Saralee’s Vineyard

Saralee’s Vineyard launched a compost and tillage field trial in 2018, initially funded for three years through a grant from the Healthy Soils Program, coordinated by the California Department of Food and Agriculture. After the grant period ended, Jackson Family Wines committed to continuing the trial to monitor long-term changes in soil health, working in collaboration with Sonoma Resource Conservation District (Sonoma RCD) to collect data across a total of 10 years. The trial aims to evaluate how different tillage frequencies interact with compost application and influence soil health, vine productivity, and soil carbon sequestration. Key soil health indicators being monitored include total organic carbon, bulk density, water infiltration, and water holding capacity. The vineyard team is also tracking vine health, productivity, and economic factors. Prior to the trial, the vineyard was managed using alternate row tillage, synthetic fertilizers, and herbicides for undervine weed control. With the start of the trial, compost was applied annually in spring to half of the area at a rate of 5 dry tons per acre , with tillage occurring in some plots shortly afterward. The experimental design includes three tillage treatments—no-till, alternate row tillage, and full tillage—laid out across two adjacent vineyard blocks (one planted with Pinot Noir and the other with Chardonnay). Each treatment is replicated three times to enable statistical analysis. Soon after the trial began, Jackson Family Wines also shifted from herbicide use to mechanical undervine weed management. Soil sampling has taken place in 2018 (baseline), 2019, 2020, 2021, 2023, and 2025, with a final sampling scheduled for 2028. Samples have been collected from both the tractor rows and vine rows to assess conditions in both zones. Data collected so far confirms notable differences in soil conditions between tractor and vine rows. Total carbon and total nitrogen levels have increased annually in plots receiving compost. Wet aggregate stability, a measure of soil’s ability to clump, and an indirect indicator of microbial activity, increased in the first year in areas with reduced tillage, though this trend has not remained consistent in subsequent years. A more detailed analysis of the 2025 data is currently underway.