3312 results

A Classification for a Geostatistical Index of Spatial Dependence

Enio Júnior Seidel, Marcelo Silva de Oliveira

09/Dec/2016

ABSTRACT: In geostatistical studies, spatial dependence can generally be described by means of the semivariogram or, in complementary form, with a single index followed by its categorization to classify the degree of such dependence. The objective of this study was to construct a categorization for the spatial dependence index (SDI) proposed by Seidel and Oliveira (2014) in order to classify spatial variability in terms of weak, moderate, and strong dependence. Theoretical values were constructed from different degrees of spatial dependence, […]

Boundary Line Model to Estimate the Nutrient Sufficiency Range in Muskmelon Leaves

Celsemy Eleutério Maia, Elis Regina Costa de Morais

09/Dec/2016

ABSTRACT: The boundary line is a method frequently used to assess the nutritional status of plants when the relationship between the variables under analysis is influenced by other interacting factors. The objective of this study was to propose and test the boundary line model to estimate the nutrient sufficiency range and nutritional status of irrigated muskmelon. The lower and upper limits of the sufficiency range were calculated as a basis for assessment of the nutritional status of muskmelon. Leaf material […]

Omission and Resupply of Nitrogen Affect Physiological and Enzymatic Activities and the Gene Expression of Eucalypt Clones

Loane Vaz Fernandes, Lílian Angélica Moreira, Nairam Félix de Barros, Cléberson Ribeiro, Júlio César Lima Neves

08/Dec/2016

ABSTRACT: The mineral nutrient uptake of plants in the field occurs in pulses, due to variations in the substance concentrations at the root surface. The fluctuations in nutrient supply probably induce changes in the plant, which are to date unknown for Eucalyptus. This study evaluated these changes in plant growth, nutritional status, photosynthesis, and gene expression, which can serve as biomarkers of the nitrogen status, of four eucalypt clones exposed to N omission and resupply. A greenhouse experiment with four […]

Rare Earth Element Concentrations in Brazilian Benchmark Soils

Ygor Jacques Agra Bezerra da Silva, Clístenes Williams Araújo do Nascimento, Yuri Jacques Agra Bezerra da Silva, Caroline Miranda Biondi, Cinthia Maria Cordeiro Atanázio Cruz Silva

08/Dec/2016

ABSTRACT: Studies regarding background concentrations of rare earth elements (REEs) are scarce and have mainly focused on a limited number of soil types from the northern hemisphere. The aim of this study was to determine REE concentrations in thirty-five benchmark soils of Brazil. Composite soil samples were taken from areas under native vegetation or with minimal anthropogenic influence. Concentrations of La, Ce, Pr, Nd, Sm, Eu, Gd, Yb, Lu, Dy, Er, Ho, Tb, Tm, Y, Sc, and Fe were determined […]

Phytoextractor Potential of Cultivated Species in Industrial Area Contaminated by Lead

Silvânia Maria de Souza Gomes Nascimento, Adailson Pereira de Souza, Vera Lúcia Antunes de Lima, Clístenes Williams Araújo do Nascimento, Joab Josemar Vitor Ribeiro do Nascimento

08/Dec/2016

ABSTRACT: High growth rate is one of the criteria used for the selection of species to be used in metal phytoextraction programs. This study was carried out to characterize the growth characteristics of sunflower (Helianthus annuus L.), castor bean (Ricinus communis L.), corn (Zea mays L), and vetiver [Vetiveria zizanioides (L.) Nash] grown on a soil contaminated with lead (Pb), with and without pH correction, to improve agronomic practices regarding phytoremediation programs. The experiment was designed as a randomized block […]

Litter Decomposition of Two Pioneer Tree Species and Associated Soil Fauna in Areas Reclaimed after Surface Coal Mining in Southern Brazil

Joice Martins de Freitas Frasson, João Luis Osório Rosado, Samuel Galvão Elias, Birgit Harter-Marques

17/Oct/2016

ABSTRACT Decomposition of leaf litter from pioneer tree species and development of associated soil meso- and macrofauna are fundamental for rehabilitation processes in reclaimed coal mining areas. The aim of our study was to evaluate decomposition of Schinus terebinthifolius and Senna multijuga to answer three basic questions: (i) What type of leaf litter degrades faster in reclaimed coal mining areas? (ii) Is leaf decomposition correlated with the stage of regeneration and exposure time? and (iii) Does the type of leaf […]

Genesis and Classification of Soils from Subtropical Mountain Regions of Southern Brazil

Denilson Dortzbach, Marcos Gervasio Pereira, Lúcia Helena Cunha dos Anjos, Ademir Fontana, Eduardo de Carvalho Silva

17/Oct/2016

ABSTRACT Soils formed in high mountainous regions in southern Brazil are characterized by great accumulation of organic matter (OM) in the surface horizons and variation in the degree of development. We hypothesized that soil properties and genesis are influenced by the interaction of parent materials and climate factors, which differ depending on the location along the altitudinal gradient. The goal of this study was to characterize and classify the soil, evaluate soil distribution, and determine the interactive effects of soil-forming […]

Carbon and Nitrogen Stocks and Humic Fractions in Brazilian Organosols

Gustavo Souza Valladares, Marcos Gervasio Pereira, Vinícius de Melo Benites, Lúcia Helena Cunha dos Anjos, Adierson Gilvani Ebeling, Roni Fernandes Guareschi

17/Oct/2016

ABSTRACT Despite limited geographic expression of Organosols in Brazil, their high carbon storage capacity and natural environmental vulnerability justifies further studies on C and N stocks in these soils and their relationship to the nature of organic matter. Evaluation of physical and chemical properties of organic soils and their ability to store C is important so as to develop sustainable management practices for their preservation. The objectives of the study were to measure the total organic carbon stock (OCst), total […]

Microbial Communities in Soil Cultivated with Muskmelon under Different Management Systems

Paula Gracielly Morais Lima do Nascimento, Beatriz Letícia Silva da Cruz, Andréa Mirne de Macêdo Dantas, Francisco Cláudio Lopes de Freitas, Márcia Michelle de Queiroz Ambrósio, Rui Sales

17/Oct/2016

ABSTRACT Microorganisms have a fundamental importance in agricultural ecosystems and may be influenced by several factors, including soil management. The aim of this study was to evaluate the effects of cropping systems and soil covers on the microbial community in soil cultivated with muskmelon (Cucumis melo L.). The experiment was conducted in a randomized complete block design with four replications. The treatments were arranged in a split plot design with cropping systems (no-tillage and conventional tillage systems) assigned to the […]

Predicting Runoff Risks by Digital Soil Mapping

Mayesse Aparecida da Silva, Marx Leandro Naves Silva, Phillip Ray Owens, Nilton Curi, Anna Hoffmann Oliveira, Bernardo Moreira Candido

17/Oct/2016

ABSTRACT Digital soil mapping (DSM) permits continuous mapping soil types and properties through raster formats considering variation within soil class, in contrast to the traditional mapping that only considers spatial variation of soils at the boundaries of delineated polygons. The objective of this study was to compare the performance of SoLIM (Soil Land Inference Model) for two sets of environmental variables on digital mapping of saturated hydraulic conductivity and solum depth (A + B horizons) and to apply the best […]

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