Periods Of Weed Interference In Maize Crops Cultivated In The First And Second Cycles

The interference of weeds in maize production may be reflected in grain yield losses that vary as a function of the density, stage and degree of aggressiveness of the species present. In the agricultural ecosystem, crops and weeds demand light, water, nutrients and space, which are frequently not available in sufficient quantities, leading to competition. The aim of this work was to determine the period of interference of weed plants, in particular of naked crabgrass (Digitaria nuda) on maize crop in the first and second harvest. The treatments were defined as increasing periods of coexistence and increasing control of weed community (7, 14, 21, 28, 35, 42, 49, and 56 days), two more controls, a control including one with weed control until the end of the culture cycle and another with coexistence until the harvest. For each period, were evaluated the stand of maize plants, length of ear, number of grains per row, number of rows per ear, cob, 100-grain weight, and grain productivity. The data obtained were subjected to analysis of variance using the F test, with average treatments compared using Tukey's test at 5% probability. Crop productivity was evaluated by means of regressions, the critical periods of interference were estimated. The critical timing of weed removal was 25 days for both harvests. The critical weed free period was 54 and 27 days for the first and second harvest respectively. For the conditions of the first and second harvest, the critical period of weed control was of 29 and 2 days respectively.3752867287

Heavy metals and micronutrients in soils under dairy grazing right on top of the river Paranaíba basin in the state of Goiás, Brazil

In Brazil, the agricultural activity is among the most competitive sectors of national economy, in which milk production has a very significant contribution. Concern about environmental contamination by this activity is related to the fact that dairy cattle manure heavy metals present in the constitution; the creation of such animals in the grazing system directly questions the possibility of any contamination by these metals in the watery, area where these animals congregate at certain times of day for drinking water and where they defecate. This study aimed to evaluate the content of copper, iron, manganese, zinc, cadmium, lead and chromium in watery areas and in conservation areas (control) of 28 properties, grouped into six “otto-basins” forming the upper basin of the Paranaíba River in the State of Goiás. The simple soil samples were collected at three depths (0-10, 10-20 and 20-30 cm) obtained from such a composite sample for each depth in the areas watered and preserved. The analysis of PCA metals pollutants in soils watery areas analyzed did not indicate the occurrence of contamination in these environments when compared to the preserved area. Observed random distribution of average levels of metals in the three studied depths in all treatments, which complicates the definition of the potential for soil contamination by feces of dairy farming originated in watery areas, under rotational grazing.A preocupação quanto à contaminação do ambiente por meio da atividade leiteira está relacionada ao fato dos dejetos destes bovinos apresentarem metais poluentes em sua constituição; na criação desses animais no sistema de pastejo direto questiona-se a possibilidade da ocorrência de contaminação por estes metais nas aguadas, área onde esses animais se aglomeram em determinados períodos do dia para beberem água e onde defecam. O presente estudo objetivou avaliar os teores dos metais cobre, ferro, manganês, zinco, cádmio, chumbo e cromo em áreas de aguadas e em áreas preservadas (testemunha) de 28 propriedades, agrupadas em seis Ottobacias hidrográficas formadoras do alto da bacia do Rio Paranaíba, no Estado de Goiás. As amostras simples de solos foram coletadas em três profundidades (0-10, 10-20 e 20-30 cm), a partir destas foram obtidas uma amostra composta para cada profundidade nas áreas de aguadas e preservadas. Pela análise de PCA os metais poluentes analisados nos solos de aguada não indicou a ocorrência de contaminação nestes ambientes quando comparados à área preservada. A distribuição aleatória dos teores médios dos metais nas três profundidades estudadas em todos os tratamentos dificulta a definição do potencial de contaminação do solo pelos dejetos originados da atividade leiteira em áreas de aguadas, sob pastejo direto3052582590Alvarenga, M.I.N., Davide, A.C., Características físicas e químicas de um Latossolo Vermelho-Escuro e a sustentabilidade de agroecossistemas (1999) Revista Brasileira de Ciência do Solo, 23 (4), pp. 933-942. , ViçosaByers, H.L., Cabrera, M.L., Matthews, M., Franklin, D.H., Andrae, J.G., Radcliffe, D.E., McCann, M.A., Calvert Jr, V.H., Phosphorus, sediment and Escherichia coli loads in unfenced streams of the Georgia Piedmont, USA (2005) Journal of Environmental Quality, 34 (11), pp. 2293-2300. , MadisonCorreia, P.R.M., Ferreira, M.M.C., Reconhecimento de padrões por métodos não supervisionados: Explorando procedimentos quimiométricos para o tratamento de dados analíticos (2007) Revista Química Nova, 30 (2), pp. 48-487. , São PauloEMBRAPA-Embrapa Informação Tecnológica, (2003) Pesquisa, desenvolvimento e inovação para o agronegócio brasileiro: Cenários 2002-2012, 92p. , Embrapa/Secretaria de Gestão e Estratégia. Brasília: Embrapa Informação TecnológicaIBGE-Instituto Brasileiro de Geografia e Estatística. Indicadores: Produção pecuária, , http://www.ibge.gov.br/home/mapa_site/mapa_site.php, Disponível em, Acesso em: 02 abr. 2012McGechan, M.B., Topp, C.F.E., Modelling environmental impacts of deposition of excreted nitrogen by grazing dairy cows (2004) Agriculture, Ecossystems e Environment, 103 (1), pp. 149-164. , AmsterdamMoura, M.C.S., Lopes, A.N.C., Moita, G.C., Moita Neto, J.M., Estudo multivariado de solos urbanos da cidade de Teresina (2006) Revista Química Nova, 29 (3), pp. 429-435. , São PauloOliver, M.A., Soil and human health: A review (1997) Journal Science Soil, 48 (4), pp. 573-592. , OxfordPereira, A.A., Borges, J.D., Leandro, W.M., Metais poluentes e micronutrientes no solo e em folhas de brachiaria decumbens às margens de rodovias (2010) Bioscience Journal, 26 (3), pp. 347-357. , UberlândiaPfafstetter, O., (1989) Classificação de bacias hidrográficas: Metodologia de codificação, 19p. , Rio de Janeiro, RJ: Departamento Nacional de Obras de Saneamento (DNOS), Trabalho não publicadoQuaggio, J.A., van Raij, B., Comparação de métodos rápidos para determinação da matéria orgânica em solo (1979) Revista Brasileira de. Ciência do Solo, 3 (3), pp. 184-187. , CampinasSEPIN-Superintendência de Pesquisa e Informação, (2012) Anuário Estatístico do Estado de Goiás-2005, , http://www.segplan.go.gov.br/, Disponível em: Acesso em: 22 junWijewardena, J.D.H., Gunaratne, S.P., Heavy metal in commonly used animal manure (2004) Annals of the Sri Lanka Dapartment of agriculture, 6 (2), pp. 245-253. , BombuwelaIn Brazil, the agricultural activity is among the most competitive sectors of national economy, in which milk production has a very significant contribution. Concern about environmental contamination by this activity is related to the fact that dairy cattle manure heavy metals present in the constitution; the creation of such animals in the grazing system directly questions the possibility of any contamination by these metals in the watery, area where these animals congregate at certain times of day for drinking water and where they defecate. This study aimed to evaluate the content of copper, iron, manganese, zinc, cadmium, lead and chromium in watery areas and in conservation areas (control) of 28 properties, grouped into six “otto-basins” forming the upper basin of the Paranaíba River in the State of Goiás. The simple soil samples were collected at three depths (0-10, 10-20 and 20-30 cm) obtained from such a composite sample for each depth in the areas watered and preserved. The analysis of PCA metals pollutants in soils watery areas analyzed did not indicate the occurrence of contamination in these environments when compared to the preserved area. Observed random distribution of average levels of metals in the three studied depths in all treatments, which complicates the definition of the potential for soil contamination by feces of dairy farming originated in watery areas, under rotational grazin

Efeitos da fertilização foliar com manganês em soja transgênica cultivada no inverno manejada com glifosato

O uso de glifosato pode ocasionar deficiência nutricional na soja RR, sendo o fertilizante com Mn utilizado para corrigir potenciais danos provocados pelo herbicida. Este trabalho tem como objetivo avaliar a disponibilidade do micronutriente Mn, aplicado via foliar, na cultura da soja RR em safra de inverno, para seus teores foliares e componentes de produção e produtividade, em resposta a diferentes doses do nutriente e estádios fenológicos de aplicação, com manejo de glifosato. O delineamento experimental usado foi em blocos casualizados e esquema fatorial (2x5) com 3 repetições, sendo 2 estádios de aplicação do Mn (V3 e R2) e 5 doses do nutriente (0,00; 22,35; 44,70; 67,05 e 89,40 g ha-1 de Mn). Os resultados indicaram que a aplicação de fertilizante comercial com Mn, na dose de 89,40 g ha-1 no estádio V3, contribuiu para a elevação dos teores foliares de Mg, já a aplicação no estádio R2 favoreceu a elevação do teor foliar de Mn e não houve contribuição dos tratamentos para o aumento dos componentes de produção e produtividade da soja RR de invernoThe use of glyphosate can cause nutritional deficiency in RR soybean, being the fertilizer with Mn used to correct potential damages caused by this herbicide. This work aimed to evaluate the availability of the micronutrient Mn, by foliar application, in RR soybean culture in winter crop, for the foliar concentrations and the yield components and productivity, in response to different doses of the nutrient and phenology stages of application, with glyphosate management. The experimental design used was in randomized blocks in factorial scheme (2X5) with 3 replications, being 2 application stages of Mn (V3 and R2) and 5 doses of the micronutrient (0.00; 22.35; 44.70; 67.05; 89.40 g ha-1 of Mn). The results indicate that the application of the commercial fertilizer with Mn, in the dose of 89.40 g ha-1 in V3 stage, contributed for the elevation of the foliar concentrations of Mg, while the application in the R2 stage provided the elevation of Mn foliar concentration, but there wasn’t contribution of the treatments for the increase of the yield components and productivity of the RR soybean in winter cropÀ Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná, BrasilS

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

Transitions of cardio-metabolic risk factors in the Americas between 1980 and 2014

Describing the prevalence and trends of cardiometabolic risk factors that are associated with non-communicable diseases (NCDs) is crucial for monitoring progress, planning prevention, and providing evidence to support policy efforts. We aimed to analyse the transition in body-mass index (BMI), obesity, blood pressure, raised blood pressure, and diabetes in the Americas, between 1980 and 2014