Bio-acclimatization of rooted mini-cuttings of Arabica F1 hybrid coffee var. Starmaya through soil amelioration with biochar derived from poultry manure

Background The mass propagation of Arabica coffee F1 hybrids via rooted mini-cuttings often results in high mortality (30%-40%) and growth stagnation during the critical acclimatization phase, limiting the rapid deployment of these climate-resilient varieties. This study investigated the efficacy of poultry manure biochar (PMB), produced via slow pyrolysis at 500°C, as a sustainable soil ameliorant to mitigate transplant shock and enhance seedling establishment across two sequential experimental rounds. Methodology: This study was conducted in two sequential phases. Round 1 implemented a randomized complete block design (RCBD) to determine the optimal PMB application dose (0%, 2.5%, 5.0%, and 10.0%) to maximize initial acclimatization success (SR), Root Biomass (RDW) and Root-to-Shoot Ratio (RSR) while round 2 validated the effectiveness of the optimal dose, assessing the sustained vigor and the field-readiness of the plantlets. Results Round 1 identified the 5% PMB treatment (T2) as optimal, significantly increasing the SR to 92.1% and root development ( 0.87 g/plant ) , showing a 35% increase in RDW compared to the control (0% PMB). This was linked to PMB's ability to stabilize substrate pH unit near the optimal 6.0. Round 2 confirmed that T2 (5% PMB treatment) maintained its superior vigor throughout the 24-week period, achieving a 90.5% SR compared to 65.1% for the control, demonstrating sustained resilience. The 5.0% PMB treatment maintained a balanced RSR (0.59) and produced high-quality arabica coffee F1 hybrid plantlet which were suitable for the immediate transplant to the field after 6 months in the nursery. Conclusion The two-round study validates the 5.0% PMB application as a scalable, and ecologically sound bio-acclimatization strategy to sustainably mitigate the transplant shock and maximized cutting survival, of Arabica coffee F1 hybrid plantlets. Also, utilizing poultry waste-derived biochar will provide a dual benefit: solving an agricultural waste challenge while simultaneously accelerating the mass production and deployment of climate-resilient coffee clones.