COMBINED EFFECTS OF IRRIGATION WATER DEPTHS WITH UREA FORMS ON RICE YIELD AND WATER PRODUCTIVITY IN THE SAHEL, BURKINA FASO

This study investigated the impact of urea forms and irrigation levels on paddy rice yields and water use efficiency. An experiment comparing super granular urea (SGU) and prilled urea (PU) under three irrigation levels (5 cm, 7.5 cm, and 10 cm) was established in a split plot design with three replications. The results show that SGU treatments showed better performance in comparison with PU in terms of growth, yield components and yield. The SGU treatment at 5 cm irrigation displayed the highest yield (marginal ≈ 4,845 kg/ha; observed ≈ 4,826 kg/ha) compared to other treatments. Principal component analysis (PCA) revealed that this productivity was strongly correlated to panicle weight and straw yield, placing the SGU treatments on the high-performance. Although the 10 cm irrigation level promoted tillers number (11.5) with SGU, it also increased water consumption without producing a significant yield gain. In contrast, SGU at 5 cm gave the best water saving (≈ 50%). Despite high experimental variability making the linear mixed model statistically not significance at the 5% level, the agronomic trends with growth parameters and PCA confirmed that using SGU combined with controlled 5 cm irrigation is the most promising strategy for optimizing rice yield and water productivity in semi-arid climate.