Cocoa farmers’ ethnoecological knowledge of soil biota and fertility management in Ghana’s agroecological zones

The sustainability of cocoa production in Ghana is constrained by declining soil fertility and the underutilization of locally held ecological knowledge. Grounded in the Socio-ecological Systems Theory, this study aimed to (i) document and compare farmers’ local ecological knowledge (LEK) of soil macrofauna across different agroecological landscapes, (ii) assess zone‑specific soil fertility management practices, and (iii) identify socio‑environmental determinants of LEK and fertility knowledge. Employing a multistage stratified sampling design, 400 smallholder cocoa farmers were surveyed using semi‑structured questionnaire-led interviews. We quantified and compared LEK with the Local Ecological Knowledge Index (LEKI) and ANOVA, soil fertility practices via Chi-Square test, and socio-environmental determinants of LEKI via Linear Mixed‑Effects Models (LMMs). Results show that LEK varies significantly among zones (F = 3.809, p = 0.025), with highest mean LEKI in the Moist Evergreen (45.00) versus Transitional (31.00) and Moist Semi‑Deciduous (30.47) zones. Water retention strategies – shade trees in Transitional (n = 134) and weed residues – differentially prevail, whereas erosion control is concentrated in the Moist Semi‑Deciduous Zone. Organic residue management (pruning vs. weed residues) follows distinct zone patterns, and crop residues remain unused. LMMs reveal that ecological zone and farm size are significant predictors of both LEKI and fertility knowledge (p < 0.001), while formal education positively influences LEK of macrofauna (p < 0.05). These findings highlight the critical role of biophysical context and landholding scale in shaping farmers’ knowledge systems. The findings suggest co‑developed extension programs, that integrate indigenous soil fauna indicators with agroecological best practices, could be effective if tailored to each zone.