The efficient use of fertilizers could help to improve soybean yields, which have remained low since its introduction in Burkina Faso. Soybean data sheets recommend the use of NPK mineral fertilizer at a rate of 150 kg/ha. However, the formulation of NPK specific to this crop has not been specified. With several NPK fertilizer formulations on the market in Burkina Faso, soybean growers use all of them to improve yields. It is therefore necessary to find the right NPK formulation for soybean production. The objective of this study was to identify the NPK fertilizer formulation that would improve soybean productivity in Burkina Faso. To this end, an agronomic experiment was conducted in a real environment during the 2022 wet season at the Gampela experimental station. The experimental set-up used was a split plot with four replications. The NPK 14-23-14, NPK 20-10-10, NPK 15-15-15 and NPK 14-18-18, were applied to two improved soybean varieties (G 196 and G 197) grown in Burkina Faso, with an absolute control (no fertilizer). The results of the analysis of variance showed a significant difference (P = 0.000) between the NPK fertilizer formulation on the foliage and seed yields of varieties G 196 and G 197. In variety G 196, plants fertilized with NPK 14-23-14 and those fertilized with NPK 20-10-10 obtained the best foliage yield (4.65 ± 0.13 t/ha) and the best seed yield (1.50 ± 0.13 t/ha), respectively. In variety G 197, the plants fertilized with NPK 14-18-18 and those fertilized with NPK 14-23-14 obtained the best foliage yield (3.84 ± 0.08 t/ha) and the best seed yield (2.60 ± 0.02 t/ha), respectively. NPK 20-10-10 could be recommended for seed production of variety G 196 and NPK 14-23-14 for seed production of variety G 197.

Soybean; NPK formulations; Growth; Yield; Burkina Faso