280 results

EFFECT OF WATER AVAILABILITY ON SOIL MICROBIAL BIOMASS IN SECONDARY FOREST IN EASTERN AMAZONIA

Lívia Gabrig Turbay Rangel-Vasconcelos, Daniel Jacob Zarin, Francisco de Assis Oliveira, Steel Silva Vasconcelos, Cláudio José Reis de Carvalho, Maria Marly de Lourdes Silva Santos

01/Mar/2015

Soil microbial biomass (SMB) plays an important role in nutrient cycling in agroecosystems, and is limited by several factors, such as soil water availability. This study assessed the effects of soil water availability on microbial biomass and its variation over time in the Latossolo Amarelo concrecionário of a secondary forest in eastern Amazonia. The fumigation-extraction method was used to estimate the soil microbial biomass carbon and nitrogen content (SMBC and SMBN). An adaptation of the fumigation-incubation method was used to […]

EFFECT OF RICE STRAW AND NITRATE LEVELS IN SOIL SOLUTION ON NITROUS OXIDE EMISSION

André Carlos Cruz Copetti, Leandro Souza da Silva, Gerson Laerson Drescher, Eduardo Augusto Müller, Rafael Lago Busanello, Frederico Costa Beber Vieira

01/Mar/2015

Among the greenhouse gases, nitrous oxide (N2O) is considered important, in view of a global warming potential 296 times greater than that of carbon dioxide (CO2) and its dynamics strongly depend on the availability of C and mineral N in the soil. The understanding of the factors that define emissions is essential to develop mitigation strategies. This study evaluated the dynamics of N2O emissions after the application of different rice straw amounts and nitrate levels in soil solution. Pots containing […]

SYMBIOTIC EFFECTIVENESS AND COMPETITIVENESS OF CALOPO RHIZOBIAL ISOLATES IN AN ARGISSOLO VERMELHO-AMARELO UNDER THREE VEGETATION COVERS IN THE DRY FOREST ZONE OF PERNAMBUCO

Altanys Silva Calheiros, Mario de Andrade Lira Junior, Mércia Virgínia Ferreira Santos, Maria do Carmo Catanho Pereira Lyra

01/Mar/2015

Biological N fixation in forage legumes is an important alternative to reduce pasture degradation, and is strongly influenced by the inoculant symbiotic capability. This paper evaluates the effectiveness of Calopo (Calopogonium mucunoides) rhizobial isolated from soil under three vegetation covers of an Argissolo Vermelho-Amarelo of the Dry Forest Zone of Pernambuco. An experiment was conducted evaluating 25 isolates, aside from 5 uninoculated controls with 0; 309; 60; 90 and 120 kg ha-1 N, and a treatment inoculated with the SEMIA […]

PEDO-TRANSFER FUNCTIONS FOR ESTIMATING SOIL BULK DENSITY IN CENTRAL AMAZONIA

Henrique Seixas Barros, and Philip Martin Fearnside

01/Mar/2015

Under field conditions in the Amazon forest, soil bulk density is difficult to measure. Rigorous methodological criteria must be applied to obtain reliable inventories of C stocks and soil nutrients, making this process expensive and sometimes unfeasible. This study aimed to generate models to estimate soil bulk density based on parameters that can be easily and reliably measured in the field and that are available in many soil-related inventories. Stepwise regression models to predict bulk density were developed using data […]

CHARACTERIZATION OF HEADWATERS PEATS OF THE RIO ARAÇUAÍ, MINAS GERAIS STATE, BRAZIL

Diêgo Faustolo Alves Bispo, Alexandre Christofaro Silva, Cristiano Christofaro, Max Leandro Naves Silva, Maurício Soares Barbosa, Bárbara Pereira Christofaro Silva, [...]

01/Mar/2015

Peatlands are soil environments that accumulate water and organic carbon and function as records of paleo-environmental changes. The variability in the composition of organic matter is reflected in their morphological, physical, and chemical properties. The aim of this study was to characterize these properties in peatlands from the headwaters of the Rio Araçuaí (Araçuaí River) in different stages of preservation. Two cores from peatlands with different vegetation types (moist grassland and semideciduous seasonal forest) from the Rio Preto [Preto River] […]

DEVELOPMENT, AUTOMATION AND PERFORMANCE OF A CONSOLIDOMETER WITH HUMAN-MACHINE INTERFACE

Reginaldo Barboza da Silva, Batista Masqueto Junior, Kléber Pereira Lanças, Francisca Alcivania de Melo Silva

01/Mar/2015

To run a consolidation test, it is necessary to use a consolidometer. This equipment, however, had not been produced and sold in Brazil until some years ago. Non-automatic models available for import, although of low cost, are nevertheless rustic and need continuous calibration of pressure levels during the consolidation test. The exclusiveness and intervention of a technician throughout the test, associated with the precarious acquisition of data in these models, are still major factors that have made consolidation of this […]

EFFICIENCY OF THE DENSE SOLUTIONS IN PHYSICAL FRACTIONATION OF SOIL ORGANIC MATTER

Paulo Cesar Conceição, Madalena Boeni, Cimélio Bayer, Jeferson Dieckow, Julio Cesar Salton, Cecilia Estima Sacramento dos Reis

01/Mar/2015

The mechanisms of stabilization of organic matter (OM) have been studied in Brazilian tropical and subtropical soils; however, few studies have evaluated the influence of the methodological part of the use of the solutions in the results. The aim of this study was to evaluate the efficiency of two salt solutions (1.8 kg dm-3 sodium iodide – NaI, and 2.0 kg dm-3 sodium polytungstate – SPT) in separation of densimetric soil organic matter (SOM) fractions in two soils (Acrisol from […]

INOCULATION AND ISOLATION OF PLANT GROWTH-PROMOTING BACTERIA IN MAIZE GROWN IN VITÓRIA DA CONQUISTA, BAHIA, BRAZIL

Joelma da Silva Santos, Tarciana de Oliveira Viana, Cristina Meira de Jesus, Vera Lúcia Divan Baldani, Joilson Silva Ferreira

01/Jan/2015

Maize is among the most important crops in the world. This plant species can be colonized by diazotrophic bacteria able to convert atmospheric N into ammonium under natural conditions. This study aimed to investigate the effect of inoculation of the diazotrophic bacterium Herbaspirillum seropedicae (ZAE94) and isolate new strains of plant growth-promoting bacteria in maize grown in Vitória da Conquista, Bahia, Brazil. The study was conducted in a greenhouse at the Experimental Area of the Universidade Estadual do Sudoeste da […]

CHARACTERIZATION OF BULK SOIL HUMIN AND ITS ALKALINE-SOLUBLE AND ALKALINE-INSOLUBLE FRACTIONS

Cuilan Li, Shuqing Gao, Qiang Gao, Lichun Wang, Jinjing Zhang

01/Jan/2015

Humic substances are the major components of soil organic matter. Among the three humic substance components (humic acid, fulvic acid, and humin), humin is the most insoluble in aqueous solution at any pH value and, in turn, the least understood. Humin has poor solubility mainly because it is tightly bonded to inorganic soil colloids. By breaking the linkage between humin and inorganic soil colloids using inorganic or organic solvents, bulk humin can be partially soluble in alkali, enabling a better […]

COMPRESSIBLITY AND PENETRABILITY OF LATOSSOLO VERMELHO-AMARELO DISTRÓFICO (OXISOL) UNDER VARIED MANAGEMENT SYSTEMS AND LAND USES

Eudes Neiva Júnior, Wellington Willian Rocha, Bruno Silva Pires, Múcio Mágno de Melo Farnezi, Moacir de Souza Dias Junior, Danilo Fernandes Borges de Freitas, [...]

01/Jan/2015

Soil compaction is one of the main degradation causes, provoked by inappropriate agricultural practices that override the limitations of the soil physical properties. Preconsolidation pressure and penetration resistance have proved effective as alternative to assess and identify soil compaction. Based on the interpretation of these physico-mechanical parameters, compaction can be prevented with a better adjusted soil management. This study was performed to generate preconsolidation pressure and penetration resistance models for Latososlo Vermelho-Amarelo distrófico (Oxisol) under various managements and uses; and […]

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