This study, carried out in San Pedro (Southwest Côte d’Ivoire), evaluates the agronomic valorization of wastewater treatment sludge (WTS) and green waste (GW) through co-composting for sustainable soil improvement and circular economy promotion. Four GW/ WTS formulations (Co1: 0/100, Co2: 25/75, Co3: 50/50, Co4: 75/25) were monitored over 90 days, with regular measurements of temperature, moisture, and pH. Mature composts were characterized for physico-chemical properties, biological maturity, and heavy metal content. A weighted multicriteria matrix, based on ten strategic indicators, identified Co3 as the optimal formulation (score 40/45), outperforming Co4, Co2, and Co1. Co3 reached 65 °C by day 40, satisfying sanitary requirements, maintained optimal moisture, increased soil organic carbon by 284 %, corrected pH to 7.9, and complied with NFU 44-051 heavy metal standards. The heatmap and hierarchical clustering analysis confirmed its superiority, positioning Co3 as a safe and effective amendment for sustainable agriculture adapted to local soils.

This study is focused on the soil morphological and physico-chemical characteristics of soils influenced by the topographical factor in Savanna area. It was carried out along three toposequences in Gogbala area of Korhogo Department, Northern Côte d'Ivoire. Soil samples were collected at each topographic unit, namely, upper slope positions, mid slope positions and bottom slope positions. Samples collected were air-dried, crushed and sieved in a 2 mm sieve preparatory to laboratory analysis. The results showed that Cambisols are the dominant soils in the study area; these are characteristic soils of reddish brown (2.5YR 4/6) to yellowish brown (10YR 4/2) at the upper and mid slope positions, and grey (10YR 5/1) at the lower slope positions. These are well drained soils whose genesis is considered to have been predominantly influenced by climate in which they occur. The profiles are weak fine granular transformation and evident changes in soil structure, color and clay content. They are dominated by sandy loam textures. Organic matter and N, available P, Exchangeable Ca, Mg contents, CEC are in the range of low to medium values. The pH values of the samples are acid (pH < 6). Fertility is low. Therefore, to perform agricultural managements in Gogbala area, decision-makers should take into soil morphological and physico-chemical characteristics consideration, suggest the need of integrated nutrient management with addition of both organic and inorganic fertilizers in the land units.