Residual Effect of Phosphate Amendments on Agronomic Parameters of Rainfed Rice in Three Agroecological Zones of Côte d'Ivoire

A study was conducted in Côte d'Ivoire to assess the after-effect of phosphate amendments on rice yield and soil properties. Eight types of amendments, composed of Moroccan phosphate rock (PRM) and triple superphosphate were tested in three agroecological zones over three consecutive years of cultivation. The results of the study showed that the application of phosphate amendments led to a significant improvement in rice grain yield in all the agroecological zones. Grain yield was ranged from 1.7 to 4.5 t/ha, compared to 0.8 to 1 t/ha in the control. Treatments with a higher proportion of PRM showed the best results. These results suggest that the input of natural phosphate rock can significantly improve rice yield in the studied agroecological zones in Côte d'Ivoire.