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| Registros recuperados: 13 | |
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| Nguyen, Hai Yen; Hua, Bach-lien; Schopp, Richard; Carton, Xavier. |
| This work addresses the linear dynamics underlying the formation of density interfaces at the periphery of energetic vortices, well outside the vortex core, both in the radial and axial directions. We compute numerically the unstable modes of an anticyclonic Gaussian vortex lens in a continuously stratified rotating fluid. The most unstable mode is a slow mode, associated with a critical layer instability located at the vortex periphery. Although the most unstable disturbance has a characteristic vertical scale which is comparable to the vortex height, interestingly, the critical levels of the successively fastest growing modes are closely spaced at intervals along the axial direction that are much smaller than the vortex height. |
| Tipo: Text |
Palavras-chave: Quasigeostrophic model; Vortices; Stratified flow; Critical level; Flow instability. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00074/18520/16331.pdf |
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| Deus,José Aridiano Lima de; Neves,Júlio César Lima; Soares,Ismail; Alvarez V.,Víctor Hugo; Albuquerque,Fabricio Martinazzo Regis de; Santos,Lauana Lopes dos; Natale,William. |
| ABSTRACT: In banana cultivation, fertilization recommendations are almost exclusively based on soil chemical analysis, without considering leaf analysis and expected yield, which can help in the adjustment of fertilization programs. The aim of this study was to develop a method to recommend macronutrient fertilization rates which integrates data on leaf analysis, soil chemical analysis, and yield. Yield, soil chemical analysis, and leaf analysis data of fertigated plantations of ‘Prata’ banana were obtained for the first and second halves of the years from 2010 to 2015. Yield was correlated with soil organic matter (SOM) and soil contents of macronutrients (P, K, Ca, and Mg) to obtain the critical level (CLNui). Then, leaf nutrient contents were plotted on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Musa spp.; Nutrient; Critical level; Boundary line; Yield. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100532 |
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| Orioli Júnior,Valdeci; Coutinho,Edson Luiz Mendes. |
| The current high price of KCl and great dependence on importation to satisfy the Brazilian demand indicate the need for studies that evaluate the efficiency of other K sources, particularly those based on domestic raw material. For this purpose, a greenhouse experiment was conducted with samples of a sandy clay loam Typic Haplustox, in a completely randomized 4 x 3 x 2 factorial design: four K rates (0, 60, 120, and 180 mg kg-1), three sources (potassium chloride (KCl), fused magnesium potassium phosphate (FMPP) and a mixture of 70 % FMPP + 30 % KCl) and two particle sizes (100 and 60 mesh), with three replications. Potassium fertilization resulted in significant increases in shoot dry matter production and in K concentrations, both in soil and plants. The... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brachiaria brizantha; Particle size; Critical level. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832009000600034 |
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| Reis,Josimar Vieira dos; Alvarez,Víctor Hugo V.; Durigan,Renan Dinardi; Paulucio,Rodrigo Bazzarella; Cantarutti,Reinaldo Bertola. |
| ABSTRACT Increasingly rational use of phosphate fertilizers by agriculture is important, especially in Brazil, due to its importance for global food security and its high dependence on phosphate fertilizers for crop production. Thus, correlation and calibration researches with soil available phosphorus (P) extractants to improve the recommendation and the use of P are extremely important. Our objectives were (i) to determine soil P recovery rates and critical levels by the extractants Mehlich-1 (M1), Mehlich-3 (M3), and Ion Exchange Resin (RTI); (ii) to adjust predictive models of P recovery rates and critical levels for each extractant, as a function of soil properties related to the soil P buffer capacity, and (iii) to adjust the an interpretation table... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Critical level; Recovery rates; Methods of soil analysis. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832020000100504 |
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| Wadt,Paulo Guilherme Salvador. |
| Farm planning requires an assessment of the soil class. Research suggest that the Diagnosis and Recommendation Integrated System (DRIS) has the capacity to evaluate the nutritional status of coffee plantations, regardless of environmental conditions. Additionally, the use of DRIS could reduce the costs for farm planning. This study evaluated the relationship between the soil class and nutritional status of coffee plants (Coffea canephora Pierre) using the Critical Level (CL) and DRIS methods, based on two multivariate statistical methods (discriminant and multidimensional scaling analyses). During three consecutive years, yield and foliar concentration of nutrients (N, P, K, Ca, Mg, S, B, Zn, Mn, Fe and Cu) were obtained from coffee plantations cultivated... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: DRIS; Critical level; Plant nutrition; Nutritional diagnosis; Soil classification; Oxisol; Coffea canephora. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832005000200008 |
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| Vieira,Renan Costa Beber; Fontoura,Sandra Mara Vieira; Bayer,Cimélio; Moraes,Renato Paulo de; Carniel,Eduardo. |
| ABSTRACT Fertilization programs for annual crops in the state of Paraná, southern Brazil, are based on studies that focused on conventional tillage and were established more than 30 years ago. The primary purpose of this study was to assess potassium (K) fertilization on long-term (>30 years) no-tillage soybean, corn, wheat, and barley crops grown in rotation on Oxisols in the central-southern region of Paraná. A total of 47 experiments were carried out from 2008 to 2013, three of which addressed K calibration and the other 44, crop response to K fertilization. Critical K soil-test value and interpretation classes were established from the ratio between relative crop yield [RY = (yield without K/max yield) × 100] and soil K levels. Winter cereals were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calibration; Critical level; Mehlich-1. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100538 |
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| Giongo,Vanderlise; Salviano,Alessandra M.; Santos,Betina R. C. dos; Leal,Emylly F.. |
| Phosphorus (P) plays an important role in the growth of root system as well as the tillering grass, being fundamental to increase the productivity of these species. The aim of this study was to evaluate the development of buffel grass cultivars and establish critical values of P in plant and soil. The experimental set up was a 4 x 5 factorial scheme (four Cenchrus ciliaris cvs.: Biloela, Aridus, CPATSA 7754 and Pusa Giant, and five doses of P2O5 - 0, 30, 60, 90 and 120 kg ha-1) with four replications. After 90 days of cultivation, dry mass of shoot (DMS) and root (DMR) production and the P accumulation (Pacc) were determined. Soil samples to determine the P content and determination of the critical level (CriLev) were also collected. The cv. Biloela... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Critical level; Root system; Pasture. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662015000100034 |
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| NAVA,GILBERTO; CIOTTA,MARLISE NARA; BRUNETTO,GUSTAVO. |
| ABSTRACT The aim of this work was to evaluate the effects of orchard fertilization with increasing rates of phosphorus (P) on yield and critical levels of P in the soil and in the leaf of ‘Fuji’ apple trees. The experiment was conducted in São Joaquim, state of Santa Catarina, southern Brazil, from 2010 to 2015, in an Inceptisol soil. The three apple orchards were planted in 2004 with the Fuji cultivar grafted on Marubakaido/ M9 rootstock and grown under a high-plant-density system (1984 trees ha-1). Annual fertilizer levels of 0, 40, 80, 120 and 160 kg ha-1 of P2O5 (as triple superphosphate) were applied to the soil surface, without incorporation, in a randomized block design with five replicates. In the first and last years (2011 and 2015), soil samples... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Malus domestica Borkh; Yield; Critical level; Leaf analysis. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452017000103001 |
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| Assis,Gleice Aparecida de; Guimarães,Rubens José; Colombo,Alberto; Scalco,Myriane Stella; Dominghetti,Anderson William. |
| With the aim of establishing critical ranges for the leaf nitrogen (N) and potassium (K) levels in fertigated coffee crops under production, an experiment was carried out in the experimental area of the Sector for Coffee Cultivation of the Department of Agriculture at the Federal University of Lavras, in Brazil. Treatments consisted of five levels of fertilizer applied through fertigation: 30%, 80%, 130%, 180% and 230% of the recommended amounts of N and K for rainfed coffee grown in Minas Gerais. A randomised block design with four replications was used. Critical ranges for nutrient concentrations in the leaves were established from the results of growth characteristics (plant height and stem diameter), leaf analyses and productivity. The results obtained... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica L.; Irrigated coffee; Critical level; Foliar diagnosis. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902015000100126 |
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| Santos,Anacleto Ranulfo dos; Mattos,Waldssimiler Teixeira de; Almeida,Ana Aparecida da Silva; Monteiro,Francisco Antonio; Corrêa,Beatriz Dias; Gupta,Umesh C.. |
| Alfalfa cultivar Crioula (Medicago sativa cv. Crioula) is grown in South Brazil and only a few studies on the plants' boron requirement are available. A greenhouse experiment was carried out with alfalfa to measure boron acquisition, production and distribution in the plant; data on critical level and production potentials were recorded. Plants were grown in ground quartz added with 1 L of solution, with the following boron rates: 0, 0.0625, 0.125, 0.25, 0.50, 1.00, and 2.00 mg L-1. Plants were harvested at 46 days of growth. Forage dry mass was increased by boron supply and dry matter accumulation was considerably low in control. Boron concentration in the leaves was higher than in the stems or roots. Boron utilization from the external solution reached... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lucerne; Medicago sativa; Plant nutrition; Micronutrient; Critical level. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000500006 |
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| Moreira, Marialva Alvarenga; Universidade Federal de Viçosa; Fontes, Paulo Cezar Rezende; Universidade Federal de Viçosa; Cecon, Paulo Roberto; Universidade Federal de Viçosa; Araújo, Roberto Fontes; Empresa de Pesquisa Agropecuária de Minas Gerais. |
| O objetivo deste trabalho foi selecionar índices para diagnóstico do estado de nitrogênio de batata-semente básica em vaso e determinar valor crítico de cada índice selecionado. Os índices, medidos na quarta folha (QF) e folha velha, aos 60 dias após o plantio, foram: intensidade do verde (determinado por tabela de cor e SPAD); área, comprimento, largura, número de folíolos, matéria fresca e seca; teor N-NO3 na seiva do pecíolo e N na matéria seca. Foram realizados três experimentos em vaso, em casa de vegetação, Universidade Federal de Viçosa. Em cada experimento utilizou-se um material de propagação que foi tubérculo-semente, mini-tubérculo e broto e foram avaliadas seis doses de N (0; 25; 50; 100; 200 e 400 mg dm-3), sendo 10% de cada dose aplicada em... |
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Palavras-chave: 5.01.01.04-8 Solanum tuberosum L.; Propagação; Nível crítico Fitotecnia Solanum tuberosum L.; Propagation; Critical level. |
| Ano: 2011 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5724 |
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| Pozza, Adélia Aziz Alexandre; UFLA; Guimarães, Paulo Tácito Gontijo; EPAMIG; Silva, Enilson de Barros; ICA; Bastos, Ana Rosa Ribeiro; UFLA; Nogueira, Francisco Dias; EPAMIG. |
| Para avaliar a dose e a forma de aplicação de sulfato de zinco foliar no crescimento e produtividade do cafeeiro Mundo Novo, instalou-se um experimento de campo em LATOSSOLO VERMELHO Distroférrico, na Fazenda Experimental da Epamig em São Sebastião do Paraíso. O delineamento experimental foi em blocos casualizados, em esquema fatorial 4 x 2, com cinco repetições e parcela de 30 plantas com seis úteis. As quantidades de sulfato de zinco (ZnSO4) foram aplicadas nas concentrações de 0; 0,5; 1,0 e 1,5%, testadas em duas ou quatro aplicações por ano agrícola. Foram avaliados por oito anos os teores foliares de P e Zn e as produções. Concluiu-se que o cafeeiro respondeu positivamente às aplicações de doses crescentes de ZnSO4 via foliar, aumentando a produção e... |
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Palavras-chave: 5.01.03.04-0 Produção de Mudas produtividade; Coffea arábica; Doses de zinco; Nível crítico; Relação P/Zn. yield; Coffea Arabica; Zinc dosis; Critical level; P/Zn ratio. |
| Ano: 2009 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/6627 |
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| Registros recuperados: 13 | |
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