Browsing by Author "Correia, Carlos M."
Now showing 1 - 10 of 156
Results Per Page
Sort Options
- Agronomic practices change the patterns of soil glomalin in olive rainfed orchardsPublication . Correia, Carlos M.; Macedo, Fabrício; Freire, António; Moutinho-Pereira, José; Arrobas, Margarida; Gonçalves, Alexandre; Rodrigues, M.A.Glomalin, a thermostable hydrophobic glycoprotein produced by arbuscular mycorrhizal fungi, plays an important role in the stability of soil aggregates and in the sequestration of C, N and heavy metals, being their concentrations dependent from agronomic practices such as tillage and application of pesticides and fertilizers. Despite the recognized importance of glomalin in soil quality, studies on olive groves are scarce. The study conducted on summer 2017 in three different rain fed orchards (cv. Cobran~osa) of Northeast Portugal revealed that both total glomalin, measured as Bradford-reactive soil protein (T-BRSP}, and the easily extractable Bradford-reactive soil protein (EE-BRSP) concentrations were lower under mechanical cultivation than on a permanent sward grazed with a flock of sheep or than on an annual legume cover crop. Moreover, higher TBRSP and EE-BRSP levels were found on orchards without phosphorus and boron supply, and also on the top soil layer (0.1 0 cm) and on tree row, mainly in younger orchards. Interestingly, one soil presented a twofold superior EE-BRSP: T- BRSP ratio than the other two soils, representing an increase of labile g lomalin, probably re lated with greater applications of copper formulations to control olive fungal diseases. This study demonstrated that less disruptive agronomic practices influences positivety the levels of glomalin, an appropriate indicator of healthy soil conditions, which in turn may favour carbon sequestration.
- Alterações climáticas e degradação do solo no interior de Portugal: um cocktail explosivo para as culturas perenesPublication . Correia, Carlos M.; Rodrigues, M.A.A agricultura é uma fonte importante de emissões de gases com efeito de estufa, contribuindo fortemente para as alterações climáticas e, ao mesmo tempo, é um dos setores económicos mais afetados, particularmente devido à modificação dos padrões de precipitação e temperatura. Sendo as regiões com clima mediterrânico "pontos quentes" das alterações climáticas, são esperados efeitos negativos nas culturas perenes no interior de Portugal, especialmente sob regime de sequeiro. Ao mesmo tempo, assistimos à degradação do solo, fenómeno que potencia as causas e as consequências das alterações climáticcas nas culturas. Neste artigo apresentamos uma visão crítica das duas grandes ameaças ambientais e socioeconómicas e deixamos em aberto possíveis soluções, de forma a minimizar os impactes da mudança no clima e a preservar para as gerações futuras este recurso natural, limitado e não renovável a curto prazo.
- Annual legume cover crops enhance the sustainability of rainfed olive orchards: from leaf ionome to tree physiologyPublication . Correia, Carlos M.; Martins, Sandra; Silva, Ermelinda; Brito, Cátia; Pinto, Luís; Moutinho-Pereira, José; Rodrigues, M.A.; Gonçalves, AlexandreThe olive sector has an important economic, social, cultural and ecological relevance in the Mediterranean region, where tillage and herbicides application still are generalized practices, although the recommendations of UE policy for a more sustainable agriculture. Cover crops with self-reseeding legumes of short-cycle, with mulch of dead vegetation during the dry season, is our option for soil management in olive tree rainfed orchards, as they provide protection against erosion, improve the physical and chemical properties, nitrogen fixation and soil moisture, enhance biodiversity and landscape beautification, while contribute to mitigation and adaptation to climate change and enable the organic production mode. The experiment was carried out during 2016 and 2017 on a commercial orchard (cv. Cobrançosa) in Northeast Portugal. The treatments laid out were: (1) ordinary tillage techniques used by local growers (two tillage trips per year) and (2) a mixture of 11 self-reseeding annual legumes (AL). The results revealed that cover crops influence positively the tree water status during the drought season, as well the nutritional status, namely the foliar concentrations of nitrogen, magnesium and manganese, both during the winter resting period and in summer, at endocarp sclerification. As a result, AL trees presented greater physiological performance during the summer, as evidenced by higher net photosynthetic rate, mainly due to inferior stomatal limitations, lower investment of resources in defensive metabolites, and enhanced yield. These results indicate that cover cropping should be included in the portfolio of adaptive management strategies against climate change, contributing to the sustainability of rainfed orchards.
- Aplicação de algas marinhas em caldas foliaresPublication . Rodrigues, M.A.; Correia, Carlos M.; Arrobas, MargaridaAplicação de algas marinhas em caldas foliaresA utilização de algas marinhas como alimento ou fertilizante agrícola é ancestral. Nos últimos anos elas têm surgido no mercado dos fertilizantes sobretudo na forma de extrato para aplicação ao solo, na água de rega, ou por via foliar. A sua concentração em nutrientes é diminuta e as doses aplicadas muito baixas, pelo que os seus efeitos nas plantas não serão devidos ao fornecimento de nutrientes. Nos últimos anos estes produtos têm vindo a ser designados de bioestimulantes e assume-se que têm um efeito positivo nas plantas para além da sua concentração em nutrientes. A designação de “bioestimulante para as plantas” foi recentemente adotada pela União Europeia, que passou a integrar uma grande diversidade de produtos para uso agrícola, incluindo os que contêm microrganismos benéficos. O uso crescente de produtos comerciais contendo algas marinhas na agricultura justifica que a investigação lhe dê atenção para que os produtores possam tirar o melhor partido do seu uso.
- Aplicação de fungos micorrízicos arbusculares reduziu o crescimento de plantas jovens de oliveira devido a competição por fotoassimiladosPublication . Lopes, João; Correia, Carlos M.; Gonçalves, Alexandre; Silva, Ermelinda; Martins, Sandra; Arrobas, Margarida; Rodrigues, M.A.Neste trabalho avaliou-se o efeito de fungos micorrízicos comerciais no desenvolvimento de oliveiras jovens cultivadas em estufa na fase de viveiro. O estudo constou de duas experiências, uma organizada num fatorial com três cultivares (Cobrançosa, Madural e Verdeal Transmontana) e três tratamentos de solo (fungos micorrízicos comerciais, zeólitos e testemunha) e outra segundo um delineamento completamente casualizado com quatro tratamentos [fungos micorrízicos comerciais, solo esterilizado, solo esterilizado mais um extrato de solo sem fungos micorrízicos arbusculares e testemunha]. A Cobrançosa desenvolveu-se melhor que as outras cultivares, apresentando bom enraizamento e melhores características iniciais de crescimento. As plantas micorrizadas apresentaram crescimento reduzido em comparação com as da testemunha. O resultado foi explicado pela competição por fotoassimilados entre o crescimento das plantas e o estabelecimento da simbiose, com a expansão das hifas dos fungos. O facto de as plantas apresentarem reduzida área foliar no início da experiência e a estufa ter uma cobertura de policarbonato de parede dupla, um tanto opaca à radiação fotossintética ativa, podem ter contribuído para reduzir a atividade fotossintética e retardar o crescimento das plantas inoculadas. Porém, nos vasos micorrizados, o carbono orgânico do solo e os teores da maioria dos nutrientes aumentaram, provavelmente devido à presença de hifas de fungos nas amostras e ao aumento da atividade enzimática do solo. Os zeólitos reduziram a produção de matéria seca das plantas e a concentração de fósforo nos tecidos em relação à testemunha, aumentando a disponibilidade no solo dos catiões que entram em sua composição. A esterilização do solo parece ter reduzido a biodisponibilidade de fósforo, talvez por ter inativado enzimas do solo. O extrato de solo sem fungos micorrízicos arbusculares não apresentou benefícios para as plantas ou qualquer efeito relevante nas propriedades do solo.
- Aplicação de hidrolisados de proteína em caldas foliaresPublication . Rodrigues, M.A.; Correia, Carlos M.; Arrobas, MargaridaOs hidrolisados de proteína e diversos outros compostos azotados extraídos de subprodutos de origem animal ou vegetal têm vindo a ter uma presença crescente na alimentação humana e nas rações para animais, bem como em produtos para a nutrição das plantas. As versões comerciais mais comuns destinadas à nutrição vegetal surgem como produtos ricos em aminoácidos livres e péptidos, e são sobretudo recomendados para aplicação foliar, embora alguns sejam também recomendados para fertirrega e hidroponia. A gama presente no mercado é extensa e de composição por vezes muito complexa, uma vez que os produtos comerciais contendo aminoácidos resultam frequentemente de misturas de hidrolisados de proteína com extratos de algas e micronutrientes. Destes produtos espera-se sobretudo um efeito “bioestimulante nas plantas”, com múltiplos benefícios potenciais para os processos fisiológicos, que possam conduzir a aumentos de produtividade e/ou qualidade dos produtos agrícolas. Contudo, a bibliografia internacional reporta também muitos fracassos com a utilização deste tipo de produtos, pelo que dispor de mais informação experimental é muito importante para se poder dar alguma orientação ao setor produtivo.
- Application of a grey anti-hail net in two apple tree cultivars: effect on physico-chemical characteristics of fruitsPublication . Pinto, Luís; Silva, Ermelinda; Gonçalves, Alexandre; Brito, Cátia; Ribeiro, C.; Fernandes, Helena Isabela Pereira; Moutinho-Pereira, José; Rodrigues, M.A.; Correia, Carlos M.Apple production in Portugal is a relevant agricultural activity, with 'Golden delicious' and 'Fuji' being included in the main cultivars. However, over the last 15 years there hás been increasing crop damage due to hailstorms and related meteorológica l extreme conditions in the Iberian Península. This concerning issue hás led farmers and researchers to find practical solutions to protect the orchards, such as netting devices. The application of anti-hail net in apple tree orchards looks to provide protection against the roughest meteorológica! effects (such as hail, strong winds, and sunburn) without hurting the development of the plant and, on the other hand, helping to improve the planfs productivity. On this work, carried out in Carrazeda de Ansiaes during 2016, was tested the application of a grey anti-hail net in an orchard with two cultivars (Golden delicious and Fuji) of apple tree (Malus domestica Borkh.). Contrais without screen net applied where also used. In order to understand the effects ofthe net, apples were collected and analyzed for their physico-chemical characteristics (total soluble solids (TSS), flesh firmness, skin strength, total titratable acidity (TTA) and fruit color Índices). The obtained results revealed a significant decrease in TSS (6. 5%) and TTA (21. 5%) on apple trees covered with anti-hail net, whereas the other traits were not affected. The drop of TTA was only significant in 'Golden delicious'. Substantial differences were found between cultivars, with higher values of brix, pH, skin "bioyield point" and flesh firmness on 'Fuji', while 'Golden delicious' presented higher lightness, chroma and hue angle. The use of a grey anti-hail net on apple orchards is a suitable alternative for the protection of apple trees against hail ensuring the production of the crop without compromising the fruit quality.
- Application of anti-hail net in apple orchards: effects on fruits chemical characteristicsPublication . Martins-Gomes, Carlos; Pinto, Luís; Silva, Ermelinda; Martins, Sandra; Gonçalves, Alexandre; Brito, Cátia; Moutinho-Pereira, José; Rodrigues, M.A.; Correia, Carlos M.; Nunes, Fernando M.Apple production in Portugal, over the last 15 years, has been subjected to increasing crop damage due to hailstorms and related meteorological extreme conditions. This problem has led farmers and researchers to find practical solutions to protect the orchards, such is the case of netting devices. The application of anti-hail nets in apple tree orchards looks to provide protection against the roughest meteorological events (such as hail, strong winds, and sunburn), while avoiding to upset the development of the plant and or, if possible, helping to improve the plant’s productivity. During 2016, this work was carried out in Carrazeda de Ansiães, a northeast Portuguese plateau zone that is a primary location for apple production, and the application of a grey anti-hail net, which reduces photosynthetically active radiation by 12 %, was tested in an orchard with the cultivars Golden delicious and Fuji of apple tree (Malus domestica Borkh). Control without screen net applied was also used. In order to understand the effects of the net, apples were collected and analysed for their chemical characteristics (total phenols, ortho-diphenols and flavonoids content, ABTS and polyphenolic profile). The obtained results in apple peel revealed, in both cultivars, a decrease in total phenols, ortho-diphenols and flavonoids concentration, whereas in the Fuji cultivar the antioxidant activity, determined by the ABTS assay, was maintained. Pulp results showed little difference with lower (P<0.001) ortho-diphenols content in Fuji cultivar and slightly lower (P<0.05) ABTS activity in Golden delicious cultivar. Peel and pulp methanolic extracts were analysed by HPLC-DAD. The phenolic profile was similar for both cultivars, with the exception of anthocyanins, being identified chlorogenic acid and derivatives of quercetin. The antihail net did not affect the phenolic profile, only decreased the polyphenols concentration. The use of a grey anti-hail net on apple orchards is a suitable alternative for the protection of apple trees against hail ensuring the production of the crop without compromising fruit quality.
- Arbuscular mycorrhizal fungi inoculation reduced the growth of pre-rooted olive cuttings in a greenhousePublication . Lopes, João Ilídio; Correia, Carlos M.; Gonçalves, Alexandre; Silva, Ermelinda; Martins, Sandra; Arrobas, Margarida; Rodrigues, M.A.The effect of commercial mycorrhizal fungi on pre-rooted olive cuttings was assessed. The study consisted of two experiments, the first arranged as a factorial design with three cultivars (Cobrançosa, Madural, and Verdeal Transmontana) and three soil treatments (commercial mycorrhizal fungi, zeolites, and control) and the second as a completely randomized design with three treatments (commercial mycorrhizal fungi, sterilized soil, and control). Cobrançosa grew better than the other cultivars, showing good rooting and initial growth features. Mycorrhizal plants showed reduced growth in comparison to those of the untreated control. This result was explained by competition for photosynthates between plant growth and the expansion of fungi hyphae. Cuttings of reduced leaf area and a twin-wall polycarbonate cover of the greenhouse, somewhat opaque to photosynthetic active radiation, may also have contributed to limit the maximum photosynthetic rate and delay the growth of the inoculated plants. Accordingly, in the mycorrhizal pots, the soil organic carbon (C) increased, probably due to the presence of fungi hyphae in soil samples. Zeolites reduced plant dry matter (DM) yield and tissue phosphorus (P) concentration compared to the control, while increasing the availability in the soil of the cations present in their initial composition. Soil sterilization seems to have reduced soil P bioavailability by inactivating soil enzymes. This study showed that the inoculation with mycorrhizal fungi of pre-rooted cuttings can delay their initial growth. Although these plants may be better prepared to grow in the field, in the short term, their lower development can be a problem for the nurseryman.
- Assessing the Effect of Plant Biostimulants and Nutrient-Rich Foliar Sprays on Walnut Nucleolar Activity and Protein Content (Juglans regia L.)Publication . Roque, João; Carvalho, Ana; Rodrigues, M.A.; Correia, Carlos M.; Lima-Brito, JoséThe cultivation of walnuts (Juglans regia L.) has become increasingly popular worldwide due to the nutritional value of the nuts. Plant biostimulants (PBs) and nutrient-rich products have been increasingly used in agriculture to improve yield, quality, and abiotic stress tolerance. However, farmers need fast laboratory studies to determine the most suitable treatment per crop or ecosystem to take full advantage of these products. Evaluating nucleolar activity and protein content can provide clues about the most appropriate treatment. This study aimed to determine how five commercial products, four PBs based on seaweed extract and/or free amino acids and one boron-enriched fertiliser used as foliar sprays, affect walnut cv's nucleolar activity and protein content. "Franquette" from an orchard located in NE Portugal was compared to untreated (control) plants. All treatments brought a low leaf mitotic index. The control showed the smallest nucleolar area, highest protein content, and highest frequency of nucleolar irregularities. Fitoalgas Green (R), Sprint Plus (R), and Tradebor (R) showed the highest nucleolar area and lowest frequencies of nucleolar irregularities. The recruitment of proteins/enzymes for response against abiotic stresses may explain the high protein content in the control. Hence, the enhanced abiotic stress tolerance of the treated trees explains their lower protein content and frequency of nucleolar anomalies. Globally, the Fitoalgas Green (R), Sprint Plus (R), and Tradebor (R) seem better suited for "Franquette" walnut trees under the edaphoclimatic conditions where trials were conducted.