The effect of topography on the spatial variability of grapevine vegetative and reproductive components

Abstract

I Congresso Luso-Brasileiro de Horticultura. Sessão ViticulturaTopography variation is one of the main causes for vineyard variability. Terrain attributes, such as slope, altitude and aspect are highly variable and have an impact on soil depth, water holding capacity, air and soil temperature, radiation exposure, among other factors. Patterns of topographic variability tend to be stable over time, therefore recognizing such patterns can potentially provide the winegrower with relevant economic returns. A study was conducted in 2015, in a vineyard located at Tapada da Ajuda, Lisbon (slope range from 7% to 9%; southern orientation). Four white varieties (Alvarinho, Viosinho, Encruzado and Arinto) were analyzed regarding their vegetative development, yield and grape quality. This study had two main objectives: (i) to evaluate the magnitude of the spatial variability among varieties and (ii) to evaluate the effect of the terrain position (TP) in each variety, individually. Smart points (SP) were selected for each variety, organized according to their slope position (uphill, mid-slope and downhill) and vegetative and reproductive data was collected at relevant phenological stages (pre-flowering, flowering, veraison and full maturation). Alvarinho and Arinto varieties presented the highest spatial variability, regardless of their position along the slope. Yield and leaf-to-fruit ratio were the most variable parameters (coefficient of variation>30% in all varieties) with no correlation with TP. Encruzado showed higher vegetative development (+36% leaf area index and +18% exposed leaf area) in downhill SPs, while Arinto presented higher bud burst percentage (+49%) and lower water-shoot development (-30%) in downhill SPs. In these cases, canopy development parameters were influenced by TP. Such information can be used for a differentiated scheduling of canopy management activities e.g. canopy thinning and water-shoot removal, tasks that are expensive and time consuming. This study created a basis for further research that can lead to more accurate vineyard design planning and managementinfo:eu-repo/semantics/publishedVersio