Moments for the application of nitrogen fertilizers to flooded rice

Abstract

MATEUS, G. P.; FELTRAN, J. C.; CRUSCIOL, C. A. C. Moments for the application of nitrogen fertilizers to flooded rice. Científica, Jaboticabal, v. 34, n. 2, p. 44-49. 2006. The important role played by nitrogen fertilizers in increasing yields is highly related to the moment the element N is made available to the plant. The objective of this experiment was thus to study the critical stage of flooded rice plants in which the availability of N would bring about the highest yields. The plants, grown in a green house, were supplied with 00 kg ha- of N at the growth stages of tillering (P), differentiation of the panicle primordium (DPP), and booting (E) as follows : () no nitrogen, (2) 00 kg ha- at P, (3) 00 kg ha- at DPP, (4) 00 kg ha- at E, (5) 50 kg ha- at P and 50 kg ha- at DPP, (6) 50 kg ha- at P and 50 kg ha- at E, (7) 50 kg ha- at DPP and 50 kg ha- at E, and (8) 33.3 kg ha- at each stage (P, DPP, and E). The split application of N at the DPP and E stages resulted in the highest yields of grains. The number of panicles, the relation between the number of panicles and the number of culms and grain yield were found to be related with the amount of N in the flag leaf.Additional keywords: Oryza sativa; lowland rice; time of application; split.