Nitrogen sufficiency index for estimating nitrogen fertilizer requirement of irrigated rice.

The proper nitrogen management is required to achieve high irrigated rice yield. This study aimed to determine the rice response to nitrogen topdressing doses and calibrate the chlorophyll meter reading. Three experiments were conducted in a randomized block design. In the first experiment, five N rates (0, 30, 60, 90, and 120 kg ha-1) were evaluated as the first, and 30 kg ha-1 N as the second topdressing, which were combined with the application of 30 kg ha-1 N as the first and five N rates, as the second topdressing. The other experiments assessed the application of 30 kg ha-1 of N, as the first, and four N rates (0, 40, 80, and 120 kg ha-1), as the second topdressing. There was a response to N application, with maximum technical efficiency reaching 33 kg ha-1 in the first and between 40 and 50 kg ha-1 in the second topdressing. The chlorophyll meter was sensitive to estimate the amount of N to be applied in topdressing, using the nitrogen sufficiency index (NSI). To each percent unit of NSI below 95%, one should apply 10 kg ha-1 of N as the first and 2-3 kg ha-1 of N as the second topdressing.

Bibliographic Details

Main Authors:	SANTOS, A. B. dos, SILVA, M. A. S. da, SILVEIRA, P. M. da, CARVALHO, G. D., STONE, L. F.
Other Authors:	ALBERTO BAETA DOS SANTOS, CNPAF; MELLISSA ANANIAS SOLER DA SILVA, CNPAF; PEDRO MARQUES DA SILVEIRA, CNPAF; GLAUCILENE DUARTE CARVALHO, SECIMA, Goiânia-GO; LUIS FERNANDO STONE, CNPAF.
Format:	Artigo de periódico biblioteca
Language:	English eng
Published:	2020-01-17
Subjects:	Nitrogen topdressing, Oryza Sativa, Nitrogênio, Fertilizante Nitrogenado, Arroz Irrigado, Clorofila, Rice, Irrigation management, Nitrogen fertilizers, Chlorophyll, Grain yield,
Online Access:	http://www.alice.cnptia.embrapa.br/alice/handle/doc/1118934
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