substrates were used to create VCLs: mushroom waste (MSHW), leaf-cutting ant waste (LCAW), and cow compost (CC). A total of 0.1 L of leachate per plant was added as a supplement to a nutrient solution (NS) and applied once weekly, twice weekly, or every fifteen days to three different treatments for each leachate. All VCLs had a positive effect on the production of lycopene; the best results were obtained by the application of the MSHW (78 mg kg(-1) fresh weight). The VCL decreased the presence of ions phytotoxic to plants by 99% and improved the soil structure by increasing the amount of organic matter and the hydraulic conductivity. However, the VCL had no effect on the physiological variables. The results support the use of leachate from CC via fertigation twice a week at a dose of 0.1 L plant(-1) because it increases lycopene content by 67%.