Efeito da adubação nitrogenada no índice da área foliar e na produtividade do arroz irrigado (Oryza sativa L.).

Abstract

In order to determine the effect of N (4 levels: 0 - 50 - 100 - 150 kg/ha) on irrigated rice leaf area index (LAI) and yi eld, an experiment was carried out in São Desidêrio Irrigation Project, in a ramdomized block design with 5 replications. The results showed that LAI varied from: 0.18 to 1.33, 0.18 to 2.54, 0.28 to 3.55 and 0.28 to 3.97 during the crop ay cle; plant heights were 58, 70, 77 and 86cm; shoots/m2: 240, 286, 276, 289 (the effective ones were: 93, 94, 96 and 95%); gra ins/panicle: 59, 53, 70, 80; esterility of grains: 3.2, 3.2, 4.1 7.1%; panicle lenghts: 15.0, 17.5, 19.5, 20.0cm; yield: 2,350; 3.124; 4,480; 5,135 kg/ha, for the increasing doses of N, respec tively. The results indicated significant differences for LAI, plant heights, panicle lengths, and yield at 1% probability by the F test. Nitrogen showed linear affects for LAI (Y=133.353 + 0,865 N with r = 0.996), plant heights (Y = 59.117 = 0.183 N with r = 0.997) and yield (Y = 2611.54 + 14.51 N with r = 0.918).