Data/hora: 24/09/2024 14:33:32

Biblioteca(s): 	Embrapa Agrobiologia.	
Data corrente: 	22/10/2003	
Data da última atualização: 	22/10/2003	
Autoria: 	WANG, C.; LIEM, T. H.; MIKKELSEN, D. S.	
Título: 	Sulfur deficiency - A Limiting factor in rice production in the lower Amazon basin. II. Sulfur requirement for rice production.	
Ano de publicação: 	1976	
Fonte/Imprenta: 	New York: IRI Research Institute, 1976.	
Páginas: 	38 p.	
Série: 	(IRI Research Institute. Bulletin, 48).	
Idioma: 	Inglês	
Conteúdo: 	When the varzea marshland soils of the lower Amazon Basin are reclaimed for rice production, S-deficiency develops limitingrice production, especially where high-analysis fertilizers containing little S are used. Pot- culture experiments and field trials with different rice cultivars showed that at least 10 kg/ha S is required from fertilizer sources for rice production on the varzea soils. The varzea soils appear able to tolerate very high levels of S ( as much as 1,000 kg/ha in field and 2,000 kg/ha S in pot experiments) without harming grain yields. Either ammonium sulfate or calcium sulfate ( in single super- phosphate) was a good source. Under pot-culture, 40,20, and 10 ppm S applied to soils supported rice production, respectively for 3,2, and 1 crops. Under field conditions, 27 kg/ha S ( 11 ppm) supported two crops. Immobilization is considered to be the major factor responsible for the reduced availability of S residual from previous crops.For grain yields of 5 to 7 tons per hectare, between 5 and 9 kg/ha of S was removed by rice, depending on the cultivar, S-application rate, and crop N-regime. Generally, increasing rates of S and N increased S-removal. On a soil basis, S-removal rates are two to three times as high in pot experiments as in field experiments. This factor should be taken into consideration when extrapolating estimation of sulfur needs from pot-culture data to field conditions. For the maintenance of rice production in the lower Amazon Basin it is recommended that 10 to 25 kg/ha S as ammonium sulfate be applied as a basal dressing for each rice crop on all types of varzea soils. 

Palavras-Chave: 	Deficiency; Production.	
Thesagro: 	Arroz; Deficiência; Enxofre; Produção.	
Thesaurus Nal: 	rice; sulfur.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Agrobiologia (CNPAB)	
Exemplares: 	CNPAB - (27874-1) - ADD - FL - -- - 633.18 -  - 000574 - DIS