Effect of fertilizer deep placement with urea supergranule on nitrogen use efficiency of irrigated rice in Sourou Valley (Burkina Faso)

摘要

The loss of nitrogen (N) can be very high in rice (Oryza sativa L.) fields, particularly in the irrigated rice cropping systems with very poor water control. Previous studies have reported very low (30 %) fertilizer N use efficiency by broadcasting in irrigated cropping systems. The effect of fertilizer N (prilled urea-PU) and briquettes-urea supergranules (USG) on rice yield performance and nutrient uptake was investigated in West Africa. Field experiments were carried out in Sourou valley in Burkina Faso in the wet season of 2012 and dry season of 2013. PU was broadcast applied and USG were point-placed deeply into the soil at 5-7 cm using the same fertilizer N rates (52 kg N ha(-1)) and two different rice varieties (FKR 19 and NERICA 62N). The results indicate that Fertilizer Deep Placement (FDP) significantly increased grain yields, particularly in the wet season as compared with broadcasting. The FDP applied to NERICA 62N produced the highest tillers and panicles numbers, leading to more yields. In wet season, FDP significantly increased agronomic efficiency by 39.43 % over PU and physiological efficiency by 24.23 %. In the dry season, differences in the average nitrogen use efficiency (NUE) between FDP and PU were not significant. The studies suggest that FDP is genotype and season-specific, and that it can be used by farmers to improve NUE and increase grain yields in the irrigated rice cropping system. Further investigations are underway to understand seasonal and genetic effect on FDP performance.