Teste de germinação para avaliação de fitotoxicidade de chorume e composto gerados em pequenas composteiras

Abstract

Solid waste represents one of the major issues of modern society, resulting from population growth, intense urbanization, and economic expansion, leading to a constant increase in waste generation. One way to reduce the amount of waste disposed of in landfills is through the composting of organic matter present in urban solid waste. Compost is the main product of composting, and despite the numerous benefits it provides to plants and soil, assessing its toxic potential before soil application is highly important. Similarly, leachate, a byproduct of composting, has the potential to be used as a biofertilizer. Germination tests are an effective way to evaluate the toxicity of compost and other substances. The present study aimed to assess the phytotoxicity of compost and leachate produced by small composting systems using germination and root elongation tests. The parameters of pH and moisture of the compost were determined according to Tedesco et al. (1995). The experiment involved evaluating the germination of komatsuna and lettuce (L. sativa) seeds in aqueous extracts derived from samples of organic compost, commercial humus, and leachate. The method adopted was an adaptation of the protocol described by Tiquia (2010). The compost showed a pH of 9.22 and an average moisture of 78%, both above the recommended values. L. sativa seeds showed greater growth than komatsuna seeds. The germination indices (GI) of the compost were greater than 70%, indicating the absence of phytotoxicity and maturity of the compost. The leachate showed no phytotoxicity at dilutions below 10%.