Mapping grapevine vigour, topographic changes and lateral variation in soils
Direct mapping of variability in soils can be a complex, time-consuming and costly process. Consequently, maps of geophysical data such as ground penetrating radar (GPR) and electromagnetic induction (EMI) are commonly used as proxies for soil maps, and these geophysical maps are most useful if they relate to variations in plant attributes such as grapevine trunk circumference. This article demonstrates that vine trunk circumference in five pinot noir vineyards is primarily influenced by changes in slope, elevation and aspect. Variability in GPR maps shows mixed correlations with vine trunk circumference data. In contrast, multi-frequency EMI surveys yield soil apparent electrical conductivity data that commonly show significant correlations with variations in vine trunk circumference data, especially when coupled with global positioning system surveys, suggesting that this is the preferred geophysical tool for mapping variability in soils.