An agroindustrial compost as alternative to peat for production of baby leaf red lettuce in a floating system

© 2018 Elsevier B.V. Peat alternatives are being developed using materials such as agroindustry compost. The aim of this work was to study whether an agroindustrial compost could be used as substitute for peat in a floating system for cultivating baby leaf red lettuce. For this, two different experiments were carried out over two growing cycles (summer and autumn) in the same greenhouse at the same time. The first experiment compared the two organic substrates (peat and compost) and the second involved a suppressive bioassay using both substrates inoculated with Pythium irregulare. The results showed that compost increased the percentage of seed germination and the quality of baby leaf red lettuce by reducing nitrate accumulation and increasing the antioxidant capacity and vitamin C content of leaves compared with peat. Furthermore, under P. irregulare pressure plants grown in compost showed less incidence of the disease (a higher percentage of plant survival) and produced higher yields. It is concluded that the agroindustrial compost used in this study shows promise as an alternative to peat for use as organic substrate in a sustainable soilless production system for baby leaf red lettuce, since it is not only able to control the effect of P. irregulare, but also improve the yield and quality of the product.