Consulta: creatorFacets:"Bendassolli,José Albertino"
Registros recuperados: 10
Data/hora: 02/06/2024 09:42:02

Perdas do nitrogênio da uréia no sistema solo-planta em dois ciclos de cana-de-açúcar
Provedor de dados: 86
Autores: Trivelin,Paulo Cesar Ocheuze; Oliveira,Mauro Wagner de; Vitti,André Cesar; Gava,Glauber José de Castro; Bendassolli,José Albertino.
O objetivo deste trabalho foi quantificar as perdas de N do sistema solo-cana-de-açúcar, nos ciclos de cana-planta e de cana-soca. Desenvolveram-se dois experimentos em vasos de 220 L, contendo solo de classe textural arenosa. Os fatores de estudo do experimento com cana-planta foram dois tipos de restos culturais incorporados ao solo e quatro doses de N no plantio. No experimento com cana-soca, estudaram-se duas formas de aplicação da uréia em superfície: sobre a palha ou sobre o solo descoberto, ou na profundidade de 15 cm, e duas fontes de K: KCl ou vinhaça. Utilizou-se uréia marcada com 15N. O delineamento experimental foi o de blocos ao acaso, com três repetições. Em cana-planta, as perdas foram de 12% do N-uréia (recuperação de 88%), que ocorreram,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Desnitrificação; Perdas de nitrogênio pelas folhas; Balanço de 15N.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002000200011

Isotope determination of sulfur by mass spectrometry in soil samples
Provedor de dados: 90
Autores: Rossete,Alexssandra Luiza Rodrigues Molina; Carneiro,Josiane Meire Toloti; Sant Ana Filho,Carlos Roberto; Bendassolli,José Albertino.
Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S) with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS) in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-)), which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2-) concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sample preparation; Soil samples; Isotopic dilution; Labeled material; Stable isotope; 34S.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000600012

Organic sulfur oxidation to sulfate in soil samples for total sulfur determination by turbidimetry
Provedor de dados: 90
Autores: Rossete,Alexssandra Luiza Rodrigues Molina; Bendassolli,José Albertino; Trivelin,Paulo Cesar Ocheuze.
Sulfur in the soil occurs in two basic forms, organic and inorganic S. The organic form accounts for 95 % of S in most soils. The effectiveness of organic S to oxidate to sulfate was evaluated for total S determination in soil samples by wet (acid) and dry-ash (alkaline) oxidation methods. To evaluate the wet method and the possible use as a reference when evaluating the dry method proposed here, a reference standard from the US National Institute of Standards and Technology (NIST) was used (Montana Soil - NIST 2710). The dry-ash oxidation process with alkaline oxidizing agents is one of the simplest oxidation methods of organic S to the sulfate form and was compared with the wet process. The objective of the study was to develop a dry method that would be...
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Sample preparation; Turbidimetric method; Spectrophotometry.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000600031

Nitrogen-15 labeling of Crotalaria juncea green manure
Provedor de dados: 63
Autores: Ambrosano,Edmilson José; Trivelin,Paulo Cesar Ocheuze; Cantarella,Heitor; Rossetto,Raffaella; Muraoka,Takashi; Bendassolli,José Albertino; Ambrosano,Gláucia Maria Bovi; Tamiso,Luciano Grassi; Vieira,Felipe de Campos; Prada Neto,Ithamar.
Most studies dealing with the utilization of 15N labeled plant material do not present details about the labeling technique. This is especially relevant for legume species since biological nitrogen fixation difficults plant enrichment. A technique was developed for labeling leguminous plant tissue with 15N to obtain labeled material for nitrogen dynamics studies. Sun hemp (Crotalaria juncea L.) was grown on a Paleudalf, under field conditions. An amount of 58.32 g of urea with 70.57 ± 0.04 atom % 15N was sprayed three times on plants grown on eight 6-m²-plots. The labelled material presented 2.412 atom % 15N in a total dry matter equivalent to 9 Mg ha-1 This degree of enrichment enables the use of the green manure in pot or field experiments requiring...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: 15N -fertilizer; Labeled legumes; Green manure.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000100027

Production of 34S-labeled gypsum (Ca34SO4.2H2O)
Provedor de dados: 63
Autores: Rossete,Alexssandra Luiza Rodrigues Molina; Bendassolli,José Albertino; Máximo,Everaldo; Sant Ana Filho,Carlos Roberto; Ignoto,Raquel de Fátima de.
Agricultural gypsum (CaSO4.2H2O) stands out as an effective source of calcium and sulfur, and to control aluminum saturation in the soil. Labeled as 34S it can elucidate important aspects of the sulfur cycle. Ca34SO4.2H2O was obtained by chemical reaction between Ca(OH)2 and H2(34)SO4, performed under slow agitation. The acid was produced by ion exchange chromatography using the Dowex 50WX8 cation exchange resin and a Na2(34)SO4 eluting solution. After precipitation, the precipitate was separated and dried in a ventilated oven at 60ºC. From 2.2 L H2SO4 0.2 mol L-1 and 33.6 g Ca(OH)2, 73.7 ± 0.6 g Ca34SO4.2H2O were produced on average in the tests, representing a mean yield of 94.6 ± 0.8%, with 98% purity. The 34SO2 gas was obtained from Ca34SO4.2H2O in the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sulfur 34; Stable isotope; Isotopic determination.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162006000400012

Sulfur utilization by rice and Crotalaria juncea from sulfate - 34S applied to the soil
Provedor de dados: 63
Autores: Trivelin,Paulo Cesar Ocheuze; Bendassolli,José Albertino; Muraoka,Takashi; Carneiro Jr.,Francisco.
In tropical soils with intensive agriculture an increasing sulfur deficiency has been verified in several crops. The low available S in these soils is caused by the continuous use of concentrated NPK fertilizers. The objective of this work was to evaluate the utilization by rice (Oriza sativa L.) and crotalaria juncea (Crotalaria juncea L.) of sulfur applied to the soil, under greenhouse conditions. Pots with 3 kg of an Argisol (Paleudalf) were used to test the isotopic technique with the stable isotope 34S, adding a solution of sodium sulfate labeled with 34S (14.30 ± 0.05 atom % of 34S) to the soil (70 mg SO4-S per kg-1 of soil) 18 days after sowing both species. The shoots of the crotalaria and rice were harvested, respectively on the 72nd and 122nd...
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Stable isotope; 34S technique; Mass spectrometry; Sulfur uptake.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000100030

15N-labeled glyphosate synthesis and its practical effectiveness
Provedor de dados: 63
Autores: Tavares,Claudinéia Raquel de Oliveira; Bendassolli,José Albertino; Ribeiro,Daniela Neves; Rossete,Alexssandra Luiza Rodrigues Molina.
Glyphosate is the herbicide with the greatest participation in the world market, and it has been used intensively in agriculture for over 30 years, especially because of its relatively low cost and high effectiveness on different species. This study describes a synthesis method of glyphosate in the form of the isopropylamine salt enriched in the stable nitrogen isotope (15N). The 15N-herbicide synthesis was performed using a phosphomethylation reaction with dialkyl phosphite and 15N-glycine. The tests were conducted at a microscale and equimolar quantities. A 20% yield was obtained at the established conditions. To test the effectiveness of the synthesized glyphosate, an experiment was performed in a growth chamber with the weed Lolium multiflorum...
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Lolium multiflorum; Isopropylamine salt; Stable isotope.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000100014

Production of single superphosphate labeled with 34S
Provedor de dados: 63
Autores: Rossete,Alexssandra Luiza Rodrigues Molina; Carneiro,Josiane Meire Toloti; Bendassolli,José Albertino; Tavares,Claudineia Raquel Oliveira; Sant'Ana Filho,Carlos Roberto.
Single superphosphate is currently one of the mostly used fertilizers as an alternative source for phosphorus and sulphur. Sulphur presents four stable isotopes (32S, 33S, 34S, and 36S) with natural abundances of 95.00; 0.76; 4.22; and 0.014% in atoms, respectively. Single superphosphate labeled with the 34S isotope was obtained from a chemical reaction in stoichiometric amounts between Ca(H2PO4)2 and Ca34SO4.2H2O. Calcium sulphate (Ca34SO4.2H2O) was enriched with 5.85 ± 0.01 atoms % of 34S. The Ca(H2PO4)2 reagent was obtained from a reaction between CaCl2.2H2O and H3PO4. The reaction between the Ca(H2PO4)2 thus produced and the labeled Ca34SO4.2H2O compound was then performed to obtain the 34S-labeled single surperphosphate. The thermal decomposition of...
Palavras-chave: Isotopic determinations; Sulphur; Stable isotopes; Mass spectrometry; Labeled compounds.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162008000100013

Produção de amônia anidra e aquamônia enriquecida em 15N a partir de (15NH4)2SO4
Provedor de dados: 63
Autores: Bendassolli,José Albertino; Trivelin,Paulo Cesar Ocheuze; Ignoto,Raquel de Fátima.
No Brasil, a aquamônia vem sendo utilizada como fertilizante nitrogenado, especialmente na cultura de cana de açúcar. Entre os fatores que influenciam a produtividade das culturas agrícolas, está a eficiência de utilização de fertilizantes nitrogenados (EUF), sendo a técnica isotópica com 15N empregada em investigações dessa natureza. Este trabalho procurou estabelecer métodos de produção de amônia anidra (15NH3) e aquosa (15NH3aq), enriquecidas em 15N, em um único sistema, a partir do sulfato de amônio previamente enriquecido no mesmo isótopo. O processo de produção de 15NH3 e 15NH3aq foi avaliado em função dos fatores: temperatura (60, 70 e 75ºC) e tempo de reação (90, 120, 150, 165, 210 e 255 minutos), fluxo de gás de arraste (140; 180 e 220 mL min-1 de...
Tipo: Info:eu-repo/semantics/report
Palavras-chave: Amônia-15N; Nitrogênio-15; Isótopo estável.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162002000300028

Dinâmica do ecótono floresta-campo no sul do estado do Amazonas no Holoceno, através de estudos isotópicos e fitossociológicos
Provedor de dados: 36
Autores: Vidotto,Elaine; Pessenda,Luiz Carlos Ruiz; Ribeiro,Adauto de Souza; Freitas,Hermes Augusto de; Bendassolli,José Albertino.
Com o emprego dos isótopos do carbono (12C, 13C, 14C) da matéria orgânica do solo (MOS) e das plantas, é apresentado um estudo comparativo entre perfis orgânicos de solos formados em depressões de áreas cobertas por ecossistemas de campos e florestas ao sul do estado do Amazonas, visando o entendimento da dinâmica da paleovegetação. A dinâmica da vegetação atual na região foi avaliada utilizando-se estudos fitossociológicos e caracterizações botânica e isotópica (delta13C) das espécies de plantas presentes em duas bordas floresta-campo. Teores de carbono orgânico total foram superiores nas camadas superficiais no campo, quando comparados com a floresta. Dados de delta13C associados à cronologia do 14C indicaram predomínio de plantas C3 no início do...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Isótopos do carbono; Dinâmica de vegetação; Holoceno; Fitossociologia; Amazônia.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672007000300010