Evaluation of millicomposts from different vegetable residues and production systems in the lettuce seedling development

Millicomposting is a new, little known, and environmentally friendly biotechnology, which facilitates the biotransformation of plant residues into stable organic matter; this process is aided by the activity of diplopods, commonly known as millipedes, which act directly on the fragmentation of plant residues, thus accelerating the decomposition rates of various residues whose C/N ratios are out of reach for traditional composting. The final product of millicomposting is millipede humus, which has been called millicompost and can contribute to supply the growing demand for substrates used to produce vegetable seedlings in rural and urban environments. In this context, this study aimed to verify the efficiency of millicomposts obtained in two different production systems, located in different environments (Rio de Janeiro and Sao Paulo) with different diplopod species in the production of lettuce seedlings. Initially, a thorough characterization of the evaluated substrates was carried out, characterizing the physical, physical-chemical, and chemical properties. The performance of different substrates in the production of lettuce seedlings was evaluated by sowing crisp lettuce cultivar Grand Rapids in 200-cell expanded polystyrene trays. The seedlings were evaluated 30 days after sowing. Millicomposts produced in RJ and SP states have differences in their physical, physical-chemical, and chemical properties. Nevertheless, both produced lettuce seedlings with similar quality, whose phytotechnical parameters were superior to the commercial substrate. In this point of view, both millicomposts are efficient as a substrate in the production of lettuce seedlings and can be produced in rural and urban environments, meeting the current need for sustainable agricultural inputs.