Influência do regime de poda na fisiologia e produção da oliveira
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2022-01-31
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A oliveira (Olea europaea L.) é uma espécie bem-adaptada às condições edafoclimáticas da região Mediterrânica. Todavia, as alterações climáticas que se fazem sentir em toda a região são uma ameaça à produção desta cultura, sobretudo em regime de sequeiro, particularmente devido à menor precipitação e à maior frequência e duração dos períodos de seca. Assim, torna-se necessário a adoção de estratégias de adaptação de forma a garantir a sustentabilidade dos olivais tradicionais. Ao mesmo tempo, a poda persiste como uma técnica cultural mal compreendida em olival, com profundos reflexos na fisiologia e produtividade das plantas. A forma como se poda deverá ser vista como uma prática que ajuda a controlar a área foliar e as atividades funcionais das plantas, pelo que é imperioso ser considerada uma operação relevante para o incremento da produtividade e para a manutenção da regularidade da produção em condições ambientais mais adversas. Neste trabalho foram estudados quatro regimes de poda num olival adulto de sequeiro (cv. Cobrançosa) localizado em São Pedro Vale do Conde, Mirandela, na região de Trás-os-Montes. As modalidades de poda aplicados foram “Não Poda”, “Poda 3 Cortes”, “Poda de pormenor” e “Poda Severa”. Após a poda procedeu-se à pesagem da lenha de poda removida para permitir o cálculo das perdas de nutrientes. Foram também avaliados o estado hídrico e nutritivo, a performance fotossintética, a produção e a qualidade do azeite obtido. Verificou-se que as plantas submetidas a regime de poda “severa”, apesar de apresentarem boa capacidade fotossintética por unidade de área foliar, devido à menor expansão vegetativa que disponibiliza mais recursos hídricos por unidade de área foliar e mais recursos nutritivos por efeito de concentração, acabaram por sofrer uma grande perda de nutrientes através da lenha de poda. Entretanto, a menor superfície assimiladora condicionou negativamente a capacidade produtiva acumulada ao longo dos anos, pelo que deverá ser uma prática a evitar. Por sua vez, o regime de “não poda”, contrariamente à opinião maioritária, foi, no tempo em que decorreu o estudo (3 anos), a modalidade com maior produção, em estreita associação com a maior área foliar. Contudo, este regime deverá apresentar problemas a médio e longo prazo, particularmente o agravamento do fenómeno de alternância de produção, particularmente devido à diminuição da capacidade fotossintética das folhas do interior da copa, como evidenciado pelos resultados apresentados, bem como à perda de área foliar pela ocorrência de necrotização de rebentos interiores e basais e a perturbações fitossanitárias. Por outro lado, potencia seriamente o risco da ocorrência de problemas hídricos em anos secos, bem como afeta algumas operações X culturais, entre as quais a colheita mecânica. Os regimes que apresentaram maior equilíbrio foram a “poda de pormenor” e a “poda 3 cortes”, com boa regularidade a nível da produção, em consequência de área foliar adequada e de controlada atividade fisiológica. Os resultados deste trabalho demonstraram que uma “boa” poda é aquela que se aproxima do não podar para permitir a oliveira ter uma área foliar adequada e que possibilite uma produção equilibrada e satisfatória ao longo dos anos, mas que deverá ser sujeita a podas anuais de forma a controlar a expansão vegetativa e a fisiologia das árvores.
The olive tree (Olea europaea L.) is a species well-adapted to the edaphoclimatic conditions of the Mediterranean region. However, the climatic changes that are felt throughout the region are a threat to the crop yield, especially under rainfed conditions, particularly due to less rainfall and the greater frequency and duration of drought periods. Thus, it is necessary to adopt adaptation strategies in order to guarantee the sustainability of traditional olive orchards. At the same time, pruning persists as a technique poorly understood in olive groves, with profound effects on the physiology and productivity of trees. Pruning should be seen as a practice that helps to control the leaf area and the functional activities of plants, so it is imperative to be considered a relevant operation for increasing productivity and maintaining regular production in adverse environmental conditions. In this work, four pruning regimes were studied in an adult olive rainfed orchard (cv. Cobrançosa) located in São Pedro Vale do Conde, Mirandela, in Trás-os-Montes region. “No Pruning”, “3 Cuts Pruning”, “Detail Pruning” and “Severe Pruning” treatments were applied. After pruning, the removed pruning wood was weighed to allow calculation of mineral nutrient losses. Water and mineral status, photosynthesis, crop yield, olives characteristics and olive oil quality were also assessed. It was found that the plants submitted to "Severe Pruning" regime, despite having good photosynthetic capacity per unit of leaf area, due to lower vegetative expansion that provides more water resources per unit of leaf area and more nutritional resources by concentration effect, end up suffering a great loss of nutrients through pruning wood. However, the smaller leaf area had negative effects on crop yield accumulated over the years, so it should be a practice to avoid. In turn, the “No Pruning” regime, contrary to the majority opinion, was, at the time the study took place (3 years), the treatment with the highest production, in closely association with the largest leaf area. Nevertheless, this regime should present problems in the medium and long term, particularly worsening the phenomenon of alternate bearing, particularly due to the decrease in the photosynthetic capacity of leaves inside the canopy, as evidenced by the results presented, as well as due to the loss of leaf area by the occurrence of necrotization of inner and basal shoots and phytosanitary disturbances. On the other hand, it seriously increases the risk of water problems in dry years, as well as affecting some operations, including mechanical harvesting. The regimes that showed the best balance were “Detail Pruning” and “3 Cuts Pruning”, with good regularity in terms of production, as a result of adequate leaf area and controlled physiological activity. The results of this work XII demonstrated that a “good” pruning is one that comes close to the “No Pruning” to allow the olive tree to have an adequate leaf area and that allows a balanced and satisfactory production over the years, but that should be subjected to annual pruning in order to control the vegetative expansion and the physiology of trees.
The olive tree (Olea europaea L.) is a species well-adapted to the edaphoclimatic conditions of the Mediterranean region. However, the climatic changes that are felt throughout the region are a threat to the crop yield, especially under rainfed conditions, particularly due to less rainfall and the greater frequency and duration of drought periods. Thus, it is necessary to adopt adaptation strategies in order to guarantee the sustainability of traditional olive orchards. At the same time, pruning persists as a technique poorly understood in olive groves, with profound effects on the physiology and productivity of trees. Pruning should be seen as a practice that helps to control the leaf area and the functional activities of plants, so it is imperative to be considered a relevant operation for increasing productivity and maintaining regular production in adverse environmental conditions. In this work, four pruning regimes were studied in an adult olive rainfed orchard (cv. Cobrançosa) located in São Pedro Vale do Conde, Mirandela, in Trás-os-Montes region. “No Pruning”, “3 Cuts Pruning”, “Detail Pruning” and “Severe Pruning” treatments were applied. After pruning, the removed pruning wood was weighed to allow calculation of mineral nutrient losses. Water and mineral status, photosynthesis, crop yield, olives characteristics and olive oil quality were also assessed. It was found that the plants submitted to "Severe Pruning" regime, despite having good photosynthetic capacity per unit of leaf area, due to lower vegetative expansion that provides more water resources per unit of leaf area and more nutritional resources by concentration effect, end up suffering a great loss of nutrients through pruning wood. However, the smaller leaf area had negative effects on crop yield accumulated over the years, so it should be a practice to avoid. In turn, the “No Pruning” regime, contrary to the majority opinion, was, at the time the study took place (3 years), the treatment with the highest production, in closely association with the largest leaf area. Nevertheless, this regime should present problems in the medium and long term, particularly worsening the phenomenon of alternate bearing, particularly due to the decrease in the photosynthetic capacity of leaves inside the canopy, as evidenced by the results presented, as well as due to the loss of leaf area by the occurrence of necrotization of inner and basal shoots and phytosanitary disturbances. On the other hand, it seriously increases the risk of water problems in dry years, as well as affecting some operations, including mechanical harvesting. The regimes that showed the best balance were “Detail Pruning” and “3 Cuts Pruning”, with good regularity in terms of production, as a result of adequate leaf area and controlled physiological activity. The results of this work XII demonstrated that a “good” pruning is one that comes close to the “No Pruning” to allow the olive tree to have an adequate leaf area and that allows a balanced and satisfactory production over the years, but that should be subjected to annual pruning in order to control the vegetative expansion and the physiology of trees.
Descrição
Dissertação de Mestrado em Engenharia Agronómica
Palavras-chave
Ecofisiologia , limpa do olival