Yield and quality of tomato with organic sources of fertilization under greenhouse conditions

Abstract

The scarcity of fertilizers that are allowed in organic agriculture (AO) encourages the search for alternatives, being the use of compost one of the most outstanding. AO has been recognized as a more sustainable system than conventional agriculture. AO is ruled by strict norms which forbid the use of most common fertilizers. The aim of this study was to evaluate the effect of various fertilization treatments on the organic production of greenhousegrown tomato. A completely randomized experimental design with five replications was used, with a 5x2 factorial arrangement. Factors A and B were: a) fertilization treatments and b) tomato genotypes. For the fertilization levels, various sources of both organic and inorganic nutrients were mixed with a base substrate; it consisted of a mixture of 50% compost plus 50% river sand in 20 L pots. Results showed no significant differences between the two genotypes (Bosky and Big Beef). The fertilization treatment consisting of a mixture of compost plus organic macroelements increased yield by 37.1% with respect to the control (without fertilizers). The same trend was observed for other variables, such as plant height and fruit quality. The treatment with compost plus a supplementation of organic macroelements was able to achieve the same general development and yield as the treatments with compost plus inorganic macroelements. The soluble solids showed higher values on treatments with compost with respect to the control without such material. The results showed that the greenhouse production of tomato using organic fertilization is a viable alternative for both organic growers and greenhouse growers committed to sustainability.