Produção de mudas de hortaliças orgânicas e de microverdes em substratos formulados com composto de casca de banana

Abstract

The reuse of industrial organic waste for agricultural purposes has aroused interest both for reducing environmental impacts and for the production of agricultural inputs, generating economic, social and environmental benefits, and the composting process is a low-cost alternative to carry out its processing. Banana is one of the main fruits produced and consumed in Brazil, and its industrialization results in the generation of large amounts of waste. However, banana peel is a material that has high humidity and pasty texture and, for its composting, it is necessary to mix it with some material with a coarser texture. Thus, the objective of this research was to evaluate the feasibility of producing substrates from the composting of waste generated in a banana agro-industry, using banana peel and grass pruning residue. Initially, a composting experiment was carried out to evaluate different proportions of the banana peel mixture with grass pruning, in addition to the inoculation of the compost. Aiming at obtaining efficient substrates for the production of seedlings of three organic vegetables and for the production of two species of microgreens, experiments were carried out to evaluate the use of different organic compounds, mixed with vermiculite in the proportion of 2:1 (v/v), having as a witness a substrate formulated from earthworm humus and fine coal. The pH and electrical conductivity (EC) of the substrates were measured throughout the development of vegetable seedlings. All the compost mixtures evaluated presented temperatures close to the environment during the 120 days of composting, probably due to the reduced size of the windrows. It was found that during seedling development, the pH of the substrates remained close to neutral or slightly alkaline, between 6.6 and 8.8. It was also observed a significant reduction of EC of all substrate formulations at 7 days after sowing and remaining at values below 150 μS cm-1, probably due to excessive irrigation. Substrates formulated with compost made up of 50% or 75% of banana peel showed equal or superior performance to the control substrate on the development of lettuce, beet and tomato seedlings, and for the production of lettuce and mustard microgreens. The substrate formulated with compost inoculated with EM (effective microorganisms) generally presented the same or lower performance compared to the other substrates evaluated. It was found that it is possible to obtain efficient organic substrates for the production of vegetable and microgreen seedlings, formulated with vermiculite and with a mixture of banana peel and grass pruning.