TY - JOUR T1 - The Use of Soils for the Delineation of Viticultural Zones in the Four Corners Region JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 290 LP - 296 DO - 10.5344/ajev.1981.32.4.290 VL - 32 IS - 4 AU - Gordon R. Dutt AU - Eugene A. Mielke AU - Wade H. Wolfe Y1 - 1981/01/01 UR - http://www.ajevonline.org/content/32/4/290.abstract N2 - Delineation of viticultural zones has been useful in making varietal recommendations and predicting wine quality. The California base 50 growing-degree-day model fails to predict zones in the Four Corners Region which are comparable to California, either in adaptable varieties, sugar and acid or color of red varieties. A new model has been developed based on modern soil surveys and altitude. The soil parameter most useful in describing viticultural adaptability is the mean annual soil temperature at 50 cm. This parameter subdivides soils into hyperthermic, thermic and messic. Most wine grapes in California are produced on thermic soils, hence, this soil group has been subdivided. Altitude (inter-related to temperature) is the secondary parameter. Zones defined are HT (hypothermic), T1 (low-level thermic), Tm (mid-level thermic), Th (high-level thermic), and M (messic). This system while encompassing the G.D.D. concept, allows for wider climatic conditions to be considered. ER -