Data/hora: 17/06/2024 08:06:24

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	16/10/1992	
Data da última atualização: 	26/10/2004	
Autoria: 	BORKERT, C. M.; FRANCA NETO, J. de B; HENNING, A. A.	
Afiliação: 	EMBRAPA-CNPSo. Londrina, PR.	
Título: 	Potassium fertilization reduces seed infection by Phomopsis sp. and improves seed quality.	
Ano de publicação: 	1989	
Fonte/Imprenta: 	In: CONFERENCIA MUNDIAL DE INVESTGACION EN SOJA, 4., 1989, Buenos Aires. Actas... Buenos Aires: AASOJA, 1989.	
Volume: 	t.5	
Páginas: 	p.2265-2275.	
Idioma: 	Inglês	
Conteúdo: 	Soybean cultivated in Southern Brazil during the past 20 years usually does not show up potassium deficiency because the crop have been grown on soils not previously cultivated. The soils are mostly oxisols and ultisols, composed primarily of kaolinite minerals and are high in iron and aluminum oxides. Release of K from non-exchangeable forms or from mineral weathering is too slow to meet crop requirements. In thes soils the native potassium is high and typically contain 120-150 ppm of exchangeable-K. However after only 4 or 5 years of soybeans-wheat double cropping withouth K application these soils become severely depleted of wxchangeable-K. Since normally not more than 10-30 k/ha/year of K2O is applied, this is insufficient for the soybean-wheat double cropping and has resulted in deficiency symptoms and reduced soybean yields after a few years of intensive cropping. soybean seeds produced under low K nutrition hd a higher level of infection by the fungus Phomopsis sp. and higher damage by stink bugs. This is because the plants with K deficiency mature earlier than well-nourished plants. Research conducted buring a four-year period showed that potassium deficiency in soybeans causes reduced seed quality and yield, with substancial decrease in the comercial value at the crop.	
Palavras-Chave: 	Brasil; Disease; Double-cropping; Fungus; Parana; Phomopsis sp; Policultura; Quality; Seed; Soybean.	
Thesagro: 	Cercospora Kikuchii; Doença; Fungo; Potássio; Qualidade; Semente; Soja; Trigo.	
Thesaurus Nal: 	Brazil; potassium; wheat.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)