Vineyard Spatial Structures of Key Soil, Vine and Fruit Metrics Are Hierarchically Associated

Understanding vineyard spatial structure can help optimise grape production and ultimately wine quality by targeting the application of inputs through precision viticulture methods. We explored the spatially dependent variability of various soil, vine and fruit parameters, including yield and grape composition, in a South Australian Shiraz vineyard located in the Barossa Valley during the 2022/23 season. Our aim was to investigate the interdependencies between spatial structures within a vineyard block as related to soil and vine metrics, including predawn leaf water potential, midday stem water potential and leaf gas exchange under different soil moisture conditions. Maps of each parameter were produced using 114 spatially separated data points per variogram. Yield components were measured at harvest, and fruit composition was assessed at harvest across the vineyard at the same points. Soil parameters were found to have stronger spatial structure than vine parameters (e.g., leaf gas exchange, stem water potential) and were therefore deemed to be better predictors of overall vineyard variability. The pattern of spatial variability of a given soil or vine parameter was influenced by the spatial pattern of the underlying parameters that influence it.