Uso do biochar de caroço de Umbu na pordução de mudas de Jurema-branca
Vivian Silva Gomes
UFERSA
Narjara Walessa Nogueira
Rômulo Magno Oliveira de Freitas
Felipe Loan Barreto de Araujo
Gutierres Silva Medeiros Aquino
Palavras-chave: Piptadenia stipulacea, Pirólise, Biocarvão, Caatinga
Resumo
The umbu tree (Spondias tuberosa Arr. Cam.) is a native fruit species of the Caatinga biome, widely valued in the Brazilian semi-arid region for its fruits of great socioeconomic and ecological importance. During the processing of umbu, a significant amount of seeds, pulp residue, and peels are discarded as waste, representing an underutilized potential. In this context, the reuse of these materials in the form of biochar emerges as a sustainable and environmentally appropriate alternative for the disposal of agro-industrial waste, especially those originating from the production of umbu pulp. This study was developed with the objective of evaluating the effect of different doses of umbu seed biochar on the initial development of Jurema-branca (Piptadenia stipulacea (Benth.) Duck) seedlings. The experiment was conducted in a greenhouse at UFERSA, in Mossoró-RN, where the seeds were also collected. The substrate used was sandy soil, to which doses of biochar were incorporated (0, 15, 30, 45 and 60 t ha⁻¹). After homogenization, the substrate remained incubated for 30 days before sowing. The experimental design was a randomized block design, with five treatments (doses) and four replicates, each unit consisting of five plants. At 60 days after thinning, the shoot length (CPA), root length (CR), collar diameter (DC), leaf dry mass (MSF), stem dry mass (MSC), shoot dry mass (MSPA), root dry mass (MSR) and total dry mass (MST) were evaluated. The robustness index (IR) and Dickson quality index (IQD) were also calculated. The data were subjected to analysis of variance, and the means compared by Tukey's test at 5% probability. The biochar differentially influenced the growth and quality of Jurema-branca seedlings. Biomass variables showed a quadratic behavior, increasing up to doses between 15 and 20 t ha⁻¹ and decreasing at higher doses. Intermediate doses favored biomass accumulation, while high amounts caused an imbalance in the substrate. Shoot length and collar diameter showed little variation between treatments, while root length showed a slight reduction at higher doses. The Dickson quality index performed best at approximately 20 t ha⁻¹. Thus, the results indicate that umbu seed biochar can be used as a substrate conditioner for the production of jurema-branca seedlings, with intermediate doses (between 15 and 20 t ha⁻¹) being the most recommended to promote greater biomass accumulation and seedling quality.