Substratos para produção de mudas utilizando resíduos agroindustriais

Abstract

This study aimed to evaluate the agroindustrial wastes available in the Cariri region State of Ceara, Brazil, such rice hulls, as sugarcane bagasse and banana stems, as options in the composition of substrates for seeding production of chrysanthemum, lettuce and tomato, as well as to evaluate the economic impact in the production costs of these seedlings. Physical and chemical analysis were performed to characterize the substrates, comparing them with substrates considered ideal in the international literature. The treatments consisted of eight substrate formulations: the commercial substrate Plantmax® Hortaliças (Pmax), carbonized rice hulls (CAC), organic compost (cattle manure, sugarcane bagass and banana stems) CBC and the volumetric mixtures: Pmax + CAC 1:1, Pmax + CBC 1:1, CBC + CAC 1:1, Pmax + CAC 1:2 and CBC + CAC 1:2. All treatments were evaluated through bioassays under greenhouse conditions, in order to produce seedlings of tomatoes with fertigation, lettuce seedlings with and without fertigation and rooting of chrysanthemum cuttings. The influence of the substrates on the seedling production was determined by vegetative biometric parameters of the top and root parts. For the rooting of chrysanthemums at 15 days, the substrates studied can be recommended. They can be used insvad of carbonized rice hulls in case of seasonal shortage. The CBC and CAC when used in combination between them or with the commercial substrate Pmax®, were efficient options for the production of lettuce and tomato seedlings in trays by improving the physical and chemical characteristics of the later. The CBC when used by itself had negative effect on seedling emergence for tomato and lettuce. The results obtained showed that it is technically and economically possible to substitute in part or completely the commercial substrate Pmax® for alternative substrates in the Cariri Region, with considerable reduction in costs of this input in the seedling production without quality reduction.