Browsing by Author "Fernandes, N."
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- Cover cropping in a sloping, non-irrigated vineyard: 1 - effects on weed composition and dynamicsPublication . Monteiro, Ana; Lopes, C.M.; Machado, J.P.; Fernandes, N.; Araújo, A.The influence of two sward treatments and soil cultivation on the composition, the structure, and the evolution of the biomass of vineyard weed communities was examined. The 3-year study (2002-2004) was carried out in a sloping, non-irrigated vineyard, cv. ‘Cabernet Sauvignon’, in the Estremadura winegrowing region of Portugal. The experimental treatments were: soil tillage (control); permanent sown cover crop - Lolium perenne ‘Nui’, L. multiflorum ‘Bartíssimo’, Festuca ovina ‘Ridu’, F. rubra ssp. rubra ‘Echo’, Trifolium incarnatum. ‘Red’, T. repens ‘Huie’ and T. subterraneum ‘Claire’; and permanent resident vegetation. Total weed biomass in the spring did not reveal significant differences between treatments, but varied annually. The management practices – e.g. time and number of soil cultivations and inter-row mowing – were determinant in weed biomass evolution. Canonical correspondence analysis revealed significant treatment effects on community structure. Three years after the experiment was set up, in the soil tillage treatment weed composition was dominated by annual broad-leaved species, namely five Geraniaceae species, Medicago polymorpha and Sonchus oleraceus. The perennial broad-leaved species Oxalis pes-caprae was also a dominant species in soil tillage. In both sward treatments there was an increase in the perennial broad-leaved and grass species. Compared to soil tillage, in the resident vegetation treatment there was a significant increase in perennial species, such as Rumex crispus, Veronica anagallis-aquatica and Polypogon monspeliensis, and in the annuals Melilotus indica and Avena sterilis. The increase in these perennial species, which are considered to compete with vines, requires more frequent mowing in the summer. In the permanent sown cover crop treatment, L. perenne and T. repens displayed the ability to re-establish successfully, and their abundance decreased or suppressed most of the annual and perennial weed species.
- Cover cropping in a sloping, non-irrigated vineyard: 2 - effects on vegetative growth , yield, berry and wine quality of Cabernet Sauvignon grapesPublication . Monteiro, Ana; Lopes, C.M.; Machado, J.P.; Fernandes, N.; Araújo, A.Grapevine vegetative growth, yield, fruit composition and wine quality were studied in the Estremadura Winegrowing Region of Portugal in a ‘Cabernet Sauvignon’ slopping non-irrigated vineyard. During three seasons three treatments were compared: soil tillage (control), permanent resident vegetation, and permanent sown cover crop. When compared to soil tillage, the inter-row sward treatments displayed a lower predawn leaf water potential from bloom to mid-ripening. These differences in vine water status did not affect vine yield or berry sugar accumulation; however, in the third season after experiment setup it induced a significant reduction in vegetative growth in the sward treatments, compared to soil tillage. This vegetative growth reduction had a positive effect on grape composition by reducing titratable acidity and increasing berry skin total phenols and anthocyanins. Those differences were also detected in the wines by the judges who gave a better classification to the wines from the sward treatments. Our results indicate that cover cropping can be a valuable tool for controlling vigour and enhancing wine quality in this winegrowing region.
- Enrelvamento da vinha: dois casos de estudo – Monção e AlenquerPublication . Monteiro, A.; Lopes, C.M.; Afonso, J.M.; Machado, J.P.; Lourenço, J.; Fernandes, N.; Carvalho, L.; Moreira, I.Estudos conducentes à avaliação das possibilidades de enrelvamento em vinhas estão a decorrer na Região dos Vinhos Verdes (sub-região de Monção) e na Estremadura (Alenquer). No ensaio de Monção, com a casta ‘Alvarinho’ e no ensaio em Alenquer, com a casta ‘Cabernet Sauvignon’, comparam-se 4 sistemas de gestão do solo. Em qualquer dos ensaios a densidade e a biomassa total da flora foi influenciada significativamente pelas técnicas de gestão do solo tendo-se também verificado uma selecção de espécies por modalidade, com incremento de gramíneas e leguminosas no enrelvamento. No ensaio de Monção, em três anos consecutivos, e comparativamente às modalidades herbicida foliar a toda a área e mobilização do solo, o enrelvamento a toda a área por espécies residentes induziu uma redução significativa da produção e vigor da videira em resultado de um menor peso unitário do cacho e do sarmento, sem afectar a qualidade do mosto à vindima. Nos dois primeiros anos do ensaio de Alenquer (2002-03) os 4 sistemas de gestão do solo - mobilização da entrelinha, cobertura orgânica morta (casca de pinheiro) alternada com enrelvamento natural permanente, enrelvamento natural permanente e enrelvamento semeado permanente - não influenciaram de forma significativa quer a produção quer o vigor das videiras. Quanto à qualidade das uvas, apenas em 2003 se registaram diferenças significativas na acidez total, tendo-se obtido valores inferiores nas modalidades com enrelvamento. Em 2002, devida à elevada precipitação ocorrida no final da maturação, na modalidade mobilizada verificou-se uma maior dificuldade de circulação da máquina de vindimar comparativamente às modalidades com cobertura do solo. Os resultados evidenciam a possibilidade de utilização dos relvados como técnicas passíveis de manipulação do vigor da videira e de melhoria da circulação das máquinas