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RESUMEN Los mecanismos físicos involucrados en el desarrollo y pronóstico de nubes y precipitación son bastante complejos y dependen del ambiente atmosférico local, especialmente cuando condiciones severas son inminentes. Investigaciones destinadas a comprender los mecanismos favorables para los diferentes escenarios atmosféricos pueden ayudar a los meteorólogos operativos a emitir alertas. Este trabajo proporciona contribuciones cualitativas y cuantitativas a partir de datos de radiosondas y radar y simulaciones numéricas para evaluar la formación de nubes convectivas, estratiformes y no precipitantes sobre el área metropolitana de Río de Janeiro, Brasil. La energía potencial disponible para convección (CAPE) y el índice Liftex (LI) mostraron valores más altos en los días convectivos (CAPE = 2600 J Kg-1 y LI = -4 ºC), seguidos de los días sin precipitación (CAPE = 1500 J Kg-1 y LI = -2 ºC) y días nublados estratiformes (CAPE = 1400 J Kg-1 y LI = -1.5 ºC). Se observó una alta convergencia del viento a niveles bajos (1000-850 hPa) y medios (850-700 hPa) en días convectivos (-16.5 s-1 y -9.6 s-1, respectivamente). En contraste, se observó divergencia del viento a los mismos niveles en días estratiformes (6.4 s-1 y 6.9 s-1) y sin precipitación (9.7 s-1 y 7.3 s-1). Se observó una mayor divergencia del viento (8.3 s-1) en los días convectivos en los niveles superiores (300-200 hPa) en comparación con los días estratiformes (3.2 s-1) y sin precipitación (2.8 s-1). Los resultados muestran un acoplamiento de la convergencia del viento, la humedad y la energía en la troposfera inferior y la divergencia en los niveles superiores en los días convectivos. A pesar de la disponibilidad de humedad en los días estratiformes y de energía termodinámica en los días sin precipitación, no se observó el acoplamiento respectivo entre estas condiciones y los forzantes dinámicos.

https://doi.org/10.20937/atm.52832 12 downloads

Efficiency of soluble and insoluble sources of manganese for soybean nutrition in the Brazilian Cerrado
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Migliavacca, Rafaela Alenbrant

; Ferraz-Almeida, Risely

; Gomes, Marcos Henrique Feresin

; Almeida, Eduardo de

; Carvalho, Hudson Wallace Pereira de

; Otto, Rafael

Pesquisa Agropecuária Brasileira

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2022, Volume 57 elocation e01721

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo O objetivo deste trabalho foi avaliar a eficiência de fontes e doses de magnésio solúvel (MnSO4.H2O) e insolúvel (MnCO3) nos processos de absorção, transporte e redistribuição deste nutriente na soja (Glycine max), bem como na produtividade da cultura, em solo de Cerrado. O delineamento experimental foi em blocos ao acaso, em arranjo fatorial 4×2 – quatro doses (150, 250, 350 e 450 g ha−1) × duas fontes (MnSO4.H2O e MnCO3) de Mn –, com quatro repetições. Nas safras de 2015/2016 e 2016/2017, realizaram-se adubações foliares no terceiro trifólio e avaliaram-se os conteúdos de Mn e a produtividade da soja. Em ambas as safras, a fertilização foliar com Mn aumentou os teores do nutriente nas folhas, nos caules e nos grãos, mas não afetou o rendimento de grãos e a produção de matéria seca. Os teores máximos de Mn nas folhas foram obtidos com doses entre 150 e 450 g ha−1. A aplicação de MnSO4.H2O aumentou a absorção, o transporte e a redistribuição de Mn na planta, com desempenho superior ao de MnCO3. A fertilização foliar com MnSO4.H2O em soja, em solo de Cerrado, aumenta os teores de Mn nas folhas, mas não a produtividade e a produção de matéria seca.

Abstract The objective of this work was to evaluate the efficiency of sources and rates of soluble (MnSO4.H2O) and insoluble (MnCO3) manganese on the processes of uptake, transport, and redistribution of this nutrient in soybean, as well as on crop yield, in Cerrado soil. The experimental design was randomized complete blocks in a 4×2 factorial arrangement – four rates (150, 250, 350, and 450 g ha−1) × two sources (MnSO4.H2O and MnCO3) of Mn –, with four replicates. In the 2015/2016 and 2016/2017 crop seasons, foliar fertilizations were carried out on the third trifoliate leaflet, and Mn content and soybean yield were evaluated. In both crop seasons, Mn foliar fertilization increased the contents of the nutrient in leaves, stems, and grains, but did not affect grain yield and dry matter production. The maximum Mn contents in leaves were obtained with rates between 150 and 450 g ha−1. The fertilization with MnSO4.H2O increased Mn uptake, transport, and redistribution in the plant, with a performance superior to that of MnCO3. Foliar fertilization with MnSO4.H2O in soybean, in a Cerrado soil, increases Mn contents in the leaves but not yield and dry matter production.

https://doi.org/10.1590/s1678-3921.pab2022.v57.01721

Achados Ecocardiográficos em Pacientes com COVID-19 com e sem Doença Cardiovascular Prévia
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Barberato, Silvio Henrique

; Borsoi, Rafael

; Roston, Fabio

; Miranda, Hudson Laerte Machado

; Patriota, Pedro

; Otto, Maria Estefania

; Beck, Adenalva Lima de Souza

; Armstrong, Anderson da Costa

; Ferreira, João Marcos Bemfica Barbosa

; Camarozano, Ana Cristina

; Silva, Letícia Braga Paciello da

; Resende, Marcos Valério Coimbra

; Vieira, Marcelo Luiz Campos

; Fernandes-Silva, Miguel Morita

Arquivos Brasileiros de Cardiologia

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dec 2021, Volume 117 N. 6 Pages 1207 - 1211

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

https://doi.org/10.36660/abc.20201300 2 downloads

Soil-app: a tool for soil analysis interpretation
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Matias, Filipe Inácio

; Sabadin, José Felipe Gonzaga

; Moreira, Lílian Angélica

; Gomes, Marcos Henrique Feresin

; Mira, Acácio Bezerra de

; Fritsche-Neto, Roberto

; Otto, Rafael

Scientia Agricola

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2021, Volume 78 N. 1 elocation e20190113

Abstract: En | Text: En | PDF: En

ABSTRACT New apps have changed the traditional way of learning and teaching; they are also applied as a quickly executed and effective method in agriculture. Soil-app is a web application with a friendly click-point interface built through packages lodged in R software. The app is an advanced model of an open-source platform to support teaching and learning activities in soil analyses and fertilizer recommendations. Soil-app includes soil test interpretation, soil amendment calculations (lime and gypsum), the fertilizer rate for the most important crops in Brazil, an NPK blend calculator, and NPK blend evaluation. It also includes experimental statistical analysis as applied to soil science. Soil-app is a user-friendly and high-performance tool, garnering fast adoption by both students and professionals. It is available for network use through the following link: http://www.genetica.esalq.usp.br/alogamas/R.html

https://doi.org/10.1590/1678-992x-2019-0113 2340 downloads

Neurological consultations and diagnoses in a large, dedicated COVID-19 university hospital
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STUDART-NETO, Adalberto

; GUEDES, Bruno Fukelmann

; TUMA, Raphael de Luca e

; CAMELO FILHO, Antonio Edvan

; KUBOTA, Gabriel Taricani

; IEPSEN, Bruno Diógenes

; MOREIRA, Gabriela Pantaleão

; RODRIGUES, Júlia Chartouni

; FERRARI, Maíra Medeiros Honorato

; CARRA, Rafael Bernhart

; SPERA, Raphael Ribeiro

; OKU, Mariana Hiromi Manoel

; TERRIM, Sara

; LOPES, Cesar Castello Branco

; PASSOS NETO, Carlos Eduardo Borges

; FIORENTINO, Matheus Dalben

; DE SOUZA, Julia Carvalhinho Carlos

; BAIMA, José Pedro Soares

; DA SILVA, Tomás Fraga Ferreira

; MORENO, Cristiane Araujo Martins

; SILVA, Andre Macedo Serafim

; HEISE, Carlos Otto

; MENDONÇA, Rodrigo Holanda

; FORTINI, Ida

; SMID, Jerusa

; ADONI, Tarso

; GONÇALVES, Marcia Rubia Rodrigues

; PEREIRA, Samira Luisa Apóstolos

; PINTO, Lecio Figueira

; GOMES, Helio Rodrigues

; ZANOTELI, Edmar

; BRUCKI, Sonia Maria Dozzi

; CONFORTO, Adriana Bastos

; CASTRO, Luiz Henrique Martins

; NITRINI, Ricardo

Arquivos de Neuro-Psiquiatria

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aug 2020, Volume 78 N. 8 Pages 494 - 500

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

RESUMO Introdução: Mais de um terço dos pacientes com COVID-19 apresentam sintomas neurológicos que variam de anosmia a AVC e encefalopatia. Além disso, doenças neurológicas prévias podem exigir tratamento especial e estar associadas a piores desfechos. Não obstante, o papel dos neurologistas na COVID-19 é provavelmente pouco reconhecido. Objetivo: O objetivo deste estudo foi relatar os motivos para solicitar consultas neurológicas por clínicos e intensivistas em um hospital dedicado à COVID-19. Métodos: Estudo retrospectivo realizado no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brasil, um centro dedicado à COVID-19 com 900 leitos (incluindo 300 leitos para unidades de terapia intensiva). O diagnóstico de COVID-19 foi confirmado por SARS-CoV-2-RT-PCR em swabs nasais. Todas as interconsultas de neurologia hospitalar entre 23 de março e 23 de maio de 2020 foram analisadas. Os neurologistas realizaram o exame neurológico, avaliaram todos os dados disponíveis para diagnosticar a patologia neurológica e solicitaram exames adicionais conforme necessidade. Diagnósticos difíceis foram estabelecidos em reuniões de consenso. Após o diagnóstico, os neurologistas participaram da condução dos casos. Resultados: Foram solicitadas consultas neurológicas para 89 de 1.208 (7,4%) em pacientes internados por COVID-19 durante o período. Os principais diagnósticos neurológicos incluíram: encefalopatia (44,4%), acidente vascular cerebral (16,7%), doenças neurológicas prévias (9,0%), crises epilépticas (9,0%), transtornos neuromusculares (5,6%), outras lesões encefálicas agudas (3,4%) e outros sintomas leves inespecíficos (11,2%). Conclusões: A maioria das consultas neurológicas em um hospital dedicado à COVID-19 foi solicitada para condições graves que poderiam afetar o desfecho clínico. Os médicos na linha de frente devem ser capazes de reconhecer sintomas neurológicos. Os neurologistas são membros importantes da equipe médica no atendimento hospitalar à COVID-19.

ABSTRACT Background: More than one-third of COVID-19 patients present neurological symptoms ranging from anosmia to stroke and encephalopathy. Furthermore, pre-existing neurological conditions may require special treatment and may be associated with worse outcomes. Notwithstanding, the role of neurologists in COVID-19 is probably underrecognized. Objective: The aim of this study was to report the reasons for requesting neurological consultations by internists and intensivists in a COVID-19-dedicated hospital. Methods: This retrospective study was carried out at Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil, a 900-bed COVID-19 dedicated center (including 300 intensive care unit beds). COVID-19 diagnosis was confirmed by SARS-CoV-2-RT-PCR in nasal swabs. All inpatient neurology consultations between March 23rd and May 23rd, 2020 were analyzed. Neurologists performed the neurological exam, assessed all available data to diagnose the neurological condition, and requested additional tests deemed necessary. Difficult diagnoses were established in consensus meetings. After diagnosis, neurologists were involved in the treatment. Results: Neurological consultations were requested for 89 out of 1,208 (7.4%) inpatient COVID admissions during that period. Main neurological diagnoses included: encephalopathy (44.4%), stroke (16.7%), previous neurological diseases (9.0%), seizures (9.0%), neuromuscular disorders (5.6%), other acute brain lesions (3.4%), and other mild nonspecific symptoms (11.2%). Conclusions: Most neurological consultations in a COVID-19-dedicated hospital were requested for severe conditions that could have an impact on the outcome. First-line doctors should be able to recognize neurological symptoms; neurologists are important members of the medical team in COVID-19 hospital care.

https://doi.org/10.1590/0004-282x20200089 2651 downloads

[SciELO Preprints] - Neurological consultations and diagnoses in a large, dedicated COVID-19 university hospital
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Studart-Neto, Adalberto Guedes, Bruno Fukelmann Tuma, Raphael De Luca E Camelo Filho, Antonio Edvan Kubota, Gabriel Taricani Iepsen, Bruno Diógenes Moreira, Gabriela Pantaleão Rodrigues, Júlia Chartouni Ferrari, Maíra Medeiros Honorato Carra, Rafael Bernhard Spera, Raphael Ribeiro Oku, Mariana Hiromi Manoel Terrim, Sara Lopes, Cesar Castello Branco Passos Neto, Carlos Eduardo Borges Dalben, Matheus De Souza, Julia Carvalhinho Carlos Baima, José Pedro Soares Da Silva, Tomás Fraga Ferreira Moreno, Cristiane Araujo Martins Silva, Andre Macedo Serafim Heise, Carlos Otto Mendonça, Rodrigo Holanda Fortini, Ida Smid, Jerusa Adoni, Tarso Gonçalves, Marcia Rubia Rodrigues Pereira, Samira Luisa Apóstolos Pinto, Lecio Figueira Gomes, Helio Rodrigues Zanotelli, Edmar Brucki, Sonia Maria Dozzi Conforto, Adriana Bastos Castro, Luiz Henrique Martins Nitrini, Ricardo

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Publication date: 2020-07-16

Abstract: En Pt

Background: More than one-third of COVID-19 patients present neurological symptomsranging from anosmia to stroke and encephalopathy. Furthermore, pre-existingneurological conditions may require special treatment and may be associated with worseoutcomes. Notwithstanding, the role of neurologists in COVID-19 is probablyunderrecognized. Objective: The aim of this study was to report the reasons forrequesting neurological consultations by internists and intensivists in a COVID-19-dedicated hospital. Methods: This retrospective study was carried out at Hospital dasClínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil, a 900-bedCOVID-19 dedicated center (including 300 intensive care unit beds). COVID-19 diagnosiswas confirmed by SARS-CoV-2-RT-PCR in nasal swabs. All inpatient neurologyconsultations between March 23rd and May 23rd, 2020 were analyzed. Neurologistsperformed the neurological exam, assessed all available data to diagnose theneurological condition, and requested additional tests deemed necessary. Difficultdiagnoses were established in consensus meetings. After diagnosis, neurologists wereinvolved in the treatment. Results: Neurological consultations were requested for 89 outof 1,208 (7.4%) inpatient COVID admissions during that period. Main neurologicaldiagnoses included: encephalopathy (44.4%), stroke (16.7%), previous neurologicaldiseases (9.0%), seizures (9.0%), neuromuscular disorders (5.6%), other acute brainlesions (3.4%), and other mild nonspecific symptoms (11.2%). Conclusions: Mostneurological consultations in a COVID-19-dedicated hospital were requested for severeconditions that could have an impact on the outcome. First-line doctors should be able torecognize neurological symptoms; neurologists are important members of the medicalteam in COVID-19 hospital care.

Introdução: Mais de um terço dos pacientes com COVID-19 apresentam sintomasneurológicos que variam de anosmia a AVC e encefalopatia. Além disso, doençasneurológicas prévias podem exigir tratamento especial e estar associadas a pioresdesfechos. Não obstante, o papel dos neurologistas na COVID-19 é provavelmentepouco reconhecido. Objetivo: O objetivo deste estudo foi relatar os motivos para solicitarconsultas neurológicas por clínicos e intensivistas em um hospital dedicado à COVID-19. Métodos: Estudo retrospectivo realizado no Hospital das Clínicas da Faculdade deMedicina da Universidade de São Paulo, Brasil, um centro dedicado à COVID-19 com900 leitos (incluindo 300 leitos para unidades de terapia intensiva). O diagnóstico deCOVID-19 foi confirmado por SARS-CoV-2-RT-PCR em swabs nasais. Todas asinterconsultas de neurologia hospitalar entre 23 de março e 23 de maio de 2020 foramanalisadas. Os neurologistas realizaram o exame neurológico, avaliaram todos os dadosdisponíveis para diagnosticar a patologia neurológica e solicitaram exames adicionaisconforme necessidade. Diagnósticos difíceis foram estabelecidos em reuniões deconsenso. Após o diagnóstico, os neurologistas participaram da condução dos casos.Resultados: Foram solicitadas consultas neurológicas para 89 de 1.208 (7,4%) empacientes internados por COVID-19 durante o período. Os principais diagnósticosneurológicos incluíram: encefalopatia (44,4%), acidente vascular cerebral (16,7%),doenças neurológicas prévias (9,0%), crises epilépticas (9,0%), transtornosneuromusculares (5,6%), outras lesões encefálicas agudas (3,4%) e outros sintomasleves inespecíficos (11,2%). Conclusões: A maioria das consultas neurológicas em umhospital dedicado à COVID-19 foi solicitada para condições graves que poderiam afetaro desfecho clínico. Os médicos na linha de frente devem ser capazes de reconhecersintomas neurológicos. Os neurologistas são membros importantes da equipe médica noatendimento hospitalar à COVID-19.

https://doi.org/10.1590/0004-282X20200089

Physicochemical characterization of fertilizers containing concentrated suspensions of CuO, MnCO3 and ZnO
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Gomes, Marcos Henrique Feresin

; Migliavacca, Rafaela Alenbrant

; Otto, Rafael

; Carvalho, Hudson Wallace Pereira de

Scientia Agricola

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2020, Volume 77 N. 6 elocation e20180384

Abstract: En | Text: En | PDF: En

ABSTRACT: The utilization of insoluble sources of micronutrients as concentrated suspensions (CSs) is increasing in Brazilian agriculture; however, much information regarding the physicochemical characterization of these products is required to demonstrate the absorption behavior by plant leaves. This study aimed to characterize the CSs available on the Brazilian market to support their potential use as foliar fertilizers. We selected five CSs containing Mn, five CSs containing Zn and three CSs containing Cu from five different companies. In each product, the mean particle size was evaluated by dynamic light scattering (DLS), the particle shape and size were evaluated by scanning electron microscopy (SEM), the aggregation degree was determined by the zeta potential and the heavy metal contents were determined by acid digestion followed by reading on ICP-OES. The mean hydrodynamic diameter of fertilizers containing Cu, Mn and Zn was 315 ± 55, 378 ± 184 and 435 ± 107 nm, respectively. The zeta potential varied from –20 to –30 mV, indicating potential particle aggregation and formation of higher structures. SEM images indicated great variation in the size and shape of the particles in each product. All products exhibited concentrations of toxic elements within the legislation thresholds. The average particle size of CSs currently marketable in Brazil does not allow their classification as nanomaterials (< 100 nm). Therefore, their foliar absorption is unlikely, once the particle size is higher than the exclusion limit observed for stomata and cuticle pathways, as well as the nutrient content as ions is low according to the solubility constant.

https://doi.org/10.1590/1678-992x-2018-0384 950 downloads

10.

Application of superphosphate complexed with humic acid in an area of sugarcane
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Zavaschi, Eduardo

; Ferraz-Almeida, Risely

; Fária, Letícia Abreu

; Otto, Rafael

; Vitti, André César

; Vitti, Godofredo Cesar

Revista Ciência Agronômica

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2020, Volume 51 N. 1 elocation e20186463

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

RESUMO Adubações com fósforo (P) apresentam baixa eficiência devido à adsorção de P na superfície da argila em solos tropicais. O superfosfato complexado com ácido húmico (SSP+HA) é apresentado como uma alternativa para melhorar a eficiência do uso do P e a produtividade das culturas. Nesse sentido, o objetivo deste estudo foi investigar o desempenho do SSP+HA na produção de cana-de-açúcar com incrementos da matéria seca (MS) e conteúdo de P nas plantas. O experimento foi conduzido com duas fontes de P (superfosfato simples-SSP; SSP+HA) e cinco doses (0; 45; 90; 135 e 180 kg ha-1 de P2O5). A dose de 135 kg ha-1 foi usada para explicar o efeito residual do P, coletando solo na cana-planta e primeiro corte. Amostras de caules, ponteiras e raízes foram coletadas para determinar MS e conteúdo de P; ambas variáveis foram usadas para calcular a eficiência de assimilação de fósforo (EaP). Os resultados mostraram que a aplicação de SSP aumentou MS e conteúdo de P nas plantas, com desempenho superior ao SSP+HA. A EaP foi maior no SSP+HA, indicando que o P foi metabolizado de forma mais eficiente, mas não refletiu no aumento de MS. As doses de P aumentaram a produtividade da cana-planta, mas não houve efeito do P aplicado em soqueira, devido ao efeito residual do P aplicado no plantio. O SSP apresentou desempenho superior ao SSP+SH no plantio da cana-de-açúcar. Mais pesquisas são necessárias para melhor ilustrar o efeito do SSP+HA na absorção e translocação do P.

ABSTRACT In tropical soils, the efficiency of phosphorus (P) fertilization is low, due to P adsorption on the surface of the clay. Superphosphate complexed with humic acid (SSP+HA) is presented as an alternative for improving P use efficiency and crop yields. The aim of this study was to investigate SSP+HA performance in sugarcane production including increases in plant dry matter (DM) and P content. The experiment was conducted with two sources of P (simple superphosphate - SSP, SSP+HA) and five doses (0, 45, 90, 135 and 180 kg ha-1 P2O5). The dose of 135 kg ha-1 P2O5 was used to explain the residual effect of P, collecting soil samples from the plant cane and first ratoon. Stalk, top and root samples were collected to determine DM and P content; both variables were used to calculate the P assimilation efficiency (PaE). Results showed that the application of SSP increased the DM and P content of the plants, with superior performance compared to SSP+HA. PaE was greater under SSP+HA, indicating that P was metabolized more efficiently; however this did not reflect in an increase in DM. AThe P rates increased the sugarcane yield in cane plant, but there was no effect of P applied in the first ratoon due to the residual effect of P applied in planting. SSP presented superior performance compared to SSP + SH in sugarcane planting. Further research is needed to better demonstrate the effect of SSP+HA on the absorption and translocation of P.

https://doi.org/10.5935/1806-6690.20200010 725 downloads

11.

Conversion of ammonium to nitrate and abundance of ammonium-oxidizing-microorganism in Tropical soils with nitrification inhibitor
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Barth, Gabriel

; Otto, Rafael

; Almeida, Risely Ferraz

; Cardoso, Elke Jurandy Bran Nogueira

; Cantarella, Heitor

; Vitti, Godofredo Cesar

Scientia Agricola

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2020, Volume 77 N. 4 elocation e20180370

Abstract: En | Text: En | PDF: En

ABSTRACT The use of nitrification inhibitors (NIs; dicyandiamide - DCD) is an alternative to reduce oxidation of ammonium (NH4+-N) to nitrate (NO3–-N) in the soil, reducing NO3–-N losses from fertilization practices. Based on the hypothesis that DCD reduces conversion of NH4+-N to NO3–-N in tropical soils and inhibits ammonia oxidizing microorganisms (AOM) abundance, soils from the Piracicaba region, São Paulo, with different textures (sand, loam and clay) were incubated with ammonium sulphate (AS) and DCD. Contents of NH4+-N, NO3–-N, soil pH, and AOM abundance were quantified periodically. Ammonium sulphate increased AOM abundance in all soils, but AS+DCD presented AOM abundances similar to the control. During 90 days of incubation, the effectiveness of DCD in reducing NO3–-N production was 1.8, 86.4, and 145.6 mg kg–1, while the effectiveness of DCD in reducing AOM abundance was 1.2, 3.0 and 2.3 × 10–3 g soil–1 for sandy, loamy, and clayey soils, respectively. DCD effectiveness was greater in loamy and clayey soils due to the naturally low nitrification in sandy soils. Application of AS treated with DCD showed potential not only to reduce NO3–-N production in loamy and clayey soils, but also to decrease the soil nitrification rate. Overall, DCD was effective in reducing AOM abundance and conversion of NH4+-N to NO3–-N in loamy and clay soils evaluated here. The increase in clay content directly influences DCD effectiveness in reducing conversion of NH4+-N to NO3–-N.

https://doi.org/10.1590/1678-992x-2018-0370 4553 downloads

12.

Optimal plant density and nitrogen rates for improving off-season corn yields in Brazil
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Faria, Italo Kaye Pinho de

; Vieira, José Luís Vilela

; Tenelli, Sarah

; Almeida, Rodrigo Estevam Munhoz de

; Campos, Leonardo José Motta

; Costa, Rodrigo Veras da

; Zavaschi, Eduardo

; Almeida, Risely Ferraz de

; Carneiro, Leandro de Mello e Silva

; Otto, Rafael

Scientia Agricola

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jul 2019, Volume 76 N. 4 Pages 344 - 352

Abstract: En | Text: En | PDF: En

ABSTRACT: Integrating plant density and nitrogen (N) management is a strategy for improving corn yields, especially for off-season corn production in the tropics. This study tested the hypothesis that increasing plant densities and N rates promotes yield gains for off-season corn production in high-yielding environments. The aim of the study was to investigate the yield performances of two hybrid versions (DKB PRO and DKB PRO3) submitted to three plant densities (55,000; 65,000 and 75,000 plants ha−1) and four N rates (control, 60, 120 and 180 kg ha−1 N). Field trials were undertaken at Uberlândia-MG (site1 and 2) and Pedro Afonso-TO (site 3), Brazil from which data on corn yield parameters were collected and analyzed. Multivariate analysis separated the three trial areas into two groups, presenting high (sites 1 and 2) and low yields (site 3), which were related to weather conditions. There was no influence of a hybrid version or plant densities on crop yields at site 1 or 2. In contrast, there was a positive response to increasing plant densities and the use of DKB PRO3 at site 3. A significant response to N was observed at sites 2 and 3, following a plateau model. Our results suggest that N application rates and plant densities do have the potential to increase off-season corn yields in low yielding environments.

https://doi.org/10.1590/1678-992x-2017-0295 1663 downloads

13.

Effect of previous soil management on sugarcane response to nitrogen fertilization
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Otto, Rafael

; Mariano, Eduardo

; Mulvaney, Richard Lesley

; Khan, Saeed Ahmad

; Boschiero, Beatriz Nastaro

; Tenelli, Sarah

; Trivelin, Paulo Cezar Ocheuze

Scientia Agricola

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feb 2019, Volume 76 N. 1 Pages 72 - 81

Abstract: En | Text: En | PDF: En

ABSTRACT: N Fertilizer recommendations must be improved to optimize N use efficiency (NUE) for bioenergy crops. A study was conducted to test the hypothesis that sites varying in historical usage of by-product differ in soil N-supplying power and sugarcane (Saccharum spp.) responsiveness to N fertilization. Our aim was to quantify soil N availability and N fertilizer rates, sources, and application timings for their effects on sugarcane yield and NUE. Three N response trials, each involving 0 to 200 kg N ha−1, were conducted in the state of São Paulo, Brazil, at sites varying historically in the usage of vinasse. Before fertilizer application and at harvest, soil inorganic N content was quantified and potential N mineralization estimated by the Illinois Soil Nitrogen Test (ISNT); stalk yield and sugar content were measured at harvest and used to estimate NUE. Sugarcane showed significant response to N fertilization only at the sites with no history of vinasse usage. Reducing the N rate from 120 to 80 kg N ha−1 showed limited potential for lowering yield (~ 1 %), while increasing the NUE by 54 %, which was far better than the 14 % increase achieved by modifying the N source or application timing. Monitoring inorganic N and ISNT levels over time to estimate soil N-supplying power has potential for predicting the responsiveness of sugarcane to N fertilization; however, ISNT interpretations must consider factors that impede mineralization or crop N utilization, such as soil acidity or a limitation on the availability of Ca or P. Soil N testing can help optimize NUE for sustainable bioenergy production.

https://doi.org/10.1590/1678-992x-2017-0147 2223 downloads

14.

Nitrogen recovery efficiency for corn intercropped with palisade grass
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Almeida, Rodrigo Estevam Munhoz de

; Favarin, José Laércio

; Otto, Rafael

; Franco, Henrique

; Reis, André Froes Borja

; Moreira, Lílian Angélica

; Trivelin, Paulo

Bragantia

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dec 2018, Volume 77 N. 4 Pages 557 - 566

Abstract: En | Text: En | PDF: En

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.

https://doi.org/10.1590/1678-4499.2017242 1215 downloads

15.

Nutrient Uptake by High-Yielding Cotton Crop in Brazil
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Vieira, José Luís Vilela

; Nardi, Kaue Tonelli

; Silva, Gabriel Rodrigues Anastácio

; Moreira, Lílian Angélica

; Zavaschi, Eduardo

; Moura, Thiago Augusto

; Otto, Rafael

Revista Brasileira de Ciência do Solo

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2018, Volume 42 elocation e0170033

Abstract: En | Text: En | PDF: En

ABSTRACT: Determining nutrient uptake and accumulation rates by cotton crops is important to define management strategies, especially for transgenic varieties, which are cultivated using high-technology approaches that require substantial investment to maximize yield. Currently in Brazil, the states of Bahia and Mato Grosso are responsible for 84.4 % of the total cotton growing area. In the present study, two trials were conducted in 2013, one that involved planting FM 940 GLT, FM 980 GLT, and FM 913 GLT varieties in the state of Bahia and the other which involved FM 940 GLT and FM 980 GLT varieties in the state of Mato Grosso. The aim of the two trials was to represent the two regions that currently encompass the largest areas of cotton cultivation. Tissue samples, consisting of leaves, stems, and reproductive components, were collected eleven times during the crop cycle for determination of nutrient content and shoot dry matter. After weighing, plant tissue samples were dried and ground to determine nutrient contents. Because there were no overall differences in nutrient contents and biomass accumulation of the varieties during the crop cycle, we undertook joint analysis of the data from all varieties at each site. Favorable climatic conditions in Bahia promoted plant biomass production that was twice as much as plants grown in Mato Grosso, with cotton yields of 6.2 and 3.8 t ha−1 of lint and seed, respectively. The maximum nutrient accumulation occurred between 137-150 days after emergence (DAE) for N; 143-148 for P; 172-185 for K; 100 for Ca; 144-149 for Mg; and 153-158 for S. Maximum uptake ranged from 218-362 kg ha−1 N; 26-53 kg ha−1 P; 233-506 kg ha−1 K; 91-202 kg ha−1 Ca; 28-44 kg ha−1 Mg; and 19-61 kg ha−1 S. On average, the sites revealed nutrient export of 14, 2, 23, 3, 2, and 2 kg t−1 of lint and seed for N, P, K, Ca, Mg, and S, respectively, with little variation among sites. Extraction of nutrients per area by cotton vary among sites, but nutritional requirement of cotton per unit of lint and seeds is similar independently of yield potential.

https://doi.org/10.1590/18069657rbcs20170033 3056 downloads

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