Main characteristics of the four vineyards studied under conventional viticulture (CV) and regenerative agriculture (RA) management. Soil type taxonomies were taken from the USDA-NRCS Web Soil Survey (https://websoilsurvey.nrcs.usda.gov/app/). Yield was averaged from 2 yr (2022 to 2023) and average yield prices were taken from the 2022 and 2023 California Grape Crush Reports (CDFA 2023b, 2024). Weed control (under-vine mechanical with a Clemens side weed knife) was performed at a 5- to 10-cm till depth, one to three times per year (spring and summer); herbicides were applied two to three times per year. Mowing occurred only in alleyways, during spring (April to May) then during summer (July to August). Synthetic fertilizers were used in the same amount and form as in the CV scenarios. AVA, American Viticultural Area; Mg, Megagram.
| Characteristics | Scenarios | ||||
|---|---|---|---|---|---|
| CV1a | CV2a | CV3a | CV4a | RA (1 to 4) | |
| Grape cultivar | Pinot noir | Chardonnay | Cabernet Sauvignon | Chardonnay | Sameb |
| Clone | Dijon 667 | FPS04 Martini | 337 | FPS04 Martini | Same |
| AVA | Russian River Valley | Russian River Valley | Alexander Valley | Russian River Valley | Same |
| Soil type | Yolo silt loamc | Yolo clay loamc | Positas gravelly loamd | Yolo sandy loame | Same |
| Rootstockf | 101-14 | 140-R | 101-14 | 5C | Same |
| Planted area (ha) | 2.04 | 6.13 | 4.11 | 13.6 | Same |
| Vine age (years) | 11 | 6 | 23 | 34 | Same |
| Vine density (vines/ha) | 5382 | 3588 | 3076 | 1122 | Same |
| Yield average (Mg/ha) | 11.6 | 19.3 | 7.03 | 9.7 | Same |
| Price average per Mg ($) | 3750 | 2500 | 3000 | 2500 | Same |
| Trellis system | Guyot | Guyot | Scott Henry | Quadrilateral cordon | Same |
| Crop management | |||||
| Soil tillage | Alternate (Rototiller) | Alternate (Disk) | Alternate (Disk) | Alternate (Disk) | No-till |
| Weed control | Herbicides and mechanical control | Herbicides and mechanical control | Herbicides only | Herbicides and mechanical control | Mechanical control only |
| Mowing | Twice/year | Twice/year | Twice/year | Twice/year | No mowing |
| Nutrient management | Synthetic fertilizers | Synthetic fertilizers | Synthetic fertilizers | Synthetic fertilizers | Compost and fertilizersg |
| Cover croppingh | Forage mix | Forage mix | Forage mix | Forage mix | Sheep forage mix |
| Livestock integration | None | None | None | None | Sheep grazing (two events/year) |
↵aCV, vineyards employing practices that support soil health, in line with certification requirements of the California Sustainable Winegrowing Alliance.
↵bIndicates the same characteristic across respective site numbers (e.g., Pinot noir for both CV1 and RA1, Chardonnay for both CV2 and RA2, etc.).
↵cFine-silty, mixed, superactive, nonacid, thermic Mollic Xerofluvents.
↵dFine, montmorillonitic, thermic Mollic Palexeralfs.
↵eFine-loamy, mixed, thermic Fluventic Haploxerolls.
↵fVitis parentage by rootstock: 101-14 (Vitis riparia × Vitis rupestris), 140-R (Vitis berlandieri × V. rupestris), and 5C (V. berlandieri × V. riparia).
↵gSynthetic fertilizers were used in the same amount and form as in the conventional scenarios.
↵hForage seed mix: generally white clover, annual barley, and rye, applied at a rate of 67 kg/ha; sheep forage seed mix: 1% Campeda Subclover, 2% Hykon Rose Clover, 2% Dwarf Essex Rape, 23% Austrian Winter Peas, 35% Winter Ryegrain, and 35% Triticale, all applied at a rate of 112 kg/ha.