[Show abstract][Hide abstract] ABSTRACT: The foliar application of micro- and macronutrients is often practiced by farmers to improve yield and seed physiological potential. For calcium and molybdenum, positive results have been observed, even in soils with high nutrient content. The purpose of this study was to assess the effects of foliar applications of calcium and molybdenum on yield and seed physiological potential in common bean plants. A randomized block design was implemented, with the treatments fixed in a factorial scheme: two molybdenum rates (with or without) and four calcium rates, with four replications. The calcium rates applied on the leaves were 0, 150, 300 and 600 g·ha-1 for the first year of the investigation (2005) and 0, 300, 600 and 900 g·ha-1 for the second year (2006). In both years, the molybdenum rates applied on the leaves were 0 g·ha-1 (without) and 75 g·ha-1 (with). The results showed that the foliar calcium application, with or without molybdenum, did not improve yield. Foliar application of calcium alone improved seed physiological potential in common bean plants when applied at the full bloom stage.
[Show abstract][Hide abstract] ABSTRACT: This study evaluates the effects of different nitrogen (N) rates (0, 50, 100, 150, and 200 kg ha−1) and sources (ammonium sulfate, urea, and ammonium sulfonitrate with a nitrification inhibitor, Entec®) applied either as a single application during sowing (next to the planting rows) or as side dressing (stage 3.2 on Zadok scale), on production components and grain yield of irrigated wheat grown under no-till in a low-elevation Brazilian cerrado and Dark Red Dystrophic Latosol with clayey-texture. It was adopted a randomized block design (5 × 3 × 2) in factorial scheme with four replications. The N sources provided similar grain yields and chlorophyll contents. Increased nitrogen rates increased grain yield up to the 120 kg N ha−1, regardless of application time and N source. Nitrogen fertilization as side dressing can be recommended based on leaf chlorophyll readings. Early application of all nitrogen fertilizers at sowing time was viable.
Journal of Plant Nutrition 06/2014; 37(11). · 0.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Common bean is an important crop in Brazil primarily because of its nutritional characteristics. Some agronomic practices, such as weed management, are fundamental to cultivation, as a means of obtaining a high crop yield. However, some studies have shown that weed management may alter the function of the cultivar cycle. Thus, this study aimed at determining the optimal phenological stage in early-maturing common bean cultivars to perform the weed control without providing reductions in yield and seed quality. The experimental design was randomized blocks with 20 treatments and four replications, in a 2×2×5 (cultivars × types of weed control × periods of weed control) factorial scheme. The periods of weed control for both cultivars (Carioca Precoce and IPR-Colibri) consisted of full cycle weeded (control), weed control at the V4-3 stage (first three nodes on the main stem with trifoliate leaves), at the R5 stage (beginning of bloom) and at the R8 stage (appearance of pods) and full cycle unweeded (no weed control). The types of weed control used were chemical (fluazifop-p-butyl + fomesafen) and mechanical (hoe). The Carioca Precoce cultivar demonstrated higher agronomic performance and yield than the IPR-Colibri cultivar, although the IPR-Colibri seeds had a higher vigor. The type of weed control (chemical or mechanical) did not affect the agronomic characteristics, yield and seed physiological potential of the cultivars. The ideal period for weed control in early-maturing common bean cultivars to obtain a higher yield and seed physiological potential was observed at the V4-3 phenological stage.
[Show abstract][Hide abstract] ABSTRACT: The lodging of some rice cultivars, at harvest time, can cause significant losses in grain yield. The use of plant regulators is one of the alternatives to reduce lodging, however, information on that subject are still scarce. This study aimed to evaluate the use of ethyl-trinexapac doses (0 g ha-1, 50 g ha-1, 100 g ha-1, 150 g ha-1, and 200 g ha-1), at the floral differentiation stage, in rice cultivars with different types of plants (Caiapó - traditional; BRS Primavera and BRS Soberana - intermediate; and IAC 202 - modern), in order to evaluate grain development and yield. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, during the 2007/2008 growing season. It was observed that the application of 50 g ha-1, 100 g ha-1, and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage of the Caiapó, BRS Soberana, and BRS Primavera cultivars, respectively, decreased plants height and eliminated lodging; it was not necessary to use growth regulator for the IAC 202 cultivar, due to its lack of lodging; the application of 50 g ha-1 and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage, improved grain yield for the Caiapó and BRS Primavera cultivars, respectively, and the 100 g ha-1 dose interfered little in the BRS Soberana cultivar.
[Show abstract][Hide abstract] ABSTRACT: Com a abertura das áreas de cerrado, o cultivo da soja se expandiu para esses locais que apresentam alto potencial de produção para essa cultura quando bem manejados. Entretanto, por se tratarem de solos altamente intemperizados, pode ocorrer, em certas áreas, deficiências de silício solúvel no solo. O objetivo do presente trabalho foi avaliar a resposta à aplicação doses de silício em diferentes estádios fenológicos da cultura da soja e verificar sua importância como nutriente na ausência de pressão de doenças. Conclui-se que a aplicação de silício na fase vegetativa promoveu um estado hídrico mais adequado ã planta, uma vez que a massa fresca foi maior. Também verificou-se que a aplicação de silício nas doses estudadas não proporcionou incrementos em produtividade
[Show abstract][Hide abstract] ABSTRACT: A rúcula é uma hortaliça folhosa que tem ganhado espaço na oferta de alimentos em várias regiões do Brasil. Sua multiplicação se dá unicamente por sementes e, sendo assim, torna-se imperioso o uso de material propagativo de alta qualidade para a implantação da lavoura. Estudos mostram que o condicionamento fisiológico de sementes promove melhorias na velocidade e na uniformidade do estabelecimento de plântulas no campo. Assim, o presente trabalho foi realizado com o objetivo de verificar o efeito do condicionamento osmótico sobre o desempenho de sementes de rúcula. Cinco lotes da cultivar Cultivada, foram submetidas ao condicionamento osmótico por 24 horas, utilizando-se os potenciais osmóticos de 0,0, -0,1, -0,2, -0,3 MPa, obtidas através de solução de Polietilenoglicol (Carbonax 6000). Utilizou-se o delineamento inteiramente casualizado com 20 tratamentos (5 lotes × 4 potenciais osmóticos) e quatro repetições. As médias foram comparadas pelo teste de Tukey e análises de regressão para os potencias osmóticos. Os dados mostraram que o condicionamento osmótico provocou melhoria na germinação e na percentagem de plantas fortes em termos de vigor
[Show abstract][Hide abstract] ABSTRACT: The quality of the seed used in the process of agricultural production is one of the main factors to be considered for the implantation of the culture, having consensus between all the segments, on the importance of the vigor of the seeds and the necessity to evaluate it. This research had the purpose of studying proccedings for controlled deterioration test, to verify their sensitivity for identifying different vigor levels of arugula seed, cv. 'Cultivada' and 'Gigante', using five lots of seeds for each. The seeds were subjected to the determination of water content and tests of germination, first germination, emergence, and to verify the efficiency in identifying different levels of vigor, were studied variations in the controlled deterioration test (seed moisture content of 18, 21 and 24%, at 45oC for 24 and 48 hours). The experiment was arranged in completely randomized design and the results were submitted to analysis of variance and means were compared by Tukey test at 5% probability. The results obtained for the controlled deterioration test showed that there was no relation with the initial assessments of the physiological potential, especially for testing of emergency. It was concluded that under the conditions tested, this test was not sensitive enough to assess the potential physiologic arugula, for both cultivars.
[Show abstract][Hide abstract] ABSTRACT: The objective was to adapt the methodology of the accelerated aging test to evaluate the physiological potential of seeds of four lots of lettuce genotypes 'Babá de verão', 'Tainá' and 'Vera' applying the traditional method and using a saturated NaCl solution. So, the seeds were subjected to determination of water content, seed germination and vigor (first count, electrical conductivity, speed emergency index, emergency tray) including the accelerated aging test conducted in periods of 24, 48, 72 hours at 41°C with and without saturated solution of NaCl. The experiment was conducted in a randomized design with four replications. The accelerated aging traditional and saturated solution of NaCl by 72h was more sensitive to stratify the lots in vigor levels. Therefore, accelerated aging of seeds of lettuce should be made using the period of 72h and can be accomplished either by the traditional method and by the saturated NaCl solution method.
[Show abstract][Hide abstract] ABSTRACT: Objetivou-se adequar a metodologia do teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de quatro lotes dos genótipos de alface 'Babá de verão', 'Tainá' e 'Vera', aplicando-se o método tradicional e com o uso de solução saturada de NaCl. Para tal, as sementes foram submetidas à determinação do teor de água, testes de germinação e vigor (primeira contagem, condutividade elétrica, emergência em bandeja, índice de velocidade de emergência) incluindo o teste de envelhecimento acelerado, conduzido nos períodos de 24, 48, e 72 horas, a 41°C com e sem solução saturada de NaCl. O experimento foi conduzido em delineamento inteiramente casualizado com quatro repetições. Os procedimentos tradicional e com o uso da solução saturada de NaCl por 72 horas foram sensíveis em estratificar os lotes em níveis de vigor, além de estarem de acordo com os demais testes utilizados. Portanto, o envelhecimento acelerado de sementes de alface deve ser feito utilizando o período de 72 horas, podendo ser realizado tanto pelo método tradicional quanto pelo método da solução saturada de NaCl.
[Show abstract][Hide abstract] ABSTRACT: Nitrogen is one of the most lixiviated plant nutrients on soil and it can also be dispersed in its gaseous form, limiting many crops yield. Thus, this study aimed to evaluate the effect of N sources (urea and ammonium sulfate) combinations, at 80 kg ha-1, isolated or combined, with or without irrigation water incorporated to the soil. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, during two growing seasons (2003 and 2004), in the winter, by using a randomized block design with 12 treatments, in a 6x2 factorial scheme, with four replications. Six N sources combinations were used: control (without N); 80 kg ha-1 of N - ammonium sulfate (AS); 20 kg ha-1 of N - urea (U) + 60 kg ha-1 of N (AS); 40 kg ha-1 of N (U) + 40 kg ha-1 of N (AS); 60 kg ha-1 of N (U) + 20 kg ha-1 of N (AS); and 80 kg ha-1 of N (U), with and without addition of irrigation water. It was possible to conclude that the nitrogen supply, regardless of the source used, provided an increase in grain yield. No difference was observed, concerning the nitrogenous fertilizer incorporated or not to the soil with irrigation water.
[Show abstract][Hide abstract] ABSTRACT: The quality of seeds used in the agricultural production process is one of the main factors considered for the development of a crop. This study investigated the effect of vigor level in the performance of six oleraceous species seeds. Commercial seeds of lettuce, eggplant, broccoli, cauliflower, rocket, and tomato were subjected to accelerated aging, for 48 and 72 hours, to obtain lots with three vigor levels, resulting in one regular lot and two lots aged for different periods. After that, the seeds were submitted to germination tests, electrical conductivity, seedling emergence in trays, seedling length and dry weight. The effect of accelerated aging becomes stronger when the exposure time of seeds to high air relative humidity and temperature increases. This exposure reduces more emphatically the seed quality for some species, such as lettuce, cauliflower, and rocket, than for others, such as broccoli, tomato and eggplant. Less vigorous seeds, in addition to lower germination and emergence, show delays in the seedling formation process.
[Show abstract][Hide abstract] ABSTRACT: The use of nitrogen fertilizer in seed production fields can improve seed yield and quality by affecting the embryo and reserve organs formation. The objective of this study was to evaluate bean seeds yield and physiologic potential, according to nitrogen top-dressing application on two cultivars. It was used a randomized blocks design, in a 2×6 factorial scheme, with 12 treatments (Pérola and IAC Carioca Eté cultivars and six top-dressing nitrogen levels: 0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1, and 150 kg ha-1) and four replications. The nitrogen application increased the seeds yield with optimal dose of 143 kg of N ha-1, for the Pérola cultivar, and 134 kg of N ha-1, for the IAC Carioca Eté cultivar, with Pérola showing higher yield levels. Changes in seeds quality were not observed when nitrogen levels increased.
[Show abstract][Hide abstract] ABSTRACT: Proper management of nitrogen fertilization and using cultivars with high productive potential are essential to obtain high wheat yield. Thus, the objective of the present study was to assess the effects of different N doses and sources, one with a nitrification inhibitor, applied at sowing or as side dressing, on the production components and yield of two wheat cultivars irrigated, under no till, cultivated in a region of low altitude Cerrado (Selvíria - MS). A randomized block design was used in a 5x3x2x2 factorial arrangement, that is, five nitrogen doses (0, 50, 100, 150 and 200kg ha-1), three nitrogen sources (ammonium sulfonitrate with nitrification inhibitor (Entec®), ammonium sulfate and urea) and two nitrogen application times (at sowing or side dressing) on two wheat cultivars ('E 22' and 'E 42') with three replications. There was no difference for grain yield between the wheat cultivars and among the nitrogen sources. The application of nitrogen totally at sowing is feasible as well as the traditional application at sowing and side dressing. The nitrogen doses increased the leaf N content of the 'E 22' cultivar, resulting in a reduction in the hectolitric mass of the 'E 42' cultivar and increased grain yield of the 'E 22' and 'E 42' wheat yield cultivars, respectively, up to doses of 126 and 122kg ha-1 N, regardless of the application time and the nitrogen source.
[Show abstract][Hide abstract] ABSTRACT: O uso de fertilizante nitrogenado, em campos de produção de sementes, pode beneficiar a produtividade e a qualidade da semente, por afetar a formação do embrião e dos órgãos de reserva. Assim, objetivou-se, com este trabalho, avaliar a produção e o potencial fisiológico de sementes de feijoeiro, em função da aplicação de nitrogênio em cobertura, em duas cultivares. Utilizou-se o delineamento de blocos casualizados, em esquema fatorial 2×6, com 12 tratamentos (cultivares Pérola e IAC Carioca Eté e seis doses de nitrogênio em cobertura: 0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1 e 150 kg ha-1) e quatro repetições. O nitrogênio promoveu aumentos na produção de sementes, com dose ótima de 143 kg de N ha-1, para a cultivar Pérola, e 134 kg de N ha-1, para a cultivar IAC Carioca Eté, com a Pérola apresentando maiores níveis de produtividade. Alterações na qualidade de sementes não foram verificadas com o aumento das doses de nitrogênio.
[Show abstract][Hide abstract] ABSTRACT: A qualidade da semente utilizada no processo de produção agrícola é um dos principais fatores considerados para a implantação da cultura. Este trabalho objetivou estudar o efeito do nível de vigor no desempenho de sementes de seis espécies oleráceas. Sementes comerciais de alface, berinjela, brócolis, couve-flor, rúcula e tomate foram submetidas ao envelhecimento acelerado, por 48 e 72 horas, para obtenção de lotes com três níveis de vigor. Obteve-se um lote normal e dois envelhecidos por diferentes períodos. Após a obtenção dos lotes, as sementes foram submetidas a testes de germinação, condutividade elétrica, emergência de plântulas em bandeja, comprimento e massa seca de plântulas. O efeito do envelhecimento acelerado torna-se mais acentuado com o aumento do tempo de exposição das sementes às condições de alta umidade relativa do ar e elevada temperatura. Esta exposição reduz, mais acentuadamente, a qualidade das sementes para algumas espécies, como alface, couve-flor e rúcula, que para outras, como brócolis, tomate e berinjela. Sementes de menor vigor, além de menor germinação e menor emergência, apresentam lentidão no processo de formação de mudas.