Data/hora: 24/06/2024 19:20:31

Biblioteca(s): 	Embrapa Clima Temperado.	
Data corrente: 	28/06/1995	
Data da última atualização: 	28/06/1995	
Autoria: 	SIQUEIRA, O. J. F. de.	
Título: 	Response of soybeans and wheat to limestone application on acid soils in Rio Grande do Sul, Brazil.	
Ano de publicação: 	1980	
Fonte/Imprenta: 	Ames : Iowa State University, 1980.	
Páginas: 	223p.	
Idioma: 	Inglês	
Notas: 	Tese Doutorado.	
Conteúdo: 	Interactions among Macrophomina phaseolina, Rhizoctonia solani, Fusarium solani and two symbiotic organisms, Glomus mosseae and Rhizobium japonicum, and their effect on the severity of soybean root and stem rot were investigated by exposing nodulated and non-nodulated seedlings to defined inoculum densities of the various organisms in greenhouse tests. Autoclaved or non-autoclaved Arredondo fine sand with 91 ppm of phosphorus and pH 6.7 was thoroughly mixed with spores or resting structures of the fungi. The mycorrhizal fungus was added at 500 chlamydospores per pot in one layer 5 cm below the seeds. Rhizobium japonicum cells were inoculated directly on the seeds at 5 mg/g of seed. The percentage of  infected roots, diseased plants, or both increased with incresing levels of inoculum of each fungus. The concentrations at which 50% of the roots were infected ( ED50) by M. phaseolina were approximately 20x103 and 150x103 sclerotia per kilogram of autoclaved and non-autoclaved soil, respectively. For R. solani the ED50s were 1.0X103 and 2.0X103 sclerotia per kilogram of autoclaved and non-autoclaved soil, respectively. Macrophomina phaseolina at 40X103 sclerotia per kilogram of soil interacted additively with R. solani at 1.0X103 sclerotia per kilogram of soil and with F. solani at 3,000X103 chlamydospores per kilogram of soil to increase root and stem rot and to reduce the plant growth response. Root and shoot weight and plant height were reduced more at 45 than at 25 days after planting, and soybean seed yield was reduced 20-30% in autoclaved and 10-16% in non-autoclaved field soil by exposure to the pathogens. The number and weight of nodules were reduced greatly by each of the theree pathogens. In the presence of the mycorrhizal fungus, G.mosseae, plant growth responses, nodule numbers and weigth, and seed yield of plants infected with M. phaseolina, R. solani and F. solani were equal to or superior to the uninoculated plants. The mean seed yield in three experiments with the variety 'Hood' was increased 49% in autoclaved and 17% in non-autoclaved field soil by G. mosseae. The populations of the three pathogens and disease severity were not reduced significantly by G. mosseae, but the colonization of roots by G. mosseae was reduced significantly by the pathogens. Growth responses of plants exposed to G. mosseae were always significantly better than those of the nonmycorrhizal controls for both nodulated and non-nodulated "Hardee" soybeans. Total nutrients in the shoots were significantly increased in plants infected with G. mosseae but were reduced in those infected with M. phaseolina.	
Palavras-Chave: 	Correção; Wheats.	
Thesagro: 	Adubação; Calagem; Calcário; Glycine Max; Soja; Solo; Solo Ácido; Trigo; Triticum Aestivum.	
Thesaurus Nal: 	acid soils; fertilizer application; limestone; soybeans.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Clima Temperado (CPACT)	
Exemplares: 	CNPSO - (21803-1) - ADD - TS - -- - 10/80 -  - 10/80 - DIS
CPAC - (16474-1) - ADD - TS - -- - T060/80 - SIQ - T060/80 - DIS
CPACT - (2536-1) - UPC - TS - -- - 00603 -  - 1980.00603 - DIS
CNPT - (29993-1) - ADD - TS - -- - TS-0413 -  - 0413 - DIS