Cover crops and nitrogen doses in wheat under no-tillage system

The application of conservation practices in production systems is essential to the sustainability of the agricultural production capacity. The use of different cover crops can reduce the need of topdressing nitrogen fertilizers in wheat crops. This study aimed at evaluating the influence of cover crops residues (millet, sunn hemp, pigeon pea, millet + sunn hemp, millet + pigeon pea and fallow ground), grown previously to the summer crop (rice), and topdressing nitrogen doses (0 kg ha-1, 25 kg ha-1, 50 kg ha-1, 75 kg ha-1, 100 kg ha-1 and 125 kg ha-1), in the development and yield of wheat under no-tillage system. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, in a Red Oxisol, in 2009/2010 and 2010/2011. The experimental design was randomized blocks, in a 6x6 factorial scheme. The cover crops developed during August/October (2009/2010) and September/November (2010/2011), previously to the summer crop, with the chemical desiccation performed respectively at 73 and 55 days after sowing. The wheat (winter) was sown in May, in both periods, and harvested at 113 (2009/2010) and 106 (2010/2011) days after emergence. The cover crops residues of pigeon pea, sunn hemp and millet + sunn hemp, preceding wheat, provided higher wheat yields, relatively to the fallow ground. The wheat yield showed a quadratic response to the increase in the nitrogen availability, reaching higher yields with the nitrogen doses estimated in 113 kg ha-1 (2010) and 98 kg ha-1 (2011)

Use of ethyl-trinexapac in upland rice cultivars

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

Dental caries experience in relation to salivary findings and molecular identification of S. mutans and S. sobrinus in subjects with Down syndrome

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)This study investigated the association between clinical and salivary or molecular parameters in Down syndrome subjects. Sixty individuals (1- to 48-year old) were clinically examined using DMFT/DMFS. Stimulated saliva was collected; salivary flow was calculated (mL/min), buffering capacity was measured using a standard pH tape. In addition, 25 mu L of saliva was diluted using 10-fold-dilution method and then placed on Mitis-Salivarius-Bacitracin agar to count colony forming units (CFU/mL) of mutans streptococci. Polymerase chain reaction analysis identified species. Caries indexes were 0.65-13.5 (DMFT) and 0.65-26.0 (DMFS) according to groups. Ninety-four percent of subjects had low flow rate (0.7-1.0 mL/min) and 44% had low buffering capacity (pH 0.05), and showed no significant association with prevalence of species by Chi-square (p > 0.05). There is no association between clinical picture and salivary or molecular parameters in Down syndrome subjects.992162167Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [04/12925-0

Uso de reguladores de crescimento no desenvolvimento e produção de crotalária

Estudos têm evidenciado a viabilidade da aplicação de reguladores de crescimento na agricultura, entretanto, informações referentes à sua utilização em crotalária ainda são escassas. Diante disto, este trabalho objetivou avaliar a influência da aplicação foliar de reguladores de crescimento (cloreto de mepiquat, etil-trinexapac e paclobutrazol), em diferentes doses (0 g ha-1, 75 g ha-1, 150 g ha-1, 225 g ha-1 e 300 g ha-1), sobre o desenvolvimento vegetativo e reprodutivo de Crotalaria juncea L. O experimento foi conduzido em 2010, em Selvíria (MS). O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 3x5 (reguladores x doses), com quatro repetições. Foram mensurados caracteres agronômicos e produtividade e os resultados submetidos ao teste F, sendo as médias de reguladores comparadas pelo teste Tukey (p < 0,05) e as de doses pela análise de regressão. Os reguladores de crescimento influenciaram no desenvolvimento vegetativo e reprodutivo da crotalária. O incremento nas doses de etil-trinexapac e paclobutrazol reduziu linearmente a altura de planta, ao passo que, para o cloreto de mepiquat e paclobutrazol, houve aumento no número de vagens e sementes por planta e redução de produtividade. A população final de plantas, número de sementes por vagem e massa de mil sementes não foram afetados pelos reguladores.Studies have pointed out the viability of the application of growth regulators in agriculture, however, information referring their use in Crotalaria juncea are still rare. Thus, this study aimed to evaluate the influence of the foliar application of growth regulators (mepiquat chloride, etil-trinexapac, and paclobutrazol), at different doses (0 g ha-1, 75 g ha-1, 150 g ha-1, 225 g ha-1, and 300 g ha-1), on the vegetative and reproductive development of Crotalaria juncea L. The experiment was carried out in 2010, in Selvíria, Mato Grosso do Sul State, Brazil. The experimental design was randomized blocks, in a 3x5 (regulators x doses) factorial scheme, with four replications. Agronomic traits, yield, and the F test results were evaluated, being the regulators averages compared by the Tukey test (p < 0.05) and doses compared by regression analysis. Growth regulators influenced the vegetative and reproductive development of Crotalaria juncea. The increase of etil-trinexapac and paclobutrazol doses reduced linearly the plant height, while the use of mepiquat chloride and paclobutrazol increased the number of pods and seeds per plant and reduced yield. The final plants population, number of seeds per pod, and weight of one thousand seeds were not affected by the growth regulators.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Resposta da crotalária a épocas e subdoses de aplicação de glifosato

The use of glyphosate sub-lethal rates can be an alternative to reduce the plant height of sunn hemp, facilitating its mechanical harvest. However, little known on the other effects that its application can result in this culture. This work aimed to evaluate the influence of application times (10; 20 and 30 days after the emergence) and glyphosate sub-lethal rates (0; 30; 60; 90 and 120 g ha(-1)), on the vegetative and reproductive development of Crotalaria juncea cultivated in no-tillage system. The experiment was conducted between the january and june months of year 2010, in Selviria, Mato Grosso do Sul State, Brazil, on a clayey Rhodic Haplustox (20 degrees 20' S and 51 degrees 24' W). The experiment design was randomized blocks in factorial arrangement 3 x 5 (application times x glyphosate rates), with four replicates. Were measured agronomic characters and productivity and the results undergone to the test F, being the times averages compared by Tukey test (P<0.05) and of rates by regression analysis. The stem diameter, seeds number per pod and mass of one thousand seeds not were affected by glyphosate application. Despite the glyphosate have provided reduction in plant height and increase of the branches number in Crotalaria juncea, not recommended the sub-lethal rates application of product per of affect straightly the culture productivity.A utilização de subdoses de glifosato pode ser uma alternativa para reduzir o porte das plantas de crotalária, facilitando a sua colheita mecânica. No entanto, pouco se sabe sobre os outros efeitos que sua aplicação pode acarretar nesta cultura. Este trabalho objetivou avaliar a influência de épocas de aplicação (10; 20 e 30 dias após a emergência) e subdoses de glifosato (0; 30; 60; 90 e 120 g ha-1), sobre o desenvolvimento vegetativo e reprodutivo de Crotalaria juncea cultivada em sistema plantio direto. O experimento foi conduzido entre os meses de janeiro e junho de 2010, no município de Selvíria, Estado de Mato Grosso do Sul, em Latossolo Vermelho distrófico (20º 20’ S e 51º 24’ W). O delineamento experimental foi o de blocos ao acaso em esquema fatorial 3 x 5 (épocas de aplicação x doses de glifosato), com quatro repetições. Foram mensurados caracteres agronômicos e produtividade e os resultados submetidos ao teste F, sendo as médias de épocas comparadas pelo teste de Tukey (P<0,05) e de doses pela análise de regressão. O diâmetro de caule, o número de sementes por vagem e a massa de mil sementes não foram afetados pela aplicação de glifosato. Apesar de o glifosato ter proporcionado redução na altura de planta e aumento do número de ramos na Crotalaria juncea, não se recomenda a aplicação de subdoses do produto por afetar diretamente a produtividade da cultura

Mecanismos de abertura de sulcos, inoculação e adubação nitrogenada em feijoeiro em sistema plantio direto

O feijão, juntamente com o arroz, constitui a base da alimentação dos brasileiros e para que possa ao mesmo tempo ser rentável ao produtor e acessível a toda população, é preciso desenvolver técnicas que elevem a produtividade com baixo custo. O objetivo deste trabalho foi estudar o efeito dos mecanismos de abertura de sulco para a deposição de fertilizantes (haste e disco duplo), da inoculação de sementes de feijão cultivar Pérola com estirpes de Rhizobium tropici com diferentes níveis de nitrogênio em cobertura (zero, 60, 120 e 180 kg ha-1) no feijoeiro cultivado em sistema plantio direto. Utilizou-se o delineamento experimental em blocos casualizados em esquema fatorial 2x2x4. O estudo foi desenvolvido no município de Selvíria (MS), em Latossolo Vermelho distrófico argiloso em 2006 e 2007. Conclui-se que o mecanismo de abertura do tipo haste promove a maior população final de plantas quando comparado ao uso do disco duplo desencontrado, incrementando a produtividade de grãos. A inoculação de sementes com Rhizobium tropici não interferiu no teor de N nas folhas bem como na produtividade de grãos. A adubação nitrogenada em cobertura proporcionou incrementos no teor de N nas folhas e na produtividade de grãos do feijoeiro de inverno.Common bean and rice make the daily staple food of the Brazilian population. There is need to improve crop management techniques to increase yield of common bean leading to a decrease in the production costs to enable reasonable prices for consumers. The objective of this study was to evaluate the effects of furrow opening mechanisms for fertilizer deposition (double disk and knife coulter), inoculation of seeds with Rhizobium tropici and different levels of nitrogen fertilization at sidedressing ( Zero, 60, 120 e 180 kg ha-1) on crop growth and yield, and leaf nitrogen (N) content. The experiment design was a randomized block in a factorial scheme 2x2x4 and it was set up on a clayey Oxisol in Selviria, State of Mato Grosso do Sul, Brazil, in 206 and 2007. Opening knife coulter caused larger final plant population than double disk and led to an increase the grain yield. The seed inoculation with Rhizobium tropici did not interfere in the leaf N content and in the grain yield. The sidedressing nitrogen fertilization provided increments of leaf N content and in the grain yield of winter common bean crop.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Influence of Cavity Disinfectant and Adhesive Systems on the Bonding Procedure in Demineralized Dentin - A One-year In Vitro Evaluation

Purpose: To evaluate the influence of a 2% chlorhexidine solution (CHX) on the bond strength and nanoleakage of two self-etching adhesive systems on demineralized dentin over a 12-month period. Materials and Methods: The middle dentin from sound third molars was exposed and demineralized in vitro. Twelve groups were formed using different adhesive systems (Clearfil Protect Bond [PB], Clearfil SE Bond [SE]) dentin treatment (with or without CHX application), and water-storage times (24 h, 6 and 12 months). Composite resin cylinders were bonded to the prepared dentin, and these specimens underwent microshear bond strength (mu SBS) testing and nanoleakage evaluation. mu SBS data were submitted to a three-way ANOVA and Tukey's test. The failure mode and nanoleakage were analyzed descriptively by score. Results: There was a statistically significant interaction only between the adhesive system and CHX, and adhesive system and water-storage times. SE showed the lowest mu SBS just at 24 h water-storage time regardless of CHX. A significant decrease in mu SBS values after 6 months of water storage occurred in all of the groups and was maintained until 12 months. Adhesive failure increased with storage time. All groups showed nanoleakage at the resin/dentin interfaces and an increased silver deposition was noticed after 6 and 12 months of water storage. The highest percentages of nanoleakage were found in CHX groups. Conclusion: CHX did not interfere with mu SBS values for either self-etching adhesive system, but water storage did. Bond strength decreased for both adhesive systems after 6 and 12 months, regardless of CHX application. Nano leakage increased with water-storage time and with CHX application.14657558

Manejo do solo e do nitrogênio em milho cultivado em espaçamentos reduzido e tradicional

Práticas agronômicas que ajudem o agricultor a elevar a produtividade e a diminuir os custos de produção devem ser estudadas para garantir a sustentabilidade da agricultura. Assim, desenvolveu-se um experimento com o objetivo de estudar o efeito do manejo do solo, do nitrogênio e do espaçamento entrelinhas na cultura do milho em dois anos agrícolas. O experimento foi instalado sobre um Latossolo Vermelho Distrófico em delineamento experimental de blocos casualizados em esquema fatorial 3 x 5 x 2 com quatro repetições. Os tratamentos foram constituídos pela combinação de três manejos do solo (grade aradora + grade niveladora, escarificador + grade niveladora e plantio direto), cinco épocas de aplicação do nitrogênio [testemunha sem N, 120 kg ha-1 na semeadura (S), 120 kg ha-1 no estádio fenológico V6, 30 kg ha-1 (S) + 90 kg ha-1 em V6, 30 kg ha-1 (S) + 45 kg ha-1 em V4 + 45 kg ha-1 em V8] e dois espaçamentos entrelinhas (0,45 e 0,90 m) com população fixa. Concluiu-se que o sistema plantio direto promoveu maior população final de plantas e maior produtividade de grãos; a aplicação precoce de todo o N proporcionou produtividade de grãos semelhante aos manejos com parcelamento, e o espaçamento de 0,90 promoveu maior massa seca dasplantas quando o preparo foi feito com grade aradora + niveladora.Agronomic practices that help the farmer raise the yield and reduce costs must be studied to ensure the sustainability of agriculture. Thinking about it, an experiment was conducted to study the effect of soil management, nitrogen fertilization and the row spacing in maize crop. It was developed in Distrophic Red Latossol. The experimental design was randomized in split plot in a factorial 3 x 5 x 2 with 4 repetitions. The treatments were constituted by the combination of three soil managements (plow harrow + floating harrows, chisel + floating harrows and no tillage), five times of nitrogen supply [control without N, 120 kg ha-1 at sowing (S), 120 kg ha-1 at V6 stage, 30 kg ha-1 (S) + 90 kg ha-1 at V6, 30 kg ha-1 (S) + 45 kg ha-1 at V4 + 45 kg ha-1 at V8] and two row spacings (0.45 and 0.90 m) with the same plants stand. It was concluded that the no tillage system promotes better plant population, and higher grain yield; the nitrogen supply only at sowing promoted grain yield similar to the treatments that the N was divided; the 0.90 m row spacing promoted greater plant stand when the soil management was done with plow harrow + floating harrow.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Fontes e épocas de aplicação de nitrogênio em feijoeiro de inverno sob sistema plantio direto

O aproveitamento do nitrogênio pelo feijoeiro é dependende da fonte, dose e época de aplicação. Com o objetivo de se avaliar o efeito de fontes e épocas de aplicação de N sobre feijoeiro cultivado em sistema plantio direto, desenvolveu-se o presente trabalho, no município de Selvíria (MS), em 2006 e 2007, com os tratamentos dispostos em delineamento de blocos casualizados, em esquema fatorial 3x6, com quatro repetições. Foram avaliadas fontes de N (ureia, entec e sulfato de amônio) e épocas de aplicação (testemunha - sem N, semeadura, estádio de desenvolvimento V3, estádio de desenvolvimento V4-5, 1/3 semeadura + 2/3 estádio V3 e 1/3 semeadura + 2/3 estádio V4-5). As fontes de N tiveram influência semelhante sobre a produtividade do feijoeiro, afetando apenas o teor de N foliar, em 2006, sendo que a utilização de entec proporcionou concentrações do nutriente, nas folhas, equivalentes às da ureia. A aplicação de todo o N na semeadura afetou a população inicial e final de plantas, em 2006, sendo que o mesmo não foi observado em 2007. As épocas de aplicação não influenciaram na produtividade de grãos da cultura, em ambos os anos de cultivo, porém, em 2006, a adubação nitrogenada incrementou a produtividade em mais de 100%, em média, independentemente da época de aplicação.The use of nitrogen by common bean is dependent on the source, dose and application time. This study aimed to evaluate the effect of N sources and application times on common bean under no-till system, in Selvíria, Mato Grosso do Sul State, Brazil, in 2006 and 2007. Treatments were disposed in a randomized blocks design, in a 3x6 factorial scheme, with four replications. Nitrogen sources (urea, entec, and ammonium sulfate) and application times (control - without N, at sowing, at the V3 development stage, at the V4-5 development stage, 1/3 at sowing + 2/3 at the V3 stage, and 1/3 at sowing + 2/3 at the V4-5 stage) were evaluated. The N sources had similar influence on common bean yield, affecting only the N leaf content, in 2006, and the use of entec provided leaf nutrient concentrations equivalent to the urea ones. The application of all available N at sowing affected the initial and final plant stands, in 2006, while the same was not observed in 2007. Application times did not influence on grains yield, for both years, however, in 2006, the nitrogen fertilization increased yield in more than 100%, on average, independently of the application time