Effect of the Organic and NPK Fertilizers on the Growth and Yield of Sweet Potato (Ipomoea batatas (L) Lam) in the Centre of Côte d’Ivoire

In Côte d’Ivoire, the sweet potato is little cultivated but stays however a culture of pension and a food mattering in certain regions. This study was conducted to assess the effect of the application of mineral (NPK 15-15-15, NPK 12-22-22) and organic (poultry manure) fertilizers on yield components of sweet potato (Ipomoea batatas (L) Lam). The experiment was conducted over two years (2016 to 2017) in experimental station of National Center of Agronomic Research (CNRA) of Bouaké in the centre of Côte d'Ivoire. The experiment was conducted following a split plot with 2 factors (variety and fertilizers) and 3 replicates. The main factor was variety with 2 levels (variety Irene and variety TIB-440060) and the subplot was fertilizers application consisted 13 levels (200, 300, 400, 500 kg ha-1 of NPK fertilizers combined 5, 10, 15 t ha-1 of organic fertilizer). Thirteen treatments based on poultry manure (T6, T7), chemical fertilizer NPK 15 15 15 (T1, T3, T4, T5) and NPK 12 22 22 (T8, T10, T11, T12) and their combination (T2 and T9) were tested. The experimental results revealed that that the effects of chemical fertilizer treatments, manure and their combination with mineral fertilizers did not influence the measured parameters. The results also showed that fertilizers improved all the agronomic parameters of sweet potato compared to the control treatment during two years of experiment. However, the Irene variety with a mean weight of 180 g tuberous roots was significantly different from the TIB variety with a mean weight of 138.73 g.

In the conditions of our study and over the two-year period, producers of sweet potatoes would benefit from using organic fertilizers with the Irene variety.