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| Freitas,Irio Fernando de; Novais,Roberto Ferreira; Villani,Ecila Mercês de Albuquerque; Novais,Sarah Vieira. |
| Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of three soils with different texture: a very clayey Red Latosol (LV), a sandy clay loam Red Yellow Latosol (LVA), and a sandy loam Yellow Latosol (LA), to three sources (triple superphosphate, reactive phosphate rock from Gafsa-Tunisia; and natural... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Phosphorus fertilizers; Rock phosphates; Phosphorus extractants. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000300013 |
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| Novais,Sarah Vieira; Novais,Roberto Ferreira; V.,Víctor Hugo Alvarez; Villani,Ecila Mercês de Albuquerque; Zenero,Mariana Delgado Oliveira. |
| ABSTRACT: Visual symptoms of Zn deficiency, induced by excessive P applications, have been observed in commercial orchid nurseries. The supply of other metallic micronutrients, such as Fe and Mn, may also be inadequate in the plant due to high application rates of P. The aim of this study was to investigate this interaction in the nutrition of Phalaenopsis plants. Experimental treatments consisted of three P rates (0.0, 0.5, and 1.0 g L-1) and three Zn rates (0.00, 0.35, and 0.70 g L-1), as well as fertilization with other basic nutrients, and a control treatment with the fertilizer B&G Orchidée(r), at 1.0 g L-1. Dry matter production was evaluated, as well as the levels of P, Zn, Fe, and Mn in both shoots and roots. Higher P rates induced higher shoot... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ornamental plants; Nutritional balance; Micronutrient. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100554 |
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| Novais,Sarah Vieira; Mattiello,Edson Marcio; Vergutz,Leonardus; Melo,Leônidas Carrijo Azevedo; Freitas,Írio Fernando de; Novais,Roberto Ferreira. |
| The Mehlich-1 (M-1) extractant and Monocalcium Phosphate in acetic acid (MCPa) have mechanisms for extraction of available P and S in acidity and in ligand exchange, whether of the sulfate of the extractant by the phosphate of the soil, or of the phosphate of the extractant by the sulfate of the soil. In clayey soils, with greater P adsorption capacity, or lower remaining P (Rem-P) value, which corresponds to soils with greater Phosphate Buffer Capacity (PBC), more buffered for acidity, the initially low pH of the extractants increases over their time of contact with the soil in the direction of the pH of the soil; and the sulfate of the M-1 or the phosphate of the MCPa is adsorbed by adsorption sites occupied by these anions or not. This situation makes... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: P adsorption; S adsorption; Available nutrient; Phosphate buffer capacity; Extractant. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401079 |
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