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| Santos,Nádia Souza dos; Alves,José Maria Arcanjo; Uchôa,Sandra Catia Pereira; Oliveira,Natália Trajano de; Albuquerque,José de Anchieta Alves de. |
| A field experiment was carried out in 2010-2011 crop years in the experimental area of the Centro de Ciências Agrárias of the Universidade Federal de Roraima, in Boa Vista, Roraima, Brazil. This study aimed to evaluate the effect of nitrogen availability on the concentrations of N, P, K, Ca, Mg and S in cassava, cultivar Aciolina, in different harvest times. A randomized block design was used in split-plot, with four replications. Dosages of N in cover were applied randomly on the plots (0, 30, 60, 150 and 330 kg ha-1), and in the subplot the harvest dates 120, 150, 180, 210, 240, 270 and 300 days after emergence (DAE). The vegetal material was collected, ground and then underwent an analysis for determination of nutrients concentrations in the leaves (N,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fertilisation; Manihot esculenta; Plants-Nutrition; Plants-Nitrogen effect. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902014000400001 |
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| Vale Júnior,José Frutuoso do; Nicodem,Steven; Melo,Valdinar Ferreira; Uchôa,Sandra Catia Pereira; Cruz,Diego Lima de Sousa. |
| ABSTRACT Soil organic matter (SOM) fractions result from a variety of environmental processes, which affect incorporation and production rates, decomposition, alteration, and/or mineralization of organic matter. The aim of this study was to characterize SOM under the environments of rain forest, wooded campinarana (grasslands), arboreal-shrubby campinarana, grassy-woody campinarana, and pioneer plants of the Viruá National Park, in the north of the Brazilian Amazon. After chemical and physical characterization and soil classification, total organic carbon (TOC), total N, microbial activity, organic C from fulvic acid fractions (FA), humic acid (HA), and humin (Hu) were determined at two depths (0.00-0.15 and 0.15-0.30 m). The TOC was lower in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil organic carbon; Humic substances; Campinarana; Quartzipsamment; Spodosol. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832016000100408 |
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| Oliveira,Natália Trajano de; Uchôa,Sandra Catia Pereira; Alves,José Maria Arcanjo; Albuquerque,José de Anchieta Alves de; Rodrigues,Guilherme Silva. |
| ABSTRACT Nitrogen is considered the most limiting nutrient for cassava, and N availability can influence the crop cycle, including earlier harvest. The aim of this study was to study the effect of harvest time on the production components of cassava, “Aciolina” cultivar, at different rates of N fertiliser. The experiment was carried out in an area newly incorporated into the productive system in a savannah ecosystem in the northern Amazon. A randomised block experimental design was used in a split plot arrangement with four replications. The N rates (0, 30, 60, 150, and 330 kg ha-1) were allocated to the main plots, and the harvest times (90, 120, 150, 180, 240, 300, and 360 days after emergence of the stalks - DAE) were allocated to the subplots. Plant... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Manihot esculenta; Cassava; Crop cycle; Nitrogen fertiliser; Amazonian savannah. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832017000100519 |
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