Animal-based organic nutrition can substitute inorganic fertigation in soilless-grown grape tomato

Abstract

ABSTRACTPurpose: In recent years, interest in plant nutrition research has arisen with a strong focus on organic forms. The aim of this study was to determine the effect of different organic fertilizers on growth, yield, fruit quality and polyphenol content in soilless grown grape tomatoes under greenhouse conditions.Materials and methods: Tomato plants were subjected to three organic nutrient solutions, which consisted of different mixtures of several OMRI (Organic Materials Review Institute) certified nitrogen fertilizers of industrially processed residues: Treatment I: solid and soluble liquid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride; Treatment II: solid and soluble liquid fertilizers of animal raw materials, by-product of marine raw material (soluble liquid), natural potassium sulphate-non-synthetic, and calcium chloride; and Treatment III: solid fertilizers of animal raw materials, natural potassium sulphate-non-synthetic, and calcium chloride to 100% [0-30 days after transplanting (DAT)], 125% [31-80 DAT], and 150% [>81 DAT]. The Steiner solution (SS) was used as a control (Treatment IV).Results: Yield did not differ between organic and conventional treatments, ranging from 3.04 to 3.35 kg m-2 while fresh weight in organic treatments was 3.14 compared to 3.2 kg m-2 in plants fed with the SS. No significant differences in plant height or fruit quality were found. The application of organic fertilizers positively affected the total hydrolysable and condensed polyphenols of tomato fruits compared to the control. Twelve phenolic compounds were identified, highlighting 3-Caffeoylquinic acid, salvianolic acid and 5,6-Dihydroxy-7,8,3’,4’-tetramethoxyflavone (Treatment I) and Medioresinol (Lignan) (Treatment II).Conclusions: The results indicated that organic fertilization through animal-based fertilizer application is a feasible alternative for grape tomato production under greenhouse conditions.