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| Registros recuperados: 38 | |
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| Mesquita,Geisa Lima; Zambrosi,Fernando César Bachiega; Cantarella,Heitor. |
| ABSTRACT We propose an approach for assessing the efficiency of coating materials on controlling nitrogen (N) availability to plants. It is based on the use of coated and soluble urea (UR) applied to corn over 3 growing cycles, as follows: coated UR with longevity of 2 (UR-2m) or 4 months (UR-4m) with application of 900 mg N∙pot−1 at the beginning of the experiment, soluble UR with a split application of 900 mg N∙pot−1 (300 mg N∙pot−1 per growing cycle, UR-3x), soluble UR with a sole application of 900 mg N∙pot−1 at the beginning of the experiment (UR-1x), and a control treatment. At the end of each growing cycle, shoots were harvested to estimate N provision by the UR by quantifying dry matter (DM) and N uptake. In the first cycle, UR-2m and UR-4m... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coating; Fertilizer efficiency; Nitrogen fertilizer; Nutrient uptake. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052017000200311 |
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| Gomes Junior, Francisco Guilhien; ESALQ - USP; Sá, Marco Eustáquio de; UNESP; Muraishi, Cid Tacaoca; UNESP. |
| A aplicação de N em cobertura é indispensável para a obtenção de altas produtividades do feijoeiro e estudos de respostas ao fertilizante em condições de semeadura direta e preparo convencional do solo ainda consistem numa necessidade fundamental. Assim, a pesquisa teve como objetivo avaliar o efeito da aplicação de N e a produtividade do feijoeiro em sistema de semeadura direta e de preparo convencional do solo. O delineamento experimental foi o de blocos casualizados em esquema fatorial (2x8+1) com quatro repetições. Os tratamentos constituíram-se da combinação das doses de 40 e 80 kg ha-1 de N aplicadas em oito épocas do estádio V4 do desenvolvimento vegetativo (V4-3, V4-4, V4-5, V4-6, V4-7, V4-8, V4-9 e V4-10), além da testemunha sem N em cobertura. O... |
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Palavras-chave: 5.01.03.05-9 Melhoramento Vegetal Phaseolus vulgaris L.; Cobertura morta; Adubo nitrogenado; Fenologia Phaseolus vulgaris L.; Mulching; Nitrogen fertilizer; Phenology. |
| Ano: 2008 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5967 |
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| Cantarella,Heitor; Trivelin,Paulo Cesar Ocheuze; Contin,Teodoro Leonardo Michelucci; Dias,Fábio Luis Ferreira; Rossetto,Raffaella; Marcelino,Rafael; Coimbra,Renato Badran; Quaggio,José Antonio. |
| Legal restrictions from burning sugarcane prior to harvest are causing a sharp increase in acreage which is harvested as green cane. The presence of a thick sugarcane trash mulch left after harvest makes it difficult to incorporate fertilisers in the soil. Since large losses of ammonia may occur when urea is surface applied to trash, it is important to find ways to improve urea-N use efficiency. The urease inhibitor NBPT slows down urea hydrolysis and thus may help decrease ammonia losses. Ammonia traps were set up in seven sugarcane fields covered with trash and fertilised with ammonium sulfate or ammonium nitrate, urea, and NBPT-treated urea. All N fertilisers were surface-applied at rates of 80 or 100 kg N ha-1. Very little N was lost when ammonium... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: NBPT; Nitrogen fertilizer; Ammonia losses. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162008000400011 |
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| Fontoura,Sandra Mara Vieira; Bayer,Cimélio. |
| Ammonia (NH3) volatilization can reduce the efficiency of urea applied to the surface of no-till (NT) soils. Thus, the objectives of this study were to evaluate the magnitude of NH3 losses from surface-applied urea and to determine if this loss justifies the urea incorporation in soil or its substitution for other N sources under the subtropical climatic conditions of South-Central region of Paraná State, Brazil. The experiment, performed over four harvesting seasons in a clayey Hapludox followed a randomized block design with four replicates. A single dose of N (150 kg ha-1) to V5 growth stage of corn cultivated under NT system was applied and seven treatments were evaluated, including surface-applied urea, ammonium sulfate, ammonium nitrate, urea with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen fertilizer; Urea; Corn; Urease. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000500020 |
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| Araújo,Juliano Ribeiro; Ramalho,Magno Antonio Patto; Bruzi,Adriano Teodoro; Abreu,Ângela de Fátima Barbosa. |
| The objective of this study was to verify the response of dry matter accumulation in bean lines (Phaseolus vulgaris L.) to different levels of nitrogen fertilizers. Six genotypes ('BRSMG Majestoso', 'Pérola', MA-I-18.13, 'Ouro Negro', 'BRSMG Talismã', and MA-I-2.5) were evaluated in Lavras, testing three N levels (0, 60, and 120 kg/ha) and using ammonium sulphate as N source. The experimental design adopted was the randomized block design in a 6 x 3 factorial structure with three replications and the plots were composed of five 5-m rows. The seeds were sown in November 2005 and July 2006. Total dry mass of five competitive plants was evaluated after 35 days from sowing, harvested from a pre-determined place in the useful area of the plots. This process was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen fertilizer; Phenology; Differential response; Phaseolus vulgaris. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542009000400007 |
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| Kering, Maru K.; Biermacher, Jon T.; Reuter, Ryan; Butler, Twain; Springer, Job D.; Rogers, James K.; Blanton, John, Jr.; Bouton, Joe H.; Guretzky, John A.. |
| Stocker cattle grazing warm season perennial grasses is an important economic activity in the southern Great Plains. Substantial increases in the price of nitrogen fertilizer is negatively affecting forage producers’ profitability. Two alternative nitrogen management systems that use annual and perennial legumes have been developed for bermudagrass pastures. The goal of the study is to determine if the legumes systems are more profitable than the conventional practice of applying synthetic sources of nitrogen. Results of the two-year grazing study show that the legume systems could not compete economically with the common practice. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Economics; Grazing; Legumes; Bermudagrass; Nitrogen fertilizer; Stocker cattle; Crop Production/Industries; Farm Management; Production Economics. |
| Ano: 2010 |
URL: http://purl.umn.edu/56525 |
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| Oliveira Filho,Jair da C.; Oliveira,Rubens A. de; Oliveira,Ednaldo M. de; Cecon,Paulo R.; Martins,Carlos E.. |
| The objective of this study was to evaluate the effects of the application of different water depths and nitrogen and potassium doses in the quality of Tanzania grass, in the southern of the state of Tocantins. The experiment was conducted on strips of traditional sprinklers, and used, as treatments, a mixture of fertilizer combinations of N and K2O always in the ratio of 1 N:0.8 K2O. This study determined throughout the experiment: plant height (PH), the crude protein (CP) and neutral detergent fiber (NDF). The highest plant height obtained was 132.4 cm, with a fertilizer dose of 691.71 kg ha-1 in the proportion of N:0.8 K2O, in other words, 384.28 kg ha-1 of N and 307.43 kg ha-1 of K2O, and water depth of 80% of the ETc. The highest crude protein content... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Nitrogen fertilizer; Irrigated pasture; Panicum maximum. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000400007 |
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| ELHAKEM,A.H.; ABD EL-SALAM,M.M.. |
| ABSTRACT: This study evaluates the effect of urea on growth of herbicide-treated maize and its accumulation in the soil. When the seedlings were 15 days old, the plots were divided into five groups. One group served as control, two received treatments with metolachlor and isoproturon at the dose of 1.5 kg ha-1 and 2.5 L ha-1, respectively. The two remaining groups received the same dose of herbicide along with urea added at a rate of 129 kg ha-1. The application of the two herbicides appeared to cause a significant decrease in shoot dry weight, photosynthetic pigments, d-aminolevulinate dehydratase enzyme [ALA-D, EC 4.2.1.24] and total soluble carbohydrates of the maize plants. The application of urea appeared to alleviate the effects of both herbicides on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Maize; Soil accumulation; Nitrogen fertilizer. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582018000100308 |
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| Lopes,Marcos Neves; Pompeu,Roberto Cláudio Fernandes Franco; Cândido,Magno José Duarte; Lacerda,Claudivan Feitosa de; Silva,Rodrigo Gregório da; Fernandes,Francisco Ronaldo Belem. |
| This study aimed to evaluate the growth index of massai grass during two regrowth cycles in a greenhouse under five levels of nitrogen (0, 150, 300, 450 and 600 mg N/dm³ of soil) and eight growth ages (5, 8, 11, 14, 17, 20, 23 and 26 days) in a split-plot design with five replications. The following variables were evaluated: net assimilation rate, herbage growth rate, relative growth rate, leaf area ratio, leaf weight ratio and specific leaf area. The effect of nitrogen was detected on the variables net assimilation rate (regrowths 1 and 2), leaf area ratio (regrowth 1), leaf weight ratio (regrowths 1 and 2), specific leaf area (regrowths 1 and 2) and herbage growth rate (regrowths 1 and 2). The growth ages influenced the relative growth rate (regrowth 2)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbage growth; Net assimilation rate; Nitrogen fertilizer; Panicum maximum × Panicum infestum. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982011001200008 |
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| Kim, C.S.; Hallahan, Charles B.; Taylor, Harold; Schluter, Gerald E.. |
| This article examines the effects of increasing market concentration level in the U.S. nitrogen fertilizer industry. Results indicate that the costs of market power are greater than the benefits of market concentration, in terms of manufacturing cost efficiency. To provide a stable nitrogen fertilizer supply at a relatively low price, it may be necessary to control natural gas price and/or reduce new import barriers from Middle East and former member states of the Soviet Union, where low cost gas is produced as a byproduct. Keywords: Nitrogen fertilizer, oligopoly, economies of size, market power, cost-efficiency. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Nitrogen fertilizer; Oligopoly; Economies of size; Market power; Cost-efficiency.; Marketing. |
| Ano: 2002 |
URL: http://purl.umn.edu/19674 |
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| Reis,Andre Rodrigues; Favarin,José Laércio; Gallo,Luiz Antônio; Malavolta,Eurípedes; Moraes,Milton Ferreira; Lavres Junior,José. |
| Nitrate reductase is the first enzyme in the pathway of nitrate reduction by plants, followed by glutamine synthetase, which incorporates ammonia to glutamine. The purpose of this study was to evaluate the nitrate reductase and glutamine synthetase activity, total soluble protein content, N and Ni content in coffee leaves during fruit development under field conditions to establish new informations to help assess the N nutritional status and fertilizer management. The experimental design was in randomized complete blocks, arranged in a 3 x 6 factorial design, with five replications. The treatments consisted of 3 N rates (0 - control, 150 and 300 kg ha-1) and six evaluation periods (January, February, March, April, May, and June) in six-year-old coffee... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica; Nitrogen assimilating enzymes; Nitrogen fertilizer. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000200009 |
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| Gomes Junior, Francisco Guilhien; ESALQ/USP; Sá, Marcos Eustáquio de; FAE/UNESP; Valério Filho, Walter Veriano; FAE/UNESP. |
| O adequado suprimento de N é primordial para se obter alta produtividade de sementes de feijão, entretanto, as respostas a esse nutriente, em sistema de plantio direto, podem variar em função da espécie e quantidade de palha. O objetivo do trabalho foi avaliar a resposta do feijoeiro à aplicação de N, em sistema de plantio direto, sobre palhada de milho, milheto e braquiária. Foram realizados três experimentos, um para cada espécie de gramínea. O delineamento experimental foi o de blocos casualizados disposto em esquema fatorial 5x2x2, correspondente a cinco doses de N (0, 30, 60, 90, 120 kg ha-1) aplicadas em duas épocas da fase vegetativa (3ª e 6ª folha trifoliolada) e duas cultivares (IPR Juriti e Pérola), com quatro repetições. A cultivar IPR Juriti... |
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Palavras-chave: 5.01.00.00-9 Agronomia Phaseolus vulgaris L.; Palhada adubação nitrogenada; Fenologia; Rendimento de sementes 5.01.03.00-8 Fitotecnia Phaseolus vulgaris L.; Mulching; Nitrogen fertilizer; Phenology; Seed yield. |
| Ano: 2008 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/3549 |
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| Teixeira, Cícero Monti; Empresa de Pesquisa Agropecuária de Minas Gerais; Carvalho, Gabriel José de; Universidade Federal de Lavras; Silva, Carlos Alberto; Universidade Federal de Lavras; Andrade, Messias José Bastos de; Universidade Federal de Lavras; Paes, José Mauro Valente; Empresa de Pesquisa Agropecuária de Minas Gerais. |
| O objetivo foi avaliar o efeito das palhadas de milheto (Pennisetum typhoides (Burm.) Stapf) e milheto + feijão-de-porco (Canavalia ensiformes (L.) DC.) e diferentes doses de nitrogênio, na nutrição mineral do feijoeiro. O delineamento foi em blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas, em Latossolo Vermelho, em plantio direto. As parcelas foram constituídas pelas palhadas e as subparcelas por um fatorial 2 x 4 + 1, representado por duas doses de N na semeadura (30 e 60 kg ha-1) e quatro em cobertura (0, 40, 80 e 120 kg ha-1), mais um tratamento adicional, correspondente a 30 kg ha-1 de N na semeadura, sem cobertura, com inoculação das sementes com Rhizobium tropici e aplicação foliar de Co e Mo. A palhada de milheto +... |
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Palavras-chave: 5.01.00.00-9 plantas de cobertura; Sistema plantio direto; Consórcio gramínea x leguminosa; Adubação nitrogenada; Fixação biológica de nitrogênio 5.01.01.03-0 cover crops; No-till; Grassy x leguminous intercropping; Nitrogen fertilizer; Biology nitrogen fixation. |
| Ano: 2010 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/4392 |
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| Registros recuperados: 38 | |
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