ESAV - DEAS - Artigo em revista científica, indexada ao WoS/Scopus
Permanent URI for this collection
Browse
Browsing ESAV - DEAS - Artigo em revista científica, indexada ao WoS/Scopus by Issue Date
Now showing 1 - 10 of 106
Results Per Page
Sort Options
- 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
- Life cycle assessment of residual forestry biomass chips at a power plant: a Portuguese case studyPublication . Ferreira, José; Viana, Helder Filipe dos Santos; Esteves, Bruno; Cruz-Lopes, Luísa; Domingos, IdalinaThe residual forest biomass (RFB) sector has been experiencing strong development at European level and particularly in Portugal mainly due to the increase of energy production from renewable sources. The aim of this study is to assess the environmental impacts of eucalyptus RFB chips production chain in Portugal. The environmental and economic impact comparison of the processes included in the production chain is presented as well. The environmental impacts were calculated by the life cycle assessment approach described in the ISO 14040 series of standards. The production chain assessed included all processes from eucalyptus forest until the delivery of RFB chips at the power plant. The main conclusion of this study is that eucalyptus wood production is the process that presents the greatest environmental impact through the product life cycle.
- Forestry activity in Portugal within the context of the European Union: a cluster in agricultural economics for sustainable developmentPublication . Martinho, VítorForestry activities may be important complements to a farmer’s income within the context of agricultural economics, or autonomous production, with determining factors upon rural dynamics and sustainable development. Taking these ideas into account, the objective of this study was to analyze the importance of forestry for sustainability in Portugal, namely in rural regions, comparatively with the context verified across other countries in the European Union. For this, data from the Eurostat (Several statistics. European Union Statistics, Luxembourg, 2015) for the European countries were used, over the period 1990–2014, and for variables that allowed to capture the interrelationships among forest indicators and economic, social and environmental variables. This statistical information was analyzed from a descriptive perspective and using the pairwise correlation matrix (complemented with the Granger causality Wald tests), through the Stata (Statistics/data analysis. StataCorp, LP, College Station, TX, 2015) software, to understand the relationships between the different indicators. As a main finding, it is worth referring that Portugal has had, in this period, a small impact on the European Union forestry conjuncture, but with great potential, namely in terms of agricultural and rural economic sustainability.
- Scoring the efficiency of Portuguese wine exports – an analysis recurring to Stochastic Frontier ModelsPublication . Mourão, Paulo Reis; Martinho, VítorO Vinho português é reconhecido como uma importante fonte de receitas económicas de base agrícola para Portugal. No entanto, as receitas deste produto diminuíram na maioria dos mercados estrangeiros na década 20012011. Neste artigo, iremos desenvolver uma tentativa original para identificar os determinantes mais importantes do valor das exportações de vinhos portugueses e os níveis de eficiência para cada país de destino. Os nossos resultados revelaram que o valor das exportações de vinhos portugueses tem uma relação positiva com o tamanho do setor público em cada país de destino, com a população rural do país de destino, e com o PIB real per capita, entre outras variáveis. A eficiência das exportações de vinho aumenta por causa do nível de inflação e do investimento direto estrangeiro per capita nas economias de destino. Também descobrimos que os destinos mais eficientes são aqueles onde o português é a língua nativa, e dois dos casos menos eficientes são a Polónia e os Estados Unidos da América, que são casos que merecem atenção especial por partedos exportadores portugueses.
- Estimating the demand curve for sustainable use of pesticides from contingent-valuation dataPublication . Costa, Cristina Amaro Da; Santos, José LimaStated-preference valuation techniques are often used to assess consumers' willingness-to-pay for food items produced in farming systems that adopt a sustainable use of pesticides (SUP). We propose an innovative valuation methodology in which dichotomous-choice contingent valuation is used to estimate the demand curve (price-quantity relationship) for such food items where price means price premium for the SUP output, quantity is the probability of choosing SUP and the conventional food product is kept available in the market at the current market price. This methodology can be used to evaluate market differentiation as a policy option to promote the SUP. The methodology is tested with data from a sample of urban consumers of fruits and vegetables in Portugal. The estimated demand curve is used to define the price level maximizing the total premium revenue for the SUP sector as a whole. This optimal level of the price premium is €77.55 (or 163% of the value of the monthly basket of fruits and vegetables at current prices). Adopting the optimal price premium will decrease the number of consumers of SUP food by 54%. The reduction is even higher for low income consumers (80%) leaving them more exposed to the risks of pesticide use.
- Are Portuguese consumers ready to understand the risks from pesticide use?Publication . Costa, Cristina Amaro Da; Fontes, Magda Aguiar; Santos, José ManuelUnderstanding consumer perceptions and attitudes towards the use of pesticides in agriculture and its risks is of utmost importance to redirect them towards food products produced in farming systems which use less or no pesticides. Based on data from a survey of 725 Portuguese urban consumers, three groups were identified: non buyers, occasional buyers, habitual buyers, considering their attitudes towards and knowledge of fruit and vegetables from integrated pest management. Knowledge about pesticides and certification systems affects preferences and should be considered as a key issue for market strategies and agricultural policies, and to ensure that consumers are able to define a healthy diet and to understand the influence of their food choices on the environment.
- Positive biodiversity-productivity relationship predominant in global forestsPublication . Liang, Jingjing; Crowther, Thomas W; Picard, Nicolas; Wiser, Susan; Zhou, Mo; Alberti, Giorgio; Schulze, Ernst-Detlef; McGuire, A David; Bozzato, Fabio; Pretzsch, Hans; de-Miguel, Sergio; Paquette, Alain; Hérault, Bruno; Scherer-Lorenzen, Michael; Barrett, Christopher B; Glick, Henry B; Hengeveld, Geerten M; Nabuurs, Gert-Jan; Pfautsch, Sebastian; Viana, Helder; Vibrans, Alexander C; Ammer, Christian; Schall, Peter; Verbyla, David; Tchebakova, Nadja; Fischer, Markus; Watson, James V; Chen, Han Y H; Lei, Xiangdong; Schelhaas, Mart-Jan; Lu, Huicui; Gianelle, Damiano; Parfenova, Elena I; Salas, Christian; Lee, Eungul; Lee, Boknam; Kim, Hyun Seok; Bruelheide, Helge; Coomes, David A; Piotto, Daniel; Sunderland, Terry; Schmid, Bernhard; Gourlet-Fleury, Sylvie; Sonké, Bonaventure; Tavani, Rebecca; Zhu, Jun; Brandl, Susanne; Vayreda, Jordi; Kitahara, Fumiaki; Searle, Eric B; Neldner, Victor J; Ngugi, Michael R; Baraloto, Christopher; Frizzera, Lorenzo; Bałazy, Radomir; Oleksyn, Jacek; Zawiła-Niedźwiecki, Tomasz; Bouriaud, Olivier; Bussotti, Filippo; Finér, Leena; Jaroszewicz, Bogdan; Jucker, Tommaso; Valladares, Fernando; Jagodzinski, Andrzej M; Peri, Pablo L; Gonmadje, Christelle; Marthy, William; O'Brien, Timothy; Martin, Emanuel H; Marshall, Andrew R; Rovero, Francesco; Bitariho, Robert; Niklaus, Pascal A; Alvarez-Loayza, Patricia; Chamuya, Nurdin; Valencia, Renato; Mortier, Frédéric; Wortel, Verginia; Engone-Obiang, Nestor L; Ferreira, Leandro V; Odeke, David E; Vasquez, Rodolfo M; Lewis, Simon L; Reich, Peter BThe biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone-US$166 billion to 490 billion per year according to our estimation-is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities.
- Efficiency, total factor productivity and returns to scale in a sustainable perspective: An analysis in the European Union at farm and regional levelPublication . Martinho, VítorFor global sustainability it is imperative to find a balance across the three main components of sustainable development which are the economic, social and environmental aspects. However, it is not a simple task to make these contexts compatible, usually because of economic pressures which transform them into opposed objectives. This framework occurs across several dimensions within society and the economy, where the agricultural sector is not an exception. The objective of this study is to analyse the efficiency, total factor productivity and returns to scale in an economic, social and environmental perspective in farms of the European Union (EU) regions through Data Envelopment Analysis (DEA) approaches. The research concerning the returns to scale will be complemented by the Keynesian models. Data obtained from the European Union Farm Accountancy Data Network (FADN) was considered. The results show that in maintaining or improving the levels of production in farms, it is often possible to greatly reduce, in some cases, the consumption of fertilizers and crop protection products. On the other hand, from a social perspective, some European Union regions are more generous in the salaries paid to farming workers and absorb more labour, which in a European context of unemployment, may be an interesting way to realistically look at and be engaged in the agricultural planning in a sustainable way, founding a balanced trade-off among the economic, social and environmental dimensions.
- A transversal perspective on global energy production and consumption: An approach based on convergence theoryPublication . Martinho, VítorThe transformation of economies and societies associated with technological advances made during the 20th century has not only significantly increased global energy consumption but also placed greater pressure upon production using non-renewable sources. Such circumstances have generated new challenges and urged governments as well as firms to identify and promote new sources of renewable energy. In response to those trends, the chief objective of the study reported here was to analyse the current global framework of the production and consumption of energy obtained from different origins in order to identify opportunities and constraints regarding energy production and consumption that exist among various countries. To that end, data from the World Bank regarding the production and consumption of global energy were analysed in light of the neoclassical and endogenous growth theories of absolute and conditional convergence, respectively, and in terms of panel data models. To reconcile the availability of data across the various countries, data for the period 1990–2013 were used. The data show signs of relevant dispersion among countries and evidence of sigma convergence in the majority of variables associated with global energy supply and demand. Conversely, other evidence indicates a significant absolute convergence of the global production and consumption of energy. Put differently, although significant differences in energy production and consumption among the world’s countries exist, so do signs of convergence, namely, that lower values in some countries are by way of approximation of those verified in countries with higher values. That situation is not necessarily detrimental in terms of renewable sources of energy; however, it is not the case in every context (in some cases the convergence is for the fossil fuel energy, for example). From a strategic perspective, the results recommend policies better customised at the various levels of decision making to promote renewable sources of energy.
- Are new rural ventures different from new urban ones? An exploratory analysis of businesses located in Portuguese incubators and science parksPublication . Pato, Lúcia; Teixeira, AuroraPurpose – Considering the differences between rural and urban spaces, the theoretical framework developed in this paper aims to uncover and rationalize the differences between rural and urban new ventures in terms of the environment surrounding the new venture, their general characteristics (e.g., sector, size), and export/economic performance. Design/methodology/approach – The theoretical framework is empirically assessed resorting to exploratory statistical analysis based on data collected from a questionnaire survey responded by 408 new ventures headquartered in Portuguese Business Incubators (BIs) and Science Parks (SPs). The data collected was treated with the Software Package for the Social Sciences (SPSS). Findings – The results evidence that rural and urban new ventures differ in terms of generic characteristics, namely sector, size, and collaborators’ human capital. Additionally, they differ concerning export and economic performance as well in relation to the perception of the municipality support. Research limitations/implications – Albeit the present study is mainly exploratory, it constitutes a stepping stone for future research into the differences between rural and urban new ventures regarding their export and economic performance determinants. Originality – The present study innovatively contributes to uncover the role of rural and urban context in entrepreneurship and adds to the scanty empirical literature in the area.