Composição de bolas de sementes para germinação de espécie perene em estratégia de revegetação de área degradada

Abstract

The revegetation of degraded areas in the Brazilian semi-arid region requires innovative techniques to overcome water scarcity and soil degradation. In this context, seed balls emerge as a promising strategy, combining physical protection and moisture retention to enhance the germination of native species such as Enterolobium contortisiliquum (Vell.) Morong (tamboril). However, gaps remain regarding the ideal compositions that balance water retention, pathogen resistance, and technical feasibility, particularly in semi-arid environments. It is hypothesized that: (1) the addition of hydrogel and organic compost in seed balls increases the substrate's water retention, favoring tamboril germination and early development; (2) balanced formulations of soil, compost, and hydrogel ensure the structural integrity of the seed balls and seedling viability; (3) under controlled conditions, seed balls with hydrogel perform comparably to direct seeding but surpass it under water deficit scenarios. The study adopted a completely randomized design (CRD), testing six treatments (BS0–BS5) with varying proportions of soil (35–60%), compost (35–49.75%), cassava starch (5–15%), and hydrogel (0–1%). Germination (5 and 10 DAS), gravimetric moisture, penetration resistance, dry biomass (shoot and root), and fungal incidence were evaluated in 24 experimental units. Data were subjected to ANOVA, Duncan’s test (p < 0.05), and Box-Cox transformation for normalization. Results indicated that treatment BS4 (50% soil, 41.5% compost, 7.5% starch, 1% hydrogel) promoted 75% plant emergence, with low fungal incidence (25%) and significant biomass production (shoot dry mass = 0.71 g; root dry mass = 0.12 g). In contrast, BS3 (45% soil, 44.25% compost, 10% cassava starch, 0.75% hydrogel) recorded 0% emergence and 100% fungal attack, while the control (BS0, direct seeding) achieved 100% emergence but exhibited a higher shoot/root biomass ratio (6.91 vs. 5.92 in BS4), suggesting lower adaptation to water stress. It is concluded that the hypotheses were partially confirmed: BS4 was optimized for water retention and plant health, standing out as a viable alternative for revegetation under semi-arid conditions, although its field performance requires further validation.