What is a Healthy Soil for Wine Grape Production? Assessing Soil Health Across California Vineyards

Project Overview

Project Type: Graduate Student
Funds awarded in 2021: $30,000.00
Projected End Date: 08/01/2023
Host Institution Award ID: G236-22-W8615
Grant Recipient: University of California Davis
Region: Western
State: California
Principal Investigator:
Dr. Cristina Lazcano
University of California Davis
Principal Investigator:
Dr. Mallika Nocco
University of California, Davis
Dr. Kerri Steenwerth
USDA/University of California Davis


  • Fruits: grapes


  • Crop Production: conservation tillage, cover crops, fertilizers, no-till, nutrient cycling, organic fertilizers
  • Education and Training: on-farm/ranch research, participatory research
  • Natural Resources/Environment: biodiversity, carbon sequestration, indicators, soil stabilization
  • Production Systems: agroecosystems
  • Soil Management: composting, earthworms, green manures, nutrient mineralization, organic matter, soil analysis, soil chemistry, soil microbiology, soil physics, soil quality/health

    Proposal abstract:

    In recent meetings, growers have expressed a strong interest in understanding soil health for wine grape production systems. The problem is that we currently lack a comprehensive assessment of soil health for the Mediterranean soils of the western U.S. This problem is more challenging for the California wine grape production industry not only due to its large soil diversity but to this crop’s unique management practices and goals. Therefore, soil health for California vineyards might have a different definition and sustainable management requirements compared to other crops.

    Preliminary data from interviews we performed indicate that most growers consider soil health as important for wine grape production. Growers described a healthy soil as one that allows them to achieve their production goals by controlling for vine vigor, maintaining vine health, and reducing soil erosion. However, many doubts and questions emerged among growers regarding what soil health indicators and soil management practices will help them achieve their goals while building soil health especially among the complex and diverse soils in the Napa Valley region. Therefore, we aim to 1) develop a definition of soil health for wine grape vineyards that meets the unique growers’ production goals, and 2) assess diverse soil health indicators in vineyards across the Napa Valley region.

    With the collaboration of growers, this study will help us improve and do targeted sustainable recommendations for conserving soils while helping growers achieve their production goals. We expect to observe trends of soil health indicators among soil types and sustainable management practices. 

    Project objectives from proposal:

    The objectives of this project are the following: 

    1. To develop a definition of soil health for wine grape vineyards that meets the unique production goals.
    2. To assess the variability of diverse soil health indicators in vineyards across the Napa Valley region.

    The outreach objectives of this project are:

    1. To integrate growers' collaboration and participation in defining and assessing soil health for such unique crops as wine grapes.
    2. To provide several informational talks for growers and develop short farmer-friendly articles (i.e. factsheets) communicating about the importance of soil health, the role of the soil organic matter and soil microbial ecology in soil health, and the main findings of our project. 
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.