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Registro Completo |
Biblioteca(s): |
Embrapa Cerrados; Embrapa Soja; Embrapa Solos; Embrapa Trigo. |
Data corrente: |
29/05/1992 |
Data da última atualização: |
02/11/2019 |
Autoria: |
WIETHÖLTER, S. |
Título: |
Predicting potassium uptake by corn in the field using the strontium nitrate soil testing method and a diffusion-controlled uptake model. |
Ano de publicação: |
1983 |
Fonte/Imprenta: |
Madison: University of Wisconsin, 1983. |
Páginas: |
244 p. |
Idioma: |
Inglês |
Notas: |
Thesis PhD. |
Conteúdo: |
The rate of potassium uptake by plants grown in soil is limited by the rate of diffusion to the roots. Calculation of diffusion rates requires a knowledge of the soil solution concentration (C[indice]1i), buffer power (b) and diffusion coefficiente (D). The Gapon equation was used to calculate selectivity coefficients for K+, Na+, Ca2+, Mg2+, Mn2+ and Al3+ from concentrations in 0.004M Sr(NO3)2 extracts and from amounts exchangeable in M NH4Cl. For a proposed routine method, C[indice]1i, b and D were calculated from the Sr(NO3)2 equilibration. This required the use of estimated selectivity coefficients obtained from regression of pH, OM, clay and cation ratios on determined selectivity coefficients. A constant-root-absorbing-power (constant-[alfa]) diffusion equation was applied to a root model that assumed an effective radius (a[indice]e) of 0.07 cm (root radius + root-radius + root-hair length). A root length:plant dry matter ratio of 1000 cm g[elevado a]-1 dry matter was used, and each root segment was assumed to effective in K+ uptake for the same time period. Initially, uptake was assumed to occur only within the root-hair cylinder, the time of effective depletion being estimated with a steady- state, interacting-root model. After depletion of the root-hair cylinder, diffusion from outside was assumed to start, with radius equal to a[indice]e and [alfa] estimated from the Michaelis-Menten equation. Root hairs had to be effective for 4-5 days to satisfy the total K+ uptake estimated from K+ content of the ear leaf. Uptake of K+ by corn at 51 field sites throughout Wisconsin was best predicted by the diffusion model (r[elevado]2=0.58 with determined selectivity coefficients and 0.51 with estimated coefficients). The K+ concentration in Sr(NO3)2 also correlated well (r[elevado]2=0.49). Exchangeable K+ was a por predictor (r[elevado]2=0.13). The diffusion model applied to data from Sr(NO3)2 equilibration appears promising as a routine soil testing method for K+. With this approach, fertilizer recommendations could be based on on theoretically-derived estimates of K+ uptake rather than on empirically-derived relationships. MenosThe rate of potassium uptake by plants grown in soil is limited by the rate of diffusion to the roots. Calculation of diffusion rates requires a knowledge of the soil solution concentration (C[indice]1i), buffer power (b) and diffusion coefficiente (D). The Gapon equation was used to calculate selectivity coefficients for K+, Na+, Ca2+, Mg2+, Mn2+ and Al3+ from concentrations in 0.004M Sr(NO3)2 extracts and from amounts exchangeable in M NH4Cl. For a proposed routine method, C[indice]1i, b and D were calculated from the Sr(NO3)2 equilibration. This required the use of estimated selectivity coefficients obtained from regression of pH, OM, clay and cation ratios on determined selectivity coefficients. A constant-root-absorbing-power (constant-[alfa]) diffusion equation was applied to a root model that assumed an effective radius (a[indice]e) of 0.07 cm (root radius + root-radius + root-hair length). A root length:plant dry matter ratio of 1000 cm g[elevado a]-1 dry matter was used, and each root segment was assumed to effective in K+ uptake for the same time period. Initially, uptake was assumed to occur only within the root-hair cylinder, the time of effective depletion being estimated with a steady- state, interacting-root model. After depletion of the root-hair cylinder, diffusion from outside was assumed to start, with radius equal to a[indice]e and [alfa] estimated from the Michaelis-Menten equation. Root hairs had to be effective for 4-5 days to satisfy the total K+ upta... Mostrar Tudo |
Palavras-Chave: |
Applied Statistics; Estatistica aplicada; Maize; Mathematical model; Modelos matematicos. |
Thesagro: |
Absorção; Milho; Potássio; Solo; Zea Mays. |
Thesaurus Nal: |
absorption; corn; potassium; soil. |
Categoria do assunto: |
-- |
Marc: |
LEADER 02972nam a2200301 a 4500 001 1841891 005 2019-11-02 008 1983 bl uuuu m 00u1 u #d 100 1 $aWIETHÖLTER, S. 245 $aPredicting potassium uptake by corn in the field using the strontium nitrate soil testing method and a diffusion-controlled uptake model. 260 $aMadison: University of Wisconsin$c1983 300 $a244 p. 500 $aThesis PhD. 520 $aThe rate of potassium uptake by plants grown in soil is limited by the rate of diffusion to the roots. Calculation of diffusion rates requires a knowledge of the soil solution concentration (C[indice]1i), buffer power (b) and diffusion coefficiente (D). The Gapon equation was used to calculate selectivity coefficients for K+, Na+, Ca2+, Mg2+, Mn2+ and Al3+ from concentrations in 0.004M Sr(NO3)2 extracts and from amounts exchangeable in M NH4Cl. For a proposed routine method, C[indice]1i, b and D were calculated from the Sr(NO3)2 equilibration. This required the use of estimated selectivity coefficients obtained from regression of pH, OM, clay and cation ratios on determined selectivity coefficients. A constant-root-absorbing-power (constant-[alfa]) diffusion equation was applied to a root model that assumed an effective radius (a[indice]e) of 0.07 cm (root radius + root-radius + root-hair length). A root length:plant dry matter ratio of 1000 cm g[elevado a]-1 dry matter was used, and each root segment was assumed to effective in K+ uptake for the same time period. Initially, uptake was assumed to occur only within the root-hair cylinder, the time of effective depletion being estimated with a steady- state, interacting-root model. After depletion of the root-hair cylinder, diffusion from outside was assumed to start, with radius equal to a[indice]e and [alfa] estimated from the Michaelis-Menten equation. Root hairs had to be effective for 4-5 days to satisfy the total K+ uptake estimated from K+ content of the ear leaf. Uptake of K+ by corn at 51 field sites throughout Wisconsin was best predicted by the diffusion model (r[elevado]2=0.58 with determined selectivity coefficients and 0.51 with estimated coefficients). The K+ concentration in Sr(NO3)2 also correlated well (r[elevado]2=0.49). Exchangeable K+ was a por predictor (r[elevado]2=0.13). The diffusion model applied to data from Sr(NO3)2 equilibration appears promising as a routine soil testing method for K+. With this approach, fertilizer recommendations could be based on on theoretically-derived estimates of K+ uptake rather than on empirically-derived relationships. 650 $aabsorption 650 $acorn 650 $apotassium 650 $asoil 650 $aAbsorção 650 $aMilho 650 $aPotássio 650 $aSolo 650 $aZea Mays 653 $aApplied Statistics 653 $aEstatistica aplicada 653 $aMaize 653 $aMathematical model 653 $aModelos matematicos
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Embrapa Trigo (CNPT) |
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Registros recuperados : 147 | |
32. | | WIETHÖLTER, S.; ROSSO, I. J. Efeito de potassio na cultura da soja e relações entre fatores do solo e da planta, no solo Passo Fundo. In: REUNIÃO DE PESQUISA DE SOJA DA REGIÃO SUL, 19., 1991, Pelotas. Ata e resumos... Pelotas: EMBRAPA-CPACT, [1993]. E em EMBRAPA. Centro Nacional de Pesquisa de p. 157 (EMBRAPA-CNPT. Documentos, 3). Trabalho apresentado na XIX Reunião de Pesquisa de Soja da Região Sul, Pelotas, 1991.Biblioteca(s): Embrapa Trigo. |
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39. | | PRESTES, A. M.; WIETHÖLTER, S. Efeito da virose do mosaico no rendimento da biomassa de cultivares de trigo. In: CONGRESSO BRASILEIRO DE FITOPATOLOGIA, 26., 1993, Aracajú. Fitopatologia Brasileira, Brasília, DF, v. 18, p. 293, ago. 1993. Suplemento.Biblioteca(s): Embrapa Trigo. |
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Registros recuperados : 147 | |
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