The potential grain yield of late flooded rice is important for decision making of producers. Yields of rice crops sown after the recommended period are restricted due to unfavorable climatic conditions. The objective of this research was to evaluate grain yield and agronomic, technical and economic efficiency of broadcast nitrogen for flooded rice sown in December in the state of Rio Grande do Sul, Brazil. The field experiment was carried out in 2005/2006, in Cachoeirinha. Treatments consisted of two sowing dates, recommended (November) and late (December), four seeding rates (50, 100, 150, and 200 kg ha-1) and four nitrogen levels (0, 60, 120, and 180 kg ha-1). The experiment had a randomized block design using split plots with three replications. Rice grain yield and response to nitrogen topdressing were reduced by the late sowing date. The doses for maximum technical and economic efficiency were reduced with the sowing delay, and nitrogen agronomic efficiency was reduced with the sowing delay and N fertilizer dose. The number of panicles m-2 did not respond to nitrogen broadcast and was one of the most limiting yield components.
Oryza sativa L.; yield components; topdressed nitrogen fertilization
