Author(s):
James Fisher, M.S., Soil science* - Soil Solutions LLC
Abstract:
A landform capable of producing high quality winegrapes has good terroir; yet the absence of just a few synergistic components can result in a substandard site, proving ruinous for viticulture. The key is to determine site suitability before planting vines.
The associative factors of a site - namely the complimentary effect of soils, terrain, and microclimate - blend to elicit conditions either favorable or deleterious for viticulture. Good terroir produces high quality wine consistently. A great vintage is the result of an ideal annual climate. Although weather conditions are beyond the control of the grape grower, viticultural practices exist which mollify their affect on wine quality. Foreknowledge of subsurface features that affect the hydrogeology of a site is critical in order to effectively employ these practices.
Geospatial mapping was performed with electromagnetic induction (EMI) to geolocate subsurface disparities within a vineyard block. Soil profile positions were located based upon apparent electrical conductivity (ECa) values. Pedology analysis revealed the causes for disparity. Results included paralithic bedrock, presence of fragipans, clay lenses, soil depth, perched water, and soil salinity.
Pedology and surface morphometry provided data correlated via pedotransfer functions to reveal trends in the site's hydrogeology. This assessment model provides guidelines for vineyard site selection, and subsequent vertical tillage procedures.
Uniformity within vineyard blocks was achieved by designating appropriate rootstocks and soil preparations, accordingly. These mapping tools were used before planting and were also used in mature vineyards in order to assess problem areas such as the location of clay lenses.
