Título:	Nitrogen sufficiency index for estimating nitrogen fertilizer requirement of irrigated rice.
Autoria:	SANTOS, A. B. dos SILVA, M. A. S. da SILVEIRA, P. M. da CARVALHO, G. D. STONE, L. F.
Afiliação:	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.
Ano de publicação:	2019
Referência:	Revista Ceres, v. 66, n. 6, p. 422-430, nov./dez. 2019.
Conteúdo:	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.
Thesagro:	Oryza Sativa Nitrogênio Fertilizante Nitrogenado Arroz Irrigado Clorofila
NAL Thesaurus:	Rice Irrigation management Nitrogen fertilizers Chlorophyll Grain yield
Palavras-chave:	Nitrogen topdressing
ISSN:	2177-3491
Digital Object Identifier:	10.1590/0034-737X201966060003
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CNPAF)