Caracterização e avaliação de vermicompostos produzidos em propriedades rurais agrícolas familiares nos municípios de Pelotas e Morro Redondo – RS

Abstract

The increase in agricultural and agro-industrial production generates a greater volume of solid waste and the need to correctly dispose of this waste. Vermicomposting is an alternative for the recovery of organic waste, the product of which is vermicompost used to replace chemical fertilizer. Therefore, it is important to evaluate the quality of vermicomposts for application in agricultural production. The general objective was to characterize and evaluate the quality of vermicomposts produced on rural family farms, as well as the management of solid waste generated in the municipalities of Pelotas and Morro Redondo (RS), two of conventional production (P1 and P3) and two organic (P2 and P4). An interview was applied to collect information about each rural property, activities carried out, the generation and management of solid waste, and the vermicomposting technique. Samples of vermicomposts were collected and subjected to chemical, phytotoxicological and microbiological analyses, with the aim of evaluating the stabilization of vermicomposts produced on the properties. Substrates were formulated by adding different proportions of carbonized rice husk (CAC) to vermicomposts from P2 (VCPO) and P3 (VCPC) and to a commercial vermicompost resulting in 16 different substrates, and agronomic performance was evaluated using lettuce seedlings. The experiment was conducted in a greenhouse at Embrapa Clima Temperado, located in Pelotas-RS. The experimental design was in randomized blocks with four replications and 17 treatments with different dosages of CAC, P2 (organic) and P3 (conventional) vermicomposts, commercial vermicompost and commercial substrate. The agronomic variables evaluated were germination, number of leaves (NF), plant height (cm), root ball, root length (cm), fresh mass (g) and shoot dryness (g). The results showed that the management of solid waste generated on properties occurs partially, some categories are allocated correctly and others require adjustments. P1, P2 and P4 are covered by the conventional collection system and P4 also has selective collection and P3 does not have collection. The owners of P1 and P4 deliver contaminating waste to PEVs. Only P1 and P2 use agricultural production residues in vermicomposting. Laboratory analyzes showed that all vermicomposts presented a C/N ratio within the standards recommended by Brazilian legislation and satisfactory results for the microbial population. The vermicompost produced in P4 obtained better results for most of the chemical parameters analyzed, however, it showed phytotoxicity for all test organisms, indicating a lack of maturity, unlike VCP1 which showed no phytotoxicity, showing that it was mature. Substrates T9 (40%VCPO + 60%CAC), T15 (60%VCPC + 40%CAC) and T16 (80%VCPC + 20%CAC) showed better results, being recommended for Regina de Verão lettuce.