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| Registros recuperados: 171 | |
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| Reis, Daniele Nogueira dos; van Straaten, Peter; Furtini Neto, Antonio Eduardo; Bittar, Sheila Maria Bretas; Curi, Nilton. |
| Knowledge of a rock’s composition allows for inferences regarding several properties, ranging from its physical characteristics to its solubility. This study aimed to evaluate the use of different extractants to solubilize the K present in rocks as a potential source of nutrients and the effects of extractant contact time and temperature on rock solubilization. Samples of two rocks and a mineral concentrated from a granitic rock were treated with ammonium dihydrogen phosphate (NH4(H2PO4)), calcium dihydrogen phosphate (Ca(H2PO4)2), sodium hydroxide (NaOH) and water (control). Sample-extractant treatments were performed using a water bath shaker at temperatures of 25 and 50°C for periods of 3, 7, 10, 20, and 30 days. The amounts of K extracted from rocks... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Minerals; Soluble K; Fertilizers; Powdered rock. |
| Ano: 2016 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/28457 |
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| Jama,Bashir; Van Straaten,Peter. |
| Phosphorus deficiency affects around 80% of the acid soils of western Kenya, but fertilizer use is limited due to high prices. This paper explores the potential of local phosphate rocks (PR) as a remedy within the context on an integrated soil fertility management approach. A promising phosphate rock is Minjingu PR (MPR, Tanzania), a sedimentary/biogenic deposit which contains about 13% total P and 3% neutral ammonium citrate (NAC) soluble P. On-farm trials in P-deficient soils in western Kenya demonstrate MPR to be as effective as triple superphosphate (TSP, 20% P) at equal P rates. The benefits are most pronounced with the integration of agroforestry technologies that improve soil fertility. Besides Minjingu PR, Busumbu PR from Uganda (BPR) is... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fertilizers; Maize; Improved fallows; Tithonia; East Africa. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652006000400012 |
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| CORBI,JULIANO J.; COSTA,CAMILA G.; GORNI,GUILHERME R.; COLOMBO,VANESSA; RIOS,LEONARDO. |
| Abstract In Brazil, innumerable regions of native landcover have been removed and replaced by agricultural cultivation, especially of sugarcane. In this culture, the application of fertilizers containing metals has caused impacts on the water resources causing contamination of stream sediments and occasioning bioaccumulation of metals in aquatic invertebrates. In the year of 2006, an environmental diagnosis of metals in sediments of streams located near sugarcane cultivation areas and in streams located in preserved areas, was published. That study pointed to high concentrations of metals in stream sediments in agricultural areas. These streams have been monitored over the last 10 years conducting analyses of metals and monitoring possible changes in land... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquatic biota; Aquatic invertebrates; Fertilizers; Riparian vegetation. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000602711 |
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| Hussain,Raad Obid; Hussain,Hayder Hamza. |
| In order to assess the radioactive level in the environment, the specific activities of 238U, 232Th and 40K were measured by using a gamma ray spectrometer based on a NaI(Tl) detector. The results showed that the specific activities of 238U, 232Th and 40K were 12.846-88.585, 1.304-26.656 and 11.598-2275.896 Bq/kg respectively. The radium equivalent activity was also calculated which varied from 0.893 to 175.244 Bq/kg. The radium equivalent average values were lower than the world average. In general, the highest level of radium equivalent value was in leafy type NPK fertilizers. The urea type had no radionuclide. The specific activity and absorbed dose rate at 1m above the ground surface (nGy/h) after NPK fertilizers agricultural applications were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Natural radioactivity; Gamma-spectrometry; Fertilizers. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000400018 |
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| Becegato,Valter Antonio; Ferreira,Francisco José Fonseca; Cabral,João Batista Pereira; Rafaelli Neto,Sílvio Luis. |
| In this study the K, U and Th radionuclide concentrations were determined in a sugar cane plantation that received large quantities of fertilizer and gypsum. Geochemical data were obtained for the clay, iron and organic matter in the soil samples, taken from depths of 0-20 and 20-40 cm. The average radionuclide concentrations were 71 Bq Kg-1 for K; 5.97 Bq Kg-1 for U, and 11.26 Bq Kg-1 for Th, and the uranium was variable (56%). The radionuclide average concentrations for the different fertilizer compositions varied in the range of 603.5 - 8855.0 Bq Kg-1 for K; 27.3 - 684.4 Bq Kg-1 for U, and 58 - 788.5 Bq Kg-1 for Th, and it was most variable for K (53%). Gypsum average concentrations were 82.6 Bq Kg-1 for K, 641.5 Bq Kg-1 for U, and 201.7 Bq Kg-1 for Th,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fertilizers; Soils; Radionuclides; Gamma-ray spectrometry. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000100001 |
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| Becegato,Valter Antonio; Ferreira,Francisco José Fonseca; Machado,William César Pollonio. |
| Gamma spectrometric measurements were obtained for the agricultural soils aiming at characterizing the spatial distribution of radionuclide concentrations (K, eU and eTh), as well for the samples of phosphatic fertilizers and agricultural gypsum. In the study areas, three types of soils occured: Eutrophic Red Nitosol (Alfisoil), Eutroferric Red Latosol of clayey texture (Oxisoil) and Dystrophic Red Latosol of medium texture (Oxisoil). The results showed that the radionuclide concentrations in more clayey soils were higher than in more sandy soils, mainly as a function of a higher adsorption capacity of the former. For the area where human activity predominated, the average contents of K, eU and eTh were respectively 54.75; 10.22 and 7.27 Bq/Kg,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gamma-rays spectrometry; Soils; Fertilizers. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132008000600022 |
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| Salinas Ramírez, Nicolás. |
| El presente estudio se dividió en dos etapas, la primera se realizó en verano del 2008, bajo condiciones de temporal y tuvo como objetivo seleccionar dentro de cultivares de diferente hábito de crecimiento, aquellos con mayor producción de biomasa, rendimiento y calidad nutrimental, en dos ambientes Montecillo (clima semiárido, CS) y San Pablo Ixayoc (clima templado, CT). Los resultados encontrados indican que en CS los cultivares de hábito de crecimiento indeterminado (CHCI) presentaron la mayor producción de biomasa, rendimiento y calidad nutrimental del ejote (235 g m-2, 1.38 kg m-2, proteína 22 %, FDA 31 %, grasa 1.9 % y fósforo 0.080 %, respectivamente) y los valores más bajos (86 g m-2, 0.41 kg m-2, proteína 19.5 %, FDA 21.4 %, grasa 1.7 % y fósforo... |
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Palavras-chave: Phaseolus vulgaris L.; Rendimiento; Calidad nutrimental; Fertilizantes; Yield; Nutritional quality; Fertilizers; Doctorado; Botánica. |
| Ano: 2010 |
URL: http://hdl.handle.net/10521/326 |
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| Matous, Petr; University of Tokyo; University of Sydney; petr.matous@sydney.edu.au. |
| Many agrarian communities in developing countries suffer from insufficient productivity and use farming practices that deteriorate the environment both locally and globally. Research suggests that social networks play a role in environmental management, different studies emphasize different aspects of network structures, and the implications of the scales at which networks operate are not explicitly discussed. Here, I ask what types of social structures in farmer networks are conducive to environmental protection and agricultural productivity enhancement, and I show that the answer depends on the scale of the investigation. Using original data representing 16 farmer groups comprising 315 households and 1575 information-sharing links, I analyzed the... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Community-based management; Cross-level interactions; Fertilizers; Social networks; Soil management. |
| Ano: 2015 |
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| GOEDERT, W. J.; REIN, T. A.; SOUSA, D. M. G. de. |
| A solubilizacao dos fosfatos naturais brasileiros e uma necessidade, em face da baixa eficiencia agronomica dos mesmos. No brasil, os produtos de transformacao mais comuns sao os superfosfatos e fosfatos de amonio, os quais se constituem em fontes de comprovada eficiencia agronomica. Contudo, ha necessidade de se obter produtos com tecnologia mais simples e que melhor aproveitem as materias-primas disponiveis no Pais. Uma das opcoes exercitadas no momento e a producao de fosfatos parcialmente acidulados com acido sulfurico. A eficiencia agronomica dessas fontes, para culturas anuais, tem sido proporcional a fracao da apatita solubilizada. Trata-se, assim, de um produto viavel, se o preco de mercado for estabelecido em funcao do teor de P2 05 soluvel.... |
| Tipo: Folhetos |
Palavras-chave: Eficiencia; Cultura anual; Phosphate fertilizers; Efficiency; Brasil; Centro de Pesquisa Agropecuária dos Cerrados; DF; Fertilização; Fosfatos; Planaltina; Use; Uso; Uso agrícola; Agricultura; Adubação; Cerrado; Fósforo; Fertilizante Fosfatado; Solo; Annuals; Agriculture; Fertilizers; Soil. |
| Ano: 1986 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/547644 |
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| Registros recuperados: 171 | |
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