992 resultados para Nitrogen fertilizers


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Mikania glomerata Sprengel leaf extracts have been used in cough syrup formulations due to the presence of active coumarin derivatives. Yields of such natural compounds in cultivated plants can be affected by several nutritional factors. To determine the effect of fertilization on biomass productivity, organ proportion and coumarin content, Mikania glomerata plants were submitted during one year to treatments with organic (humus or manure) and inorganic (different levels of nitrogen) fertilizers. Coumarin concentration was raised by organic fertilization, inorganic nutrients induced increased phytomass (stem and leaf) yield, however no fertilized plants showed enhanced leaf production.

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Nitrous oxide (N2O) is involved in both ozone destruction and global warming. In agricultural soils it is produced by nitrification and denitrification mainly after fertilization. Nitrification inhibitors have been proposed as one of the management tools for the reduction of the potential hazards of fertilizer-derived N2O. Addition of nitrification inhibitors to fertilizers maintains soil N in ammonium form, thereby gaseous N losses by nitrification and denitrification are less likely to occur and there is increased N utilization by the sward. We present a study aimed to evaluate the effectiveness of the nitrification inhibitor dicyandiamide (DCD) and of the slurry additive Actilith F2 on N2O emissions following application of calcium ammonium nitrate or cattle slurry to a mixed clover/ryegrass sward in the Basque Country. The results indicate that large differences in N2O emission occur depending on fertilizer type and the presence or absence of a nitrification inhibitor. There is considerable scope for immediate reduction of emissions by applying DCD with calcium ammonium nitrate or cattle slurry. DCD, applied at 25 kg ha-1, reduced the amount of N lost as N2O by 60% and 42% when applied with cattle slurry and calcium ammonium nitrate, respectively. Actilith F2 did not reduce N2O emissions and it produced a long lasting mineralization of previously immobilized added N.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Agronomia (Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Nitrogen (N) is the most required nutrient for corn plants and, in order to supply this demand in highly productive crops, mineral fertilizers are used, especially urea. The disadvantage of urea is the loss of N-NH3 to atmosphere. To reverse this situation, some technologies have been developed, such as nitrification and urease inhibitors, which are used as additives to urea. This work aimed at evaluating the agronomic efficiency of urea stabilized with urease and nitrification inhibitors applied to cover the 2013/2014 corn crop. We evaluated 11 nitrogen fertilizer applied in coverage: urea + PA (41.6% N, 3% Cu); urea + PA (41.6% N, 1.5% Cu); urea + PA (41.6% N, 3% Zn); urea + PA (41.6% N, 1.5% Zn); urea + PA (41.6% N, 0.34% Cu, 0.94% B); urea + PA (41.6% N, 0.25% Cu, 0.68% B); urea + PA (41.6% N); urea (44.3% N, 0.15% Cu, 0.4% B); urea (43% N, 0.1% Cu, 0.3% B, 0.05% Mo); pearled urea (46% N); urea + 0,8% DMPP (45% N) and the control, which did not receive nitrogen topdressing. The evaluations were: Nitrogen losses through volatilization, content and accumulation of N, boron (B), copper (Cu) and zinc (Zn) to the dry matter of aerial parts, grains, and in straw and grain productivity. Fertilizers stabilized with urease and nitrification inhibitors did not reduce the volatilization of ammonia volatilization, when compared to pearled urea. Urea with 0.8% of DMPP nitrification inhibitor (3,4-dimethylpyrazole phosphate) provided higher loss by volatilization, lower productivity and agronomic efficiency compared to pearled urea. The coating of urea with Cu, B and Zn did not increase the accumulation of these nutrients in grains and MSPA plants. The use of fertilizers stabilized and coated with micronutrients did not increase the productivity and agronomic efficiency compared to conventional urea.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)