Texas terroir: gis characterization of the texas high plains ava

The Texas High Plains AVA is one of eight officially recognized wine regions in Texas, established in 1993. Six local wineries, including the second-largest in Texas, are supported by approximately 50 vineyards, which are also major suppliers of grapes to Texas wineries outside the region. The distinctive characteristics of the Texas High Plains AVA have contributed to the region’s reputation for producing medal-winning red wines with excellent color and good tannins, primarily from Cabernet Sauvignon and Merlot. The large region (3.6 million ha) is known for its semi-arid climate with hot summers and mild winters, and very deep, well-drained soils. However, little detailed information is available on the spatial variability of growing conditions within the region. The Texas AVA GIS was constructed with datasets describing soils, elevation, topography, and climatic variables of significance to grape production for all 8 winegrowing regions in the state. Growing degree-days (GDD) and ripening period mean temperature (RPMT) in the Texas High Plains AVA decrease from southeast to northwest as elevation increases. The range of GDD is 2028 to 2653. RPMT ranges from 23.8-26.7oC in August and 19.9-22.6oC in September. Precipitation ranges from 41.4-63.7 cm, increasing from west to east. High solar radiation contributes to vine fruitfulness and color development in red wine grapes. Vineyards are predominantly planted on the reddish-brown, deep fine sandy loam and sandy clay loam soils (Amarillo, Patricia, and the related Brownfield series). Patricia soils predominate in the southern portion of the AVA; Amarillo is overall more common and found primarily in central areas of the region. An interactive website was created for public access to the GIS – the Winegrowing Regions of Texas [txwineregions.tamu.edu]. Such data will be critical for vineyard site selection and matching grape cultivars to site as the region’s wine industry continues to expand and experiment with warm-climate cultivars.