The Use of Si-Based Fertilization to Improve Agricultural Performance

Silicon (Si) is a “quasi-essential” element, associated to stresses/limitations alleviation in crops. However, stressful situations are becoming the norm, due to climate change, human exhaustion of natural resources, land degradation and loss of soil biodiversity. In this context, Si becomes a critical element, capacitating crops to grow more and better with less. A total of 467 articles up to 2021 were selected, reporting 501 experiments (lab-oriented and field trials) resulting in 682 cases where different Si-based fertilizers were used to study crops/plants with agronomic value to evaluate its physiological and/or agronomic performance under a specific motivation. Results show that 63% of cases testing Si-fertilization show increase in productivity, while 13% refuted this observation and 24% did not evaluate plant growth. Crop physiological responses was registered in 42% of the cases and only 3% did not report any alteration, although 55% did not evaluate these indicators. Symptom alleviation, in cases where stresses/limitations were studied, was registered in 74% of the cases with a low number of negative outcomes (9%). Field trials where crop yield was measured after application of Si-fertilization show that 69% of different measurements (599) register a yield improvement ≥ 5%, while 18% of the measurements registered between 0 and 5% and only 14% reported yield loss. Si-fertilization is therefore and important factor to improve crop yield and capacitate crops with resilience to endure future limitations. Its inclusion in modern agriculture should be considered in larger scales to adapt crops to the current challenges of sustainable agriculture and food provision.info:eu-repo/semantics/publishedVersio

New strategies to overcome water limitation in cultivated maize: Results from sub-surface irrigation and silicon fertilization

The increasing growth of the world's population has established an unprecedented pressure in the availability of fresh water resources, with food production systems consuming over 70% of the world's fresh water withdrawals. Other pressures include climate change effects and the increasing number of semi-arid regions. The present challenges are therefore the maintenance of high production rates with fewer resources, especially in regions where water is becoming less accessible. In this study, we have tested the effect of sub-surface irrigation and silicon fertilization in maize growth with and without water limitation. These solutions have been suggested as effective in drought conditions but an overall study of their effects on the soil water balance and root length density is lacking. We have conducted a pot experiment with maize for 101 days where measurements in soil water content and root length were taken. Also, Hydrus 2-D was used to simulate the root water uptake and calculate the water balance. Results show that both sub-surface irrigation and silicon fertilization increase the root system by 21% and 34% respectively in water stress situation. Also, in the case of no water stress, silicon fertilization still induces an increase of 11% in the root development, showing that this solution has positive effects even when the crop is not hydrologically limited. Indeed the root water uptake was higher for the silicon treatment when no water limitation was present (71.6 L), compared to the sub-surface irrigation (62.5 L) and the control (62.3 L). While sub-surface irrigation generally decreased evaporation, the silicon treatment lowered drainage by promoting a better and more efficient root water uptake.info:eu-repo/semantics/publishedVersio

Editorial: Silicon cycling in agricultural soils under current anthropogenic influences

info:eu-repo/semantics/publishedVersio

As freguesias e as políticas educativas locais: as necessidades e as obrigações

Dissertação apresentada para obtenção do grau de Mestre em Ciências da Educação Área de especialização em Administração Escolar 2013Perante um cenário de políticas de descentralização de competências educativas do Ministério da Educação para os Municípios e destes para as Freguesias através de protocolos de delegação de competências, decidiu-se tentar compreender de que forma é que as Freguesias participam na gestão dos estabelecimentos de Educação Pré-Escolar e Escolas do 1º ciclo, bem como na definição e promoção de políticas educativas locais. Através do estudo de duas Freguesias (Benfica e Carnide), do concelho de Lisboa, pretendeu-se: analisar o quadro legal que regulamenta a ação das Juntas de Freguesia na área educativa; revelar o trabalho que é desenvolvido por estes órgãos de poder local, seja por imposição legal, por decisões protocolares ou por livre iniciativa; identificar as motivações que justificam as suas ações voluntárias; mostrar como se organizam internamente para a concretização do seu trabalho e caraterizar as relações que estabelecem com a restante comunidade local e a Câmara Municipal. Para tal, recorreu-se ao estudo de caso como estratégia de investigação e a entrevistas e análise documental como técnicas de recolha de dados. O procedimento de análise da informação recolhida seguido foi o da análise de conteúdo. Concluiu-se que estas duas Juntas de Freguesia desenvolvem trabalho para além daquilo que legalmente lhes compete e daquilo que acordaram com o Município através do protocolo de delegação de competências assinado, movidas sobretudo pelas lacunas que encontram na satisfação de necessidades dos seus habitantes, mas também porque encaram a área da educação como uma vertente fundamental da formação dos cidadãos. Para além disso, promovem a participação ativa dos cidadãos e tentam ao máximo construir com estes a política educativa do seu território. Sentem portanto que satisfazem necessidades, mas também que cumprem obrigações morais e políticas e que desempenham democraticamente aquilo a que se propuseram quando órgãos eleitos localmente.ABSTRACT Faced with a situation of decentralization policies of educational powers from the Ministery of Education to the Municipalities and from these to the Parish Councils through protocols of delegation of powers, we decided to try to come to understand the way the Parish Councils participate in the management of Pre-schools and 1st cycle schools, as well as the definition and promotion of local educational policies. Based on the analysis of two Parish Councils (Benfica and Carnide) of Lisbon County, we aimed at the following: analyse the framework which establishes the proceedings of the Parish Councils within the Educational area; reveal the work developed by these agents of the local authority, being it through legal obligation, through protocol decisions or through free enterprise; identify the motivations that justify their voluntary deeds; show their internal organization directed for the development of their work, and feature their relationship within the remainder local community and within the County. For that purpose we resorted to a case study as an investigation strategy, and to interviews and documentary analysis based on data collection. The procedure followed to construe the information gathered was the analysis of its content. The conclusion reached was that these two Parish Councils develop work that goes beyond what is legally required from them and moreover, from what they had established with the County through the protocols of delegation of powers agreed upon. They are mainly moved by the gap found in the meeting of the inhabitants’ needs, but also because they consider the educational field as a central factor in the formation of the citizens. Furthermore, they promote the active participation of the citizens and try their best to build together with them the educational policy for their territory. Thus, they feel that they meet needs, and in addition meet moral and political obligations alongside with the democratic accomplishment of what they had committed to when locally elected

“BalSim”: A Carbon, Nitrogen and Greenhouse Gas Mass Balance Model for Pastures

Animal production systems are increasingly required to co-produce meat products and other ecosystem services. Sown biodiverse pastures (SBP) were developed in Portugal as an improvement over semi-natural pastures (SNP). SBP increase yields and animal intake during grazing, are substantial carbon sinks, and the abundance of legumes in the mixtures provides plants with a biological source of nitrogen. However, the data available and the data demands of most models make integrated modelling of these effects difficult. Here, we developed “BalSim”, a mass balance approach for the estimation of carbon and nitrogen flows and the direct greenhouse gas (GHG) balance of the two production systems. Results show that, on average, the on-farm GHG balance is 2.6 and 0.8 t CO2e/ha.yr for SBP and SNP, respectively. Ignoring the effects of carbon sequestration, and taking into account only non-CO2 emissions, the systems are responsible for 17.0 and 16.3 kg CO2e/kg live weight.yr. The annual analysis showed that non-CO2 emissions were highest in a drought year due to decreased yield and stocking rate. We also showed through scenario analysis that matching the grazing level to the yield is crucial to minimize emissions and ensure reduced feed supplementation while maintaining high soil carbon stocks.info:eu-repo/semantics/publishedVersio

An Overview of Sustainability Assessment Frameworks in Agriculture

Recent research established a link between environmental alterations due to agriculture intensification, social damage and the loss of economic growth. Thus, the integration of environmental and social dimensions is key for economic development. In recent years, several frameworks have been proposed to assess the overall sustainability of farms. Nevertheless, the myriad of existing frameworks and the variety of indicators result in difficulties in selecting the most appropriate framework for study site application. This manuscript aims to: (i) understand the criteria to select appropriate frameworks and summarize the range of those being used to assess sustainability; (ii) identify the available frameworks to assess agricultural sustainability; and (iii) analyze the strengths, weaknesses and applicability of each framework. Six frameworks, namely SAFA, RISE, MASC, LADA, SMART and public goods (PG), were identified. Results show that SMART is the framework that considers, in a balanced way, the environmental, sociocultural and economic dimensions of sustainability, whereas others focused on the environmental (RISE), environmental and economic (PG) and sociocultural (SAFA) dimension. However, depending on the scale assessment, sector of application and the sustainability completeness intended, all frameworks are suitable for the assessment. We present a decision tree to help future users understand the best option for their objective

Silicon Mobilization in Soils: the Broader Impact of Land Use

Dissolved Si (DSi) provision from land systems triggers diatom growth and CO2 sequestration. Soils and ecosystems act as a Si “filter”, transforming DSi originated from mineral weathering into biogenic Si (BSi) after DSi uptake by plants, or into other pedogenic forms of Si (non-BSi). Land use changes the quantity of BSi and non-BSi pools along the soil profile. However, methods used to isolate Si pools include chemical extractions at high temperatures and alkaline environments and therefore are unable to provide information concerning the dissolution potential of BSi and non-BSi pools under normal conditions of temperature and pH. Here, we conducted a batch experiment where forest, pasture and cropland soil samples were mixed with water at 25 °C and pH 7. The soil samples were collected from a temperate land use gradient located in the Belgian Loess Belt. We measured dissolved Si and aluminium (Al) during 80 days. BSi and non-BSi pool contents along the soil profile were known, as they had been established previously through chemical extraction. Results show that BSi and non-BSi enriched samples present distinct Si and Al dissolution curves. While non-BSi pools contribute significantly with immediate availability of Si, BSi pools present an initial slow dissolution. Therefore, croplands that were depleted of phytoliths and had poorly organic horizons display higher concentrations of initial dissolved Si, while pastures and forests, where pedogenic pools dominate only at depths below 40 cm, have more limited initial Si release.info:eu-repo/semantics/publishedVersio

Parto no domicílio na voz das mulheres: uma perspectiva à luz da humanização

This paper is a descriptive exploratory study developed with the objective of getting acquainted with life experiences, preparation, feelings and motivations of women who have chosen home childbirth. The subjects of the research comprised ten women who had at least one experience of home childbirth in Porto Alegre, in the last five years. The data was gathered through semi-structured interviews, which were analyzed according to Minayo’s proposal. It indicates that the women who opted for home childbirth don’t accept what the hospital system offers to women in labor at present time, but they do recognize that, for a few women, hospital delivery is the best choice, whether for reasons that involve personal decisions or health ones.Tratase de un estudio descriptivo exploratorio, cuyo objetivo fue conocer a las vivencias, preparación, sentimientos y motivaciones de las mujeres que eligieram el parto en casa. Participaron de esta investigación diez mujeres que tuvieron, por lo menos, una experiencia de parto en casa, en Porto Alegre, en los últimos cinco años. Las informaciones fueron colectadas por medio de entrevista semi-estructurada y analizadas a través de la propuesta de Minayo. Los datos indican que las mujeres, que eligieron parto en casa, no aceptan lo que el sistema hospitalario ofrece a las parturientas actualmente, pero reconocen que, para algunas mujeres, el parto hospitalario es la mejor opción para ellas, sea por razones que envuelven decisiones personales o de salud.Trata-se de um estudo descritivo, exploratório, cujo objetivo foi conhecer as vivências, preparação, sentimentos e motivações de mulheres que optaram por partos domiciliares. Participaram da pesquisa dez mulheres que tiveram, pelo menos, uma experiência de parto domiciliar, em Porto Alegre, nos últimos cinco anos. As informações foram coletadas por entrevista semi-estruturada e analisadas segundo a proposta de Minayo. Os dados indicam que as mulheres que optaram por partos domiciliares não aceitam o que o sistema hospitalar atualmente oferece às parturientes e reconhecem que, para algumas, o parto hospitalar é necessário, por questões que envolvem decisões pessoais ou de saúde

Dá-lhe P

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