Evaluation of substrates produced from cellulose residues for propagation of ornamentals and vegetables

Abstract

The propagation of plants by means of substrates has become one of the most recurrent practices of the floricultural and horticultural industry because it increases the quality of the products, decreases the production costs and the losses by deaths of the seedlings. In this study, 12 treatments elaborated with mixtures of cellulose and fruit residues, burned rice husk, coal slag, or peat were characterized by porosity tests, water activity, chemical composition, phytotoxicity, and physicochemical tests. Subsequently, it was assessed in a randomized complete block design the effect of the treatments on the growth and viability of lettuce (Lactuca sativa) and tomato (Solanum lycopersicum) evaluating their germination, biomass production, and length of the roots; and the effect of the treatments in the rooting of carnation (Dianthus caryophyllus) and gypsophila (Gypsophila paniculata) evaluating the viability and length and weight of roots. It was found that all treatments have a porosity (75-83 %), water retention capacity (6.90-11.28), phytotoxicity and physicochemical properties suitable for their application as substrates. However, the results for rooting and germination tests showed that only rice husk treatments can be used in all species with a viability level higher than 80 % for lettuce and tomato, and between 60-90 % for the gypsophila and the carnation. One of the substrates composed of cellulose residues and fruit with rice husk and the compounds only for rice husk were suitable for the rooting of carnation and therefore can be a suitable mixture for the propagation of this species.