Evaluating effects of a new liquid vermicompost-based product on fruit quality in organic strawberries (Fragaria x ananassa Duch.)

Lack of appropriate fertilisers is a bottleneck in organic agriculture, which can lead to reduced yields and, consequently, reduced profitability. Therefore, the aim of this study was to develop a new formulation of a vermicompost-based biopreparation (VCMo) and to investigate the effects of this product on the composition of primary and secondary metabolites of the fruit of organically cultivated strawberries (Fragaria x ananassa Duch. cv Senga Sengana). Sugars, organic acids and phenolic compounds in strawberry fruit cultivated with three application modes of VCMo (rhizosphere inoculation (RI); combination of rhizosphere inoculation and foliar spraying (RI+FS); and foliar spraying (FS)) and a control (untreated soil and plants) were characterised and quantified by HPLC with a refractive index detector for sugars and organic acids, and HPLC-DAD-MSn for phenolic compounds. Strawberry fruit obtained from plants exposed to the combined application of rhizosphere inoculation and foliar spraying showed the highest concentrations of total sugars and total organic acids. There were no significant differences between the methods of VMCo application for concentrations of phenolic acids, but rhizosphere inoculation on its own resulted in the highest total concentration of the five groups of flavonoids identified (anthocyanins, flavanols, flavanones, flavonols and flavones). The results of the study suggested that rhizosphere inoculation with VCMo on its own or in combination with foliar spraying could be a useful tool for organic strawberry cultivation, contributing to the production of healthy and good quality fruit at the same time as providing opportunities to reduce environmental pollution.