CERNAS - Artigo em revista científica, indexada ao WoS/Scopus
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- Greenhouse Gas Emissions and Ryegrass Yield after Application of Solid-Liquid Pig Slurry and Biochar to an Agricultural SoilPublication . Pereira, José Luís da Silva; Perdigão, Adelaide; Bonifácio, Gabriel; Figueiredo, Vitor; Marques, Francisco; Trindade, Henrique; Ferreira Wessel, DulcineiaBackground: The application of animal slurry to the soil improves its quality, as manure contains many nutrients for plants. However, this could negatively impact the environment. Objective: This field study investigated the effects of the addition of biochar after the mechanical separation of Whole pig Slurry (WS) into Solid (SF) and Liquid Fractions (LF) on Greenhouse Gases (GHG) emissions (N2O, CO2, and CH4) and ryegrass (Lolium multiflorum Lam. cv magnum) yield. Methods: Biochar (1.0 kg m-2) was applied in plots alone or together with each of the three slurries (80 kg N ha-1) in a total of eight treatments with three replications, including just soil with and without biochar as controls. Soil properties, Greenhouse Gas (GHG) fluxes, and yield were measured during theautumn/winter growing season. Results: The results showed that the addition of biochar to these three slurries significantly increased the soil pH and showed no impact on the other physicochemical properties. The GHG emissions were not significantly different between treatments with and without biochar. The N use efficiency increased significantly in SF > WS > LF, whereas no differences were observed among these three slurries with and without biochar. Conclusion: It can be concluded that the addition of biochar combined with WS or SF/LF to sandy-loam soil appears to have no impact on GHG emissions and ryegrass yield during the autumn/winter season. Overall, this finding suggests that amounts higher than 1.0 kg m-2 of biochar combined with SF may need to be applied to soil to reduce GHG emissions and nitrate leaching and increase N use efficiency and crop yield
- Eating habits and food knowledge in a sample of portuguese university studentsPublication . Guiné, Raquel; Ferreira, Manuela; Duarte, João; Nunes, Bruno; Morais, Patrícia; Sanches, Rafaela; Abrantes, RomanaThe choice to adopt a healthy diet is complex, since food choices and eating behaviours are influenced by various factors, such as biological, social, environmental, demographic and psychological aspects. The transition from secondary school to university is a critical period that involves many social and physical environmental changes, which may lead to an unhealthy lifestyle. This study investigated the eating habits, food knowledge and the level of information about a healthy diet in a sample of 670 university students in Portugal. In general, the participants had a good food knowledge and satisfactory eating habits, as well as a satisfactory level of information about a healthy diet. There were found significant differences in the participants’ food knowledge among age groups and according to the area of studies. Most of the students revealed satisfactory eating habits, with significant differences between age groups, the area of studies and the practice of high competition sport. The results pointed to the necessity of improving educational programs which can contribute to increase university students’ food knowledge and consequently improve their eating habits.
- Structural characterization of lignin from Grape Stalks (Vitis vinifera L.)Publication . Prozil, Sónia; Evtuguin, Dmitry V.; Silva, Artur M. S.; Cruz-Lopes, LuísaThe chemical structure of lignin from grape stalks, an abundant waste of winemaking, has been studied. The dioxane lignin was isolated from extractive- and protein-free grape stalks (Vitis vinifera L.) by modified acidolytic procedure and submitted to a structural analysis by wet chemistry (nitrobenzene and permanganate oxidation (PO)) and spectroscopic techniques. The results obtained suggest that grape stalk lignin is an HGS type with molar proportions of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units of 3:71:26. Structural analysis by 1H and 13C NMR spectroscopy and PO indicates the predominance of β-O-4′ structures (39% mol) in grape stalk lignin together with moderate amounts of β-5′, β-β, β-1′, 5-5′, and 4-O-5′ structures. NMR studies also revealed that grape lignin should be structurally associated with tannins. The condensation degree of grape stalks lignin is higher than that of conventional wood lignins and lignins from other agricultural residues.
- Densification and heat treatment of maritime pine woodPublication . Esteves, Bruno; Ribeiro, Fábio; Cruz-Lopes, Luísa; Ferreira, José; Domingos, Idalina; Duarte, Marta; Duarte, Sónia; Nunes, LinaPine (Pinus pinaster Ait.) wood samples were subjected to a combined treatment by densification and heat treatment. Samples were densified before and after heat treatment. The heat treatment was made inside an oven at 190ºC during 2 to 6 h and wood densification was made in a hot press at around 48 bar pressure and temperatures between 160ºC and 200ºC for 30 min. Compression-set, compression-set recovery after three cycles of water soaking followed by oven drying, density, hardness, bending strength and stiffness and durability against subterranean termites were determined after the treatment. Results show that densification increases density, hardness, bending strength, stiffness and durability against termites. Heat treatment applied after the densification is more effective in reducing compression-set recovery than if applied before.
- Social Justice: Disparities in Average Earnings across Portuguese MunicipalitiesPublication . Martinho, VítorAn ever-ongoing discussion these days involves the disparities in monthly earnings across di erent genders, geographical locations, levels of education, economic sectors, and skills and careers, with various economic and social consequences. In fact, in a framework such as that in which we live in nowadays (with pertinent concerns about economic and social convergences across several indicators), investigating these disparities would be interesting in order to complement the basis that is considered for the design of social policies. There are few studies considering the approaches here developed for this topic. The objective of this study is to analyse the disparities in the average monthly earnings received by employees across Portuguese mainland municipalities over the period 2004–2012, considering as additional analysis criteria geographical location, gender, levels of qualification, levels of education, economic sectors, professional activities, and further qualifications. For this both a cluster and factor analysis were considered to better identify municipalities with similar characteristics and correlations among variables. The results show that the disparities in the monthly average earnings between the Portuguese municipalities are related to three indexes associated with gender, qualifications, and chosen professions. The findings presented are specific to the Portuguese framework; however, the approaches developed in this study may be applied in other contexts to explore the dynamics related with the topic of social justice.
- Bridges between family farming and organic farming: a study case of the Iberian PeninsulaPublication . Guiné, Raquel; Gaião, Davide; Costa, Daniela; Correia, Paula; Guerra, Luis T.; Esteves Correia, Helena; Costa, Cristina Amaro DaThe aim of this work was to identify procedures adopted by family farms in the centre and north of Portu- gal and Galicia (Spain), and to verify whether they resem- ble those used in organic farming. A checklist was pre- pared in Portuguese and Spanish and applied personally to managers of family farms. The participation was volun- tary and 125 valid responses were collected. The results show that farmers included in the study owned small family farms where labour is mainly per- formed by the family, and tended to adopt, in general, good agricultural practices, many of which are common to organic farming, such as crop rotation, avoidance of GMO or avoidance of phytoregulators. However, they failed to adopt some important practices, including the use of seeds inoculated with mycorrhizae, composting, biological and biotechnical control or avoidance of chemical control for plant protection. It was further concluded that gender and age of the farmers did not significantly influence the type of agricultural practices, contrarily to the level of educa- tion and region, which were significantly associated with many of the cultural interventions investigated.
- Estimating relationships between forest fires and greenhouse gas emissions: circular and cumulative effects or unidirectional causality?Publication . Martinho, VítorGreenhouse gas emissions have relevant implications on increases in global temperatures. In turn, forest fires cause significant damage to populations and economic activities, compromising sustainable development and sustainability. However, sometimes, these two phenomena seem to be interrelated. The objective of the study presented here is to investigate the relationship between forest fires and gas emissions. This interrelationship was analysed for the European Union countries where forest fires have had relevant consequences (Portugal, Spain, France, Italy and Greece), over the last decades (1980-2012). In a first step, the level of correlation among greenhouse gas emissions (kt of CO2 equivalent) and the dimension of the forest fires (measured through the burnt area (ha)) was analysed. In a second phase, the causality between these two variables was examined. Finally, the most adjusted model for the relationship between the dimension of the forest fires and global warming was then estimated. It is worth highlighting that, in Portugal, Spain, France and Italy, there is significant correlation among the two variables. For Greece, significant correlation was only found with the variables in growth rates. On the other hand, the most adjusted models estimated for Portugal, Spain, France and Italy are nonlinear, and for Greece, a linear relationship was found. The directional causality varies across the several countries considered. For Portugal and France, considering values of 2012, an increase of 1 ha of burnt area increased the greenhouse gas emission in around 0.09 and 2.61 kt of CO2 equivalent, respectively. In Greece, when the burnt area (ha) growth rate increases 1 percentage point, the greenhouse gas emissions (kt of CO2 equivalent) growth rate increase 0.003 percentage points. Finally, for Spain and Italy, it is the greenhouse gas emissions that cause the burnt area.
- Testing for Structural Changes in the European Union’s Agricultural SectorPublication . Martinho, VítorOver recent decades several European and global occurrences have had an impact on the European Union’s economic sectors, and subsequently on farms. In fact, the various Common Agricultural Policy (CAP) reforms, namely those since 1992, and the global financial and economic crises, specifically after 2008, seem to have had several e ects on the dynamics of the entire European Union agricultural sector and on the performance of farms. However, there is doubt as to whether these events were enough to promote structural breaks in European Union farms. In this way, the main objective of this study is to analyse both the known and unknown structural breaks in European farms, between 1989 and 2016. To this purpose, data from the Farm Accountancy Data Network (FADN) from the twelve former member-states (the countries with the longer time series) and methodologies based on the Chow test and on the Quandt likelihood ratio (QLR) were considered. The results show that the structural breaks are di erent across the several twelve former European Union countries and among the several variables considered. In any case, the financial and economic crises, as well as changes in the European Union’s methodologies relative to statistical information, seem to have had a greater impact on the European farms than the several CAP reforms (with the exception of the reform of 1992 the trade liberalization). However, the several consequences of all these European and world events on European farms seem to be delayed for some years.
- Drying kinetics and mass transfer properties in the drying of thistle flowerPublication . Guiné, Raquel; Fontes, Luísa; Lima, Maria JoãoThistle flowers, and particularly their stigmas, are used to coagulate milk in the production of a number of traditional Portuguese cheeses due to their high milk-clotting activity provided by the high content of aspartic proteases. The aim of the present work was to determine the mass transfer properties of thistle flower under different drying conditions: natural drying and convective drying. Convective drying took place in a convection chamber set at different temperatures (35 to 65 °C) and the process was terminated when the sample presented a moisture content of about 5% or less. The traditional drying method was also used, placing the thistle flowers in a dry place sheltered from the sun, and leaving them to dehydrate at the variable room temperature. The present work allowed for the conclusion that convective drying was much faster than natural drying, and that the drying rate increased with temperature. The drying curve revealed an initial constant rate period followed by a falling rate. All the five thin layer models tested to fit the experimental data were shown to adequately describe the drying of the thistle flowers, but the best one was the Page model. The drying constant increased with temperature as did the effective diffusivity and the mass transfer coefficient. The results allowed one to estimate the activation energy for moisture diffusion (57 kJ/mol) and for convective mass transfer (78 kJ/mol). Thus this study showed the possibilities for designing efficient drying processes for the thistle flower used for milk-clotting in the manufacture of traditional cheeses.
- Best management practices from agricultural economics: Mitigating air, soil and water pollutionPublication . Martinho, VítorOften the several stakeholders involved in the agricultural sector place a greater emphasis on the negative externalities from farming production rather than on the solutions and approaches to mitigate, namely impacts from pollution. The scientific literature, in certain circumstances, follows this tendency leaving a vast chasm of enormous potential left to be explored. It is important to contribute towards the reduction of this gap, highlighting the best management practices implemented across the agricultural sector around the world, specifically to make them more visible and give incentive to the several agents in adopting and spreading their use. In this way, the main objective is to stress the best management practices presented by the global scientific literature from the farming sector. To achieve this objective methodology based on bibliometric analysis-factor-analysis-literature survey approach was considered, applied to 150 documents obtained from the Web of Science (core collection) related with the following topics: best management practice; agricultural economics; air, soil and water pollution. As main insights, it is worth referring the best management practices to deal with problems from agricultural production, such as, for example, the use of agricultural residues as feedstock for renewable energies. With regard to sustainable development in the agricultural sector, concepts such as "sustainable remediation" have their place. On the other hand, the agricultural and environmental policies and the agricultural costs associated with the several farming practices also play a determinant role here. Finally, only fraction of the scientific documents analysed (16 papers) belong to the group of studies related to policies, showing that there are potential subjects to be addressed here in future studies related with these topics. The same happens for cost-benefit analyses (24 documents).