Abstract Background Diversified crop systems provide several advantages for crop production and the agricultural ecosystem. In contrast, growing the same crop for consecutive years increases weeds, insects, and diseases issues, adding further cost to crop production owing to their management. Objective The objective was to evaluate the effects of six different winter cover crops and compare the impacts of a diversified rotation system in contrast to the succession system, combined with three different post-emergence herbicide management looking up to soybean yield, aboveground mass production, and weed density impact. Methods The experiment was performed over 2014 to 2018, using a randomized block design with four replications. Cover crop treatments were 1) fallow 2) wheat 3) rye 4) rye + turnip 5) rye + vetch 6) black oats. At the time of cover crop termination, weed density was counted and aboveground mass was measured. The crop rotation system was an alternated soybean and corn using three different post-emergence herbicide treatments, and the succession system was soybean each year. When a significant effect was observed after test F, the Tukey test (p ≤ 0.05) was applied to compare treatment effects. Results Rye + vetch as a cover crop, rotation system, and herbicide usage showed a higher impact on weed density. Rye + turnip has produced more aboveground biomass. Soybean yield was higher after wheat. Conclusions Cover crops implementation, crop rotation system, and herbicide usage have increased biomass production and crop yield, and reduced weed density showing integrated weed management as a key strategy for production systems.

Resumo O controlo e a mitigação dos fenómenos de salinização e/ou sodização dos solos são considerados um dos principais desafios da agricultura de regadio. Em Portugal, a Lezíria Grande de Vila Franca de Xira é uma região com riscos de salinização e sodização do solo acrescidos pela sua localização costeira e com influência das marés. Neste estudo, pretendeu-se avaliar a dinâmica da água e dos sais num Fluvissolo com rotação de milho e azevém anual e avaliar futuros riscos de salinização do solo induzidos pela rega. Este estudo iniciou-se com a calibração do modelo Hydrus-1D para prever o teor de água no solo e o transporte de solutos com medições de campo (de Junho 2017 a Outubro 2018). O Hydrus-1D simulou com sucesso o teor de água no solo (RMSE= 0.019 m3m-3 e R2= 0.94), o teor de sólidos dissolvidos (TDS) no solo (RMSE= 0.212 g L-1 e R2= 0.77) e a redução na absorção de água pelas raízes devido ao stress osmótico. Em seguida, o modelo foi usado na previsão de riscos de salinização do solo com uma análise de cenários considerando diferentes qualidades da água de rega (ECw de 1.5, 3 e 5 dS m-1). Observou-se que com a subida da ECw para 5 dS m-1, a concentração média de solutos no perfil de solo explorado pelas raízes aumenta para níveis superiores aos tolerados pela cultura de milho. O Hydrus-1D simulou o teor de água no solo e o teor de sólidos dissolvidos no solo com sucesso e é uma ferramenta muito útil no planeamento e gestão da rega e na previsão de riscos de salinidade do solo.

Abstract The mitigation of soil salinization and/or sodicization phenomena are considered one of the main challenges of irrigated agriculture. In Portugal, Lezíria Grande of Vila Franca de Xira is a region with increased salinization and sodicization risks due to the influence of tidal movement on groundwater. This study aimed to evaluate soil water and salt dynamics in an irrigated Fluvisol with a crop rotation of maize and annual ryegrass and to predict irrigation-induced risks of soil salinization. We first calibrated the Hydrus-1D model for predicting soil water flow and solute transport with observed field data (from June 2017 to October 2018). Hydrus-1D successfully simulated soil water content (RMSE= 0.019 m3m-3 and R2= 0.94), the total dissolved solids (TDS) in the soil (RMSE= 0.212 g L-1 and R2= 0.77) and the reduction in water uptake by roots due to osmotic stress. Afterward we evaluate future risks of soil salinization performing a scenario analysis considering irrigation with different water qualities (with an electrical conductivity of the irrigation water, ECw, of 1.5, 3 and 5 dS m-1). We observed that when the ECw increases to 5 dS m-1, the average solute concentration in the root zone rises to levels above the threshold tolerance of maize. Hydrus-1D successfully simulated soil water content and the total dissolved solids and is a very useful tool in planning and managing irrigation and in predicting soil salinity risks.

A microbiota intestinal constitui a maior comunidade de bactérias no corpo humano e a sua alteração está associada a diversas patologias. Diversos estudos referem que a microbiota intestinal pode ter um papel preponderante na espondiloartrite. Os mecanismos sugeridos, que poderão estar implícitos nesta relação, incluem a permeabilidade intestinal, a estimulação do sistema imunitário, o mimetismo molecular, entre outros. O papel da alimentação na modulação da microbiota enquanto medida preventiva ou terapêutica na espondiloartrite, parece ser algo promissor e suficientemente relevante para motivar mais investigação futura, principalmente de translação.

The gut microbiota is the major bacterial community in the human body, and its imbalance, dysbiosis, is associated with various pathologies. Many studies support the notion that the gut microbiota plays an important role in spondyloarthritis. The possible mechanisms, which may be implicit in this relationship, include intestinal permeability, stimulation of the immune system, molecular mimicry, among others. The role of diet in modulating the microbiota as a preventive or therapeutic measure in spondyloarthritis appears to be promising and sufficiently relevant to motivate further future research, especially translation research.