583 resultados para Eficiência do nitrogênio
Resumo:
Objetivou-se avaliar o efeito de teores crescentes de PB na MS total da dieta (11,5; 13,0; 14,5 e 16,0%) sobre os consumos e a digestibilidade total dos nutrientes e a produção e composição do leite de vacas leiteiras no terço inicial da lactação. O experimento foi constituído de quatro períodos experimentais de 15 dias, sete para adaptação dos animais à dieta e oito para coleta de dados. Foram utilizadas oito vacas, manejadas em cochos individuais, distribuídas em dois quadrados latinos balanceados 4 × 4. Utilizou-se concentrado à base de farelo de algodão e fubá de milho (40%) e, como volumoso, cana-de-açúcar corrigida com 1% de uréia + sulfato de amônio (9:1), na proporção de 60% (% MS). Os consumos médios diários de nutrientes, exceto EE e CNF, diferiram à medida que os teores de PB da dieta aumentaram. Os teores de PB na dieta não afetaram os coeficientes de digestibilidade aparente total dos nutrientes. A produção de leite corrigida ou não para 3,5% de gordura e seus componentes (gordura, PB e lactose), expressa em g/dia, e o nitrogênio uréico no leite (NUL) tiveram efeito linear crescente, enquanto a eficiência de utilização de N sofreu efeito linear negativo dos teores de PB da dieta. A dieta com 16% PB resultou em valores numericamente maiores de consumo e produção do leite e de seus componentes se comparada às dietas com menores teores de PB.
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Avaliou-se o efeito do nitrogênio no sistema radicular da espécie Panicum maximum Jacq. cv. IPR-86 Milênio, sob pastejo. As doses de N utilizadas foram 0; 150; 300 e 450 kg/ha.ano. As densidades de raízes no pré-pastejo foram avaliadas no quinto ano de aplicação de N, em três profundidades (0-10; 10-20 e 20-40 cm), com crescimento aos 7; 14; 21 e 35 dias após o pastejo. O método de pastejo utilizado foi o de lotação rotacionada. Os valores máximos de densidades de comprimento e de massa das raízes no pré e no pós-pastejo foram obtidos nas doses de N de 204; 206; 192 e 197 kg/ha, respectivamente. Nas doses de N de 0, 150 e 300 kg/ha, o crescimento das raízes (em densidade de comprimento) aumentou, em média, até 29 dias após o pastejo, enquanto, na dose 450 kg/ha, o aumento foi linear. Independentemente da dose de N, 60 a 25% do sistema radicular do cultivar IPR-86 Milênio concentrou-se nas camadas de 0-10 e 10-20 cm de profundidade, respectivamente.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Objetivou-se avaliar o efeito do fornecimento, no período das águas, de suplementos formulados com diferentes fontes de proteína sobre os parâmetros nutricionais de bovinos de corte em recria. Foram utilizados cinco novilhos mestiços Holandês × Zebu com peso vivo médio inicial de 300 kg, fistulados no esôfago e no rúmen, distribuídos em cinco piquetes de Brachiaria decumbens de 0,3 ha, em delineamento quadrado latino incompleto (5 × 5), com quatro períodos e cinco tratamentos, em quatro períodos experimentais de 14 dias. Como tratamentos, avaliaram-se suplementos à base de farelo de soja (FS), farelo de algodão (FA, 38% PB), farelo de glúten de milho (FGM, 60% PB) e farelo de trigo + uréia (FTU) e um tratamento testemunha, constituído apenas de mistura mineral (MM). A quantidade diária de suplemento fornecida foi fixada para fornecer aproximadamente 180 g de PB/dia. As fontes protéicas afetaram apenas o consumo de carboidratos não-fibrosos (CNF) e o de PB, que foi maior quando fornecido o suplemento à base de farelo de algodão e menor quando fornecida a mistura mineral. Não houve efeito das fontes protéicas sobre as digestibilidades total e parcial dos nutrientes. O pH e os níveis de nitrogênio amoniacal do líquido ruminal (N-NH3) não foram influenciados pelas fontes protéicas avaliadas, mas todos os valores mantiveram-se nos limites favoráveis à digestão da forragem. As fontes de proteína não afetaram a eficiência microbiana, em média 9,96 g PBmic/100g NDT, nem as concentrações de nitrogênio uréico no plasma (NUP), média de 12,78 mg/dL, e a excreção de nitrogênio na urina (NUr), média de 63,14 g/dia.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O objetivo neste estudo foi identificar possíveis alterações na composição e no processo de compostagem dos dejetos produzidos por bovinos Canchim e Nelore em diferentes períodos do confinamento alimentados com diferentes proporções de volumoso e concentrado. O experimento foi conduzido em delineamento inteiramente casualizado em esquema fatorial com parcelas subdivididas no tempo. As parcelas foram compostas por quatro tratamentos: dejetos provenientes de duas dietas (40% de volumoso e 60% de concentrado e 60% de volumoso e 40% de concentrado) e dois genótipos (Canchim e Nelore) e as subparcelas pelos três períodos de coleta dos resíduos (início, meio e final). A eficiência do processo de compostagem foi avaliada pelas reduções de volume, sólidos totais, sólidos voláteis, frações fibrosas, carbono orgânico e temperatura, além do número mais provável de coliformes totais e termotolerantes e teores de nitrogênio e macro e microminerais. Não houve efeito do genótipo nem do período de coleta dos resíduos sobre a composição dos dejetos, no entanto o aumento da proporção de volumoso na dieta levou a menor eficiência do processo de compostagem dos dejetos. Também foram observadas reduções de 100% no número mais provável de coliformes totais e termotolerantes e aumento no teor dos nutrientes no composto final.
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O objetivo do experimento foi verificar o efeito do nitrogénio no solo, parcelado de diferentes formas e aplicado durante o período de "verão", combinado com pulverização foliar de ureia e/ou ácido giberélico, sobre a produção e qualidade de Setaria anceps Stapf cv. Kazungula. O nitrogênio (60 kg/ha/ano) foi aplicado segundo quatro formas de parcelamento: Testemunha (sem nitrogênio), N20M40 (20 kg/ha de N em novembro + 40 kg/ha de N em março), N30M30 (30 kg/ha de N em novembro + 30 kg/ha de N em março), F20M40 (20 kg/ha de N em fevereiro + 40 kg/ha de N em março). No início do período de "inverno" foram aplicados os quatro tipos de pulverizações foliares: Testemunha (sem ácido giberélico ou uréia), uréia a 2%, ácido giberélico a 50 ppm e uréia a 2% + ácido giberélico a 50 ppm. Os resultados revelaram que o parcelamento do nitrogénio no solo não influiu no aumento da produção de matéria seca do capim setária no período de "verão", apesar de proporcionar um incremento da mesma no corte de "inverno". Observou-se, ainda, uma boa distribuição da produção de matéria seca entre "verão" e "inverno", apresentando essa última estação 34,52% da produção total anual, em média. Os diferentes tipos de pulverização não influíram significativamente sobre a produção de matéria seca e a composição química bromatológica da forrageira no período de "inverno".
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This research was conducted to evaluate the productive performance (live weight gain and carcass weight gain and gain efficiency) of animals from four zebu breed slaughtered in three maturity stages. Thirty-six bulls from Gyr, Guzera, Mocho Tabapua and Nellore with twenty-four months of average age and average initial live weight of 357.6, 362.0, 368.6 and 376.4 kg, respectively, were used. The bulls, from each breed, were randomly assigned to individual pens and were full-fed a diet containing 50% concentrate (DM basis) and distributed to three category (1, 2 and 3) of slaughter weights. The bulls from category 1, 2 and 3 were slaughtered when reached the individual live weight of 405, 450 and 500 kg, respectively. At slaughter the empty body weight was determined. The Nellore breed bulls showed greater average empty body weight gain and carcass gain in relation to the other breeds, which did not differ among themselves. There were no differences among breeds regarding to feed efficiency (empty body weight gain efficiency and carcass gain efficiency per unit of metabolizable energy intake). The slaughter weight did not influence the empty body weight gain and carcass gain, but animals slaughtered at higher slaughter weights showed lower gain efficiency and spent more time in feedlot.
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The objective of this research was to test the control of Brevipalpus phoenicis (Geijskes, 1939) by the hexythiazox and quinometionato products in citrus crop with and without adhesive spread and when submitted to artificial rain. The plants were sprayed at 2, 4, 8, 24 and 48 hours. When dried, the fruits were collected (eight/plants) and half of them were washed in laboratory with artificial rainfall on the basis of 30 mm/h during 15 minutes establishing the following treatments: T1 - hexythiazox + washing; T2 - hexythiazox + agral + washing; T3 - quinometionato + washing; T4 - quinometionato + agral + washing; T5 - control + agral + washing; T6 - hexythiazox; T7 - hexythiazox + agral; T8 - quinometionato; T9 - quinometionato + agral; T10 - control + agral. Thus, all the fruits were inoculated with ten females of B. phoenicis and five days later the mites alive were counted and eliminated. Approximately 15 days later the number of larvae alive were also counted. The results obtained allowed the following conclusions: a) the acaricides were efficient to control B. phoenicis; b) the rainfall (washing) did not alter the efficiency; c) the agral did not change the results.
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To determine the effects of the pre-slaughter showering on some meat quality parameters, the biochemical changes in the Longus colli muscle and the bleeding efficiency were studied. Thirty-six Nelore steers were slaughtered in a commercial slaughterhouse. Eighteen animals were submitted to pre-slaughter showering; a control group of eighteen animals were slaughtered without showering. Samples were collected for evaluations in the muscle depth, in the anterior portion of longus colli muscle,just before chilling. Bleeding efficiency was evaluated through the ratio of muscle haemoglobin/blood haemoglobin using blood samples taken five seconds after bleeding, and muscle sample taken before chilling. Longus colli muscle samples were also used to determine glycogen, glucose, pH and acidity, 5, 24 and 48 hours after slaughtering. Multivariate methods were used to evaluate biochemical data and the bleeding efficiency data analysis followed the randomized block design. Haemoglobin retained in the muscle and bleeding efficiency were not affected (P > .05) by pre-slaughter showering. The pre-slaughter showering did not affect (P > .05) the glycolysis. There was a significant effect of time in glycogen, glucose, pH and acidity, in the first 24 hours.
Resposta do abacaxizeiro 'Vitória' a doses de nitrogênio em solos de tabuleiros costeiros da Paraíba
Resumo:
Informations about fertilization and mineral nutrition of the new fusariosis-resistant pineapple cultivars are still scarce, despite the importance of this crop. The purpose of this study was to evaluate the effect of increasing doses of N on fruit yield and quality of the pineapple cultivar 'Vitoria' grown on a 'Humiluvico Espodossolo' in the region of Tabuleiros Costeiros, in the state of Paraiba. The experiment was arranged in a randomized block design, using five N doses (100, 200, 300, 500 and 600 kg ha(-1)N, as urea) applied 60, 180 and 270 days after planting (dap) with three replications. The following variables were evaluated: length and fresh matter of the 'D' leaf; contents of N, P and K in the portions with and without chlorophyll, 300 and 420 dap; average weight, yield, physical properties (fruit weight, length and medium diameter; crown weight and length) and chemical properties (pH, soluble solids -SS, titrable acidity - AT, and the SS/AT ratio) of the fruits at harvest. Increasing N doses linearly increased length and fresh matter of the 'D' leaf and N content and decrease both P and K contents of the chlorophyll portion 300 dap, but did not affect nutrient contents 420 dap; in the chlorophyll-free portion. Increasing N doses, also, led to an increase in K contents 320 dap, but to reductions 420 dap. Individual fruit weight and total yield increased with increasing N doses, as maximum values of 1.0 kg and 37.9 t ha(-1) were estimated at doses of 409.0 and 439.0 kg ha(-1) N, respectively. The N doses did not affect the fruit quality properties, which were compatible with the characteristics described for this cultivar.
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The inoculation of soybean crop with Bradyrhizobium bacteria is a widespread practice, due to excellent results achieved in productivity, however, some doubt still arise in relation the need of application of mineral nitrogen at sowing. In that mean, this work aimed to evaluate the response of the doses at inoculant and mineral nitrogen in the sowing of crop soybean in area of first cultivation. The experiments were carried in the experimental field of the University of the Estate of Mato Grosso, Campus of Alta Floresta - MT, Brazil, in the growing seasons of 2006/2007 and 2007/2008. The experimental design was randomized blocks, in a factorial escheme 2 x 4, with four replications. The factors consisted in the inoculation of seeds with Bradyrhizobium japonicum *(3 e 6 mL kg(-1) of seeds), and nitrogen fertilizer at sowing *(0, 10, 20 e 40 kg ha(-1)). The following variables were evaluated: plant height, insertion height of first pod, number of pod per plant, number of grain per pod, mass of 100 grain and grain productivity. In the two growing seasons there was no significant difference for doses of inoculants applied in first year of cultivation with soybean. To nitrogen application at sowing of soybean crop there was quadratic effect to plant height and of insertion height of first pod and growing linear to number of pod per plant in the second year of cultivation, however, without significant increase the productivity.
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With technological innovations, such as irrigation, the bean has been grown by producers who have the most varied levels of technology that, in suitable times, allows the planting great success in grain yield. The aim of this study was to evaluate the response of the dry bean to different managements of irrigation and nitrogen fertilization with no-tillage system, in Aquidauana - MS, Brazil. The experiment was conducted at the Universidade Estadual de Mato Grosso do Sul (UEMS), with the soil of the area classified as Alfisol, using the bean crop "Perola" sown on June 30, 2007. The experimental design was a randomized block split-plot consisting of three blocks and two replications within each block. The plots were composed of three management of irrigation, by the Class A pan method, using Hargreaves-Samani equation, and management by tensiometry (-40 kPa), with water replacement of 16.5 mm for all irrigation plots. The subplots consisted on four rates of nitrogen fertilization (0; 50; 100 and 150 kg ha(-1)), in which the nitrogen source was urea. It was concluded that the irrigation management through the Class A pan and Hargreaves-Samani equation conduced to higher grain yields of bean, 3031.11 and 3005.02 kg ha(-1) respectively.
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The objective of this work was to evaluate the effect of nitrogen sources and rates on maize nutrition and grain yield under no-tillage system in sandy soil. The experiment was conducted in a Typic Quartzipsamment, in the city of Cassilandia, State of Mato Grosso do Sul, Brazil. A completely randomized block design was used in a factorial array 3x4 with four replicates. Treatments consisted of three sources [urea, extruded urea with starch (Starea), and ammonium sulfonitrate with nitrification inhibitor of 3,4-dimethylpyrazole-phosphate (Entec (R) 26)] and four rates (0, 45, 90 and 180 kg ha(-1)) of nitrogen, applied in side-dressing when the plants presented four and six expanded leaves. The nitrogen source affected N, K, and S concentration in the leaf, but did not interfere in the components of production and maize grain yield. Nitrogen application like ammonium sulfonitrate promoted higher concentrations of N, K and S in the maize leaf in relation to the urea, especially in the larger rates studied. Side-dressing nitrogen fertilization increased the number of ears per plant, number of grains per ear and grain yield, grown under no-tillage system in sandy soil, independent of the used source.
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The study aimed to evaluate the yield and fruit quality of papaya 'Sunrise Solo' as function of nitrogen and boron fertilization. The experiment had a randomized block design with four replications, two plants per plot with a single border. To make up the treatments, we used the experimental array Plan Puebla III, which set the rates for nitrogen (0.0 to 111.2 - 200 - 288.9 - 400 g plant(-1), and B (0.0 - 0.83 - 1.5 - 2.16 - 3.0 g plant(-1)), in a total of ten treatments. The addition of nitrogen increased the yield, average fruit weight and number of fruits per plant. The nitrogen and boron increased the diameter and length of the fruit, amount of seeds and content of soluble solids. The pH of the pulp decreased linearly with increasing doses of nitrogen and boron. It was observed a significant effect of N rates on the level of vitamin C.