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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Adsorção e disponibilidade de fósforo em solos com diferentes composições mineralógicas

BROGGI, Fábio 26 March 2004 (has links)
Submitted by (lucia.rodrigues@ufrpe.br) on 2016-07-11T14:09:38Z No. of bitstreams: 1 Fabio Broggi.pdf: 313666 bytes, checksum: 5c9049f2869aabb927ddb314196c3d6d (MD5) / Made available in DSpace on 2016-07-11T14:09:38Z (GMT). No. of bitstreams: 1 Fabio Broggi.pdf: 313666 bytes, checksum: 5c9049f2869aabb927ddb314196c3d6d (MD5) Previous issue date: 2004-03-26 / In order to study the influence of soil mineralogy on phosphate adsorption, samples from subsurface of five soils received doses of soluble sources of phosphorus. Such doses were defined recording to maximum phosphate adsorption capacity (MPAC) and corresponded to 0; 0.2; 0.4; 0.8 and 1.0 levels. After addition, soils samples were incubated for differents periods (90, 60, 30, 15 and 0,5 day) aiming to reach the P adsorption equilibrium at the same day. Mehlich-1, Mehlich-3, Bray-1 and CaCl2 0,01 mol L-1 extractants were used to recover P from incubated soil samples. A block design experiment, factorial scheme, was utilized (2 soils, 5 doses and 5 periods of incubation). The soil characteristics that best estimed both the phosphorus capacity (PC) and the recovery of applied phosphorus were remaining P (rem-P) and MPAC. Soils with highest MPAC and PC, and lowest rem-P, presented higher reversibility of non-labile P (residual P) in lesser period of incubation. The 60 mg L-1 P concentration, employed in the rem-P characterization, does not seem adequate for proper P adsorption characterization of higly weathering soils. / Amostras subsuperficiais de cinco solos receberam doses de P aplicadas a partir de fontes solúveis, em função de suas capacidades máximas de adsorção de fósforo (CMAP), correspondentes aos níveis: 0; 0,2; 0,4; 0,8; 1,0. As amostras foram incubadas por 90, 60, 30, 15 e 0,5 dia. Os períodos de incubação foram iniciados em diferentes épocas de modo a se ter, num mesmo e último dia, os diferentes períodos de equilíbrio solo-P satisfeitos, quando retirou -se amostras para a determinação do P recuperado pelos extratores Mehlich-1, Mehlich-3, Bray-1 e CaCl2. 0,01 mol L-1. O experimento consistiu de um fatorial 5 x 5 x 5 (cinco solos, cinco doses e cinco tempos de incubação), distribuídos em blocos ao acaso, com três repetições. As características dos solos que melhor refletiram o fator capacidade de P (FCP) e a taxa de recuperação do P aplicado foram o P remanescente (P rem) e a CMAP. Os solos com maior CMAP, FCP e menor P rem, apresentaram um aumento crescente de P residual em um menor espaço de tempo . A concentração de 60 mg L-1 de P, empregada na caracterização do P rem, parece insuficiente para uma adequada caracterização de solos altamente intemperizados no que diz respeito ao seu potencial de adsorção.

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