Nitrogen and phosphorus deficiencies are some of the main factors restricting irrigated rice (Oryza sativa L.) productivity in Burkina Faso. Urea supergranules (USG) have been proven to increase rice yield but this increased productivity is likely to be constrained because P is becoming limiting in irrigated rice systems. Field experiments were carried out with rice variety Nerica 62N in Sourou valley in the wet season of 2012 and in the dry season of 2013. The effect of two sizes (1.8 and 2.7 g) of USG and five levels of phosphorus (0, 20, 30, 40 and 50 kg P ha-1) were studied in a split plot design on rice yields. The use of USG 2.7 g did not significantly increase rice yields compare with USG 1.8 g in both seasons. P application significantly increased rice yields. The 1.8 g USG significantly increased the agronomic efficiency (AE) by 48.9% over the USG 2.7 g in the 2012 wet season while the increase in AE was 24.4% in the 2013 dry season. The best AE 42 kg kg-1 in 2012 and 25 kg kg-1 in 2013 were obtained with 50P and 30P. This study suggests that USG can be used by farmers in small rate (USG 1.8 g) to improve nitrogen use efficiency and the application of 30 kg P kg-1 seems to be adequate to increase yield in irrigated rice cropping system.
S. Iacob, K. Nieuwenhuis, N. Wijngaards, G. Pavlin, and B. Veelen. Intelligent Distributed Computing III, Proceedings of the 3rd International
Symposium on Intelligent Distributed Computing - IDC 2009, volume 237 of Studies in Computational Intelligence, page 237--242. Springer, (October 2009)