420 resultados para Fenologia foliar
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Na região de Jales (SP), a produção de uva 'Niagara Rosada' obtida de videiras podadas em períodos de ocorrência de baixas temperaturas é, em geral, insatisfatória, apresentando pequena produtividade e cachos com qualidade inadequada à comercialização. Essa qualidade da produção está intimamente relacionada à efetiva brotação. Assim, este trabalho teve o objetivo de avaliar a aplicação do ethephon em diferentes doses antes da poda, visando a melhorar a brotação e a qualidade dos cachos, em seis experimentos, durante os anos de 2001 e 2002. Foram testadas as doses de 0; 3; 6 e 9 L.ha-1 de ethephon aplicado via foliar. Concluiu-se que o uso de ethephon, na dose de 9 L.ha-1, proporcionou cachos e bagas maiores e com maiores pesos, comprimento e largura, melhorando o aspecto dos mesmos. A aplicação de ethephon não afetou os teores de sólidos solúveis totais e a acidez total titulável, não alterando o sabor da uva 'Niagara Rosada'.
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A produção da videira 'Niagara Rosada' em regiões tropicais e subtropicais do Brasil tem sido freqüentemente prejudicada, principalmente devido à dificuldade de emissão e desenvolvimento das brotações após a poda de produção, realizada nos meses de ocorrência de temperaturas mais baixas, o que tem causado redução nas produções e desestímulo aos viticultores. Para solucionar esse problema, foram conduzidos três experimentos, em pomares comerciais localizados na região Noroeste do Estado de São Paulo, com o objetivo de estudar o efeito do Ethephon, aplicado antes da poda de produção, na emissão e desenvolvimento das novas brotações e na duração do período da poda até a floração. Foram testadas quatro doses de ethephon (0 mg.L-1; 720 mg.L-1; 1.440 mg.L-1; 2.160 mg.L-1) aplicadas via foliar antes da poda de produção, nos meses de junho e julho de 2002. Observou-se que a aplicação de Ethephon proporcionou maior número de gemas brotadas, maior comprimento e diâmetro do ramo e não alterou o período da poda à floração. Especialmente quando da ocorrência de condições climáticas desfavoráveis e quando as plantas apresentaram satisfatório grau de enfolhamento, a aplicação de ethephon, na dose de 2.160 mg.L-1, foi a mais efetiva.
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Objetivou-se estudar os efeitos de ácido giberélico (GA3) (i.a.), nas concentrações de 50 e 100 mg L-1, acrescido do espalhante adesivo Extravon® a 0,05%, em duas aplicações via foliar e do paclobutrazol (PBZ) (i.a.), em doses de 2 e 4 g por planta, aplicado via solo, em uma única aplicação, na antecipação da floração do maracujazeiro-amarelo, em Araguari-MG. O delineamento experimental empregado foi em parcelas subdivididas, com cinco tratamentos (parcelas) e dois tratamentos (subparcelas), com quatro repetições e quatro plantas por parcela. Foram identificados 12 ramos terciários por parcela, com seis ramos expostos à luminosidade predominante pela manhã e seis com luminosidade predominante à tarde. Avaliaram-se os dois lados da espaldeira aos 103 dias após a primeira aplicação dos tratamentos, observando-se o comprimento dos ramos e de entrenós, número de nós e de botões florais. Os reguladores não promoveram respostas significativas para o comprimento dos entrenós e o número de botões florais. Porém, observaram-se indícios de maior número de botões florais com PBZ 2 g. O maior comprimento dos ramos foi obtido com GA3 100 mg L-1, sob luminosidade, pela manhã. Ao se compararem os tratamentos nas duas condições de luminosidade, o PBZ 4 g, independentemente da condição de luminosidade, proporcionou o menor comprimento dos ramos.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Soil acidity is one of the most important factors limiting agricultural production in the tropics. For this reason, the objective of this research work was to evaluate the effects of soil liming on the performance of carambola (Averrhoa carambola) trees. The experiment took place at the Citrus Experimental Station in Bebedouro, state of São Paulo, Brazil. The soil was a Typic Haplustox (V = 26% at the 0- to 20-cm layer) between August 1999 and July 2003. The following doses of limestone were employed: 0, 1.85, 3.71, 5.56, and 7.41 t ha(-1). During 40 months after the experiment was set up, soil chemical attributes were periodically examined. For a period of 2 years, the trees had their leaves analyzed for micro-and macronutrients; their trunk diameter, height, and crown volume measured; and the production of fruits determined. Liming improved in evaluated chemical attributes of the soil: pH, calcium (Ca), magnesium (Mg), BS, V, and hydrogen and aluminium (H + At) from the upper 60 cm of soil when the samples were taken from both the line and between the lines of plants. In the leaves, the levels of Ca and Mg also increased. The highest fruit yields were observed when soil base saturations reached 45% on the lines and 50% between the lines, as well as when foliar levels of 8.0 g of Ca and 4.7 a of Mg per kilogram of leaves were attained.
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A utilização de mudas de goiabeira com adequado estado nutricional determina o sucesso da implantação de um pomar. O objetivo deste trabalho foi determinar crescimento e acúmulo de macronutrientes em mudas de duas cultivares de goiabeira obtidas por estaquia herbácea. O delineamento utilizado foi o inteiramente casualizado, com parcelas subdivididas, com três repetições. Assim, foram utilizadas como parcelas duas cultivares de goiabeira (Paluma e Século XXI) e, como subparcelas, sete coletas de plantas ao longo do período experimental (120 dias), em solução nutritiva. As plantas foram avaliadas quinzenalmente quanto a: altura, número de folhas, diâmetro do caule, área foliar e massa de matéria seca (folhas, caule e raízes). Nos diferentes órgãos das mudas, determinou-se o acúmulo de macronutrientes. Houve acúmulo quadrático de matéria seca das mudas de goiabeira com o tempo de cultivo. A muda de goiabeira da cultivar Século XXI tem maior exigência de macronutrientes que a da cultivar Paluma, e o período de maior exigência é a partir dos 75 e 45 dias, para ambas as cultivares. O acúmulo de macronutrientes pelas mudas de goiabeira das cultivares Paluma e Século XXI foi de: K (726 e 696), N (552 e 585), Ca (293 e 302), S (73 e 66), P (64 e 66) e Mg (39 e 41) mg por planta, respectivamente.
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O objetivo deste trabalho foi avaliar, em casa de vegetação, os efeitos de doses de esterco bovino e de calcário na formação de mudas de guanandi (Calophyllum brasiliense Cambèss.). Foram avaliadas quatro doses de cada fator, combinadas em esquema fatorial 4x4. O delineamento experimental foi inteiramente ao acaso com quatro repetições, e cada parcela continha cinco mudas. O substrato foi formado pela mistura, em volume, de oito partes de subsolo e duas partes de areia, e doses de esterco correspondentes a 0, 2, 4 e 6 partes que, em massa, equivalem a 0, 101, 175 e 229 kg m-3. As doses de calcário foram calculadas para elevar a saturação por bases (V%) a 20, 35, 50 e 65%. Aos 120 dias, foram avaliados: altura, diâmetro do colo, número de folhas, área foliar e matéria seca das partes aérea e radicular das mudas. em substrato constituído de subsolo+areia, a calagem e a adubação com esterco bovino não são necessárias para produção de mudas de guanandi.
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There are few studies that relate the micronutrient manganese nutritional status and production of fodder. The objective was to evaluate the application of manganese in the nutrition and growth of Mombaca grass. The completely randomized design was used with five manganese levels (0, 15, 30, 60, 120 mg dm(-3)) and four replicates. Each experimental unit consisted of a pot filled with 3.5 dm(-3) of soil from Oxisol (Mn = 0.6 mg dm(-3)), containing four plants. Two harvests were set, the first 44 days after sowing and the second 38 days after the first cut. The concentration of manganese in the soils, the manganese content of leaves, number of tillers, plant height, shoot dry mass in each slice and the root system of Mombaca grass were evaluated. The applied rates of manganese resulted in increased accumulation of Mn in the plant, and there was an increase in dry mass of Mombaca grass, with maximum production, obtained from derivation, of 5.9 and 6.3 g plant(-1) for levels of 121 and 71 mg dm(-3) of Mn in the first and second cut respectively. The Mombaca grass has showed high manganese's tolerance, the critical level of toxicity was 841 mg kg(-1) in the second cut.
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Given the importance of heart, especially among the high brassica consumption, coupled with the scarcity of studies that report symptoms of nutritional disorders in the culture, the work was carried out to evaluate the effect of the omission of macronutrients in the development and nutritional status of cabbage, and describe visual symptoms of nutritional deficiency. The experiment was conducted under greenhouse conditions in the UNESP, Jaboticabal, SP. The experiment was arranged in completely randomized design with three replications and seven treatments, corresponding to complete nutritive solution (macro and micronutrients) and individual N, P, K, Ca, Mg and S omission. Plant height, number of leaves, leaf area, shoot, root and whole plant dry mass and macronutrient levels were determined and nutritional deficiency symptoms were described. Individual omissions of N, P, K or Ca were limiting for cabbage growth, considerably reducing plant height, number of leaves, and shoot, root and whole plant dry mass. Nutritional deficiency symptoms were observed for each element. Shoot macronutrient levels in control and nutrient omission treatments were, respectively: N = 31.0-11.9; P = 5.3-0.60; K = 63.5-4.8; Ca = 25.9-4.8; Mg = 5.2-0.5; S = 10.3-1.4 g kg(-1).
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The present research had he objective to evaluate rice response to zinc application forms on the nutrition, growth and dry matter production, in vase conditions. The experiment was carried out in a completely randomized design, with five treatments (leaf Zn, incorporated Zn, located Zn, Zn saw seed and witness - whitout zinc), in four repetitions during two cycles of cultivation with 42 days of duration each. Plastic vase of 7L, were filled with Red Distrofic Latosol (Zn = 0.3 mg dm(-3) in DTPA). The application of Zn saw soil in both culture of the rice improved its level in the soil, being distinguished it from located form. In the first cycle, the application of Zn saw leaf promoted greater absorption of the nutrient for the rice plants, while in the second cycle leaf application was followed by the saw soil incorporated. The biggest dry matter production occurred with application of leaf saw in the first cycle and saw soil (incorporated and located) in the second rice cultivation.
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Foliar diagnosis is a method for assessing the nutritional status of agricultural crops, which helps in the understanding of soil fertility and rationalized application of fertilizers taking into account economic and environmental criteria. The study aimed to use the landrelief as criteria to assist in interpreting the spatial variability of nutrient content of the citrus leaf. The leaves were collected at regular intervals of 50 m, totaling 332 sampling points. Data were analyzed by descriptive statistics, geostatistics and induction of decision tree. With the aid of digital elevation model (MDE) and the profile planaltimetric, the area was divided into three different landrelief and sub-strands. The highest values for nutrients from the leaves of citrus were observed at the top (concave area) segments on a half-slope and lower slope. The nutrients from the citrus leaves showed high values of correlation (above 0.5) with the altitude of the study area. The technique of geostatistics and the induction of decision tree show that the relief is the variable with the greatest potential to interpret the maps of spatial variability of nutrients from the citrus leaves.
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The cultivation of pastures in Brazil is mostly done with the species Brachiaria spp. However, there is little research on nutrition with manganese for this forage. It was aimed to asses the effects of manganese in the development and nutrition of marandu grass. The experimental design used was fully randomized, consisting of five rates of manganese ( 0, 15, 30, 60 e 120 mg dm(-3)) and four repetitions. The experimental unit was formed in a vase filled with a Red Latosol dystrophic. There were two cuts, the first after 38 days of transplanting seedling and the second 30 days after the first cut. Was evaluated the content of manganese leaf, the dry mass of the shoot, the number of tillers and the leaf area. The levels of manganese increased its accumulation in the plant, second cut compared to the first cut. The marandu grass showed high tolerance to manganese toxicity, reaching a high leaf content in the shoot without affecting plant growth.
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The culture of the maize is responsive the fertilization with zinc, however, its efficiency can be affected by the method of aplication. Thus, this work had as objective to evaluate the effect of the methods of zinc application in the nutritional state and the initial growth of the culture of the maize. The experiment was in a completely randomized design, with five treatments in four repetitions. The experimental unit was composed for a pot (7 L) filled with a distrofic Red Latosol, clayey texture, with four plants of maize. The treatments had been constituted by four ways of zinc application: in the soil incorporated (3 mg Zn dm(-3)), and located (1 mg Zn dm(-3)); foliar (solution of 23 mg Zn L(-1)); e in seed (40 g Zn kg(-1) of seed) and beyond the witness (control). The treatments had been applied during two cultivation of 42 days, except the Zn incorporated in the soil. In the end of each culture, the cut of the plants for the evaluation of the growth variable (leaf height, number, the diameter of stems and dry matter) and the determination of the zinc text was carried through in the soil and the aerial part. The zinc application promoted increment in the height and the production of matter of the maize. The zinc application soil (incorporated and located), foliar and seed had been similar in the initial development of the culture, however, the foliar way promoted greater absorption of the nutrient for the plant.