Table 1 Geology, soils, soil chemistry and wine quality in Sonoma County
Formation
Soil Series
Franciscan Complex 12040my
Graywacke Sandstone,
Kinmanshale
Dibble,JosephineAtwell-MaymanSuther-KneelandHely-HugoLaughlin, Atwell
Ophiolite-Iron rich
igneous rock
Serpentine mélange
Soil parameterschemistry
Comments
Ca/Mg/K/
Vineyards
Clay loam sand with
clay layers
14/6.2/1
med-hi CEC
Boomer (w of Dry Red, heavy clay loam
Creek), Comptche 17.2/5.2/1, med-hi
CEC
Yorkville-Raynor- Green sheared matrixHenneke
clay, hard rock
Montara
knockers. –
8.6/6.1/1
Wilson Grove Formation Gold Ridge,
Sandy clay loam, gold
3-5my
Sebastopol
clay layer 16”
Fine sandstone with
(Altamont), Empire 3.0/1.5/1
volcanic ash
low CEC
High quality grapes, some
Add K and lime to balance
Chemistry and lower pH
Iron horse, Timbervine,
Porter-Bass
Long time to establish vinePlants excellent deep flavors
Rafanelli, Peterson,
Bradford Mountain
Poor balance, Major
Mg problem, possible
Ni toxicity, not good soil
For wine grapes.
Great chemical balance,
Drainage.texture perfect for
pinot noir in Russian river
appellation. Dehlinger,
Dutton-Goldfield, IronHorse
Sonoma Volcanics 3-8my
Volcanic ash/rhyolite
Kidd, Forward,
Laniger, Felta,
Goulding,
Spreckles,
Rocky, light hard
sand,
7.3/2.2/1
low CEC
Perfect chemical balance,
Drainage good, High
Quality Grapes; Peter
Michael, Benziger NW
Rocky, sandy clay
loam
7.7/2.3/1, low to med
CEC
Perfect chemical balance,
Clay content moderate
Turley Vineyard, Benziger
SE
Basalt lavas
Toomes, Guenoc,
Cohasset
River and terrace
deposits-1my-recent
Glen Ellen Formation –
older gravels(1my)
Pebbly sandy clay
loam
Huichicha, Cotati, 9.6/4.6/1, med-high
Zamora, Cortina, CEC
Yolo
Pleasanton, Cole, 22.5/13.2/1, med-high
Clough, Blucher,
CEC
River Floodplain
River Terrace (bench)
Spreckles, Felta,
Fan and landslide
Cole, HareDiablo
Arbuckle,
Lake, Basin and tidal flats Clear LakeReyes
Good soil for quality grapes
Good climate on SR plain
Clay Hardpan at depth.
Poplar, J,
High mg, but high Ca balances out Excellent wine
quality. Jordan, Rochioli,
Foppiano
9.8/3.4/1, med-high Very high mg to k ratio
CEC
Soil needs K amendment
Shlumberger
21.2/25.6/1, med-high Hi mg and hi ca, well
CEC
Drained Chemistry function
of source, Christopher Creek
22.5/13.2/1, very high Problem soils with high Mg
CEC
content, high clay