Disponibilidade e capacidade de suprimento de potássio de solos com diferentes mineralogias

• Ano de defesa: 2008
• Autor(a) principal: Faria, Arlindo Ferreira de
• Orientador(a): Venegas, Victor Hugo Alvarez
• Banca de defesa: Fontes, Maurício Paulo Ferreira , Paiva, Haroldo Nogueira de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: K trocável; K não trocável; Extratores
• Palavras-chave em Inglês: Exchangeable K; Non-exchangeable K; Extractors
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5401

The K accumulated in the plants cultivated in a successive way in the soils can be larger than the amount available in the soil initially, because in some cases, there is the participation of ways of the K that initially were not available to the nutrition of those plants. Thus, this work had the following objectives: evaluate the extractors Mehlich-1, Mehlich-3, NH4OAc 1 mol L-1 pH 7, H2SO4 0,5 mol L-1 boiling and e HNO3 2 mol L-1 boiling, as measures of availability of K in a short and long term; correlate the tenors of K obtained by those methods, with the contents of K in the aerial part of the corn plants from cultivation and in accumulative form. The experiment, factorial: 7 x 6, corresponded to seven soils (two Red- Yellow Latosols, one Red Latosol, two Cambisols, two Red- Yellow Argisols) of the State of Minas Gerais and six doses of added K (0; 50; 100; 200; 300 e 500 mg dm-3 of K) being the source KCl. The experiment was accomplished in randomized blocks with four repetitions. The liming, in the soils that needed it, and the doses of K were applied simultaneously, being the soils incubated by a period of 35 d. After that period, subsamples were collected for the determination of the K available by Mehlich-1, Mehlich-3, NH4OAc 1 mol L-1 pH 7, H2SO4 0,5 mol L-1 boiling and HNO3 2 mol L-1 boiling, before each cultivation. In the moment of the planting, the application of the doses of P and S was in agreement with the remaining P of each soil; a dose of 100 mg dm-3 of N was also applied. During the transport of each cultivation, a weekly dose of 50 mg dm-3 of N e B, Cu, Fe, Mn, Mo and Zn was applied in the following doses: 0,20; 0,33; 0,39; 0,92; 0,04 and 1 mg dm-3 respectively. Four corn plants were cultivated per pot. When 45 d of cultivation were passed, the plants were cut, then were dry, grinded in Wiley mill type and mineralized by the nitric - perchloric mixture (3:1); this proceeding happened with each cultivation. The total tenor of K was determined in the original samples of the seven soils. In the interval of each cultivation, samples of soil were subjected to extractors of K. The statistical analyses consisted of analyses of variance, regression and correlation. It was verified that along the cultivations the tenors of K extracted from all of the extractors were decreasing, ommitting the production of dry matter on the part of the corn plants that were cultivated. The H2SO4 0,5 mol L-1 boiling and HNO3 2 mol L-1 boiling, were the extractors that presented the largest capacity of recuperation of K in the seven soils in all of the cultivations, for they possess the largest force of extraction of K. The soils, PVAe1 and PVAe2 presented the largest tenors of extracted K for the five extractors along the cultivations. The critical levels of K went increasing when they were calculated in an accumulated way of the first to the seventh cultivation, to obtain larger productions of dry matter. The largest critical levels of K were obtained by the soils PVAe1 and PVAe2. There was contribution of available and non available fractions for all of the extraction methods in the nutrition of the corn plants cultivated in all the seven soils. It was observed that the accumulated contents of K in the aerial part of the corn plants in the six doses of K were highly correlated with the tenors of the nutrient in the soil obtained through the extractions with Mehlich-1, Mehlich-3 and NH4OAc 1 mol L-1 pH 7. That indicates that those extractors were appropriate to esteem the readiness of K during the growth of the plants for the first cultivation and in accumulative form of corn in the seven cultivations accomplished. The tenors of extracted K for Mehlich-1, Mehlich-3 e NH4OAc 1 mol L-1 pH 7 were highly correlated amongst themselves.