Savannah Soils Fertility Diagnosis for Optimal Cotton (Gossypium Hirsutum L.) Management in Northern Côte d'Ivoire

In savannah environments, soil constituents nature and structuration undergo significant and rapid transformation which could impair their use. Some of these transformations are due to changes in human activity, resulting from unsuitable cultivation practices, and overexploitation of the land, which is accompanied by a decline in cultivated soils fertility. A baseline survey was conducted to diagnose cotton-grown soils in terms of fertility and long-term sustainable utilization. Six locations were selected in the vast cotton cultivation zone in northern Côte d’Ivoire. Soil pH varied from slightly acidity to neutral, suggesting good acidity level for optimum cotton growth. However, there were deficiencies in nutrients, which differed from one soil to another: soil organic carbon was lower than 5 %, total N was very low in Boundiali and Korhogo, and soil assimilable phosphorous was very low in Boron, Diawala and Ferkessédougou. Soil grouping using a principal component analysis showed some similarities among the studied cotton-grown soils and constitutes a clue to align soils fertilization strategies. The analysis of soil amendments should focus on macronutrient and specific secondary nutrients like Ca, S, and Mn input. Furthermore, cotton-grown soils fertilization should be done through organic amendment.