42 results

Greenhouse gas emission caused by different land-uses in brazilian Savannah

Marcos Siqueira Neto, Marisa de Cássia Piccolo, Ciniro Costa Junior, Carlos Clemente Cerri, Martial Bernoux

01/Feb/2011

The conversion of native forests by cutting and burning into farming areas leads to alterations in the dynamics of soil organic matter, with changes in emissions of greenhouse gases (GHGs: CO2, CH4 and N2O) from the biosphere to the atmosphere. These cause an average temperature rise and, consequently, global climate change. The aim of this study was to examine relationships between the fluxes of CO2, CH4 and N2O with moisture, microbial biomass and inorganic N forms in soil with different […]

Soil air permeability in a Rhodic Hapludox under different tillage systems

Sueli Rodrigues, Alvaro Pires da Silva, Neyde Fabíola Balarezo Giarola, Jadir Aparecido Rosa

01/Feb/2011

Air permeability (Kα) can be used to assess soil structure changes resulting from different tillage systems. This study tested the hypothesis that the reduced soil disturbance in no-tillage results in continuous pores and better soil aeration conditions. The objective was to evaluate the aeration of a Rhodic Hapludox under conventional tillage (CT) and no-tillage (NT), based on soil air permeability (Kα), air-filled porosity (εa) and indices of pore continuity (K1 and N). Eighty undisturbed soil cores (2 treatments x 2 […]

Tillage systems and nutrient sources affecting soil cover, temperature and moisture in a clayey oxisol under corn

Milton da Veiga, Dalvan José Reinert, José Miguel Reichert

01/Dec/2010

Tillage affects soil physical properties, e.g., porosity, and leads to different amounts of mulch on the soil surface. Consequently, tillage is related to the soil temperature and moisture regime. Soil cover, temperature and moisture were measured under corn (Zea mays) in the tenth year of five tillage systems (NT = no-tillage; CP = chisel plow and single secondary disking; CT = primary and double secondary disking; CTb = CT with crop residues burned; and CTr = CT with crop residues […]

Effects of different management systems on porosity of oxisols in Paraná, Brazil

João Tavares Filho, Daniel Tessier

01/Jun/2010

Soils play a fundamental role in the production of human foods. The Oxisols in the state of Paraná are among the richest and most productive soils in Brazil, but degradation and low porosity are frequently documented, due to intensive farming involving various management strategies and the application of high-tech solutions. This study aims to investigate changes in the porosity of two Red Oxisols (Latossolos Vermelhos), denoted LVef (eutroferric) and LVdf (dystroferric) under conventional and no-tillage soil management, with a succession […]

Mineralogy of a red latosol under different management systems for twenty-four years

Daniele Gonçalves, Wellington Claiton Leite, André Maurício Brinatti, Sérgio da Costa Saab, Kelly Cristiane Iarosz, Yvone Primerano Mascarenhas, [...]

01/Dec/2008

The search for management systems that preserve or improve soil qualities, the mineralogical as well as the organic composition, with a view to higher yields, is becoming more and more intense. The objective this study was to qualitatively verify the mineralogical effects of different management types: conventional , minimum and no-tillage for 24 years on a Red Latosol in Ponta Grossa, PR, Brazil, by the following techniques: X-ray diffraction, X-ray fluorescence and Fourier transform infrared. No significant changes in the […]

Soil physical characteristics and organic carbon content under different land uses

Jacson Tavares de Oliveira, Ana Maria Souza dos Santos Moreau, Arlicélio de Queiroz Paiva, Agna Almeida Menezes, Oldair Vinhas Costa

01/Dec/2008

In the watershed Água Fria, in Barra do Choça (BA), native vegetation and environmentally protected areas have been replaced by coffee and pasture cultivation. This study evaluated the physical characteristics, particle size distribution, water dispersible clay, flocculation, mean weight diameter and aggregate stability index and organic C concentration of soils under different land uses, in the area surroundings the above watershed. Soil samples were collected from six different fields: two coffee plantations (manual and mechanical cultivation), two pastures and two […]

Physical properties and organic matter content of an ultisol cultivated with cassava under different managements

Rogério Ferreira da Silva, Clovis Daniel Borges, David Martins Garib, Fábio Martins Mercante

01/Dec/2008

The maintenance and improvement of soil quality are crucial to the stability, sustainability and productivity of natural ecosystems and agroecosystems. The understanding and quantification of the impact of tillage systems in their physical quality are fundamental in the development of sustainable agricultural systems. This study was carried out to evaluate the effects of management practices on physical properties and organic matter content of an Ultisol cultivated with cassava following the use of distinct cover crops. A field experiment was carried […]

Comparison of the methods fumigation-extraction and fumigation-incubation in the evaluation of microbial biomass C in a Dark Red Oxisol

Osvaldino Brandão-Junior, Mariangela Hungria, Julio Cezar Franchini, Carlos Roberto Espindola

01/Oct/2008

More and more studies, including in Brazil, have suggested the use of microbial biomass carbon (MBC) as a bioindicator of soil quality. Most studies employ two methods: the pioneer of fumigation-incubation (FI), in which the MBC is estimated based on CO2 emission from fumigated and non-fumigated soil samples after 10 days of incubation and fumigation-extraction (FE), in which MBC is estimated based on C extraction from fumigated and non-fumigated soil samples after 12 h. However, in Brazil the correlation between both […]

Root abundance of maize in conventionally-tilled and zero-tilled soils of Argentina

Miguel Angel Taboada, Carina Rosa Alvarez

01/Apr/2008

Maize root growth is negatively affected by compacted layers in the surface (e.g. agricultural traffic) and subsoil layers (e.g. claypans). Both kinds of soil mechanical impedances often coexist in maize fields, but the combined effects on root growth have seldom been studied. Soil physical properties and maize root abundance were determined in three different soils of the Rolling Pampa of Argentina, in conventionally-tilled (CT) and zero-tilled (ZT) fields cultivated with maize. In the soil with a light Bt horizon (loamy […]

Qualitative and quantitative changes in soil microbiota and biological nitrogen fixation under different soybean managements

Alan Alves Pereira, Mariangela Hungria, Julio Cezar Franchini, Glaciela Kaschuk, Lígia Maria de Oliveira Chueire, Rubens José Campo, [...]

01/Dec/2007

In this study, quantitative and qualitative microbiological parameters were evaluated to detect differences related to soil and crop management. The study was carried out in a field experiment installed 14 years ago on a Rhodic Eutrudox, in Londrina, PR, Brazil. Treatments were a combination of a crop sequence (S) (soybean/wheat) and a crop rotation (R) (lupin/maize/black oat/soybean/wheat/soybean/wheat/soybean), either under conventional tillage (CT) or no-tillage (NT). Evaluations were performed when all systems were under the soybean cropping season, at full flowering. […]

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