3290 results

Multinomial Logistic Regression and Random Forest Classifiers in Digital Mapping of Soil Classes in Western Haiti

Wesly Jeune, Márcio Rocha Francelino, Eliana de Souza, Elpídio Inácio Fernandes Filho, Genelício Crusoé Rocha

18/Jun/2018

ABSTRACT Digital soil mapping (DSM) has been increasingly used to provide quick and accurate spatial information to support decision-makers in agricultural and environmental planning programs. In this study, we used a DSM approach to map soils in western Haiti and compare the performance of the Multinomial Logistic Regression (MLR) with Random Forest (RF) to classify the soils. The study area of 4,300 km2 is mostly composed of diverse limestone rocks, alluvial deposits, and, to a lesser extent, basalt. A soil […]

Water Erosion in Oxisols under Coffee Cultivation

Henrique Mendes Júnior, André Silva Tavares, Walbert Reis dos Santos Júnior, Marx Leandro Naves Silva, Breno Régis Santos, Ronaldo Luiz Mincato

18/Jun/2018

ABSTRACT Water erosion is one of the main environmental impacts of land use. When soil and water losses occur, nutrients essential for the growth and maintenance of plants are removed, with harmful outcomes on the sustainability of agriculture and the environment. In addition, they lead to other deleterious effects, such as sedimentation and eutrophication of water bodies. Estimation of soil losses due to water erosion in sub-basins is essential for prediction of soil degradation, especially in areas of semi-intensive cultivation, […]

Relationship between Coffee Leaf Analysis and Soil Chemical Analysis

Jailson Silva Sousa, Júlio César Lima Neves, Herminia Emilia Prieto Martinez, Víctor Hugo V. Alvarez

29/May/2018

ABSTRACT: Research focused on adequate nutrition of plants is essential in modern coffee production to increase yield and develop more efficient management strategies with greater environmental and economic sustainability. The objectives of this study were to establish critical and optimal levels of soil fertility properties for high yielding Arabica coffee crops using the Boundary Line method and, then, relate the macronutrient contents in the diagnostic leaf of coffee to the macronutrients available in the soil using the Quadrant Diagram of […]

Transpiration Reduction Factor and Soybean Yield in Low Land Soil with Ridge and Chiseling

Paulo Ivonir Gubiani, Eduardo Augusto Müller, André Somavilla, Anderson Luiz Zwirtes, Rodrigo Pivoto Mulazzani, Enio Marchesan

10/May/2018

ABSTRACT Water and oxygen deficiencies in the soybean crop cultivated on lowland soils are an important topic of research. The objective of this study was to investigate changes in water and oxygen supply and soybean yield caused by soil management in lowland soils. A soybean crop was grown under four soil conditions: no-tillage (NT), chiseling (CH), ridge tillage on no-tillage (NTR), and ridge tillage on chiseling (CHR). Soil bulk density, total porosity, macro- and microporosity, air permeability, and saturated hydraulic […]

Mineralogy and Concentration of Potentially Toxic Elements in Soils of the São Francisco Sedimentary Basin

Edilene Pereira Ferreira, Ricardo Marques Coelho, Gustavo Souza Valladares, Laura Milani da Silva Dias, Ana Carolina Cunha de Assis, Rafael Cipriano da Silva, [...]

10/May/2018

ABSTRACT Lithological and geomorphological variations determine formation of soils with different mineralogical constitutions and can influence the distribution of potentially toxic elements (PTE). The aim of this study was to determine the contents of PTE and mineralogical assemblages along soil profiles of different classes and parent materials and to investigate the association among these factors in the São Francisco sedimentary basin in the northern part of the state of Minas Gerais (Brazil). Eight soil pedons of different classes that developed […]

Clay Mineralogy of Subtropical Soils under Long-Term Organic Fertilization in No-Tillage Systems

Fabrócio de Araújo Pedron, Cledimar Rogério Lourenzi, Carlos Aberto Ceretta, Juliana Lorensi, Adriana Cancian

03/May/2018

ABSTRACT: Organic fertilization effect on physical-chemical properties in no-tillage systems in tropical soils has been widely investigated, but little is known about the effects of this practice on the mineralogy of the clay fraction. This study aimed to evaluate the clay-fraction mineralogy of two subtropical soils, fertilized with organic residues in long-term no-tillage systems. An Alfisol fertilized with 0, 40, and 80 m3 ha-1 yr-1 pig slurry was evaluated for eight years, and an Oxisol with 0, 8, and 16 […]

Soil Erodibility under Natural Rainfall Conditions as the K Factor of the Universal Soil Loss Equation and Application of the Nomograph for a Subtropical Ultisol

Elemar Antonino Cassol, Tiago Stumpf da Silva, Flávio Luiz Foletto Eltz, Renato Levien

03/May/2018

ABSTRACT: Erodibility represents the intrinsic susceptibility of the soil to the erosion process, represented by the K factor in the Universal Soil Loss Equation (USLE). In Brazil, there are few field experiments determined with a series larger than ten years of data, which are the most reliable for quantifying the K factor. The aim of this study was to determine the K factor of the USLE by the direct method, relating soil losses determined in the field under standard conditions […]

Nitrous Oxide Emissions in a Wheat/Corn Succession Combining Dairy Slurry and Urea as Nitrogen Sources

Celso Aita, Felipe Tonetto, Rogerio Gonzatto, Stefen Barbosa Pujol, Janquieli Schirmann, Juliano dos Santos Depoi, [...]

03/May/2018

ABSTRACT: The impact on nitrous oxide (N2O) emissions caused by combining dairy slurry (DS) and urea to supply crops with nitrogen (N) is still not well characterized. The main objective of this study was to compare the differences between N2O emissions in the cases of exclusive use of urea and the combined use of DS and urea as N sources to no-tillage wheat and corn. We also compared N2O emissions between two DS application methods (surface-broadcast vs. injection), as well […]

Soil CH4 and N2O Emissions from Rice Paddy Fields in Southern Brazil as Affected by Crop Management Levels: a Three-Year Field Study

Tiago Zschornack, Carla Machado da Rosa, Cecília Estima Sacramento dos Reis, Gabriel Munhoz Pedroso, Estefânia Silva Camargo, Daiane Carvalho dos Santos, [...]

20/Apr/2018

ABSTRACT Rice yield increases in response to improvements in crop management, but the impact on greenhouse gas (GHG) emissions in the subtropical region of Southern Brazil remains unknown. A three-year field study was developed aiming to evaluate the impact that an increase in crop management levels (high and very high) has on soil methane (CH4) and nitrous oxide (N2O) emissions, as compared to the level (medium) currently adopted by farmers in Southern Brazil. Differences in crop management included seed and […]

Hardening and Stability of Plinthic Materials of the Araguaia River Floodplain under Different Drying Treatments

Angélica Pires Batista Martins, Glenio Guimarães Santos, Virlei Álvaro de Oliveira, Deyvid Diego Carvalho Maranhão, Leonardo Santos Collier

20/Apr/2018

ABSTRACT Plinthite and petroplinthite occur frequently in Brazilian soils, but there is little information on the behavior of these materials. The aim of the present study was to assess the effect of different drying periods on the hardening and stability of plinthic materials of soils in the floodplain of the Araguaia River and the João Leite stream in Goiás. Soil samples were collected, with the aid of 0.10 m high and 0.15 m diameter PVC cylinders, directly from the plinthic […]

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