Soil or geology? And what’s the difference? Some observations from the New World

Observational historical geology seeks to establish the evolutionary history of the surface of Earth. This approach is applicable not only to bedrock, but to the soft material that lies at the surface, the stuff called soil by most people. The geologic perspective provides a view of this material that is quite different from that of soil science, at least as practiced by many in America. Examples from the Walla Walla Valley of Washington and Oregon, and from the Napa Valley, illustrate the differences between these approaches. In Napa, correlation of grape character and viticultural realities with geologic observations suggests some underlying shared factor, perhaps drainage and water accessibility, but possibly influences of substrate temperature or microbiology. In addition, the geologic approach has proven useful in designing drainage and irrigation systems.