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.

Millet (Pennisetum glaucum (L.) R. Br.) is one of the staple foods of the populations of northern Côte d’Ivoire. And, farmers serve as both producers, curators of millet biodiversity and are also repositories of knowledge to determine and differentiate the varieties of millet in their possession. It therefore seems necessary to carry out an investigation with them, in order to benefit from their knowledge on the management methods of the millet accessions cultivated in their possession as well as on the socio-cultural characteristics of the genetic diversity of millet. To do this, 176 producers in the savannah district were questioned during a survey. They were predominantly male and belonging to a diversity of ethnic groups using different local names to designate millet. Three varieties of millet were identified there, namely late and intermediate local varieties, with gray colored seeds, and early varieties which are improved with olive-yellow or light yellow seeds. The results showed that it is a food present in all the ceremonies of the peoples of the North and is consumed in several culinary forms. However, its cultivation is in decline due to certain constraints encountered there and would be neglected in favor of cash crops such as corn, cotton and cashew nuts. Given the important place this culture occupies within the populations of northern Côte d’Ivoire, actions must be taken to contribute to the promotion and development of its culture.

Faced with climatic hazards that lead to the abandonment of some traditional local varieties of maize (Zea mays L.), a study was undertaken in northern Côte d'Ivoire. Its objective was to determine the effectiveness of different manure on the productivity of these local maize varieties under water deficit conditions during the reproductive phase. The experimental device was a split-plot, the first factor of which was fertilizers and the second, variety. A water deficit was observed during the reproductive phase of the maize varieties studied with a higher ETo accumulation than the water available for the plants. The application of chicken droppings and cattle droppings has reduced the development cycle of black seed maize. The depressive effect of water deficit on yield was more pronounced on the control, unlike chicken dropping and cattle dropping manure, which yielded six times more than the control in the black seed variety. As a result, these manures have reduced the depressive effect of water deficit on the yield of this variety. The use of these manures in maize cultivation could be an alternative to the consequences of the water deficit recorded during the reproductive phase in maize.