Dessecação em pré-colheita do trigo: nova preocupação para a qualidade do cereal no consumo humano

Uma alternativa, empregada pelos produtores do cereal trigo, para garantir produtividade é a aplicação de herbicidas dessecantes na pré-colheita. No entanto, essa prática pode acarretar na contaminação química do produto colhido. Diante do exposto, objetivou-se com a presente revisão, fazer um levantamento, a partir de estudos científicos, sobre o efeito da dessecação na pré-colheita do trigo com o uso de herbicidas, na qualidade fisiológica dos grãos de trigo destinados ao consumo humano e animal. No Brasil, a região Sul tem a maior área cultivada com este cereal, 1.714 milhões de hectares em 2017. Nos últimos anos os produtores rurais, a fim de minimizar a deterioração da qualidade dos grãos no campo e garantir a produtividade, passaram a adotar a prática de aplicação de herbicidas dessecantes na pré-colheita. Entretanto, essa prática pode resultar no transporte dos produtos químicos até os grãos ou sementes, resultando na contaminação química do produto final, onde, em sua grande maioria é destinado à produção de farinha. Os resultados da revisão bibliográfica são heterogêneos, apresentando em alguns casos efeitos negativos da dessecação em pré-colheita aos grãos e/ou sementes, enquanto em outros não existe a mesma constatação. Dessa forma, o produtor sempre que utilizar um defensivo agrícola, deve seguir o receituário agronômico, bem como ficar atento às indicações da bula do produto, de modo a respeitar as doses e período de carência entre aplicação e colheita. Ainda há a necessidade de técnico especializado, necessidade de tal procedimento, viabilidade em determinada localidade, registro dos produtos químicos para este fim e se estes deixam resíduos nos grãos que possam comprometer a saúde humana

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

Alteração química e mineralógica de argissolo vermelho distrófico submetido ao eflúvio ácido de rejeito de carvão

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Alteração química e mineralógica de argissolo vermelho distrófico submetido ao eflúvio ácido de rejeito de carvão

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Organic matter in four brazilian soil types : chemical composition and atrazine sorption

Soil organic matter is the main sorptive soil compartment for atrazine in soils, followed in a minor scale by the inorganic fraction. In this study, the soil organic matter quality and atrazine sorption were investigated in four different soil types. The pedogenic environment affected the humification and therefore the chemical composition of the organic matter. The organic matter contribution to atrazine sorption was larger (60-83%) than that of the inorganic fraction. The organic matter capacity in retaining the herbicide was favoured by a higher decomposition degree and a smaller carboxylic substitution of the aliphatic chains

Organic matter in four brazilian soil types : chemical composition and atrazine sorption

Soil organic matter is the main sorptive soil compartment for atrazine in soils, followed in a minor scale by the inorganic fraction. In this study, the soil organic matter quality and atrazine sorption were investigated in four different soil types. The pedogenic environment affected the humification and therefore the chemical composition of the organic matter. The organic matter contribution to atrazine sorption was larger (60-83%) than that of the inorganic fraction. The organic matter capacity in retaining the herbicide was favoured by a higher decomposition degree and a smaller carboxylic substitution of the aliphatic chains

Adubação nitrogenada em cobertura para produção de trigo duplo propósito em sistema Integrago de Produção Agropecuária

Nowadays, there are numerous arrangements of Integrated Systems of Agricultural Production, due, the particularities of each region and/or rural enterprise. The use of dual-purpose species such as, for example, BRS Tarumã® wheat further intensifies the system, because there is plant-animal production in a short time. Study aimed to evaluate the production and chemical composition of dual purpose wheat pastures managed with different DAN during periods of spikelet terminal (ST) and anthesis (AN), aiming crop production (pasture and grain) and animal (milk and / or meat). The experimental randomized block design with five treatments (0, 75, 150, 225 e 300 Kg de N ha-1, in the form of ammonium nitrate) and four replications. The average biomass values before the first and the second grazing were respectively: 2,164 and 2,127 kg DM per hectare and the waste of about 824 and 1,772 kg of DM per hectare and the daily average accumulation rate between the two grazing DM was 86 kg per hectare at 17 day intervals. The variables, number of spikes per square meter, grain number per square meter, thousand grain weight, hectoliter weight and grain yield did not differ (P>0.05) between treatments. Nitrogen fertilization increases linearly (P=0.0017) the size of the spikes depending on nitrogen rates. For the linear variable layering increased (P=0.0001), indicating the susceptibility of the crop to high levels of nitrogen. The application of nitrogen fertilizer levels in dual purpose grazed wheat before the spikelet terminal stage and anthesis does not influence on grain yield variables. The nitrogen fertilization on wheat double purpose must be fractionated at tillering and after each grazing increasing the remobilization rate of nitrogen by culture.Atualmente, há inúmeros arranjos de Sistemas Integrados de Produção Agropecuária, em função, das particularidades de cada região e/ou empresa rural. A utilização de espécies de duplo propósito como, por exemplo, o trigo BRS Tarumã® intensifica ainda mais o sistema, pois há produção vegetal-animal em curto espaço de tempo. Objetivou-se avaliar a produção e a composição bromatológica de pastagens de trigo duplo propósito manejadas com diferentes DAN nos períodos de espigueta terminal (ET) e antese (AN), almejando produção vegetal (pastagem e grão) e animal (leite e/ou carne). Utilizou-se delineamento experimental de blocos casualizados com cinco tratamentos (0, 75, 150, 225 e 300 Kg de N ha-1, sob a forma de nitrato de amônia) e quatro repetições. Os valores médios de biomassa antes do primeiro e do segundo pastejo foram respectivam ente de: 2.164 e 2.127 Kg de MS por hectare e os resíduos da ordem de 824 e 1.772 Kg de MS por hectare e a taxa de acúmulo diária média entre os dois pastejos foi 86 Kg de MS por hectare em 17 dias de intervalo. As variáveis número de espigas por metro quadrado, número de grão por metro quadrado, peso de mil grãos, peso do hectolitro e produção de grãos não diferiram (P>0,05) entre os tratamentos. A adubação nitrogenada aumentou linearmente (P=0,0017) o tamanho das espigas, em função das doses de nitrogênio. Para a variável acamamento houve aumentou linear (P=0,0001), evidenciando a susceptibilidade da cultura para elevadas doses de nitrogênio. A aplicação de doses de adubação nitrogenada em trigo duplo propósito pastejado antes dos estádios de espigueta terminal e antese não influencia nas variáveis de rendimento de grão. A adubação nitrogenada em trigo duplo propósito deve ser fracionada no perfilhamento e após cada pastejo aumentando a taxa de remobilização do nitrogênio pela cultura

Produção de trigo duplo propósito com diferentes doses de adubação nitrogenada em cobertura

Currently, the practice of Crop-Livestock Integration is stimulated as a way of increasing the generation of foreign exchange for Brazil. Integrated systems improve land use efficiency as well as preserve, recover and increment or soil fertility. The aim of this research was to evaluate how different doses of nitrogen fertilization can affect production and quality of dual purpose wheat submitted to grazing. The experimental designed was randomized block with five treatments (0, 75, 150, 225 and 300 Kg N ha-1, like ammonium nitrate) and four repetitions. The forage yield, the percentage crude protein (P=.0001) and acid detergent insoluble protein (P=.0054) had a linear increased because of the nitrogen addition doses. The crude protein percentage changed the estimate of all soluble carbohydrates (P=.0001) and non-fibrous carbohydrates (P=.0186), but did not influence the, nitrogen detergent fiber corrected with ash and proteins percentage contributing for content cell. The crops production (P=.0001) and the number of kernels per ear (P=.0001) showed significantly difference because of the nitrogen additions dose, increasing the number of fertile flowers. The nitrogen topdressing alters forage production, the chemical composition and the production of dual purpose wheat grains subjected to grazing.Atualmente, é estimulada a prática de Integração Lavoura-Pecuária (ILP) como forma de incrementar a geração de divisas para o Brasil. Os sistemas integrados melhoram a eficiência de uso da terra, bem como preservam, recuperam e/ou incrementam a fertilidade do solo. Objetivou-se avaliar a produção e a composição bromatológica de trigo duplo propósito (TDP) manejado sob pastejo com diferentes doses de nitrogênio em cobertura (DAN): 0, 75, 150, 225 e 300 Kg de N ha-1, sob a forma de nitrato de amônia. Utilizou-se delineamento experimental de blocos casualizados com quatro repetições. A produção de forragem e os teores de proteína bruta (P=0,001) e proteína insolúvel em detergente ácido aumentaram (P=0,0054) linearmente, em função das DAN. O teor de proteína bruta (P=0,0001) impactou sobre as estimativas de carboidratos totais e de carboidratos não fibrosos, mas não influenciou (P=0,0186) os teores de fibra em detergente neutro corrigidas para cinzas e proteínas contribuindo para manutenção dos teores de conteúdo celular. A produção de grãos P=(0,0001) e o número de grãos por espigas diferiram (P=0,0001), em função das DAN, aumentando o número de flores férteis. A adubação nitrogenada em cobertura altera a produção de forragem, a composição bromatológica e a produção de grãos de trigo duplo propósito submetido à pastejo

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure <= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.13Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt