Monthly biol application sustains yield and profit in CCN-51 cacao with partial synthetic input substitution

<title>Abstract</title> <p>Substituting synthetic agrochemicals with biologically based inputs is increasingly promoted to improve the sustainability of tropical cropping systems, yet empirical evidence from commercial cacao plantations remains limited. This study evaluated the agronomic and economic consequences of partially replacing synthetic foliar fertilizers and fungicides with an on‑farm fermented biol in a CCN‑51 cacao monoculture on the Ecuadorian coast. Methods: Six management regimes were evaluated over two consecutive production cycles. Pod production, dry bean yield, disease incidence (Frosty Pod Rot and Witches’ Broom), climatic variables, and production costs were analyzed using mixed‑effects models and partial budget analysis. Despite substantial differences in foliar input regimes, cumulative pod production and dry bean yield remained statistically comparable among treatments, indicating that partial substitution did not compromise productivity when soil fertilization was maintained. Disease incidence was not significantly affected by treatment but was associated with rainfall patterns occurring one to two months prior to symptom expression, confirming the dominant role of climate. Economic performance varied markedly with application frequency: biol applications every 15 days generated negative returns (net margin −884 USD ha⁻¹; benefit–cost ratio 0.9), whereas monthly applications (50% biol) restored profitability comparable to conventional management (BCR 2.2) with production costs of approximately 1.10 USD kg⁻¹. Strategic monthly substitution of foliar synthetic inputs with a 50% biol offers a viable entry point for reducing chemical dependency in intensive cacao systems, but only when embedded in an integrated management framework that includes rational application schedules, climate‑informed sanitation, and labor efficiency.</p>