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| Registros recuperados: 14 | |
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| Cancellier,Eduardo Lopes; Silva,Douglas Ramos Guelfi; Faquin,Valdemar; Gonçalves,Bruno de Almeida; Cancellier,Leandro Lopes; Spehar,Carlos Roberto. |
| ABSTRACT High nitrogen losses by ammonia volatilization are expected when urea is used as the source of N. The use of controlled-release urea and urease inhibitors are possible strategies to reduce such losses and increase nitrogen use efficiency. This study aimed to evaluate nitrogen losses by ammonia volatilization from stabilized, slow and controlled release urea and its absorption by maize grown under no-till in an improved Cerrado soil. Four N sources were used: conventional urea, urea + N-(n-butyl) thiophosphoric triamide (NBPT), urea + Cu and B and urea coated by sulfur + polymers. These N sources were surface applied along the rows using three N doses of 100, 150 and 200 kg ha-1. No N was added to the control. Data were collected regarding N losses... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen fertilizers; NH3-N losses; Polymer sulfur coated urea; Urease inhibitors; Zea mays L. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542016000200133 |
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| Dominghetti,Anderson William; Guelfi,Douglas Ramos; Guimarães,Rubens José; Caputo,André Luiz Carvalho; Spehar,Carlos Roberto; Faquin,Valdemar. |
| ABSTRACT Ammonia volatilization (N-NH3) is one of the main pathways of Nitrogen loss reducing nitrogen use efficiency in coffee orchard. This work aimed at quantifying ammonia volatilization (N-NH3) losses from N-sources to be used in coffee plantations fertilization in Brazil. The experiment was conducted in the field on a dystrophic red latosol (Ferralsol in FAO's classification) at the Coffee Research Sector, University of Lavras, MG, Brazil. The experimental design was of complete randomized blocks with three repetitions of the following treatments: conventional urea, ammonium nitrate and urea + 0.15% Cu and 0.4% B, urea + anionic polymers, urea + elementary sulfur (S0) + polymers, and urea + plastic resin. These N sources were split into three doses... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffee arabica; Slow and controlled release and stabilized fertilizers; Ammonium nitrate; Urea. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542016000200173 |
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| Silva,José Antonio da; Pompeu,Dávia Guimarães; Costa,Olavo Flores da; Gonçalves,Daniel Bonoto; Spehar,Carlos Roberto; Marangoni,Sérgio; Granjeiro,Paulo Afonso. |
| Chenopodium quinoa seeds have high protein content. The nutritional value of quinoa is superior compared with traditional cereals. Its essential amino acid composition is considered next to the ideal, and its quality matches that of milk proteins. In this study, the seed storage proteins from Chenopodium quinoa were extracted, fractionated, partially purified, and characterized. The structural characterization was performed by Tricine-SDS-PAGE and two-dimensional electrophoresis, and it confirmed the presence of proteins of molecular weight of 30 and 7kDa, probably corresponding to lectins and trypsin inhibitors, respectively. The functional characterization of these proteins evidenced their activity as antinutritional factors due to their in vitro... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chenopodium quinoa; Seeds; Lectins; Protease inhibitor; In vitro digestibility. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612015000100074 |
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| Teixeira,Danielly Leite; Spehar,Carlos Roberto; Souza,Luiz Augusto Copati. |
| O objetivo deste trabalho foi caracterizar e avaliar 48 acessos de três espécies de amaranto (Amaranthus caudatus L., A. cruentus L.,e A. hypochondriacus L.) para cultivo na entressafra no Cerrado. Realizou-se seleção preliminar para sete descritores, em casa de vegetação, e os acessos com genótipos promissores foram selecionados para serem testados no campo. O delineamento experimental usado foi o de blocos casualizados, com três repetições. O material utilizado foi o que apresentou características agronômicas desejáveis, tais como ausência de espinhos, hábito ereto e presença de inflorescência. Os ensaios foram realizados em Planaltina, DF, na entressafra, com irrigação, por dois anos. Em geral, os acessos floresceram 45 dias após a emergência e as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amaranthus caudatus; Amaranthus cruentus; Amaranthus hypochondriacus; Plantio direto; Adaptação; Característica agronômica. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000100006 |
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| Spehar,Carlos Roberto; Teixeira,Danielly Leite; Cabezas,Waldo Alejandro Rúben Lara; Erasmo,Eduardo Andrea Lemus. |
| A diversificação do sistema produtivo depende de espécies com rápido crescimento, tolerância ao déficit hídrico, produção de biomassa, ciclagem de nutrientes e utilização humana e animal. As espécies Amaranthus caudatus, A. cruentus e A. hypochondriacus apresentam essas características e sementes claras, sem dormência. Distinguem-se das invasoras A. spinosus, A. hybridus, A. blitum e A. viridis, com sementes escuras e dormentes. Os grãos, com excelente qualidade protéica, atendem à demanda por dietas especiais, livres de glúten e podem ser usados na alimentação animal. O A. cruentus BRS Alegria, primeira recomendação ao cultivo granífero no Brasil, originou-se da variedade AM 5189, dos Estados Unidos, na qual realizou-se seleção massal. Em sucessão à soja,... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000500015 |
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| Santos,Roberto Lorena de Barros; Spehar,Carlos Roberto; Vivaldi,Lucio. |
| The quinoa (Chenopodium quinoa Willd.) cultivation, one of the most promising in double cropping with soybeans or maize, depends on weed control. The objective of this work was to evaluate quinoa reaction to herbicide residue in a savannah soil. Six herbicide treatments, trifluralin, pendimethalin, clomazone, imazaquin, trifluralin + imazaquin and control, were applied, prior to summer cultivation of soybean, in a Dark-Red Latosol (typic Haplustox). Soybean cultivar BR 9 Savana was grown and soil samples were collected at 15, 38, 100, 145 and 206 days after treatment and stored at -5ºC. Bioassays were conducted in greenhouse, using quinoa, cultivar Q18. Imazaquin was the most harmful to quinoa seedlings, up to 206 days after application, followed by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chenopod; Weed control; Toxicity; Yields. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000600014 |
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| Marchi,Giuliano; Guelfi-Silva,Douglas Ramos; Malaquias,Juaci Vitória; Guilherme,Luiz Roberto Guimarães; Spehar,Carlos Roberto; Martins,Eder de Souza. |
| Abstract: The objective of this work was to evaluate the solubility of the micronutrients copper, nickel, and zinc, chemically extracted from silicate agrominerals, as alternative sources of potassium for lettuce (Lactuca sativa) and rice (Oryza sativa) cultures, as well as their availability to the plants. The micronutrient contents of five agrominerals (alkaline ultramafic, biotite schist, volcanic breccia, phlogopite schist, and mining by-product from Chapada) were evaluated, after being extracted by the citric acid, hydrochloric acid, diethylenetriaminepentaacetic acid, 3051A, neutral ammonium citrate, and Mehlich-3 methods. The agrominerals, at the doses of 0 (control), 200, 400, and 600 kg ha-1 K, were mixed to soil where lettuce and rice were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Copper; Mining by-product; Nickel; Nutrient availability; Zinc. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2020000100600 |
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| Spehar,Carlos Roberto; Santos,Roberto Lorena de Barros. |
| A diversificação da agricultura possibilita implementar a renda, reduzir custos, disponibilizar nutrientes, proteger o solo, reduzir impacto ambiental negativo e ofertar alimentos. A quinoa (Chenopodium quinoa Willd.), uma Chenopodiaceae originária dos Andes, destaca-se por tolerância à seca, elevada qualidade da proteína, baixo colesterol, ausência de glúten (útil a pacientes celíacos), e uso na alimentação animal. A espécie apresenta diversidade, com ciclo variável entre 80 e 150 dias no Brasil central. Os frutos, do tipo aquênio, são pequenos, achatados e sem dormência. BRS Piabiru, primeira recomendação de quinoa ao cultivo no Brasil, originou-se da linhagem EC 3, selecionada em uma população procedente de Quito, Equador. Após dois anos de ensaios, foi... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2002000600020 |
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| Souza,Luiz Augusto Copati; Spehar,Carlos Roberto; Santos,Roberto Lorena Bastos. |
| Um grupo de sementes lavadas e 35 acessos de quinoa (Chenopodium quinoa Willd) foram avaliados pelo método de coluna de espuma e sua coloração foi decomposta pelo modelo RGB (R, vermelho; G, verde; B, azul) com o objetivo de avaliar a influência do teor de saponina na cor do grão. Sementes amarelas apresentaram alto teor de saponina. Houve correlação negativa (p£0,05) entre o teste de coluna de espuma e as bandas R (r = -0,751), G (r = -0,660) e B (r = -0,594). Estabeleceram-se quatro grupos de similaridade. Foram considerados amargos os acessos do grupo 4 (sementes amarelas) e doces os acessos do grupo 1 (sementes brancas). A dispersão observada representa provável diferença na freqüência gênica, refletida pela cor e teor de saponina. |
| Tipo: Info:eu-repo/semantics/report |
Palavras-chave: RGB; Genótipo; Glicosídeo; Correlação; Análise multivariada. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2004000400014 |
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| Spehar,Carlos Roberto. |
| High available aluminium and low levels of calcium below the ploughed zone of the soil are limiting factors for agricultural sustainability in the Brazilian Cerrados (Savannahs). The mineral stresses compound with dry spells effect by preventing deep root growth of cultivated plants and causes yield instability. The mode of inheritance for grain yield and mineral absorption ratio of a diallel cross in soybeans [Glycine max (L.) Merrill] grown in high and low Al areas was identified. Differences among the genotypes for grain yield were more evident in the high Al, by grouping tolerant and non-tolerant genotypes for their respective arrays in the hybrids. A large proportion of genetic variance was additive for grain yield and mineral absorption ratio in both... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aluminium; Calcium; Cultivar; Additive; Dominance; Breeding. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X1999000600011 |
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| Spehar,Carlos Roberto; Santos,Roberto Lorena de Barros. |
| Twenty six breeding lines, selected from individual plant progenies of hybrids among varieties Amarilla de Marangani, Blanca de Junín, Chewecca, Faro 4, Improved Baer, Kancolla, Real, and Salares-Roja, had their agronomic characters evaluated, in Planaltina, DF, Brazil (15º36'S and 47º12'W), 1,000 masl, in randomized complete blocks, on a Ferralsol, previously limed and fertilized. Grain yield was positively associated with plant height, inflorescence length and diameter, and plant cycle. Genetic gain can be attained by selection based in these characters for commercial production of quinoa in tropical regions. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chenopodium quinoa; Breeding line; Selection; Yield; Cerrado. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2005000600012 |
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| Silva,Douglas Ramos Guelfi; Marchi,Giuliano; Spehar,Carlos Roberto; Guilherme,Luiz Roberto Guimarães; Rein,Thomaz Adolpho; Soares,Danilo Araújo; Ávila,Fabrício William. |
| The expansion of Brazilian agriculture has led to a heavy dependence on imported fertilizers to ensure the supply of the growing food demand. This fact has contributed to a growing interest in alternative nutrient sources, such as ground silicate rocks. It is necessary, however, to know the potential of nutrient release and changes these materials can cause in soils. The purpose of this study was to characterize six silicate rocks and evaluate their effects on the chemical properties of treated soil, assessed by chemical extractants after greenhouse incubation. The experimental design consisted of completely randomized plots, in a 3 x 6 factorial scheme, with four replications. The factors were potassium levels (0-control: without silicate rock... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Multi-nutrient fertilizer; Nutrient available; Potassic rock; Rock powder; Soil amendment. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832012000300025 |
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| Guelfi-Silva,Douglas Ramos; Marchi,Giuliano; Spehar,Carlos Roberto; Guilherme,Luiz Roberto Guimarães; Faquin,Valdemar. |
| The aim of this study was to evaluate the effect of alternative sources of nutrients on the nutrition, yield and efficiency of potassium fertilization in lettuce. The experiment was carried out in a greenhouse, using 3.7 kg pots filled with a dystrophic red-yellow Latosol of medium texture. The experimental design was randomized, with treatments divided into a 4 x 6 factorial: four doses of potassium (0; 200; 400; 600 kg ha-1 K2O) and six alternative sources of nutrients (breccia, ultramafic, biotite schist, phlogopite, and mining and Chapada by-products), with four replications. Content and accumulation were determined for potassium (K), copper (Cu), zinc (Zn) and nickel (Ni) in the lettuce shoots, and from these data two indices were calculated for the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lactuca sativa L; Silicate rocks; Mining by-products. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902013000200008 |
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| Registros recuperados: 14 | |
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