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Nova Viçosa, Brazil

Lo Monaco P.A.V.,Federal University of Vicosa | De Matos A.T.,DPS UFV | Andrade Ribeiro I.C.,Federal University of Vicosa | Da Silva Batista A.P.,Federal University of Vicosa | And 2 more authors.
Revista Caatinga

The use of natural coagulants and organic filters locally produced and low financial cost can provide attenuation problems in discharge of wastewaters, without treatment, into watercourses. Was evaluated in this study the efficiency of the coagulation process, using the Ca(OH)2 in the preparation of Moringa seed extract, followed by filtration sawdust in the treatment of sewage. In the tank of 150 L containing sewage was added a solution of the moringa seed extract prepared with Ca(OH)2 0.011 mol L-1 at a concentration of 2.2 grams of seed per liter of wastewater to be treated. The coagulated effluent was applied to organic filter and the filtrate volume was converted in pore volume. Physical and chemical analyses were carried out in the influent and effluent of the two treatment structure for the evaluation of treatment efficiency. The treatments by coagulation followed by filtration provided removals of 98.0, 75.3, 75.8, 75.0, 79, 7, 59.0 and 88.3% of turbidity, Total Solids, Total Fixed Solids, Total Volatile Solids, Total Suspended Solids, Suspended Solids Fixed and Volatile Suspended Solids and of 51.2, 88.7, 72.6; 33.5 and 38.5% of Biochemical Oxygen Demand, Chemical Oxygen Demand, Phosphorus, Nitrogen and Sodium. Source

Chagas C.S.,Rua Jardim Botanico | Fernandes Filho E.I.,DPS UFV | Rocha M.F.,Federal Rural University of Rio de Janeiro
Revista Brasileira de Engenharia Agricola e Ambiental

In Brazil, the digital elevation models (DEMs) are usually produced by users themselves and little attention has been given to their limitations as source of spatial information. The objective of this study was to evaluate different DEMs to help in choosing an appropriate model to derive topographical attributes used in a digital soil mapping based on a neural networks approach. The evaluation consisted of the following analysis: determination of root mean square error (RMSE) of elevation; analysis of the spurious depressions; comparison between mapped drainage and numeric drainage and between derived contour lines and original contour lines; and analysis of the derived contribution basins. The results demonstrated that RMSE was not enough to evaluate the quality of these models. DEMs derived from contour lines (CARTA, obtained using the TOPOGRID module) presented better quality than those derived from remote sensors (ASTER and SRTM). These presented great amount of errors that can negatively affect the establishment of relationships between topographical attributes and local conditions of soils. Source

Cunha J.C.,Federal Rural University of Pernambuco | Freire M.B.G.S.,Federal Rural University of Pernambuco | Ruiz H.A.,Brazilian National Council for Scientific and Technological Development | Fernandes R.B.A.,Brazilian National Council for Scientific and Technological Development | Alvarez V. V.H.,DPS UFV
Revista Brasileira de Engenharia Agricola e Ambiental

Laboratories in different regions of Brazil do not standardize the procedures for particle size analysis. Solutions of sodium hydroxide (NaOH), sodium hexametaphosphate and sodium carbonate [(NaPO3)n + Na2CO3] are the most commonly used in the chemical dispersion of the particle of soil. Te high pH of the NaOH solution favors the dispersion in soils with clay minerals of variable-charge in the clay fraction, as oxides of iron and aluminum present in tropical soils. Based on this statement it was aimed to test the efficiency of NaOH (D1), [(NaPO3)n + Na2CO3] (D2) and [(NaPO3)n + NaOH] (D3) solutions as chemical dispersants in the particle-size analysis of two horizons of 26 reference soils of the State of Pernambuco. Te comparison between the dispersants was performed using the statistics test L&O. Te comparison of D2 = f (D1) and D3 = f (D1) showed no agreement between the dispersants. Te intercept in the linear regression equation for the clay fraction, significant at 0.01 and negative, showed highest clay values when using D1. Te NaOH solution was the most suitable dispersant to determine the texture of the analysed samples, representative of 82% of the total area of the state. Source

Vasconcelos B.N.F.,DPS UFV | Ker J.C.,Federal University of Vicosa | Schaefer C.E.G.R.,Federal University of Vicosa | Poirier A.P.P.,Federal University of Minas Gerais | Andrade F.V.,Federal University of Espirito Santo
Revista Brasileira de Ciencia do Solo

The occupation and territorial dispersion of the first settlers in South America, especially in Brazil, are still little known and require continuous interdisciplinary studies involving anthropology, archeology, and soil science. Under natural limestone shelters, pre-Columbian populations lived for thousands of years, introducing and removing materials of different nature and from different origins, resulting in the development of very peculiar anthropogenic soils, which have been little investigated so far. To deepen the knowledge on this type of soil, we evaluated the physical, chemical and mineralogical properties of the soil of two limestone shelters, Lapa do Boquete and do Malhador, located in the National Park Cavernas do Peruaçu, in northern Minas Gerais, which is considered one of the most important archaeological regions of the country. The samples were subjected to the physical, chemical and mineralogical analyses, total attack, total organic carbon, and fractionation of inorganic P forms. The chemical properties of these soils are consistent with the calcareous nature of the local rock, with high pH values (> 7.7). The cation exchange complex consists almost entirely of exchangeable bases, especially Ca and Mg, reaching V valuesof 100 %. High P contents (131-749 mg dm-3) were also extracted (Mehlich-1). The predominant soil fraction was sand, with a loamy texture in all layers. The presence of oxides with magnetic attraction in all fractions is noteworthy, especially in the sand fraction, mainly associated with the carbonized layers. The soil matrix is made predominantly by 1:1 silicate minerals (kaolinite) associated with 2:1 minerals, mainly illite. According to the results, soil genesis is polycyclic, marked by pronounced climate changes, and associated with distinct periods of human occupation, resulting in the formation of pedogenetic layers that seem unrelated with each other. Source

Cunha J.C.,Federal University of Pernambuco | Ruiz H.A.,Federal University of Espirito Santo | Freire M.B.G.S.,Federal Rural University of Pernambuco | Alvarez V. V.H.,Federal University of Vicosa | Fernandes R.B.A.,DPS UFV
Revista Brasileira de Ciencia do Solo

The electrical charges in soil particles are divided into structural or permanent charges and variable charges. Permanent charges develop on the soil particle surface by isomorphic substitution. Variable charges arise from dissociation and association of protons (H+), protonation or deprotonation, and specific adsorption of cations and anions. The aim of this study was to quantify the permanent charges and variable charges of Reference Soils of the State of Pernambuco, Brazil. To do so, 24 subsurface profiles from different regions (nine in the Zona da Mata, eight in the Agreste, and seven in the Sertão) were sampled, representing approximately 80% of the total area of the state. Measurements were performed using cesium chloride solution. Determination was made of the permanent charges and the charges in regard to the hydroxyl functional groups through selective ion exchange of Cs+ by Li+ and Cs+ by NH4 +, respectively. All the soils analyzed exhibited variable cation exchange capacity, with proportions from 0.16 to 0.60 and an average of 0.40 when related to total cation exchange capacity. © 2014 Revista Brasileira de Ciencia do Solo. All rights reserved. Source

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