Cassava has long been cultivated without fertilization, on poorly maintained soils whereas extensive knowledge advocates the effectiveness of fertilization not only in increasing the crop yield but also improve its root quality. The present study was carried out (1) to evaluate the agronomic performance of cassava (2) its root quality and (3) the profitability in response to the application of split doses of NPK fertilizers. The fresh cassava tuber roots yield was significantly higher (between 38.47 and 43.46 t ha-1) when highest doses of N (60 and 90 kg ha-1) and K (80 and 120 kg ha-1) were combined. Simultaneous application of the highest doses of nitrogen (90 kg ha-1) with any dose of potassium (40, 80 and 120 kg ha-1) yielded the highest cassava root dry matter, nitrogen, phosphorus and potassium content. On the other hand, low doses of nitrogen (40 and 60 kg ha-1) in the presence of increasing doses of potassium (120 and 80 kg ha-1) induced the highest HCN contents in cassava roots. The highest gross and net benefits were achieved with the simultaneous application of N at a minimum dosage of 60 kg ha-1 in combination with the tested dosages of K (40, 80 and 120 kg ha-1). Increasing the dose of potassium up to 120 kg ha-1 and that of nitrogen to 90 kg ha-1 is a valuable asset to increase the yield as well as the profitability of high-quality cassava tuber roots if phosphorus is not limiting.

Keywords: Agronomic performance, Cassava, fertilization, profitability