Eco-eficiência na indústria extractiva : uma estratégia para o desenvolvimento sustentável

Processo de extracção de mármore da pedreira do Rosal; processo de transformação em comprimentos livre

Steam reforming of biomass gasification gas for hydrogen production: From thermodynamic analysis to experimental validation

ABSTRACT: Biomass gasification produces syngas composed mainly of hydrogen, carbon monoxide, carbon dioxide, methane, water, and higher hydrocarbons, till C4, mainly ethane. The hydrocarbon content can be upgraded into richer hydrogen streams through the steam reforming reaction. This study assessed the steam reforming process at the thermodynamic equilibrium of five streams, with different compositions, from the gasification of three different biomass sources (Lignin, Miscanthus, and Eucalyptus). The simulations were performed on Aspen Plus V12 software using the Gibbs energy minimization method. The influence of the operating conditions on the hydrogen yield was assessed: temperature in the range of 200 to 1100 degrees C, pressures of 1 to 20 bar, and steam-to-carbon (S/C) molar ratios from 0 (only dry reforming) to 10. It was observed that operating conditions of 725 to 850 degrees C, 1 bar, and an S/C ratio of 3 enhanced the streams' hydrogen content and led to nearly complete hydrocarbon conversion (>99%). Regarding hydrogen purity, the stream obtained from the gasification of Lignin and followed by a conditioning phase (stream 5) has the highest hydrogen purity, 52.7%, and an hydrogen yield of 48.7%. In contrast, the stream obtained from the gasification of Lignin without any conditioning (stream 1) led to the greatest increase in hydrogen purity, from 19% to 51.2% and a hydrogen yield of 61.8%. Concerning coke formation, it can be mitigated for S/C molar ratios and temperatures >2 and 700 degrees C, respectively. Experimental tests with stream 1 were carried out, which show a similar trend to the simulation results, particularly at high temperatures (700-800 degrees C).info:eu-repo/semantics/publishedVersio

Olive yield and physicochemical properties of olives and oil in response to nutrient application under rainfed conditions

The effects of mineral fertilizers on the physicochemical properties of olives and oil under rainfed conditions is scarce. In this three-year study, the results of a nitrogen (N), phosphorus (P), potassium (K) and boron (B) fertilization trial carried out in a young rainfed olive grove and arranged as a nutrient omission trial are reported. The control consisted of the application of N, P, K and B (NPKB) and four other treatments corresponded to the removal of one of them (N0, P0, K0 and B0). Olive yield and several variables associated with the physicochemical properties of olives and oil were evaluated. The NPKB treatment increased olive yield compared to the treatment that did not receive N (N0). Although dependent on the climate conditions of the crop season, the NPKB treatment increased fruit weight and the pulp/pit ratio and its fruits tended to accumulate more oil than K0. However, the phenolics concentrations on fruits and oil tended to be lower. All olive oil samples were classified in the “extra virgin” category and all showed a decrease in its stability between 3 and 15 months of storage, regardless of treatment, especially in N0, P0 and B0 treatments. The results of the sensorial analysis indicate that all the oils fell into the medium fruitiness and greenly-fruity category. Only in P0 and B0 were defects detected, namely muddy sediment. Thus, this study seems to indicate the importance of N application, but also a balanced nutrient application and that further studies are needed, given the difficulty in finding clear trends in the response of measured variables to fertilizer treatments.Ermelinda Silva acknowledges the financial support provided by national funds through FCT -Portuguese Foundation for Science and Technology (PD/BD/128274/2017), under the Doctoral Programme “Agricultural Production Chains—from fork to farm” (PD/00122/2012) and from the European Social Funds and the Regional Operational Programme Norte 2020. This research was funded by the Operational Group “Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas”, funded by PT2020 and EAFRD (European Agricultural Fund for Rural Development). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UIDB/00690/2020) and CITAB (UIDB/04033/2020) and also to AgriFood XXI Project, No. NORTE-01-0145-FEDER- 000041, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014–2020). Ermelinda Silva also acknowledges the present financial support throughout project NORTE-06-3559-FSE-000103 funded by the Fundo Social Europeu (FSE) and FCT research unit Centre BIO R&D Unit (UIDB/05083/2020).info:eu-repo/semantics/publishedVersio

Leguminous cover crop to adapt olive rainfed orchards to climate change

Leguminous cover crops have the potential to contribute to soil protection against erosion and improve carbon sequestration, soil and water quality and might help agricultura! systems become more resilient to climate change. The aim of this study was to investigate the effects of a cover crop of self-reseeding annuallegumes of short growing cycle on physiological and biochemical responses of twenty-six-year-old olive trees (Olea europaea L. cv. Cobrançosa) grown under rainfed conditions, when compared with conventional tillage. The results showed that the leguminous cover crop ameliorates the physiological and biochemical performance of olive tree during the drought season, judging by the rise of net photosynthesis, transpiration rate and stomatal conductance, whereas the opposite pattern was observed for the concentration of total phenols and for total antioxidant activity in leaves. ln addition, it was observed an increase on yield, size and weight of olive fruits. These results indicate that the use of well-designed, locally-tailored cover crop mixtures, associated with an appropriate mowing time, is a very promising strategy to implement in olive orchards under water scarcity. Thus, cover cropping is a win-win strategy as it increases farm benefits and provides ecosystem services.This work was funded by the INTERACT project- "Jntcgrative Research in Environment, Agro-Chains and Technology", no. NORTE-01-0145-FEDER-000017, in its !ines of research entitled ISAC, co-tinanced by the European Regional Devclopment Fund (ERDF) through NORTE 2020 (North Regional Operational Program 20 14/2020). SM (PD/BD/135327/2017), EM (PD/BD/128274/2017) and CB (PD/BD/52543/2014) acknowledge the financ ial support provided by the FCT-Portuguese Foundatíon for Science and Technology, under the Doctoral Programme "Agricultura] Production Chains- from fork to farm" (PD/00122/2012).info:eu-repo/semantics/publishedVersio

Zeolites and Biochar modulate olive fruit and oil polyphenolic profile

Soil degradation processes and climate change threaten the sustainability of Mediterranean rainfed olive orchards, with repercussions on crop yield and quality of olives, olive oil and olive by-products. Using soil amendments can enhance soil fertility for sustained environmental quality and plant performance. For two years, we evaluated, under rainfed conditions, the effects of a fertilizer compound (FC) and its combination with zeolites (ZL) and biochar (BC) amendments on soil moisture, yield, fruit and oil polyphenols and quality indices. The polyphenolic composition was strongly influenced by treatments, although no effects were observed on crop yield. ZL improved soil moisture (average increase of 26.3% compared to FC), fruit fatty acid composition (increase of 12.4% in oleic/linoleic ratio in 2018) and oil quality, BC enhanced the concentrations of polyphenols with high nutritional value (average annual increase of 25.6, 84.8 and 11.6% for 3,4-dihydroxyphenylglycol, oleuropein and rutin, respectively). In contrast, olive oil from FC fruits showed the poorest quality, with oxidation and hydrolytic breakdown signals. The applied soil amendments appear to be a promising sustainable strategy to implement in olive rainfed orchards.Doctoral fellowship under the Doctoral Program “Agricultural Production Chains—from fork to farm” (PD/00122/2012) provided by the FCT-Portuguese Foundation for Science and Technology to S. Martins (PD/BD/135327/2017). This research was funded by the Operational Group “Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas”, funded by PT2020 and EAFRD (European Agricultural Fund for Rural Development). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CQ-VR (UIDB/00616/2020), CIMO (UIDB/00690/2020) and CITAB (UIDB/04033/2020) and also to AgriFood XXI Project, No. NORTE-01-0145-FEDER-000041, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014–2020).info:eu-repo/semantics/publishedVersio

Use of kaolin as a summer stress alleviating product in olive orchards under rainfed conditions

In a changing world, where is expected the temperatures rising and the reduction in precipitation in some semi-arid areas of the globe, the search for new agronomic practices that help crops to maintain and/or increase yields and quality is a continuous challenge. Kaolin (KL) exogenous application has been considered a short-term solution to alleviate the adverse effects of summer stress. The formed particle film increases the reflection of excess radiation reducing the risk of leaf damage from heat load accumulation and solar injury. Olive trees (Olea europaea L.) cultivated under rainfed conditions were sprayed with KL (5%) during two consecutive years in the beginning of the summer season. In general, relatively to the control group, KL-sprayed plants showed an enhancement in leaf water status, stomatal conductance and photosynthetic capacity and a reduction in leaf sclerophylly. In the severest period analyzed, at the end of the second-year summer, KL has lost the effectiveness of keeping gas exchange above the control measurements. However, in both years, allowed a faster restauration of the physiological functions in early autumn and contributed to higher crop yield. Overall, the results of the present investigation revealed that KL were effective in preventing the adverse effects of summer stress on crop performance and yield.Doctoral fellowship under the Doctoral Program “Agricultural Production Chains – from fork to farm” (PD/00122/2012) provided by the FCT-Portuguese Foundation for Science and Technology to C. Brito (PD/BD/52543/2014). Institution CITAB, for its financial support through the European Investment Funds by FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Program, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013.info:eu-repo/semantics/publishedVersio

Mycorrhizal fungi were more effective than zeolites in increasing the growth of non-irrigated young olive trees

Four soil treatments, consisting of two commercial mycorrhizal fungi, one zeolite and an untreated control, were arranged in a factorial design with two foliar fertilization treatments, a foliar spray and a control to study the effects of commercial mycorrhizal fungi and zeolites on the growth of young, rainfed olive trees planted in very acidic soil. The concentrations in the plant tissues of most of essential nutrients, particularly nitrogen (N), phosphorus (P), potassium (K) and boron (B), did not significantly change with the soil treatments, whereas leaf N and B concentrations significantly increased with foliar fertilization. Leaf calcium (Ca) and magnesium (Mg) levels were found to be much lower than their respective sufficiency ranges and increased with soil amendments, also giving positive outcomes for plant water status, photosynthetic activity and assimilation area. Ultimately, the mycorrhizal fungi increased the growth of the young trees, whereas the effect of zeolites was much smaller and not significantly different to the control. Thus, it seems that in this very acidic soil and under rainfed conditions, the major benefits for plants from the application of mycorrhizal fungi and zeolites were the alleviation of drought stress and tissue Ca and Mg disorders.info:eu-repo/semantics/publishedVersio

A fertilização mineral com alta dose de azoto aumentou a produção de azeitona em olival de sequeiro, mas reduziu a matéria orgânica do solo em comparação com o uso de três corretivos orgânicos

Resíduos orgânicos de atividades domésticas ou agroindustriais devem ser reciclados, sendo o seu uso como corretivo de solo uma possibilidade interessante. Neste estudo, avaliouse durante quatro anos o efeito da aplicação de resíduos sólidos urbanos (RSU), estrume de curral (EC), cinzas de biomassa suplementadas com azoto (C+N), fertilização inorgânica comum na região (50 kg ha-1 de N, P20 S e K20) como testemunha (T) e T suplementada com 70 kg N ha- 1 (dose elevada de azoto, N+) em olival de sequeiro gerido com mobilização tradicional. O tratamento W aumentou a produtividade em comparação com os outros tratamentos (+ 165% do que RSU), tendo o N disponível mostrado ser a principal razão, em estreita associação com os incrementos da atividade fotossintética e da dimensão da superfície assimiladora a partir do terceiro ano do estudo. Por outro lado, em geral, as árvores tratadas com corretivos orgânicos apresentaram taxas fotossintéticas líquidas similares às plantas que receberam fertilização mineral convencional. As aplicações de RSU e EC aumentaram o teor de matéria orgânica no solo, os níveis de fósforo e a capacidade de troca catiónica, deixando boas indicações para o futuro, embora tenham fornecido pouco N às éÍrvores. O tratamento W reduziu significativamente o teor de matéria orgânica no solo (-63% do que RSU), resultado atribuído em parte ao sistema de gestão do solo por não permitir o desenvolvimento de vegetação herbácea, mas também a um efeito conhecido como interação do N adicionado, aspeto que compromete a sustentabilidade dessa estratégia de fertilização. Embora os RSU e as cinzas de biomassa possam estar associados a riscos de contaminação ambiental com metais pesados, neste estudo os níveis de metais no solo ou nos tecidos das plantas não foram preocupantes, pelo que a sua utilização nos olivais pode ser recomendada embora os seus efeitos devam continuar a ser monitorizados.Este trabalho foi financiado por Fundos Nacionais através da FCT - Fundação para a Ciência e a Tecnologia, no âmbito do projeto UIDB/04033/2020" e pelo Grupo Operacional Novas práticas em olivais de sequeiro: estratégias de mitigação e adaptação às alterações climáticas (Iniciativa ID 278).info:eu-repo/semantics/publishedVersio

Managing soils for mitigation and adaptation of rainfed olive trees to climate change

The olive sector has an important economic, social, cultural and ecological relevance in the Mediterranean region, where tillage still is a generalized practice, although the recommendations of UE policy for a more sustainable agriculture. In fact, tillage has negative side-effects, including increased soil erosion and high labor and fuel requirements, and relevant changes on soil quality indicators, as bulk density, porosity, water-holding capacity, organic matter content and microbial activity. The study conducted in two different rainfed orchards (cv. Cobrançosa) of Northeast Portugal revealed that cover crops with self-reseeding legumes of short-cycle, with mulch of dead vegetation during the dry season, and a permanent sward grazed with a flock of sheep, are better options for soil management in olive tree rainfed orchards. Both practices influence positively the olive tree water status during the drought season, as well the nutritional status, contributing to greater physiological performance during the summer, as evidenced by higher net photosynthetic rate, mainly due to inferior stomatal limitations, and enhanced yield. Moreover, these less disruptive agronomic practices increased the levels of total and easily extractable glomalin, a thermostable hydrophobic glycoprotein produced by arbuscular mycorrhizal fungi, that play an important role in the stability of soil aggregates and in the sequestration of nitrogen and carbon. These results indicate that these practices should be included in the portfolio of management strategies against climate change, contributing to the sustainability of rainfed orchards under a changing environment.This work was funded by the INTERACT project – “Integrative Research in Environment, Agro-Chains and Technology”, no. NORTE-01-0145-FEDER-000017, in its lines of research entitled ISAC, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020).info:eu-repo/semantics/publishedVersio

Weather year-to-year variations determine the influence of kaolin and salicylic acid in olive fruits and oil phenolic composition

Olive tree (Olea europaea L.) growing area is threatened by the current and predicted adverse environmental conditions, affecting negatively the quality of the olive products, largely known for its benefits in human diet. Thus, agronomic strategies may be implemented to offset those negative effects. During two consecutive years young olive trees under rainfed conditions were sprayed in the beginning of the summer season with 100 M salicylic acid (SA), a stress signaling phytohormone, or with kaolin 5% (KL), a heat and irradiance reflecting clay. The distinct weather conditions during the fruit development stage, with higher rainfall close to the harvest and the early frost events, in the first year, and the warmer and drier summer, in the second year, contributed to the increase in phenolic compounds in fruits and in olive oil from the first to the second year. Both KL and SA increased crop yield, while, in general, phenolics concentrations of both olives and oil were increased and decreased by the applied products in the first and second year, respectively. This dissimilar response was modulated by the distinct weather conditions, demonstrating the effectiveness of the applied products in attenuating the frost-promoted degradation of phenolic compounds in the first year and in mitigating the extreme adverse conditions felt in the summer of the second year. The phenolic composition was also distinctly affected, since total phenols, ortho-diphenols and flavonoids exhibited different trends. It is hard to conclude a specific influence of the applied products on olives and oil phenolic composition, since the weather year-to-year variations determine different plant responses.Doctoral fellowship under the Doctoral Program “Agricultural Production Chains – from fork to farm” (PD/00122/2012) provided by the FCT-Portuguese Foundation for Science and Technology to C. Brito (PD/BD/ 52543/2014). Institution CITAB, for its financial support through the European Investment Funds by FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Program, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013.info:eu-repo/semantics/publishedVersio