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All publications of “Leônidas Carrijo Azevedo Melo”

5 results

LOSS OF EXTRACTION CAPACITY OF MEHLICH-1 AND MONOCALCIUM PHOSPHATE AS A VARIABLE OF REMAINING P AND ITS RELATIONSHIP TO CRITICAL LEVELS OF SOIL PHOSPHORUS AND SULFUR

Sarah Vieira Novais, Edson Marcio Mattiello, Leonardus Vergutz, Leônidas Carrijo Azevedo Melo, Írio Fernando de Freitas, Roberto Ferreira Novais

01/Jul/2015

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, […]

Transfer of cadmium and barium from soil to crops grown in tropical soils

Leônidas Carrijo Azevedo Melo, Evandro Barbosa da Silva, Luís Reynaldo Ferracciú Alleoni

01/Dec/2014

Phytotoxicity and transfer of potentially toxic elements, such as cadmium (Cd) or barium (Ba), depend on the availability of these elements in soils and on the plant species exposed to them. With this study, we aimed to evaluate the effect of Cd and Ba application rates on yields of pea (Pisum sativum L.), sorghum (Sorghum bicolor L.), soybean (Glycine max L.), and maize (Zea mays L.) grown under greenhouse conditions in an Oxisol and an Entisol with contrasting physical and […]

Soil organic carbon and total nitrogen as related with coffee spacing

Otacílio José Passos Rangel, Carlos Alberto Silva, Paulo Tácito G. Guimarães, Leônidas Carrijo Azevedo Melo, Antônio Claret de Oliveira Junior

01/Oct/2008

The density and arrangement of trees influences the production of plant residues in coffee agroecosystems. This differentiated input of biomass regulates the contents of soil-C and -N. This study aimed to evaluate the contents of organic C and total N in a Typic Hapludox, in different spacings of (Coffea arabica L.) trees and tree rows. The experiment was carried out from 1992 to 2004 on an experimental farm of EPAMIG, in Machado (Minas Gerais State, Brazil). The treatments consisted of […]

Characterization of the organic matrix of residues from different origins

Leônidas Carrijo Azevedo Melo, Carlos Alberto Silva, Bruno de Oliveira Dias

01/Feb/2008

The humification degree and the chemical nature of organic residues are essential factors controlling their degradation and nutrient release. To characterize the organic matrix, samples of sewage sludge, poultry, pig, cattle and quail manure, besides commercial compost, organic substrate and humic material were analyzed for: pH, electric conductivity, cation exchange capacity (CEC), water retention capacity, concentration of total N and mineral N, organic matter, total organic carbon (TOC) and the TOC fractions: humic acid C-fraction; fulvic acid C-fraction, water soluble […]

Liming in a latosol under influence of cover crops: acidity neutralization

Tullio Raphael Pereira de Pádua, Carlos Alberto Silva, Leônidas Carrijo Azevedo Melo

01/Oct/2006

Lime mobility and soil acidity correction can be influenced by liming management and the quantity and quality of soil organic matter. Acidity neutralization in function of the lime incoporation and surface liming was evaluated in a red Latosol (Oxisol) under different antecedent vegetation covers (eucalyptus, forest, pasture and pine). The study was carried out from November 2002 to January 2003 at the Soil Science Department of the Lavras Federal University. After 30 days of incubation of soils with lime, the […]