Low Cotton Yield is Associated with Micronutrient Deficiency in West Africa

Core Ideas Low cotton yield is associated with micronutrient deficiency. Previous study linked low cotton yield to shortage in soil organic matter but not to NPK. The results reflected NPK addition by agency (Compagnie Malienne pour le Developpement de Textiles) promoting cotton growth. We detected a deficiency in Fe, Zn, and Cu in fields with low‐yield cotton. Micronutrients amendment (possibly by foliar application) is suggested. Changing the protocol for cotton cultivation by Compagnie Malienne pour le Developpement de Textiles is recommended. Despite the positive contribution of the Compagnie Malienne pour le Developpement de Textiles (CMDT) to cotton production in West Africa through fertilizer supplies, soil degradation is relatively fast. A previous research in the Kita region, Mali, showed a substantial drop in cotton yield after several years of cultivation. While being accompanied by a drop in the soil organic matter (SOM), no shortage in NPK was registered in the low‐yield plots, suggesting that soil degradation may stem from a deficiency in secondary nutrients or micornutrients. Soil analysis showed a substantial decline in Mg, Fe, Cu, and Zn with time, with the amounts of Fe, Cu, and Zn being significantly lower at the low‐yield plots, pointing to the possibility that these micronutrients are the first to be affected by SOM depletion, and therefore can be considered as “limiting factors” for cotton growth in the region. In comparison to virgin and long‐fallow soils (reference soils), Fe and Cu reached ∼50% of the reference soils within ∼5 to 6 yr and Zn within ∼10 yr. The findings point to the apparent importance of micronutrient to cotton yield. Addition of micronutrients to the macronutrients as part of the CMDT protocol sis recommended.