Diversity and Abundance of Populations of Bean-Nodulating Rhizobia as a Function of Liming and Cropping History in Acidic Brazilian Soils

2002 ◽  
pp. 546-546
Author(s):  
D. S. Andrade ◽  
P. J. Murphy ◽  
K. E. Giller
Keyword(s):  
Brazilian Soils

scholarly journals Maghemite in Brazilian Iron Ores: Quantification of the Magnetite-Maghemite Isomorphic Series by Χ-ray Diffraction and the Rietveld Method, and Confirmation by Independent Methods

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 346
Author(s):  
Renata Hiraga ◽  
Otávio Gomes ◽  
Reiner Neumann
Keyword(s):  
Solid Solution ◽  
Rietveld Method ◽  
Isomorphic Substitution ◽  
Iron Ores ◽  
Reflected Light ◽  
Magnetite Crystal ◽  
Brazilian Soils ◽  
Isomorphic Series ◽  
Ore Characterization ◽  
Ray Patterns

Maghemite (γ-Fe2O3) is a mineral formed from magnetite oxidation at low temperatures, an intermediate metastable term of the magnetite to hematite oxidation and could be mixed with both. It has magnetic susceptibility similar to magnetite, crystal structure close to magnetite with which it forms a solid solution, while compositionally it equals hematite. Maghemite is thus easily misidentified as magnetite by Χ-ray diffraction and/or as hematite by spot chemical analysis in iron ore characterization routines. Nonstoichiometric magnetite could be quantified in samples of Brazilian soils and iron ores by the Rietveld method using a constrained refinement of the Χ-ray patterns. The results were confirmed by reflected light microscopy and Raman spectroscopy, thus qualitatively validating the method. Χ-ray diffraction with the refinement of the isomorphic substitution of Fe2+ by Fe3+ along the magnetite-maghemite solid solution could help to suitably characterize maghemite in iron ores, allowing for the evaluation of its ultimate influence on mineral processing, as its effect on surface and breakage properties.

scholarly journals Use of pedological maps in the identification of sensitivity of soils to acidic deposition: application to Brazilian soils

2004 ◽  
Vol 76 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Adolpho J. Melfi ◽  
Celia R. Montes ◽  
Adilson Carvalho ◽  
Maria Cristina Forti
Keyword(s):  
Spatial Distribution ◽  
Clay Minerals ◽  
Acidic Deposition ◽  
Clay Fraction ◽  
Terrestrial Ecosystem ◽  
Environmental Studies ◽  
Saline Soils ◽  
Variable Amount ◽  
Brazilian Soils ◽  
Soil Distribution

The pedogeochemical maps present the spatial distribution of soils according to crystalochemical parameters (clay fraction) and physic-chemical aspects of the sorting complex (CEC and BS). These maps are adequate tool for environmental studies and particularly, for the analysis of the terrestrial ecosystem sensibility to acidic deposition. The pedogeochemical maps of the Brazilian soils, elaborated using FAO SoilWorld Map, allowed establishing the soil distribution according to 5 classes of vulnerability to acidic deposition, as defined by Stockholm Environmental Institute (SEI). From these maps, it is observed that about 50% of the Brazilian soils are high vulnerable to acidic deposition and can be included within the most sensitive class. This group is formed by well-developed and mature soils, constituted by clay minerals of kaolinite type associated with variable amount of gibbsite. About 8% of the soils can be considered as the least sensitive class. They correspond to Topomorphic Vertisols (Vertissolo, Embrapa 1999), Planosols (Planossolo, Embrapa 1999) and saline soils. Finally, the remaining soils represent the balanced media that dominate the northeastern semiarid zones and the south and northeastern subtropical zones.

scholarly journals Sorption of Clomazone in Brazilian Soils with Different Physical and Chemical Attributes1

2016 ◽  
Vol 34 (2) ◽  
pp. 357-364 ◽  
Author(s):  
G.A.M. PEREIRA ◽  
L.H. BARCELLOS JR. ◽  
V.A. GONÇALVES ◽  
D.V. SILVA ◽  
A.T. FARIA ◽  
...  
Keyword(s):  
Dry Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Samples ◽  
Chemical Characteristics ◽  
Abstract Knowledge ◽  
Analysis Of Similarity ◽  
Brazilian Soils ◽  
Physical And Chemical ◽  
Different Soils

ABSTRACT Knowledge of herbicides sorption by colloids predicts its movement in the soil profile and its effectiveness in controlling weeds and crops poisoning when directly applied to the soil. This knowledge becomes even more important for herbicides which have long persistence in the soil. In this research, clomazone sorption was estimated by the biological method in Brazilian soil samples with different physical and chemical characteristics, cultivated with sugarcane crops. As an indicator of the presence of clomazone in the soil, Sorghum bicolor was used. The data relating to assessments of poisoning and accumulation of dry matter of the plants were subjected to multivariate analysis of similarity among variables. After that, clomazone doses that caused 50% of intoxication in sorghum plants grown (C50) as well as sorption ratio (SR) of the herbicide in different soil types were estimated. There was similarity greater than 80% for data regarding the percentage of intoxication and accumulated dry matter, with the option to use only those related to the first variable. RS and C50 were higher in Organosol and lower in red-yellow Latosol with and without changing the pH. It was concluded that the clomazone dose to be recommended must be differentiated for different soils, since the value of clomazone sorption in the soil is dependent on its attributes, and the organic matter content is of the utmost importance.

scholarly journals Magnetic separation and evaluation of magnetization of Brazilian soils from different parent materials

Geoderma ◽  
2000 ◽  
Vol 96 (1-2) ◽  
pp. 81-99 ◽  
Author(s):  
M.P.F. Fontes ◽  
T.S. de Oliveira ◽  
L.M. da Costa ◽  
A.A.G. Campos
Keyword(s):  
Magnetic Separation ◽  
Parent Materials ◽  
Brazilian Soils

Neutral sugars in melanins synthesized by actinomycetes from Brazilian soils

1998 ◽  
Vol 27 (2) ◽  
pp. 162-167 ◽  
Author(s):  
A. A. Linhares ◽  
Luiz Fernando Linhares ◽  
Rosalie R. R. Coelho
Keyword(s):  
Brazilian Soils ◽  
Neutral Sugars

scholarly journals P-sorption and desorption in Savanna Brazilian soils as a support for phosphorus fertilizer management

2013 ◽  
Vol 37 (6) ◽  
pp. 521-530 ◽  
Author(s):  
Flávio Araújo Pinto ◽  
Edicarlos Damacena de Souza ◽  
Helder Barbosa Paulino ◽  
Nilton Curi ◽  
Marco Aurélio Carbone Carneiro
Keyword(s):  
Clay Content ◽  
Soil Characteristics ◽  
Fertilizer Management ◽  
Phosphorus Fertilizer ◽  
Phosphorus Adsorption ◽  
P Sorption ◽  
Brazilian Soils ◽  
Soil Clay ◽  
Sand Base ◽  
Soil Clay Content

Phosphorus (P) sorption by soils is a phenomenon that varies depending on soil characteristics, influencing its intensity and magnitude, which makes it a source or drain of P. The objective of this study was to determine the Maximum Phosphorus Adsorption Capacity (MPAC) and desorption of P from soils under native Savanna Brazilian and verify the correlation between MPAC and P Capacity Factor (PCF) with the chemical and physical properties of these soils. The study was conducted in seven soils under native Savannas. The Langmuir isotherms were adjusted from the values obtained in sorption assays, being evaluated the MPAC, the energy adsorption (EA) and PCF, which was calculated according to the levels of P-adsorbed and P-sorbed. Values of MPAC were classified as high in most soils, ranging from 283 up to 2635 mg kg-1 of P in the soil and were correlated with soil organic matter, clay, silt, sand, base saturation and pH. The PCF was higher in soils where the MPAC was also higher. The use of only one attribute of soil (clay content) as a criterion for the recommendation of phosphated fertilization, as routinely done, is susceptible to errors, needing the use of more attributes for a more accurate recommendation, as a function of the complexity of the interactions involved in the process.

scholarly journals Carbon sequestration in clay and silt fractions of Brazilian soils under conventional and no-tillage systems

2014 ◽  
Vol 71 (4) ◽  
pp. 292-301 ◽  
Author(s):  
Cecília Estima Sacramento dos Reis ◽  
Deborah Pinheiro Dick ◽  
Jennifer da Silva Caldas ◽  
Cimélio Bayer
Keyword(s):  
Carbon Sequestration ◽  
No Tillage ◽  
Tillage Systems ◽  
Brazilian Soils

scholarly journals Sporocarpic species of arbuscular mycorrhizal fungi (Glomeromycota), with a new report from Brazil

2005 ◽  
Vol 19 (3) ◽  
pp. 633-637 ◽  
Author(s):  
Bruno Tomio Goto ◽  
Leonor Costa Maia
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Atlantic Forest ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Northeast Brazil ◽  
Natural Areas ◽  
Agricultural Ecosystems ◽  
Brazilian Soils ◽  
First Time

The arbuscular mycorrhizal fungi (AMF) are widely distributed in terrestrial ecossystems; however the sporocarpic species are less documented on AMF surveys. Five of these species were found in natural areas of Atlantic Forest and in agricultural ecosystems of Northeast Brazil: Glomus glomerulatum, G. sinuosum, G. coremioides, G. fuegianum and G. taiwanensis, with the last one being registered for the first time in Brazilian soils.

Study of Pyrene Adsorption on Two Brazilian Soils

2010 ◽  
Vol 219 (1-4) ◽  
pp. 297-301 ◽  
Author(s):  
Silvio César Godinho Teixeira ◽  
Roberta Lourenço Ziolli ◽  
Mônica Regina da Costa Marques ◽  
Daniel Vidal Pérez
Keyword(s):  
Brazilian Soils
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