Avaliação de doses e datas de aplicação de nitrogênio no feijão-comum por meio de modelo de simulação.

A adubação nitrogenada é um dos fatores responsáveis pelo alcance de altas produtividades na cultura do feijoeiro, portanto, o manejo adequado do nitrogênio é fundamental para que as necessidades da cultura sejam atendidas, garantindo boas produtividades e diminuindo o custo de produção e os riscos de poluição ambiental. O objetivo deste trabalho foi avaliar in silico o efeito de diferentes doses e épocas de aplicação de nitrogênio na produtividade do feijão-comum, em três safras de cultivo, em diferentes datas de semeadura, para as condições edafoclimáticas de Goiás.Evento online

Avaliação econômica da aplicação de doses de nitrogênio na cultura do feijão-comum.

O nitrogênio (N) é o nutriente que mais limita a produtividade do feijoeiro e, portanto, é aplicado em grandes quantidades, o que torna o custo de produção mais oneroso. Objetivou-se com este estudo avaliar a viabilidade econômica da aplicação de diferentesdoses de nitrogênio na cultura do feijoeiro, para as condições edafoclimáticas de Goiás.Evento online

Modeling of Soybean under Present and Future Climates in Mozambique

Citation: Talacuece, M. A. D., Justino, F. B., Rodrigues, R. D., Flores, M. E. P., Nascimento, J. G., & Santos, E. A. (2016). Modeling of Soybean under Present and Future Climates in Mozambique. Climate, 4(2), 14. doi:10.3390/cli4020031This study aims to calibrate and validate the generic crop model (CROPGRO-Soybean) and estimate the soybean yield, considering simulations with different sowing times for the current period (1990-2013) and future climate scenario (2014-2030). The database used came from observed data, nine climate models of CORDEX (Coordinated Regional climate Downscaling Experiment)-Africa framework and MERRA (Modern Era Retrospective-Analysis for Research and Applications) reanalysis. The calibration and validation data for the model were acquired in field experiments, carried out in the 2009/2010 and 2010/2011 growing seasons in the experimental area of the International Institute of Tropical Agriculture (IITA) in Angonia, Mozambique. The yield of two soybean cultivars: Tgx 1740-2F and Tgx 1908-8F was evaluated in the experiments and modeled for two distinct CO2 concentrations. Our model simulation results indicate that the fertilization effect leads to yield gains for both cultivars, ranging from 11.4% (Tgx 1908-8F) to 15% (Tgx 1740-2Fm) when compared to the performance of those cultivars under current CO2 atmospheric concentration. Moreover, our results show that MERRA, the RegCM4 (Regional Climatic Model version 4) and CNRM-CM5 (Centre National de Recherches Meteorologiques - Climatic Model version 5) models provided more accurate estimates of yield, while others models underestimate yield as compared to observations, a fact that was demonstrated to be related to the model's capability of reproducing the precipitation and the surface radiation amount

Produtividade do feijoeiro-comum irrigado na época das águas em Goiás.

O objetivo deste estudo foi quantificar o aumento de produtividade do feijoeiro irrigado com diferentes níveis de recarga de água no solo e datas de semeadura na época das águas em Goiás, como forma de mitigar possíveis quedas na produção, ocasionadas pelos veranicos

Viabilidade da irrigação suplementar do feijoeiro na época das águas.

O estudo visou quantificar o retorno econômico proporcionado pela irrigação suplementar do feijoeiro na época das águas. A produtividade do feijoeiro foi simulada para 30 anos no modelo de cultura Cropgro-Dry Bean para a cultivar Pérola, considerando as datas de semeadura de 1º de novembro a 1º de janeiro e quatro manejos hídricos: sem irrigação; irrigação com 70%, 50% e 30% do total de água disponível no solo (TAD). As irrigações a 70%, 50% e 30% do TAD aumentaram a produtividade em 26,7% a 41,4%; 5,5% a 14,5%; e 0,4% a 2,4% , respectivamente . A demanda média foi de 53 mm ciclo-1 no manejo de 70% do TAD e de 19 mm ciclo-1 no de 50% e de 30%, sem necessidade de irrigação na maioria das estações de cultivo. O atraso na semeadura em relação a 1º de novembro reduziu a produtividade do feijoeiro. O preço mínimo de venda de R$1,85 a R$2,83 por kg é requerido para uma taxa interna de retorno superior a 12%. A irrigação a 70% do TAD fornece índice econômico semelhante e/ou superior, e produtividade maior que o sistema de sequeiro

Dust Transport to the Taylor Glacier, Antarctica, During the Last Interglacial

Changes in the composition of dust trapped in ice provide evidence of past atmospheric circulation and earth surface conditions. Investigations of dust provenance in Antarctic ice during glacial and interglacial periods indicate that South America is the primary dust source during both climate regimes. Here, we present results from a new ice core dust archive extracted from the Taylor Glacier in coastal East Antarctica during the deglacial transition from Marine Isotope Stage 6 to 5e. Radiogenic strontium and neodymium isotopes indicate that last interglacial dust is young and volcanic, in contrast to the observed preindustrial and Holocene (Marine Isotope Stage 1) dust composition. The dust composition differences from the last interglacial and current interglacial period at the site require a profound difference in atmospheric transport and environmental conditions. We consider several potential causes for enhanced transport of volcanic material to the site, including increased availability of volcanic material and large‐scale atmospheric circulation changes.Plain Language SummaryFluctuations in the isotopic composition of dust particles transported atmospherically and trapped in East Antarctic ice during glacial and interglacial periods provide glimpses into past earth surface conditions and atmospheric dynamics through time. Here we present new ice core records of dust from the Taylor Glacier (Antarctica), extending back to the transition into the last interglacial period (~130,000 years ago). Dust deposited at this site during the last interglacial period has a significantly more volcanic dust composition compared to the current interglacial dust, caused by a pronounced wind direction change and/or increased subaerial exposure of volcanic material. The distinct dust compositions during two separate interglacial periods suggest significant differences in conditions at the dust source areas and atmospheric dynamics to this peripheral Antarctic site.Key PointsLast interglacial dust composition in Taylor Glacier ice is distinct from MIS 1 recordSr and Nd isotope signatures indicate a young volcanic sourceGeochemical data suggest a change in provenance and atmospheric circulation between MIS 5e and MIS 1Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148354/1/grl58638_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148354/2/grl58638.pd

Asian soybean rust: modeling the impact on soybean grain yield in the Triângulo Mineiro / Alto Paranaíba Region, Minas Gerais, Brazil.

Understanding the impact of Asian soybean rust on soybean yield is of great importance in the crop simulation model for this crop become it is possible to predict yield using different sowing dates and growth conditions. The goal of this study were to evaluate the performance of two soybean cultivars in Triângulo Mineiro/Alto Paranaíba, MG, Brazil and the effects of soybean rust on the yield of these cultivars using the CSM-CROPGRO Soybean model. Two soybean cultivars NK 7074 (early) and UFUS-Impacta (medium late), which differ in their development cycles, were growing in Uberaba city during the 2009/2010 growing season. The validation for cultivar UFUS-Impacta was conducted comparing the measured and simulated yield data considering three different sowing dates in the Uberlândia city during the 2002/2003 growing season. Daily meteorological data obtained from six meteorological stations of the National Institute of Meteorology (INMET ). To determine the performance of the soybean cultivars and the effect of soybean rust on yield, three different scenarios were used: no occurrence of rust (NOR) and occurrence of rust with inoculum concentrations of U5.000 and U10.000 urediniospores/mL. For all environments studied, the early cultivar had the best performance than the medium late cultivar. Soybean rust had the most effect on yield for the U10.000 scenario than for the U5.000 scenario. The best soybean performance occurred for Araxá and Uberaba cities. The South-Southeast area of the Triângulo Mineiro/Alto Paranaíba region was the most sensitive to the effect of rust on yield compared to the North region

Grass and forage research indexed by the Web of Science from 2005 to 2015.

Beef and milk production in Brazil is mainly pasture-based (Assis et al., 2005; ABIEC, 2018; FERRAZ; FELÍCIO, 2010). There is around 160 million ha of pasturelands in Brazil, which represents 45% of the agricultural area (IBGE, 2017). Sown pastures represent around 70% of the total pasture areas and are located mainly in the North, Southeast and Center-West regions of Brazil (IBGE, 2018). Grass and forage research in Brazil has shifted focus along the years. Traditionally, grass and forage research focused mostly on topics related to forage and animal production. Currently, besides the search for increasing production to fulfill a growing worldwide animal protein demand, grass and forage research faces new challenges like land degradation, climate change, competing land use, environmental impacts, including natural resources utilization, deforestation, loss of biodiversity, fragmentation, and loss of habitats, reduction on ?labor force? in rural areas, sustainability, among others. Indicators on science and technology reflect the central tendencies on scientific, technological and innovative activities from a country, institution or knowledge area. The development of specific indicators on science and technology on grass and forage science may be helpful for planning and evaluating activities of research groups and policy-makers alike. Based on specific indicators on science and technology it is possible to identify the main topics and grass and forage science research groups, and also verify if their activity is related to the main problems from the pasturebased animal production sector. This information may contribute to the more efficient use of research resources and to the progress of scientific advance on pasture-based animal production sustainability and competitiveness