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Registros recuperados: 9
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Carbon Stocks in Compartments of Soil Organic Matter 31 Years after Substitution of Native Cerrado Vegetation by Agroecosystems Rev. Bras. Ciênc. Solo
Ferreira,Eloisa Aparecida Belleza; Bustamante,Mercedes Maria da Cunha; Resck,Dimas Vital Siqueira; Figueiredo,Cícero Célio de; Pinto,Alexandre de Siqueira; Malaquias,Juaci Vitória.
ABSTRACT Changes in carbon stocks in different compartments of soil organic matter of a clayey Latossolo Vermelho Distrófico (Typic Haplustox), caused by the substitution of native savanna vegetation (cerrado sensu stricto) by agroecosystems, were assessed after 31 years of cultivation. Under native vegetation, a stock of 164.5 Mg ha-1 C was estimated in the 0.00-1.00 m layer. After 31 years of cultivation, these changes in soil C stocks were detected to a depth of 0.60 m. In the case of substitution of cerrado sensu stricto by no-tillage soybean-corn rotation, a reduction of at least 11 % of the soil C pools was observed. However, the adoption of no-tillage as an alternative to tillage with a moldboard plow (conventional system) reduced CO2 emissions by...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Conventional tillage; No-tillage; Microbial biomass; Particulate organic matter.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100507
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Characterization of cover crops by NMR spectroscopy: impacts on soil carbon, nitrogen and phosphorus under tillage regimes Rev. Ciênc. Agron.
Carvalho,Arminda Moreira de; Marchão,Robélio Leandro; Bustamante,Mercedes Maria da Cunha; Alcântara,Flávia Aparecida de; Coser,Thais Rodrigues.
The objective of this study was to investigate the chemical composition of cover crops by solid-state CPMAS 13C NMR spectroscopy and its effects on carbon, nitrogen and phosphorus in a Typic Acrustox. Cover crops (Crotalaria juncea, Canavalia brasiliensis, Cajanus cajan, Mucuna pruriens and Raphanus sativus) and natural fallow were studied in rotation with maize under conventional and no-tillage regimes. Tissues of Crotalaria juncea, Canavalia brasiliensis, Mucuna pruriens and Raphanus sativus were analyzed using CPMAS 13C NMR spectroscopy. Soil samples were collected at the end of the growing season of the cover crops (September 2002) and during the grain filling period in corn from 0-5 and 5-10 cm layers. Cajanus cajan presented the lowest content of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brazilian Savanna; Solid-state CPMAS 13C NMR spectroscopy; Organic matter; Ecological Intensification.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000500012
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Decomposição de resíduos vegetais em latossolo sob cultivo de milho e plantas de cobertura Rev. Bras. Ciênc. Solo
Carvalho,Arminda Moreira de; Bustamante,Mercedes Maria da Cunha; Sousa Junior,José Geraldo de Abreu; Vivaldi,Lúcio José.
A degradação dos solos pode ocorrer pelo seu preparo intensivo, combinado com monocultivos que produzem pequenas quantidades de resíduos vegetais com decomposição acelerada. O objetivo deste estudo foi avaliar a decomposição dos resíduos vegetais, em Latossolo Vermelho-Amarelo sob cultivo de milho em sucessão a plantas de cobertura, nos sistemas plantio direto e com incorporação desses resíduos. As espécies vegetais cultivadas em sucessão ao milho foram: crotalária juncea (Crotalaria juncea L.), feijão-bravo-do-ceará (Canavalia brasiliensis M. e Benth), guandu cv. Caqui (Cajanus cajan (L.) Millsp), mucuna-cinza (Mucuna pruriens (L.) DC), girassol (Helianthus annuus L.), milheto BN-2 (Pennisetum glaucum (L.) R. Brown) e nabo-forrageiro (Raphanus sativus...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Cerrado; Matéria orgânica; Plantio direto; Composição química; Sacolas de serapilheira.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000700029
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Effects of fire on soil nitrogen dynamics and microbial biomass in savannas of Central Brazil PAB
Nardoto,Gabriela Bielefeld; Bustamante,Mercedes Maria da Cunha.
The objective of this work was to study the effects of fire on net N mineralization and soil microbial biomass in burned and unburned cerrado stricto sensu sites. The study was carried out from April 1998 to April 2000. The pH values were significantly higher in the burned site while soil moisture content was significantly higher in the unburned site (P<0.05). The soil C/N ratio was 22/1 and the available NO3-N ranged between 1.5 and 2.8 mg kg-¹ dry weight. However, the NH4-N concentration ranged between 3 and 34 mg kg-1 dry weight in the burned site and between 3 and 22 mg kg-1 dry weight in the unburned site. The NH4-N increased after fire, but no significant changes were observed for NO3-N (P<0.05). The NO3-N accumulation occurred in short periods...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Nitrogen mineralization; Nitrification; Inorganic compounds; Burning.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000800008
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Emissão de óxidos de nitrogênio associada à aplicação de uréia sob plantio convencional e direto PAB
Carvalho,Arminda Moreira de; Bustamante,Mercedes Maria da Cunha; Kozovits,Alessandra Rodrigues; Miranda,Leo Nobre de; Vivaldi,Lúcio José; Sousa,Danielle Matias de.
O objetivo deste trabalho foi avaliar emissões de NO e N2O até cinco dias após a primeira fertilização de cobertura com uréia em milho, em Latossolo Vermelho argiloso distrófico, sob plantio convencional e direto. A adubação de cobertura foi de 60 kg ha-1 de N. O experimento foi conduzido na Embrapa Cerrados, Planaltina, DF, com delineamento de blocos ao acaso, com três repetições, sendo o terceiro cultivo de milho, em rotação com soja. Os fluxos de NO e N2O foram medidos em câmaras de PVC instaladas em cada parcela. Houve emissão alta de NO imediatamente após (5,4 ng N cm-2 h-1) e no terceiro dia (4,8 ng N cm-2 h-1) após aplicação de uréia e irrigação. Um dia após fertilização, a emissão de NO reduziu-se a 1,9 ng N cm-2 h-1, e cinco dias depois, alcançou...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Óxido nítrico; Óxido nitroso; Fertilização nitrogenada; Plantas de cobertura; Irrigação; Cerrado.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2006000400020
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Forms of phosphorus in an oxisol under different soil tillage systems and cover plants in rotation with maize Rev. Bras. Ciênc. Solo
Carvalho,Arminda Moreira de; Bustamante,Mercedes Maria da Cunha; Almondes,Zayra Azeredo do Prado; Figueiredo,Cícero Célio de.
Phosphorus fractions play a key role in sustaining the productivity of acid-savanna Oxisols and are influenced by tillage practices. The aim of this study was to quantify different P forms in an Oxisol (Latossolo Vermelho-Amarelo) from the central savanna region of Brazil under management systems with cover crops in maize rotation. Three cover crops (Canavalia brasiliensis, Cajanus cajan (L.), and Raphanus sativus L.) were investigated in maize rotation systems. These cover crops were compared to spontaneous vegetation. The inorganic forms NaHCO3-iP and NaOH-iP represented more than half of the total P in the samples collected at the depth of 5-10 cm during the rainy season when the maize was grown. The concentration of inorganic P of greater availability...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Organic matter; Available phosphorus; Phosphorus sequential fractionation; Organic phosphorus; Inorganic phosphorus.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832014000300029
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Microbial communities in Cerrado soils under native vegetation subjected to prescribed fire and under pasture PAB
Viana,Laura Tillmann; Bustamante,Mercedes Maria da Cunha; Molina,Marirosa; Pinto,Alexandre de Siqueira; Kisselle,Keith; Zepp,Richard; Burke,Roger A.
The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerrado stricto sensu" and "campo sujo"), under different fire regimes, and a 20-year-old active palisadegrass pasture in the Central Plateau of Brazil. Microbial biomass was higher in the native plots than in the pasture, and the highest monthly values were observed during the rainy season in the native plots. No significant differences were observed between fire regimes or between communities from the two native vegetation types. However, the principal component (PC) analysis...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Land use; Microbial diversity; PLFA; Savannas; Seasonality.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2011001200012
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Nitrogen oxides and CO2 from an Oxisol cultivated with corn in succession to cover crops PAB
Carvalho,Arminda Moreira de; Bustamante,Mercedes Maria da Cunha; Coser,Thais Rodrigues; Marchão,Robélio Leandro; Malaquias,Juaci Vitória.
Abstract The objective of this work was to evaluate the effect of two legumes (Crotalaria juncea and Mucuna pruriens), as cover crops, and of natural fallow, as a control treatment, on the emissions of NOx, N2O, and CO2 from an Oxisol cultivated with corn, under conventional and no-tillage systems, in the Cerrado region, in Central Brazil. Variations of CO2 fluxes in the soil were explained mainly by soil humidity and, in the legumes, under conventional system, by soil NH4+-N concentration. Plots with legumes under no-tillage system had higher annual emissions of CO2, NOx, and N2O than natural fallow. Results show that the use of legumes as cover crops favors the emissions of NOx-N + N2O-N and CO2-C. However, when considering the potential for mitigation...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Crotalaria juncea; Mucuna pruriens; Carbon and nitrogen stocks; Cerrado; Mitigating greenhouse gases.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2016000901213
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Soil fertility status, carbon and nitrogen stocks under cover crops and tillage regimes Rev. Ciênc. Agron.
Carvalho,Arminda Moreira de; Marchão,Robélio Leandro; Souza,Kleberson Worslley; Bustamante,Mercedes Maria da Cunha.
The aim of the present study was to evaluate the effects of cover crops on the soil's chemical fertility, in particular its carbon and nitrogen content, in a Typic Acrustox under conventional and no-tillage corn systems. We hypothesized that the no-tillage system associates with cover crops maintains or increases soil carbon and nitrogen stocks and enhance soil fertility. The no-tillage system did not present higher carbon and nitrogen stocks than conventional tillage, but resulted in higher concentrations of exchangeable bases, higher CEC, and higher base saturation in the surface soil layer, mainly under use of Canavalia brasiliensis. Carbon and nitrogen stocks (up to 40 cm depth) differ significantly between the different cover crop species. The use of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brazilian Cerrado; No-tillage system; Ecological intensification; Low carbon agriculture.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000500007
Registros recuperados: 9
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