A SOIL CATENA FROM ROCK FLOUR VINEYARD, THE DALLES, OREGON

Rock Flour Vineyard, located east of the The Dalles (45°35'40”N, 121° 01' 56”W), has young Cabernet and Bordeaux style grapes vines. Terroir is the physical environment of the vineyard- it's the soils and climate; soils play a large role in the terroir and can create a different grape flavor within one vineyard. We wanted to explore how soils could affect the vineyard terroir. The area is covered in silt that could either have been deposited as loess or flood silts from the Missoula Floods. A catena study was done on the main south facing slope of the vineyard. The fields where the young vines were planted had been farmed for 50 years creating an Ap layer at all the sites. The shoulder and the foot slope both show similar characteristics including the Ap and a well developed Bw. We believe the Bw to be roughly 10,000 -15,000 years old. At the upper back slope pit we found an Ap layer similar to the shoulder and below that a stage 3 caliche over 100,000 years old. There is not a Bw horizon above the caliche, and there are stage 1 and stage 2 layers below the stage 3 caliche. The lower backslope pit yielded a stage 3 caliche beneath a Bw. The age gap between the different soil types leads us to believe there was significant erosion, maybe due to scouring by the Missoula Floods followed by the deposit of the silt. At the toe slope we encountered an overthickened A horizon due to slope processes. Due to the thick plowed A horizons and mid-slope Bk horizons, the soils are classified as (from shoulder to toe slope): Typic Haploxeroll, Andic Calcixeroll, Calcic Haploxeroll, and Cumulic Haploxeroll. With variable soils along the length of the catena the terroir varies producing different grapes along the slope resulting in different wines.