Avaliação do efeito “priming” na qualidade do vermicomposto de Eichhornia crassipes

Abstract

In eutrophicated environments, aquatic macrophytes reproduce rapidly and occupy large areas, hindering the multiple uses of water resources. The use of the biomass of these plants in vermicomposting represents a sustainable alternative. The objective of this work consists in the evaluation of the vermicomposting using macrophyte biomass and the addition of organic and inorganic substances to this process. The hypothesis that motivated this study is that the enrichment by organic and inorganic substances increases the fertility of the produced compost and the consumption of the biomass by the annelids. The enrichment of macrophyte biomass during vermicomposting by inorganic NPK (1.75% and 3.5%) and organic glucose (0.25 g/L and 0.5 g/L) solutions was tested. Humidity and temperature did not prove to be limiting to the process, remaining within the standard for vermicomposting. The pH and the electrical conductivity also had an expected behavior for vermicomposting. The efficiency of biomass consumption of the treatments with NPK were 21.57% and 8.7% higher than the control. For the treatments with glucose, the efficiency was 51.5% and 40.5% higher than the control. Both treatments showed superior quality of the compost formed when compared to the control. Regarding humification, the enrichment with NPK was intermediate, with higher values of humic substances formed and higher humification indicated by the E2/E3 ratio. The enrichment with glucose showed higher nutritional potential due to higher biomass consumption efficiency, higher humification represented by the E4/E6 ratio, and higher fertility values for total organic matter, nitrogen, phosphorus, and calcium. The data confirmed the initial hypothesis that both organic and inorganic enrichment would improve the quality of the generated compost and biomass consumption. Glucose caused a positive effect to the compost formed, with increased fertility and vermicomposting efficiency, besides being low cost, easy to obtain and apply. Despite the improvement in the composts, they prove to be inadequate for full use as fertilizer, being suggested the combination with other fertilizers and favoring soil moisture and structuring.