INSIGHTS INTO TERROIR FACTORS FROM A DENSE NETWORK OF VINEYARD SOIL AND WEATHER STATIONS, SUNNYSLOPE DISTRICT, IDAHO
Soils are all Entisols or Aridisols, dominated by sand, sandy loam, or loamy sand, and are well to exceptionally-well drained. Profiles and parent materials are split evenly between soils with simple profiles and single parent material, soils having buried and sometimes restrictive horizons, and soils with strongly contrasting, and sometimes cobbly, layered parent materials. Soils with simple profiles tend to occupy lower elevation sites while sites with buried or more complex layering are higher up the interfluve. Sites that are lower in elevation are also typically cooler (fewer growing degree days). The instrumentation also revealed differences between sites with respect to cold damage vulnerability - this difference is attributable to differences in potential for cold air to drain from vineyard sites. The winter of 2016-17 in the District was extreme by all measures, breaking records for snow on the ground as well as near record low temperatures. Sites that had both higher gradient slopes and space to accommodate cold air drainage recorded less extreme cold temperatures (-26°C) than sites with no to low gradient slopes with no space to accommodate cold air drainage (-31°C). Differences between sites provide data that, in future plantings, may inform selection of cultivar choice to fit the characteristics of the vineyard.