Nitrogen Management Strategies to Improve Growth and Yield of Rice under Irrigated Conditions

An experiment was carried out at the Soil and Irrigation Research Centre, Kpong of the University of Ghana, Legon in 2023 and 2024 to study the influence of nitrogen (N) management strategies on rice growth and yield. The design was a splitsplit plot design with nitrogen (N) rate (90 and 120 kg ha-1 ) as the main plot, basal N: topdress N ratio (50%:50%, 40%:60%, and 60%:40%) as a subplot, and mode of basal N application (one time and 2-split) as sub-subplot. There were three replicates and the rice variety Legon Rice 1 (Ex Baika) was used. The N rates of 90 and 120 kg ha-1 were not different in grain yield with average grain yields of 5164 and 5295 kg ha-1 , respectively. There was no difference in grain yield among the basal: topdress N ratios of 50%:50%, 40%:60%, and 60%:40% with yields of 5269, 5152, and 5266 kg ha-1 , respectively. However, applying basal N as 2-split recorded an average yield of 5677 kg ha-1 and this was significantly higher than the one-time application of basal N which had a mean grain yield of 4781 kg ha-1 , representing a yield difference of 15.7 %. For environmental and economic reasons, irrigated rice farmers on the Vertisols of the Accra Plains can adopt the option of applying N at 90 kg N ha-1 with the basal N applied as two splits using a basal: topdress N ratio of 60%:40% or 50%:50% since this has the potential to increase yield.