Chromolaena odorata is a fast-spreading invasive plant species that poses a serious threat to agricultural ecosystems, particularly in sub-Saharan Africa. Despite its reputation as a harmful weed, there has recently been an increase in interest in its potential use as an organic soil improver. This study evaluates the impact of C. odorata biomass on soil physicochemical properties, specifically pH and moisture content, as well as on the agronomic performance of maize (Zea mays). The experiment was conducted in Zépréguhé, in the Haut Sassandra region of central-western Côte d’Ivoire, using a randomised complete block design. Four treatments were tested: C. odorata biomass alone; C. odorata combined with a 170 kg/ha mineral fertiliser (NPK 15-15-15); mineral fertiliser alone; and an untreated control. A single maize variety (LG-501) was used to ensure consistency across the treatments. The agronomic parameters measured included plant height, the number of leaves, the stem base diameter and the yields of ears and grain. Soil pH and moisture were also assessed. The results showed that the treatments involving C. odorata significantly enhanced plant growth and increased soil moisture, while slightly neutralising soil acidity. Applying C. odorata alone produced the highest yields (10.74 t/ha for ears and 7.62 t/ha for grain), outperforming the mineral fertiliser treatment and the control. The combination treatment also yielded good results, albeit slightly lower. These results suggest that C. odorata biomass could be used as an effective, inexpensive alternative to or addition to synthetic fertilisers, thereby promoting soil health and sustainable maize production in tropical agroecosystems.

Traffic roads intensification contribute to ambient air pollution of the city of Abidjan, in Ivory Coast, as other African capitals. Biomonitoring methods based on spectrals and anatomicals plants leaves characteristics are effective to assess urban environment quality. Measurements of reflectance in the visible and taking stomatal imprints have been made on leaves of Ficus polita Vahl. Leaves were collected in roads vicinity and in parks of the city of Abidjan. Measurements of reflectance allow to distinguish road environment pollution relatively to parks while stomatal density (DS) revealed leaves anatomical response to road atmosphere quality. Air pollution impact on leaves physiology was determined by Normalised Dorsiventral Asymmetry Index (NDAI) and Stress Index (SI). NDAI is higher in parks than roadsides. Besides DS increasing values are observed with distance from the road when the contrary tendency is observed with SI. These results make it possible to consider an operational approach for assessment and monitoring of urban environment quality based on radiometric index and stomatal parameter.