Effects of different soil management practices on soil mechanic resistance and seed depth placement in a maize crop in Alentejo, Portugal Mediterranean region.

No tillage, minimum tillage and conventional tillage practices are commonly used in maize crops in Alentejo, affecting soil physic conditions and determining seeders performance. Seeders distribution can be evaluated in the longitudinal and vertical planes. Vertical plane is specified by seeding depth (Karayel et al., 2008). If, in one hand seeding depth uniformity is a goal for all crop establishment , in the other hand, seeders furrow openers depth control is never constant depending on soil conditions. Seed depth uniformity affects crop emergence, Liu et al. (2004) showed an higher correlation between crop productivity and emergence uniformity than with longitudinal plants distribution. Neto et al. (2007) evaluating seed depth placement by measuring maize mesocotyl length under no tillage conditions in 38 farms concluded that 20% of coefficient of variation suggests the need of improvement seeders depth control mechanisms. The objective of this study was to evaluate casual relationships and create spatial variability maps between soil mechanic resistance and vertical distribution under three different soil practices to improve seed depth uniformity.

A partial study of vertical distribution of conventional no-till seeders and spatial variability of seed depth placement of maize in the Alentejo region, Portugal

The requirements for a good stand in a no-till field are the same as those for conventional planting as well as added field and machinery management. Among the various factors that contribute towards producing a successful maize crop, seed depth placement is a key determinant. Although most no-till planters on the market work well under good soil and residue conditions, adjustments and even modifications are frequently needed when working with compacted or wet soils or with heavy residues. The main objective of this study, carried out in 2010, 2011 and 2012, was to evaluate the vertical distribution and spatial variability of seed depth placement in a maize crop under no-till conditions, using precision farming technologies and conventional no-till seeders. The results obtained indicate that the seed depth placement was affected by soil moisture content and forward speed. The seed depth placement was negatively correlated with soil resistance and seeding depth had a significant impact on mean emergence time and the percentage of emerged plants. Shallow average depth values and high coefficients of variation suggest a need for improvements in controlling the seeders’ sowing depth mechanism or more accurate calibration by operators in the field.

Spatial variability of seed depth placement of maize under no tillage in Alentejo, Portugal

Among the various factors that contribute towards producing a successful maize crop, seed depth placement is a key determinant, especially in a no-tillage system. The main objective of this work was to evaluate the spatial variability of seed depth placement and crop establishment in a maize crop under no-tillage conditions, using precision farming technologies. The obtained results indicate that seed depth placement was significantly affected by soil moisture content, while a very high coefficient of variation of 39% was found for seed depth. Seeding depth had a significant impact on mean emergence time and percentage of emerged plants. Shallow average depth values and the high coefficient of variation suggest a need for improvement in controlling the seeders sowing depth.

Contribute to the Study of Vertical Distribution of Conventional No-Till Seeders and Spatial Variability of Seed Depth Placement of Maize in Alentejo, Portugal

Entre os vários fatores que contribuem para a produção de uma cultura de milho, a distribuição vertical dos semeadores avaliada através da localização da semente em profundidade é um fator-chave, especialmente na técnica de sementeira direta. Simultaneamente, dada a complexidade dos ecossistemas naturais e agrícolas em sistemas de agricultura de conservação, a gestão diferenciada e localizada das parcelas assume um importante papel na análise e gestão da variabilidade das propriedades do solo e estabelecimento das culturas, nomeadamente utilizando informação geo referenciada e tecnologia expedita. Assim, o principal objetivo desta Tese foi a avaliação em culturas de milho da variabilidade espacial da localização de semente em profundidade e estabelecimento da cultura em sementeira direta usando sistemas convencionais de controlo de profundidade, tendo-se comparado com diferentes sistemas de mobilização e recorrendo a tecnologias de agricultura de precisão. Os ensaios decorreram na região Mediterrânea do Alentejo, em propriedades agrícolas no decorrer das campanhas de 2010, 2011, 2012 e 2015 em 6 diferentes campos experimentais. O trabalho experimental consistiu em ensaios com avaliações in loco do solo e cultura, consumo de combustível das operações e deteção remota. Os resultados obtidos indicam que não só o sistema de mobilização afetou a localização da semente em profundidade, como em sementeira direta a profundidade de sementeira foi afetada pelo teor de humidade do solo, resistência do solo à profundidade e velocidade da operação de sementeira. Adicionalmente observaram-se condições heterogéneas de emergência e estabelecimento da cultura afetadas por condições físicas de compactação do solo. Comparando os diferentes sistemas de mobilização, obteve-se uma significativa redução de combustível para a técnica de sementeira direta, apesar de se terem observado diferenças estatísticas significativas considerando diferentes calibrações de profundidade de sementeira Do trabalho realizado nesta Tese ressalva-se a importância que as tecnologias de agricultura de precisão podem ter no acompanhamento e avaliação de culturas em sementeira direta, bem como a necessidade de melhores procedimentos no controlo de profundidade dos semeadores pelo respetivos operadores ou ao invés, a adoção de semeadores com mecanismos ativos de controlo de profundidade. ABSTRACT Among the various factors that contribute towards producing a successful maize crop, seeders vertical distribution evaluated through seed depth placement is a key determinant, especially under a no-tillage technique. At the same time in conservation agriculture systems due to the complexity of natural and agricultural ecosystems site specific management became an important approach to understand and manage the variability of soil properties and crop establishment, especially when using geo spatial information and affording readily technology Thus, the main objective of this Thesis was to evaluate the spatial variability of seed depth placement and crop establishment in maize crops under no-tillage conditions compared to different tillage systems, using conventional seed depth control no till seeders and precision farming technologies. Trials were carried out in the Mediterranean region of Alentejo, in private farms along the sowing operations season over the years 2010, 2011, 2012 and 2015 in 6 different experimental fields. Experimental work covered field tests with in loco soil and crop evaluations, fuel operation evaluations and aerial sensing. The results obtained indicate that not only tillage system affected seed depth placement but under no till conditions seed depth was affected by soil moisture content, soil resistance to penetration and seeders forward speed. In addition uneven crop seedling and establishment depended on seed depth placement and could be affected by physical problems of compaction layers. Significant reduction in fuel consumption was observed for no till operations although significant differences observed according to different setting calibrations of seed depth control. According to the results, precision agriculture is an important tool to evaluate crops under no till conditions and seed depth mechanisms should be more accurate by the operators or is determinant the adoption of new active depth control technology to improve seeders performance.

Breve apunte acerca de un manuscrito ornitológico redactado por Philip W. Munn durante su exilio en Portugal (1941-1945): The birds of the Balearic Islands (June, 1943)

Se presenta un bosquejo acerca de un documento de excepcional valor histórico para la ornitología balear: el manuscrito de Las Aves de las Islas Baleares (1943), redactado en inglés por el ornitólogo británico Philip Winchester Munn durante su exilio lisboeta.

Os espectadores de cinema em Portugal nos últimos 40 anos: o caso da cidade de Bragança

O número de espetadores de cinema tem variado ao longo dos tempos. Nos últimos 40 anos, em Portugal, o sentido é globalmente descendente devido sobretudo à internet e às novas tecnologias de comunicação. Esta informação pode ser comprovada com os números fornecidos pela base de dados “ Pordata” e por alguns estudos realizados nesta área. O cinema é uma arte em constante mudança e que influencia a sociedade, mas é ao mesmo tempo influenciado por ela, constituindo mesmo o seu autorretrato. Sem a interação com a sociedade contemporânea a sétima arte não evolui nem desperta paixões. Este facto pode determinar os altos e baixos na história do cinema

Revisiting a series of epithelial salivary gland tumors in children and adolescents in southern Portugal

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

The other side of protest music: the extreme-right and skinhead culture in democratic Portugal (1974-2015)

Although Portugal does not have a significant radical right presence in its party system, in the last decades the country did witness the development of a neo-Nazi skinhead movement that expresses its white nationalist nature and goals through the musical genres of Rock Against Communism (RAC) and the related Oi!. Utilizing various historical sources and theoretical analysis, this study contextualizes the development of nationalist music in Portugal, both before and especially during the democratic period (1974-2015). It focuses on its protagonists, domestic and international networks, as well as on the few attempts to establish a common cause with radical right-wing political parties at the turn of the century and in present times.

The chronic food deficit of early modern Portugal : curse or myth?

Two historiographical currents have debated whether early modern Portugal was cursed by an excessive dependence on foreign food imports as a result of being unable to feed its population, or not. In this short paper, the first long-run systematic quantitative study of this question, we show that the former view is a myth and therefore could not be a curse. Throughout the entire period, a certain amount of grain was in fact imported but cereal purchases abroad never represented more than a diminutive percentage of total food consumption. More importantly, the country carried out a diversified trade in foodstuffs which was seldom seriously out of balance. Portuguese agriculture showed itself consistently capable of specializing in different foodstuffs for export. It was thus not hopelessly inefficient and succeeded reasonably well in meeting the basic nutritional needs of the population.

The Presence of the Past: Perceptions of Authoritarianism and Democratic Transition in Contemporary Portugal. [Special Issue]

Revista / Org.

Portugal. In economics, we call it conflict of interest! CEPS Commentary, 12 April 2013

Faced with limited options for coming up with the funds needed to pay off the next instalment on its bailout loan, Portugal is advised in this Commentary by economist Leonor Coutinho to trim the number of public sector employees, in combination with an increase in public sector working hours, among the lowest in Europe. In her view, these measures will have the best long-term implications both in terms of fiscal sustainability and of labour productivity, and may finally allow the country to resume the catching-up process that has been stalled since the start of EMU.