VINHOS QUE PENSAM - parte III|III GESTÃO NUTRICIONAL DA VINHA: SENSORES MULTIESPECTRAIS ATIVOS PRÓXIMOS

Os objetivos do presente trabalho: • caracterizar a concentração de N, P, K, Ca, Mg, Zn, Mn, e Fe da copa da vinha, baseada em observações multiespectrais e análises de plantas; • avaliar a possibilidade de utilização de sensores multiespectrais ativos próximos na gestão nutricional da vinha

VINHOS QUE PENSAM - parte II/III UTILIZAÇÃO DA CONDUTIVIDADE ELÉTRICA APARENTE DO SOLO NA INSTALAÇÃO E GESTÃO DAS CULTURAS: EXEMPLIFICAÇÃO NA VINHA

o principal objetivo deste trabalho passou por verificar: • a relação entre a CEa do solo e os indicadores de textura; • se a CEa do solo poderá ser um parâmetro importante na instalação e gestão de parcelas de vinha ou outro tipo de culturas

Green manure legumes affect seasonal soil and leaf CO2 exchange rates in an olive rainfed orchard

Management methods that decrease requirement for agricultural chemicals are needed to reduce adverse environmental impacts. Moreover, they can play an important role in atmospheric C02 emission and fixation. We propose green manure legumes to reduce erosion, soil compaction and nitrate pollution, to improve biodiversity, soil carbon sink and fertility, to save fossil fuels and to increase yield and the nutritional value of food products. The research was carried out near Mirandela, Northeast Portugal, on a 15- year commercial olive orchard (Olea europaea L. cv. Cobrançosa), grown under rainfed conditions

Sustainable management of olive rainfed orchards by the introduction of leguminous cover crops

The olive sector has a crucial economic, social, cultural and ecological relevance in the Mediterranean region, where tillage and herbicides application are still generalized practices. However, these practices oppose the recommendations of UE Common Agricultural Policy and thus, management methods that decrease requirement for agricultural chemicals are needed to reduce adverse environmental impacts. Moreover, they can play an important role in atmospheric C01 emission and fixation. We propose green manure legumes to reduce erosion, soil compaction and nih·ate pollution, to improve biodiversity, soil carbon sink and fertility, to save fossil fuels and to increase yield and the safety and nutritional value of food products. The 3-yearfield study carried out in Northeast Portugal revealed that self-reseeding annual legumes is a promising strategy since increase the summer soil water content, the vegetative growth and the physiological tree pe1jormance, that was reflected in a 38% higher cumulative yield then tillage techniques.PTDC-AGR-AAM/098326/200

Sequestro de carbono no olival: mito ou realidade?

O homem, através de diversas atividades econom1cas, tem contribuído para o aumento da concentração de dióxido de carbono (C02) na atmosfera. A queima de combustíveis fósseis, o fabrico de cimento a partir de carbonatos e a desflorestação com expansão da área agrícola são as principais atividades humanas associadas à emissão de C02 para a atmosfera . O C02 é um gás com efeito de estufa, capaz de reter radiação térmica, contribuindo para o aquecimento global. Para mitiga r o aquecimento global têm vindo a ser promovidos mecanismos que retirem carbono (C) da atmosfera e o fixem em formas inertes nos ecossistemas terrestres. O sequestro de carbono ocorre principalmente através da fotossíntese em que organismos fotossintéticos como as plantas fixam carbono e libertam oxigénio para a atmosfera. A vegetação terrestre e os solos podem, assim, constituir-se como importantes reservatórios de carbono e contrariar a tendência de aumento da concentração de C02 na atmosfera. Atendendo a que os apoios comunitários na nova PAC serão sobretudo concedidos em função dos serviços ecossistémicos que os diferentes setores prestarem à sociedade e que o sequestro de carbono é um dos principais serviços ecossistémicos que a agricultura pode prestar, apresenta-se uma estimativa do carbono que um olival tradicional de sequeiro (árvores mais solo) pode fixar nos primeiros 10 anos de vida a seguir à instalação. Foi tido em conta a quantidade de folhas, raminhos, casca e lenho de cada um dos diversos componentes da árvore, a percentagem de matéria orgânica e o teor de carbono na matéria orgânica de cada um daqueles componentes. No solo, foi tido em conta o potencial de acumulação de carbono no solo estimado a partir de uma situação inicial de solo mobilizado passando para uma situação em que se permite o desenvolvimento de vegetação herbácea no coberto. Assim, uma árvore bem desenvolvida com 10 anos de idade representa uma quantidade de carbono de 9, 71 kg árvore·1 [75% na parte aérea (medida) e 25% na parte radicular (estimada)], o que representa 2,0 t C _ha·1 • No solo, se durante 10 anos forem implementadas medidas que promovam o acréscimo em 1% no teor de matéria orgânica do solo (profundidade 0-20 cm) relativamente à massa total do solo, serão fixadas 14 t C ha-1

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

Comparing N recovery from legumes grown as green manures in olive orchards

Green manuring is probably the only option for extending on a great scale the acreage of organic fanning in the perennial crops of the Mediterranean basin such as olive groves. Olive growers, in general, do not have animals so the availability of organic manures is not sufficient to maintain soil fertility. In addition, the organic composts approved for organic farming on the market have high prices and are sometimes speculative, in relation to their fertiliser value (Rodrigues et al., 2006). In NE Portugal there is a long tradition in the cultivation of white lupin (Lupinus a/bus) as a means of improving soil fertility. However, little is known about the dry matter yield and N fixation potential of lupin in these agrosystems, and also of the transfer of fixed N to the trees. In this work the results of dry matter yield and N recovery by lupin, vetch (Vicia villosa) and a mixture of self-reseeding annual legumes are presented. The trial also included plots of oats (Avena saliva) and natural vegetation

Battery-like behavior of Ni-ceria based systems: synthesis, surface defects and electrochemical assessment

NiO, CeO2 and respective composites are extensively used in energy storage devices due to mostly their high electrochemical activity. However, the assessment of battery-like behavior of Ni-ceria based systems comprising (Ni or Gd)-doped ceria combined with NiO seems to be neglected in the literature. In this work, NiO and ceria-based solid solutions composite powders were obtained by a co-precipitation synthesis method. The structure and particle size of the calcined powders were investigated by X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM), respectively. Oxidative states of composites were inspected by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of powders was evaluated by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. Refinement of the XRD patterns showed that powders have nanosized crystallites and mean size of particles within 20 – 70 nm were revealed by FESEM. The improved specific capacity of the NiO-CeO2 electrode material (about 2.5 times higher than that of NiO-CGO at 5 mV s−1) is due to an increase in Faradic reactions taken place on its surface with a higher fraction of defects (namely Ni3+, Ce3+ and oxygen vacancies), as determined by XPS. The superior electrochemical performance of the NiO-CeO2 electrode is also confirmed by electrochemical impedance spectroscopy.publishe

On a class of 4D Kahler bases and AdS_5 supersymmetric Black Holes

We construct a class of toric Kahler manifolds, M_4, of real dimension four, a subset of which corresponds to the Kahler bases of all known 5D asymptotically AdS_5 supersymmetric black-holes. In a certain limit, these Kahler spaces take the form of cones over Sasaki spaces, which, in turn, are fibrations over toric manifolds of real dimension two. The metric on M_4 is completely determined by a single function H(x), which is the conformal factor of the two dimensional space. We study the solutions of minimal five dimensional gauged supergravity having this class of Kahler spaces as base and show that in order to generate a five dimensional solution H(x) must obey a simple sixth order differential equation. We discuss the solutions in detail, which include all known asymptotically AdS_5 black holes as well as other spacetimes with non-compact horizons. Moreover we find an infinite number of supersymmetric deformations of these spacetimes with less spatial isometries than the base space. These deformations vanish at the horizon, but become relevant asymptotically.Comment: 34 pages, 3 figures. v2: formula (8.35) and other minor typos corrected; references added; accepted for publication in JHE

Use of kaolin as a reflective clay improves olive tree physiological and yield responses under different environmental conditions

Olive tree (Olea europaea L.) growing area is threatened by the current and predicted adverse environmental conditions, affecting negatively plant performance and yield. Thus, agronomic strategies to offset those negative effects and improve olive orchards sustainability need to be implemented. In this regard, we propose the use of kaolin particle film, a natural heat and irradiance reflecting clay. To achieve a more comprehensive response about kaolin (5%) action, during two consecutive years we performed two different experiments, in different geographical locations of Portugal north-west with “Cobrançosa” cultivar: established olive trees under conventional rainfed conditions and under deficit irrigation (27.5% of ETc). Generally, during the summer period, kaolin was effective in improving water status and photosynthetic response, by reducing both stomatal and non-stomatal limitations. Moreover, improved leaf gas exchange restauration after the first rains persists during the winter months in rainfed conditions. Kaolin also reduces leaf sclerophylly, inducing shade-related leaf characteristics. As a result of better physiological performance achieved with kaolin application, yield increased 97% and 54.6% in rainfed and deficit irrigation conditions, respectively. Overall, the results of the present investigation revealed a cost-effective strategy to attenuate the negative effects of summer stress in olive trees, while allows to save water. Ultimately, this practice might contribute to increase the sustainability and competitiveness of this sector and anticipate solutions to the negative effects of climate change.This work was funded by the INTERACT project – “Integrative Research in Environment, Agro-Chains and Technology”, no. NORTE-01-0145-FEDER-000017, in its line 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