Abstract Changes in the physical and biogeochemical properties of water columns are frequently associated with cold fronts and mesoscale convective systems due to increased cloud cover. The effects of low-level jet (LLJ) events on thermal stratification and water quality, however, remain undescribed, particularly for tropical reservoirs. Here, water temperature time series are combined with meteorological data, LIDAR observations, ERA5 reanalysis data, and hydrodynamical modeling to investigate the impact of an event of LLJ over the Furnas hydropower reservoir in Brazil. The LLJ event was characterized by dry, intense, and persistent winds (~10 m s-1) blowing for more than 12 hours over the main fetch of the reservoir. In the downwind side of the lake, the surface mixed layer depth increased by 50% during the LLJ event. The changes to the water column were produced by a combination of wind-induced upwelling, shear-driven mixing, and nocturnal convective overturning, different from the heat balance expected during passing cold fronts and mesoscale convective systems. The results suggest that both momentum and heat fluxes during LLJ events need to be accounted for in lake modelings to reproduce the vertical mixing process.

SUMMARY Maturity-onset diabetes of the young (MODY) is a heterogeneous group of monogenic forms of diabetes mellitus with distinct clinical features. Clinical dermatological phenotypes in MODY patients are very rare in literature. This report describes a patient with HNF1A-MODY presenting with necrobiosis lipoidica (NL) and granuloma annulare (GA). A 39-year-old asymptomatic woman, with atypical diabetes diagnosed at age 17, has a confirmed HNF1A mutation on exon 2 (c.392G>A, p.R131Q), classified as Pathogenic by the ACMG guidelines. She has reasonable metabolic control using oral anti-diabetic medications and has no chronic diabetic complications. Clinical and histologic diagnoses of both NL and GA were made. We discuss these conditions and their association with MODY.

RESUMO O desenvolvimento de cultivares mais tolerantes à seca é essencial para a manutenção da produção agrícola mundial. Objetivou-se realizar uma seleção precoce de genótipos de Coffea arabica tolerantes à seca, avaliando-se sua divergência funcional por meio de análises morfológicas, anatômicas e fisiológicas. Mudas de 14 genótipos foram submetidas ao estresse hídrico imposto pela irrigação por 18 dias. Foram medidos parâmetros de crescimento e anatômicos, potencial hídrico foliar e trocas gasosas. Em condições irrigadas e seca prolongada (18 dias), a divergência entre os genótipos foi determinada principalmente por características morfológicas, como área foliar, diâmetro do caule e, consequentemente, massa seca da parte aérea. Sob seca moderada (14 dias), parâmetros como potencial hídrico, espessura da cutícula, densidade estomática, número de vasos do xilema e eficiência do uso da água foram importantes para a divergência do grupo com maior capacidade de manter seu estado hídrico. Os genótipos 1,2,4,11 e 12 possuem características que contribuíram para a manutenção do estado hídrico, como maior espessura de cutícula, densidade estomática, menor número de vasos xilemáticos e espessura do floema, maior comprimento de raiz e maior eficiência de uso de água. A divergência funcional combinando análises morfológicas, anatômicas e fisiológicas em resposta à seca moderada indicou a seleção precoce dos genótipos 1, 2, 4, 11 e 12 como mais tolerantes à seca durante a fase de muda.

ABSTRACT The development of more drought-tolerant cultivars is essential for the maintenance of global agricultural production. This study aimed to perform an early selection of drought-tolerant Coffea arabica genotypes by evaluating their functional divergence using morphological, anatomical and physiological analyses. Seedlings of 14 genotypes were subjected to the drought stress imposed by irrigation for 18 days. Growth and anatomical parameters, leaf water potential and gas exchanges were measured. Under irrigated conditions and prolonged drought (18 days), the divergence among the genotypes was determined mainly by morphological traits, such as leaf area, stem diameter and, consequently, shoot dry mass. Under moderate drought (14 days), parameters such as water potential, cuticle thickness, stomatal density, number of xylem vessels and water-use efficiency were important for the divergence of the group with the highest ability to maintain its water status. The genotypes 1, 2, 4, 11 and 12 have characteristics that contributed to the maintenance of water status, such as greater cuticle thickness, stomatal density, smaller number of xylem vessels and phloem thickness, bigger root length and greater water-use efficiency. The functional divergence combining morphological, anatomical and physiological analyses in response to the moderate drought indicated the early selection of the genotypes 1, 2,4, 11 and 12 as more drought tolerant during the seedling stage.

RESUMO O objetivo deste estudo foi comparar resinas compostas bulk- -fill de baixa e alta viscosidade quanto à microdureza Knoop (KHN), resistência de união a microtração (MTBS) em cavidades oclusais e carga à fratura (FS) em molares com restauração mesio-oclusal-distal. Amostras em forma de disco com diferentes espessuras (2 ou 4 mm) de resinas bulk-fill de baixa viscosidade (SDR Flow, Dentsply) e alta viscosidade (Filtek BulkFill, 3M ESPE; e Tetric-N Ceram Bulk Fill, Ivoclar Vivadent) foram obtidas para análise de KHN no topo e na base (n = 10). A MTBS em dentina e o padrão de fratura foram avaliados em molares humanos com cavidades oclusais restauradas com (n = 10): resina composta nanoparticulada convencional (Z350XT, 3M ESPE), resinas bulk-fill de baixa viscosidade (Filtek Bulk-fill Flow, 3M ESPE) ou alta viscosidade (Filtek BulkFill). Foram investigados a FS e o padrão de fratura de molares humanos em restaurações mesial-ocluso-distais sub metidas ou não à ciclagem termomecânica (n = 10), sendo: dente íntegro (controle), e restaurações baseadas em resina composta microhíbrida convencional (Z250, 3M ESPE); resinas bulk-fill de baixa viscosidade (SDR Flow) ou alta viscosidade (Filtek BulkFill). Os dados foram submetidos a split-plot ANOVA (KHN), one-way ANOVA (MTBS), two-way ANOVA (FS) seguidos do teste de Tukey (α = 0,05). Para KHN, não houve diferença significativa entre o topo e a base para as resinas compostas. Para MTBS, não foram detectadas diferenças significativas entre os materiais; entretanto, a resina bulk-fill de baixa viscosidade apresentou menor frequência de falhas adesivas. Para FS, não houve diferença significativa entre os materiais e o dente íntegro, independentemente da ciclagem termomecânica. As resinas bulk-fill de baixa e alta viscosidade têm microdureza e resistência à microtração comparáveis quando usados em restaurações oclusais. Da mesma forma, as resinas bulk-fill apresentam resistência à fratura semelhante em molares com restaurações mesio-oclusal-distais.

ABSTRACT The aim of this study was to compare low- and high-viscosity bulk-fill composites for Knoop microhardness (KHN), microtensile bond strength (MTBS) to dentin in occlusal cavities, and fracture strength (FS) in molars with mesialocclusal- distal restoration. Disk-shaped samples with different thicknesses (2 or 4 mm) of low-viscosity (SDR Flow, Dentsply) and high-viscosity bulk-fill composites (Filtek BulkFill, 3M ESPE; and Tetric-N Ceram Bulk Fill, Ivoclar Vivadent) were prepared for top and bottom KHN analysis (n=10). MTBS to dentin and fracture pattern was evaluated in human molars with occlusal cavities restored with (n=10): conventional nanocomposite (Z350XT, 3M ESPE), low-viscosity (Filtek Bulk-fill Flow, 3M ESPE) or high-viscosity bulk-fill composites (Filtek BulkFill). The FS and fracture pattern of human molar with mesial-occlusal-distal restorations submitted or not to thermomechanical cycling were investigated (n=10) using: intact tooth (control), and restoration based on conventional microhybrid composite (Z250, 3M ESPE), low-viscosity (SDR Flow) or high-viscosity bulk-fill composites (Filtek BulkFill). The data were submitted to split-plot ANOVA (KHN), one-way ANOVA (MTBS), two-way ANOVA (FS) followed by Tukey’s test (α=0.05). For KHN, there was no significant difference for the resin composites between the top and bottom. For MTBS, no significant differences among the materials were detected; however, the low-viscosity composite presented lower frequency of adhesive failures. For FS, there was no significant difference between composites and intact tooth regardless of thermomechanical cycling. Low- and high-viscosity bulk-fill composites have comparable microhardness and microtensile bond strength when used in occlusal restorations. Likewise, the bulk-fill composites present similar fracture strength in molars with mesio-occlusal-distal restorations.

ABSTRACT This study evaluated the nutritional quality, yield, and storage protein modulation in soybean grains in response to levels and sources of sulfur (S) in a dystrophic Ultisol. We used five levels of S (0, 50, 100, 150 and 200 mg kg –1 ) and four sources of S (elemental S pastille - ESPA, gypsum - GY, gypsite - GI and elemental S powder - ESPO). Plants treated with 50 mg kg –1 of GY, GI, and ESPO and 200 mg kg –1 of ESPA had the largest grain yield values. Low S supply resulted in lower yields for all S sources tested. Sulfur deficiencies were observed at all levels for ESPA, resulting in lower concentrations of globulin and higher concentration of glutelin and albumin in the grains, possibly because the S content in the leaf was below the range adequate for soybean, leading to in lower yield values. In general, the application of S sources (GY, GI, and ESPO) increased all protein fractions. The results show that proper application of S is essential to optimize soybean yield and increase storage proteins in the grains. The granulometry of ESPA and ESPO fertilizers was a key factor for the availability of S to soybean plants. This study presents relevant information on S fertilization of soybeans, which could provide better grain nutritional quality and increased storage proteins with benefits to animal health.

RESUMO Uma quinta parte da população mundial consome pouco zinco (Zn), causando deficiências que podem causar danos celulares, retardo no crescimento e diminuir o sistema imunológico. Nesse trabalho avaliou-se o efeito do tempo de condicionamento osmótico de sementes de beterraba em soluções enriquecidas com Zn sobre a fisiologia, o crescimento, a produção e a biofortificação da raiz. Dois experimentos em estufa foram conduzidos durante primavera de 2015 e outono de 2016. Em cada experimento foram testados 24 tratamentos os quais compreenderam as combinações de três concentrações de Zn (0, 10 e 30 mg mL-1), duas fontes de Zn (sulfato e cloreto) e quatro tempos (12, 16, 20 e 24 horas), sob arranjo de blocos casualizados com quatro repetições. A concentração de Zn, principalmente como sulfato, afetou todos os parâmetros avaliados nas plantas de beterraba, massa fresca e seca de raiz, fotossíntese e a concentração de Zn na raiz (biofortificação). Em comparação ao controle, a massa fresca da raíz incrementou 70 e 100 g por planta com 10 mg mL-1 Zn durante os experimentos de 2015 e 2016, respectivamente. A mesma concentração por 16 horas provocou a maior concentração de Zn nas raízes atingindo 121 e 42 mg kg-1 em 2015 e 2016, respectivamente. Assim, o condicionamento osmótico de sementes em soluções enriquecidas com Zn, melhora as respostas fisiológicas das plantas, promovendo incrementos no crescimento, na produção e na biofortificação das raízes de beterraba. Portanto, esse método pode ser utilizado para biofortificar agronomicamente plantas de beterraba, independente da fonte de Zn.

ABSTRACT One-fifth of the world's population consumes too little zinc (Zn) causing deficiencies that can damage cells, stunt growth, and decrease immune response. This study evaluated the effect of time on the priming of beet seeds, in solutions enriched with Zn, on physiology, growth, production, and root biofortification. Two greenhouse experiments were conducted during spring 2015 and autumn 2016. In each experiment, 24 treatments were tested which comprised various combinations of three Zn concentrations (0, 10, and 30 mg mL-1), two Zn sources (sulphate and chloride), and four time periods (12, 16, 20, and 24 h), arranged in a randomised block design with four replicates. The concentration of Zn, mainly as sulphate, affected all parameters evaluated in the beet plants, such as fresh and dry root mass, photosynthesis, and root Zn concentration (biofortification). Compared to the control, fresh root mass increased 70 and 100 g per plant with 10 mg mL-1 of Zn during the experiments in 2015 and 2016, respectively. The same concentration for 16 h produced the highest Zn concentration in the roots, achieving 121 and 42 mg kg-1 in 2015 and 2016, respectively. Priming seeds in solutions enriched with Zn, thus, benefited the physiological response of the beet plants by promoting increases in growth, production, and biofortification of beet roots. Therefore, this method can be used to biofortify beet plants agronomically, regardless of the Zn source.

RESUMO O zinco (Zn) é um dos micronutrientes mais deficientes em solos agrícolas no Brasil. Objetivou-se nesse estudo avaliar a nutrição, produção de grãos e exportação de nutrientes em função da fertilização de Zn em feijoeiro-comum (Phaseolus vulgaris L.) cultivado sob sistema de plantio direto. Dois experimentos de campo foram conduzidos usando a cultivar IPR Campos Gerais (feijão carioca) e a cultivar BRS Esteio (feijão preto). Os tratamentos foram compostos pela aplicação de Zn no solo durante a semeadura e pela pulverização foliar de Zn no estádio fenológico de florescimento. A aplicação de Zn no solo teve efeito sobre o teor foliar de Zn da IPR Campos Gerais, mas não afetou a produtividade de grãos. Entretanto, a pulverização foliar de Zn elevou consideravelmente o teor foliar de Zn, resultando em aumento e redução na produtividade de grãos da IPR Campos Gerais e BRS Esteio, respectivamente. Os teores foliares de N, Ca, S e Mn foram afetados pela aplicação de Zn no solo e/ou foliar, enquanto que os teores foliares de P, K, Mg, Cu e Fe não foram influenciados pelos tratamentos. Considerando os tratamentos que não receberam Zn, as exportações de nutrientes obedeceram à ordem para os macronutrientes N > K > P > Ca ≈ S > Mg e à ordem para os micronutrientes Fe > Mn > Cu > Zn. A pulverização foliar de Zn elevou as exportações de Zn, P, Ca, Mg, S, Mn, Cu e Fe na IPR Campos Gerais, enquanto que a aplicação de Zn no solo resultou em maior exportação de P, K e Mn na BRS Esteio.

ABSTRACT Zinc (Zn) is one of the most deficient plant micronutrients in agricultural crops. The objective of this study was to evaluate plant nutrition, grain yield and nutrient export rate in response to soil and foliar Zn fertilization in common bean (Phaseolus vulgaris L.). Two field experiments in no-till system were carried out using two common bean cultivars, BRS Esteio (black bean) and IPR Campos Gerais (Carioca bean). Treatments were composed of soil Zn application during sowing and foliar Zn spray at flowering stage. Soil Zn application had effect on leaf Zn concentration in IPR Campos Gerais and did not affect grain yield of both cultivars. Foliar Zn spray increased leaf Zn concentration by approximately two times in both cultivars, but negatively affected the grain yield in BRS Esteio. Leaf concentration of N, Ca and S were affected by soil Zn application and leaf concentration of Mn was affected by foliar Zn spray, while leaf concentration of P, K, Mg, Cu and Fe were not influenced by the soil and foliar Zn treatments. In treatments without Zn, the descending order of nutrient export rate from the experimental site was as follows: N > K > P > Ca ≈ S > Mg for macronutrients and Fe > Mn > Cu > Zn for micronutrients. Foliar Zn spray increased the export rate of Zn, P, Ca, Mg, S, Mn, Cu and Fe in IPR Campos Gerais, while soil Zn application resulted in higher export rate of P, K and Mn in BRS Esteio.

ABSTRACT The recommendations of nitrogen (N) fertilization in garlic are still based on different varieties of the current types that are infected with phytopathogenic virus. There are several methods for recommendation of nitrogen (N) fertilization in garlic, but there are no enough methods for N diagnosis in garlic obtained by meristem culture. The objective of this work was to evaluate methods for diagnosing the nutritional status of virus-free garlic subjected to N doses through the use of a specific NO3- meter in soil solution and foliar sap, portable chlorophyll meter, N content in the leaf, and its relationship with yield and quality of the bulbs. The experiments were conducted with the use of virus-free seed bulbs from the meristem culture from three sites in the 2015 growing season and two locations in the 2016 growing season in South Brazil. The treatments consisted of the application of five nitrogen doses (0, 100, 200, 300, and 400 kg ha-1) distributed in three applications during the crop cycle: 1/3 in planting, 1/3 between 30 and 40 days after planting, and 1/3 after visual bulb differentiation. The highest commercial yield was associated with doses between 269 and 307 kg ha-1 of N and the content of 26 g kg-1 of N, in the diagnostic leaf. The relative chlorophyll content was the only diagnostic technology that showed a significant correlation with commercial yield in all experimental conditions. The evaluation of the N status in the virus-free garlic crop by a portable chlorophyll meter can be a quick strategy for recommending N fertilization and ensuring high yields.

ABSTRACT Selenium (Se) is considered a beneficial chemical element for plants, but in high concentrations it may present symptoms of toxicity. The present study aimed to evaluate 11 concentrations of Se (0; 0.1; 0.5; 1; 5; 10; 20; 40; 80; 400; 800 mg.L-1) to determine the low and high (toxicity) critical levels to seed germination of cowpea (Vigna unguiculata). In addition, alterations in the rate of photosynthetic pigments, lipid peroxidation and sugars during the initial growth development of seedlings were analysed. Seeds exposed to 800 mg.L-1 of Se showed a decrease of 20% of seed germination index compared to the control treatment. The decrease in seedling growth reflected in the increase of total sugars and sucrose concentration in both the shoot and root in response to exposure to Se concentration. There was a decrease in the concentration of leaf chlorophyll, carotenoids and pheophytin from seedlings exposed to high Se concentration. The rate of lipid peroxidation and the hydrogen peroxide concentration in the shoot was reduced up to the concentration of 1 mg.L-1 with subsequent increase in response to Se concentration applied. In the roots, the lipid peroxidation rate increased at concentrations higher than 80 mg.L-1. The highest oxidation rate of the cellular lipid membrane in response to Se occurred in the shoot, due to oxidation reactions in the chloroplast. Degradation of photosynthetic pigments and accumulation of total sugars and sucrose can be considered efficient biomarkers to indicate the toxicity of Se in cowpea seedlings and probably in other crops.

Resumo O Projeto “uso de VANT para prospecção eólica em sistemas aquáticos” consistiu num esforço multi-instrumental e multi-institucional para estudar a camada limite atmosférica influenciada por extensos corpos d’água e pelas feições do entorno como colinas, rampas e mudanças abruptas de rugosidade. Dois trabalhos de campo foram conduzidos em setembro e novembro de 2016 ao longo do sistema aquático e no seu entorno. Durante os experimentos foram utilizadas duas torres anemométricas, uma instalada sobre uma ilha e outra sobre uma colina. Além disso, um sistema flutuante para prospecção eólica, desenvolvido no âmbito do projeto, foi utilizado para hospedar uma torre de 10 m e um LIDAR Doppler que possibilitou o levantamento de perfis a 200 m, algo inédito em sistemas aquáticos continentais brasileiros. O perfil vertical de temperatura e umidade foi levantado por balões cativos e, um VANT, adaptado para realizar perfis verticais do vento foi utilizado pela primeira vez no Brasil, e é objetivo deste trabalho apresentar os detalhes de seu desenvolvimento bem como da validação dos respectivos dados. Este artigo tem como objetivo também apresentar um visão geral sobre o projeto e descrever a instrumentação e desenho amostral utilizado. Artigos adicionais, submetidos para esta revista, consideram diferentes aspectos da pesquisa e trazem resultados inéditos sobre escoamentos sobre colinas, a influência do fetch nestes sistemas e os aspectos moduladores da estabilidade atmosférica nestes ambientes.

Abstract The Project “unmanned aerial vehicles to wind assessment in aquatic systems” was a multi-institutional and multi-instrument experiment carried out to measure, in detail, the spatial characteristics of mean wind over a large tropical aquatic system and how is the flow modulated by hill, ramp and abrupt roughness change. Two field experiments were conducted during September and November 2016 in the Furnas reservoir and surrounding, an extensive (~1,250 km2) Brazilian typical reservoir. During the experiments, two towers were deployed on a hill and isle, and on the anchored buoy was installed a 10 m mast and a Doppler Lidar with a stabilizing mechanism. Vertical profile of temperature and humidity was obtained by attach sensor to tethered balloon. The present paper provides an overview of the Project as a whole, including a detailed description of the study area and the instrumentation and attempts to prove the viability of using an unmanned 6-motors rotorcraft, commonly known as a hexacopter, as a promising low-cost alternative to traditional platforms for vertical profiling in the atmospheric boundary layer.

ABSTRACT Objective To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. Subjects and methods We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. Results We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. Conclusion The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Resumo O presente estudo apresenta uma aplicação do modelo de mesoescala WRF à simulação de um episódio de vento intenso e persistente que ocorre com frequência irregular no reservatório de Guapé, MG. Tal evento altera a rotina da população na região, fazendo com que, por exemplo, a embarcação que faz a travessia entre as cidades de Guapé e Capitólio interrompa o serviço. Durante um destes episódios, ocorrido em 22 de setembro de 2016, foram realizadas medidas utilizando um LIDAR Zephir ZP300 e uma torre anemométrica, e estes dados foram posteriormente utilizados para validar as simulações. Para a avaliação dos resultados, foram comparadas pressão, temperatura, umidade e velocidade do vento simuladas e observadas. A análise dos perfis verticais de velocidade simulados sugere a presença de um jato de baixos níveis, posicionado em torno de 500 m acima da superfície, gerado por um gradiente de temperatura pós-frontal, cuja parte inferior teria sido acelerada pelo relevo e pela variação de rugosidade superficial terra-água. Mais estudos encontram-se atualmente em andamento para que se possa sugerir à população e às autoridades locais algum tipo de ação preventiva.

Abstract This study presents an application of the WRF mesoscale model to the simulation of an intense and persistent wind episode that occurs with irregular frequency in the Guapé reservoir, MG. Such an event changes the routine of the residents, forcing for example, the ferryboat between the cities of Guapé and Capitólio to interrupt the service. During one of these episodes, occurred on September 22th, 2016, measurements were made using LIDAR Zephir ZP300 and an anemometric tower, and these data were later used to validate the simulations. For the evaluation of the results, simulated and observed pressure, temperature, humidity and wind velocity were compared. The analysis of the simulated vertical velocity profiles suggests the presence of a low level jet, positioned around 500 m above the surface, generated by a post-frontal temperature gradient, whose lower part would have been accelerated by the topography and by the variation of the surface roughness following the land-water interface. More studies are currently under way to suggest to the population and local authorities some kind of preventive action.

RESUMO A dinâmica de biomassa e nutrientes do milho pode ser alterada quando consorciado com Brachiaria (syn. Urochloa spp.). Objetivou-se investigar a dinâmica de biomassa, nitrogênio (N), fósforo (P) e potássio (K) para sistemas de produção de milho consorciado com espécies de Brachiaria. Campos experimentais foram conduzidos durante a safra e safrinha, em esquema de parcelas subdivididas. As parcelas principais foram compostas por espécies de braquiária (B. brizantha,B. ruziziensis, e B. Convert) consorciadas com milho, além de monocultivo de milho. As subparcelas consistiram de períodos de amostragem da forragem, variando de 0 a 60 dias após a colheita do milho. O consórcio não afetou a produtividade de grãos, acúmulo e partição de nutrientes no milho. Após a colheita de grãos, B. brizantha obteve a maior taxa de acúmulo de biomassa na safra (69 kg ha-1 dia-1) e safrinha (17 kg ha-1 dia-1). O acúmulo de nutrientes variou amplamente entre as espécies de Brachiaria e estação de cultivo: 0.2-1.2 kg ha-1 dia-1 para N; 0.01-0.07 kg ha-1 dia-1 para P; e 0.13-0.8 kg ha-1 dia-1 para K. Contudo, o maior acúmulo de nutrientes foi registrado para B. brizantha, seguida de B. ruziziensis e B. Convert. A curto prazo, o milho consorciado com Brachiaria na safra obteve maior efeito sobre a ciclagem de nutrientes e produção de biomassa. O consórcio entre milho e B. brizantha na safra foi a melhor opção para aumentar a produção de biomassa e a ciclagem de N, P e K.

ABSTRACT The corn biomass and nutrient dynamics may be altered when it is intercropped with Brachiaria (syn. Urochloa spp.). The present study aimed to investigate the dynamics of biomass, nitrogen (N), phosphorus (P) and potassium (K) for farming systems that produce corn intercropped with Brachiaria species. Field experiments were performed during the season and off-season, in a split-plot design. The main plots were composed of Brachiaria species (B. brizantha,B. ruziziensis and B. Convert) intercropped with corn, in addition to corn monocropping. The subplots consisted of three forage sampling periods, ranging from 0 to 60 days after the corn harvest. The intercropping arrangements did not affect the corn grain yield, nutrient accumulation and partitioning, relatively to the corn monocropping. After the grain harvest, B. brizantha achieved the greater biomass accumulation rate in both the season (69 kg ha-1 day-1) and off-season (17 kg ha-1 day-1). The nutrient accumulation ranged widely between the Brachiaria species and planting seasons: 0.2-1.2 kg ha-1 day-1 for N; 0.01-0.07 kg ha-1 day-1 for P; and 0.13-0.8 kg ha-1 day-1 for K. However, the greatest nutrient accumulation was found for B. brizantha, followed by B. ruziziensis and then B. Convert. In the short-term, corn intercropped with Brachiaria in the season showed the largest effect on the nutrient cycling and biomass yield. The intercropping between corn and B. brizantha in the season was the best way to enhance the biomass yield and the N, P and K cycling.

RESUMO: Para facilitar o processo de semeadura de espécies forrageiras é comum a mistura de sementes com fertilizantes, seja em cultivo exclusivo, consorciado ou na implantação de sistemas integrados de produção agropecuária. Entretanto, a salinidade e acidez do fertilizante, em longos períodos de mistura, supõe-se ação deletéria na qualidade fisiológica das sementes. Dessa forma, o estudo teve como objetivo verificar o efeito de dez tempos de mistura (0, 3, 6, 12, 24, 36, 48, 72, 96 e 120 horas) do fertilizante granulado NPK 04-30-16, sobre vigor e germinação de sementes de Urochloa brizantha cv. Marandu. O experimento foi conduzido em delineamento experimental inteiramente casualizado, com três repetições. Houve efeito negativo da mistura de fertilizante com as sementes para o grau de umidade, condutividade elétrica, emergência, índice de velocidade de emergência, comprimentos de plântula e de radícula em função do incremento do tempo de mistura com fertilizante, de 3 a 120 horas de exposição.

ABSTRACT: To facilitate seeding process of forage species, a common practice is to mix seeds with fertilizers in monocropping and intercropping or in implementing integrated livestock production systems. However, in prolonged periods of contact, the fertilizer’s salinity and acidity negatively affect the seeds’ physiological quality. Therefore, this study intends to verify the effect of ten periods (0, 3, 6, 12, 24, 36, 48, 72, 96, and 120 hours) of exposure to granular NPK fertilizer 04-30-16 on the vigor and germination of Urochloa brizantha cv. Marandu seeds. The experiment was conducted in a completely randomized design with three replication. The fertilizer and seed mixture registered a negative effect on seed moisture content, electrical conductivity, emergence, emergence speed index, and seedling and radicle length as the period of exposure to the fertilizer increased from 3 to 120 hours.

ABSTRACT Intercropping corn and palisade grass is a technique to increase straw production, soil C contents, nutrient cycling and crop yield. However, concerns arise from nitrogen (N) uptake by the intercropping crop causing reduction in the yield of the corn. Our objective was to evaluate N recovery efficiency (NRE), and the N dynamics in the soil-plant system in corn intercropped with palisade grass. A field trial was carried out in Bahia, Brazil, evaluating two cropping systems: corn (monoculture) and corn intercropped with palisade grass sowed between rows on the same day as the corn crop, with four replicates in a completely randomized block design. Nitrogen (150 kg∙ha–1of 15N-urea) was applied at sowing to determine NRE, which means the amounts of N-fertilizer uptake in corn and palisade grass, the amounts of N-fertilizer in soil and the 15N-fertilizer balance. Neither the NRE (63.3% in monoculture and 57.2% in intercropping) nor corn grain yield (9,800 kg∙ha–1 in monoculture and 9,671 kg∙ha–1 in intercropping) was affected by intercropping, which accumulated only 2.1 kg∙ha–1 of N-fertilizer or 1.4% N rate. In addition, palisade grass yielded 2,265 kg∙ha–1 of dry matter. The balance indicated that 82.4% of N-fertilizer was recovered in the monoculture and 86.9% in the intercropping. Intercropping palisade grass does not affect grain yield or N corn nutrition and has the potential to increase straw production contributing to maintenance of no-till.