938 resultados para Doses de potássio


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The crambe is a brassica with high content of oil used for biodiesel production and that has aroused interest in the short cycle and low production cost. However, there are doubts about their response to phosphated fertilization. The objective of this study was to evaluate the effect of different doses of phosphorus on yield, physiological quality, chemical composition and oil content of crambe seeds. The treatments consisted of five doses of phosphorus (0, 25, 50, 75 and 100 kg ha(-1)) applied at sowing. There was no effect of phosphorus on mineral composition and oil content of the seeds of crambe that showed the following averages: 30.11 N, 7.46 P, 7.35 K, Ca 10.06, 6.58 mg and 8.98 g kg(-1) S; 36.25 Cu, Fe 169.40, 36.75 Mn 73.60 mg kg(-1) Zn and 30.22% oil. It was concluded that the productivity of crambe increases with phosphorus rates of up to 100 kg ha(-1), but its use does not affect the survival rate of plants, dry mass, the mass of thousand seeds, the physiological quality, chemical composition and oil content of the seed.

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Background. Melatonin is a free radical scavenger with important actions in the study of renal ischemia and reperfusion (I/R). This study evaluated possible renal protection of high doses of melatonin in an experimental model of I/R in which rats were submitted to acute hyperglycemia under anesthesia with isoflurane.Method. Forty-four male Wistar rats, weighing more than 300 g, were randomly divided into 5 groups: G1, sham (n = 10); G2, melatonin (n = 10; 50 mg.kg(-1)); G3, hyperglycemia (n = 9; glucose 2.5 g.kg(-1)); G4, hyperglycemia/melatonin (n = 10; 2.5 g.kg(-1) glucose + melatonin 50 mg.kg(-1)); and G5, I/R (n = 5). In all groups, anesthesia was induced with 4% isoflurane and maintained with 1.5% to 2.0% isoflurane. Intraperitoneal injection of melatonin (G1, G4), glucose (G3, G4), or saline (G1, G5) was performed 40 minutes before left renal ischemia. Serum plasma values for creatinine and glucose were determined at baseline (M1), immediately following reperfusion (M2), and 24 hours after completion of the experiment (M3). Histological analysis was performed to evaluate tubular necrosis (0-5).Results. Serum glucose was higher at M2 in the groups supplemented with glucose, hyperglycemia (356.00 +/- 107.83), and hyperglycemia/melatonin (445.3 +/- 148.32). Creatinine values were higher at T3 (P = .0001) for I/R (3.6 +/- 0.37), hyperglycemia/melatonin (3.9 +/- 0.46), and hyperglycemia (3.71 +/- 0.69) and lower in the sham (0.79 +/- 0.16) and melatonin (2.01 +/- 1.01) groups, P < .05. Histology showed no necrosis injury in the G1, lesion grade 2 in the G2, and severe acute tubular necrosis in the G3: (grade 4), G4: (grade 5) and G5: (grade 4) groups (P < .0001).Discussion. Melatonin protected the kidneys submitted to I/R in rats without hyperglycemia; however, this did not occur when the I/R lesion was associated with hyperglycemia.Conclusions. Due to its antioxidant and antiapoptotic action, melatonin was able to mitigate, but not prevent acute tubular necrosis in rats with hyperglycemia under anesthesia by isoflurane.

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A.P. Puga, R.M. Prado, B. Mattiuz, D.W. Vale, and I.M. Fonseca. 2013. Chemical composition of corn and sorghum grains cultivated in Oxisol according to different application methods and doses of zinc. Cien. Inv. Agr. 40(1):97-108. In general, tropical soils present low concentrations of zinc (Zn), and the deficiency of Zn is recognized as a world nutritional problem for cereal production and human beings. Therefore, the main goal of this study was to assess the effects of different methods of Zn application on the quality of corn and sorghum grains grown in Oxisol. Two experiments were set up in the experimental area of UNESP (campus of Jaboticabal, Brazil). The following nine treatments were applied: three doses of Zn by banded application (seed furrows), three doses of Zn by incorporation into soil (0-20 cm depth), foliar application, seed application, and control (no Zn applied). The treatments were arranged in randomized blocks with four replicates. The contents of Zn, carbohydrates and proteins were determined for corn and sorghum grains. Regardless of the method, Zn application promoted higher contents of this micronutrient in corn and sorghum grains. The banded application method of Zn in soil promoted greater contents of total carbohydrates, starch and protein in both cultures. The incorporation of Zn into the soil method provided higher contents of soluble carbohydrates in both corn and sorghum grains.

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

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The Orchidaceae is one of the most numerous and diversified families in the Plant Kingdom. Miltonia flavescens Lindl. is a native orchid to the southern region of Brazil. Studies related to the nutrition and fertilization of orchids are scarce, specific and existent only for few species. The objective of this work was to evaluate the effect of different doses of a slow release fertilizer (Osmocote (R) 9/15/12 + micro) on the development of M. flavescens var. stellata Regel cultivated in pots with pine bark and coconut fiber (1:1, v:v) as the substrate. The treatments consisted of: no fertilizer application (control), application of 2.5 g, 5 g and 10 g of fertilizer per liter of substrate. The experimental design was set in randomized blocks, with five replications and three plants per plot. The experiment was carried out along 25 months and the fertilizer was applied every five months. The evaluated plant parameters were: length of the longest pseudobulb, number of pseudobulbs, diameter of pseudobulbs, number of shoots, number of leaves and flowering. There was a significant increment on all evaluated characteristics with the increase of the fertilizer dose. The highest dose provided a more profuse flowering, with a larger number of flower stems and flowers, in addition to bigger flower stems and flowers. These results show that the supply of nutrients in an appropriate amount is of a great importance for the development and flowering of M. flavescens.

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The preventive efficacy of ivermectin and abamectin administered in different routes (subcutaneous, intramuscular and pour-on) and doses (200 and 500mcg kg(-1)) against Cochliomyia hominivorax in the scrotal sac of cattle after castration, was evaluated. Animals from six different farms, in the state of Sao Paulo and Minas Gerais, Brazil were used. For each study, 3045 uncastrated bulls, depending on the number of groups, were selected. On day zero of the study, the procedure was carried out by the method of bloody castration and the animals were treated after this process. The efficacy of ivermectin and abamectin administered via the pour-on (500mcg kg(-1)), subcutaneous (200mcg kg(-1)) as well as the efficacy of abamectin intramuscularly (200mcg kg(-1)) were evaluated. In each experiment, one group of animals was kept as control. The animals were evaluated from the 3rd to the 14th day after castration process/treatment. The efficacy values for both active principles were <= 30% the next day 10 post-treatment (PT), and in five experiments, both ivermectin and abamectin, regardless of the route of administration, were ineffective (0.0%) on the day 10th PT. Based on the results found in this study, conducted in different properties from southeastern Brazil, both ivermectin and abamectin, when used the protocol presented, were considered ineffective in preventing scrotal myiasis in bulls, irrespective of the route of administration and dose used.

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Pós-graduação em Agronomia (Agricultura) - FCA

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O objetivo do trabalho foi estudar as características morfogenéticas e estruturais do capim-Tanzânia, a produção de forragem, as perdas de nitrogênio (N) por volatilização, reservas orgânicas e a avaliação do sistema radicular sob doses de nitrogênio sob pastejo. O experimento foi instalado na área Fazenda Experimental de Iguatemi da Universidade Estadual de Maringá, no período de março de 2007 a março de 2008. O delineamento experimental utilizado foi de blocos completos ao acaso, com parcelas subdivididas com quatro repetições. Nas parcelas, encontravam-se as doses de N (0, 150, 300 e 450 kg ha-1 de N) e, nas sub-parcelas, as estações do ano. As perdas de N por volatilização foram quantificadas depois da adubação N (1, 2, 3, 6, 9, 12 e 15 dias). As amostragens das raízes foram realizadas nas profundidades de 0-10, 10-20 e 20-40 cm. A aplicação do fertilizante N na pastagem foi parcelada em três aplicações. A produção de massa seca total e de lâmina foliar de forragem respondeu linearmente até 282 kg ha-1 de N na estação do verão. A adubação nitrogenada exerce efeito positivo nas taxas de alongamento e aparecimento foliar, e no número de folhas vivas em plantas de capim-Tanzânia nas estações da primavera e verão. Elevadas adubações nitrogenadas associada a intervalos menores de pastejo promovem uma maior porcentagem de lâmina foliar; no manejo de pastos de capim-Tanzânia sob lotação rotacionada com altura de 70 cm na entrada dos animais para o pastejo e saída com 30 cm de altura do resíduo. A interação entre o nível de adubação e o período depois da aplicação de uréia foi significativa para a variável volatilização acumulada de N-NH3. A aplicação da uréia acarreta perdas percentuais mais elevadas de N nos três primeiros dias após a aplicação. A perda média acumulada de N-NH3 no período para as três estações do ano... (Resumo completo, clicar acesso eletrônico abaixo)