Data/hora: 01/06/2024 02:48:01

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	11/06/1996	
Data da última atualização: 	11/06/1996	
Autoria: 	FAGI, A. M.; DE DATTA, S. K.	
Título: 	Environmental factors affecting nitrogen efficiency in flooded tropical rice.	
Ano de publicação: 	1980	
Fonte/Imprenta: 	Fertilizer Research, v.2, n.1, p.53-59, 1981.	
Idioma: 	Inglês	
Conteúdo: 	How environmental factors modify the effect of time of nitrogen application on grain yield and yield components of rice (Oryza sativa L.) were studied under field experiments during the 1975 dry and wet seasons on a fertile Maahas clay soil (an isothermic clayey mixed AquaticTroupudalf). Two rice varieties, one early maturing (IR28) and one medium maturing (IR26), which are higly responsive to nitrogen fertilizer, were tested. These varieties were planted monthly from January through December. Three nitrogen levels were applied in a single or in split doses to examine the maximum nitrogen efficiency under different climatic conditions. Low solar radiation values during the reproductive growth periods of both varieties reduced the spikelet number per unit area. IR26 rice, with an excessive number of spikelets per panicle, was more sensitive to solar radiation. It produced a high percentage of unfilled spikelets at low solar radiation. Nitrogen levels higher than 120 kg N ha-1 were required to obtain maximumgrain yields from both varieties under high solar radiation values during the reproductive growth periods. At low solar radiation levels, 60 kg N ha-1 was adequate to get an optimum grain yield with fertilizer efficiency. Increased grain yields greater than 1.0 t ha-1 were obtained when the nitrogen fertilizer was applied at appropriate times. Proper application minimized the adverse effects of low solar energy. 	
Palavras-Chave: 	Arroz tropical; Flooded tropical rice; Iniciacao de panicula; Numero de espigas; Oryza sativa L; Panicle initiation; Spikelet numer.	
Thesagro: 	Nitrogênio; Radiação Solar.	
Thesaurus Nal: 	nitrogen; solar radiation.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (32531-1) - ADD - SP - -- - SP2907 -  - 2907 - DIS