Produção de mudas de Cordia trichotoma a partir do biochar obtido de resíduos de podas urbanas

Abstract

The increasing generation of waste from urban tree pruning management enables the development of sustainable solutions for transformation into new products. Accordingly, biochar, a carbonaceous material produced by pyrolysis, stands out for its relevant properties for substrate activity, promoting greater water and nutrient retention, carbon stability, and mitigation of climate change. Therefore, this study aimed to evaluate the effect of biochar produced from urban pruning waste as a substrate conditioner for the production of Cordia trichotoma seedlings. To this end, the biomass and the biochar produced through pyrolysis in an adapted reactor were chemically and physically characterized. The experiment was arranged in a completely randomized design with seven treatments, five replications, and ten tubes per plot. The treatments consisted of biochar incorporated into the commercial substrate in different proportions (0%, 5%, 10%, 15%, 20%, 25%, and 50%). The variables evaluated were the percentage of emergence (E%), emergence speed index (ESI), stem diameter, height, shoot dry mass (SDM) and root dry mass (RDM), total dry mass (TDM), Dickson quality index (DQI) with samples collected at 60, 120, 180, and 240 days, and clod quality with evaluations of Ease of Removal from the Tube (ERT) and Root Aggregation Assessment (RAA). Morphological data were collected at 60 days after emergence, 120, 180, and 240 days, and analysis of variance was applied, and, when significant, Scott-Knott mean grouping tests were performed at a 5% probability of error. The biochar produced presented a fixed carbon content of 59.62% and a gravimetric yield of 38%. Treatment with 15% biochar provided the best results for E% (91%), IVE (0.352), height (12.11 cm), stem diameter (3.18 mm), MSPA (1.091 g), MSR (1.445 g) and IQD (0.564) at 240 days. It is concluded that the incorporation of urban pruning waste biochar at a concentration of 15% is the most suitable for the production of Cordia trichotoma seedlings, as it promotes the best balance between water retention, aeration and seedling quality.