T( 20090 . Effect of split application of nitrogen on growth and yield of aerobic rice

Abstract: Aerobic rice is a new system of cultivation gaining importance under water constraint situations and research on optimum dose and time of nitrogen application is timely warranted. Field experiment was carried out at Wetland Farm of Tamil Nadu Agricultural University, Coimbatore during kharif, 2006 to study the effect of different split doses of nitrogen, Leaf Colour Chart (LCC) and Soil Test Crop Response (STCR) based nitrogen management on growth and yield of aerobic rice. The results showed that nitrogen management at LCC value of 4 (150 kg N ha-1) produced significantly higher tillers (369.3 m-2) at maximum tillering stage, plant height (81.7 cm) at maturity, dry matter at flowering (5.71 t ha-1) and grain yield (2915 kg ha-1) than LCC value of 3 that produced grain yield of 2211 kg ha-1. Soil test crop response based nitrogen application produced markedly lower grain yield (2475 kg ha-1) than the LCC value 4 of nitrogen management. Among the different split doses of nitrogen, application of 150 kg N ha-1 in four splits – 1/6 at 15 DAS, 1/3 at tillering, 1/3 at PI, 1/6 at flowering recorded higher tillers (361 m-2), plant height (77.0 cm), dry matter at flowering (5.20 t ha-1) and grain yield (2827 kg ha-1) over four equal splits where the grain yield was 2673 kg ha-1. Four splits (1/5 at 15 DAS, 1/5 at tillering, 2/5 at PI, 1/5 at flowering) of 150 N ha-1 also recorded comparable yield of 2783 kg ha-1 than other split doses. Thus, nitrogen application with LCC value of 4 or application of 150 kg N ha-1 in four splits – 1/6 at 15 DAS, 1/3 at tillering, 1/3 at PI, 1/6 at flowering is considered a suitable nitrogen management technique in aerobic rice cultivation at Coimbatore