Restoring Plant Diversity and Soil Health in Napa and Sonoma Vineyards: scaling up an agroecologically based pest management strategy

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2008: $30,000.00
Projected End Date: 12/31/2010
Region: Western
State: California
Principal Investigator:
Houston Wilson
UC Berkeley -- ESPM
Miguel Altieri
University of California, Berkeley

Annual Reports


  • Fruits: grapes
  • Additional Plants: ornamentals


  • Crop Production: strip tillage
  • Education and Training: demonstration, networking, on-farm/ranch research, participatory research
  • Farm Business Management: whole farm planning
  • Natural Resources/Environment: indicators, hedges - woody
  • Pest Management: biological control, compost extracts, cultural control
  • Production Systems: agroecosystems, holistic management
  • Soil Management: organic matter, soil quality/health
  • Sustainable Communities: social networks

    Proposal summary:

    On farm research.

    We will initiate a participatory on-farm research project involving eight wine grape growers in Napa and Sonoma Counties aimed at rectifying farming system homogeneity and the loss of native habitat. Through multiple strategies of increasing the vegetational diversity of vineyard landscapes, an appropriate ecological infrastructure will be created which serves to enhance biological control of key arthropod pests (Altieri and Nicholls 2004; Gurr et al. 2004). The following growers: Quintessa, Ridge, Medlock-Ames, Robert Mondavi, Franciscan, Sainstbury, Robert Sinskey and Oakville Ranch Vineyards have all committed to participate in the project. All of the farmers involved in this study are either certified organic or follow IPM guidelines. The majority of the participating growers practice mono-cropping in their vineyards and depend upon conventional and/or certified organic external inputs for pest control and soil fertility management. These farmers are motivated to move beyond input dependence and establish agroecological designs that will increasingly allow their farming systems to internally sponsor effective pest regulation and soil fertility.

    Our three-year goal is to test a suite of agroecological strategies with a wide range of grape varietals and in a wide range of growing conditions throughout Napa and Sonoma Counties. At each participating vineyard, a one to two acre experimental plot will be established to assess the effectiveness of several agroecological farming practices on soil quality indicators and populations of key insect pests and associated natural enemies. Two main strategies will be used to enhance biodiversity on the participating vineyards: (a) planting of summer cover crops including Common Buckwheat (Fagopyrum esculentum) between vine rows and Sweet Alyssum (Lobularia maritime) under the drip line between vine plants and (b) plant selected species of California native vegetation in the form of enriched hedgerows surrounding the vineyards.

    The effectiveness of flowering summer cover crops to increase populations of natural enemies and to regulate populations of key vineyard pests will be assessed using multiple analytical techniques. Additionally, the effects of soil fertility management treatments on the presence of soil invertebrate fauna considered to be sensitive indicators of soil health will be extensively measured. These one to two acre treatment blocks will be compared with the normal vineyard management practices used by each vineyard operation. Finally, the influence of native California vegetation (from adjacent plant communities and selectively planted hedgerow corridors) will be assessed to determine the impact of such vegetation on populations of key insect pests, their natural enemies and soil fauna diversity.

    This project is an excellent opportunity to scale-up the agroecological approaches that our group has been experimentally testing for the last seven years. Our past research has consistently shown that breaking vineyard monoculture structure with cover crops and/or surrounding vegetation is an effective way to enhance conservation biological control in vineyards and to promote more preventative approaches to pest management. Moreover, we will complement plant diversification schemes with organic soil fertility management treatments in order to assess the enhancement of soil organic matter content, the activation of soil biological activity and the improvement of soil quality.

    Educational Outreach:

    We will be organizing periodic site visits with participating growers in order to present and discuss findings, observe the implementation of the treatments at various sites and exchange relevant management ideas. In addition to providing the land, seeds, labor, water and miscellaneous needs for the experiment, participating farmers will be key partners in the research and extension process.

    In order facilitate farmer-to-farmer exchanges of information, we will provide two group meeting opportunities for the participating growers to meet and discuss the progress and findings of the project. Producers, managers and farm-workers will be able to visit all the vineyards and observe firsthand the various agroecological designs at work. Producers, farm workers and researchers will closely work together in the agroecological assessments, discussing processes and trends that become evident as the season unfolds.

    During the growing season, we will be organizing a field day featuring two to three model vineyards that will present the practices and preliminary outcomes of the study to the Napa Sustainable Winegrowing Group and the broader grower community. The content of the field day will focus on the identification of successful farm designs and analysis of the differences between these and less successful designs. These field days will provide opportunities for other farmers to observe firsthand the agroecological practices being used in the experimental plots and to discuss the efficacy of the practices with researchers and other growers. The field days will also provide an opportunity to encourage additional growers to initiate a similar agroecological conversion process within their own vineyards.

    As described above, we expect producers, managers and a team of farm-workers to actively engage in multiple aspects of the project, including the monitoring of insect populations and soil and crop health parameters. We will conduct several training sessions (in Spanish) for the farm laborers who work for the participating vineyards. The training sessions will address such topics as: agroecology, the components and rationale behind the vineyard research and hands-on training in monitoring techniques. Producers will also have a key role during field days as disseminators of best management practices to other farmers in the region. We have already jointly planned the cover cropping and organic fertilization practices to be used in each experimental plot for the fall 2007. Additionally, in several of the participating farms (Saintsbury, Quintessa, Ridge, and Franciscan Vineyards), growers have been collaborating with researchers in the design and location of multi-functional hedgerows for conservation biological control. Further, we expect each of the growers to have significant input into the written materials produced as part of the study summary in order to create relevant and accessible educational literature for other growers. Our intention is to publish such findings in the industry periodicals most commonly read by regional growers. Finally, we will also produce brochures, farmer friendly publications and a website to disseminate research results widely. At the end of the study we will produce a manual of agroecological diversification tailored to IPM, transitional and organic farmers.

    Project objectives from proposal:

    1. Project Goals and Western SARE goals

    Good Stewardship:

    Continual expansion of vineyard monocultures in Napa and other regions results in habitat fragmentation seriously compromising the activity of natural enemies of agricultural pests increasing outbreak possibilities (Altieri et al 2005), while diminishing other important ecosystem services (e.g. water purification, biodiversity conservation). The goal of our research is to define, in a participatory process with vineyard growers, plant diversification strategies that optimize the soil food web and native biological control services by creating a functional ecological infrastructure within and around vineyards (Altieri and Nicholls 2004; Gurr et al. 2004). In three to five years, we expect a minimum of 50 farmers testing or fully adopting the new agroecological schemes on their vineyards, thus enhancing natural processes of biological control and nutrient cycling and also promoting natural resource stewardship and wildlife conservation.

    Enhance quality of life:

    By reducing dependence on chemical inputs, growers will lower production costs and attract tourists to more aesthetically pleasing and biologically diverse vineyard landscapes. We also expect farmers to profit from increasingly discerning consumer demands for wine quality and environmental sustainability. Providing farm-workers with hands-on training in field monitoring techniques will enhance their skills to become effective agroecological scouts and be paid more fairly for such services.

    Health and safety:

    Napa Valley is sprayed with more than 2,000,000 pounds of agricultural chemicals each year, which pose risks to the local flora, fauna and human populations, and that threaten the health of the Napa River and its principle tributary (DPR 2003; PANNA 2005). By eliminating farmers’ pesticide dependence, the health and safety of farmworkers and growers will be protected, while diverse farms will contribute to, and benefit from, biodiversity conservation and enhanced ecosystem services within their vineyards and watersheds.

    Crop Diversification:

    The proposed designs will promote vegetational diversity in the vineyard landscapes which in turn will enhance the biodiversity of beneficial invertebrates (natural enemies, pollinators, soil meso and macro fauna, etc.) (Gurr et al, 2004). Enhanced biodiversity will perform ecosystem services beyond grape production such as nutrient cyling, biological control, regulation of hydrologic cycles, etc.

    Regional economic, social and environmental goals:

    Napa Valley has close to 48,000 acres of vineyards and accounts for 18% of certified organic vineyards in the state (Cox, 2000). Solid results from our research will progressively encourage higher numbers of producers to adopt agroecological designs, thus collectively defining premier regions for agroecological fine wine production and increasing market demand for sustainably-grown wines.

    2. Distinctiveness of Proposed Project

    We propose to scale-up agroecological approaches that break vineyard monoculture structures with cover crops and/or hedgerows and corridors, enhancing biological control (Altieri et al, 2005). We have been repeatedly approached by wine grape growers to assist them in re-designing their vineyards to manage insect pests ecologically. This demand stems from the fact that despite the use of IPM techniques, many vineyards continue to experience high levels of pest pressure, an expected trend in monoculture that lack functional biodiversity (Gurr et al 2004).

    What is unique about this proposed project is its participatory nature, with active involvement of farmers in the implementation of the designs as well as the monitoring, allowing the testing of a suite of agroecological strategies in several environments. At each participating vineyard, a one - acre experimental plot will be established to assess the effectiveness of several designs on soil quality indicators and populations of insect pests and natural enemies. Strategies to enhance plant biodiversity include: (a) summer cover crops - Common Buckwheat between vine rows and Sweet Alyssum under the drip line between vine plants and (b) enriched hedgerows surrounding the vineyards. Diversification will be complemented with organic soil fertilization treatments to enhance organic matter content and soil fauna. We expect grapes grown in soils with high organic matter and active soil biology to exhibit lower abundance of insect pests (Altieri and Nicholls, 2003). Summer cover crops effects on natural enemies and pest populations, as well as influence of selectively planted hedgerows on foliage and soil fauna will be assessed using well tested methods (Nicholls et al, 2000, 2001; Daane and Costello, 1998). Effects of soil fertility management treatments on soil invertebrate fauna considered to be sensitive indicators of soil health will be measured using known monitoring techniques (Anderson and Ingram 1993).

    3. Project Outreach to Producers

    Participating growers will engage in two cross visits to observe agroecological designs at work and exchange relevant management ideas. Producers, farm-workers and researchers will work together in the agroecological assessments, discussing observed processes and trends. Once a year, a field day will be held featuring tow to three model vineyards showcasing designs and practices to the non-participating farmers who will be able to observe firsthand the agroecological practices. Additional growers will be encouraged to initiate a similar agroecological conversion process, encouraged by our producers who will play a key role as disseminators of best management practices. Findings will be published in periodicals most commonly read by growers, including a manual of agroecological vineyard diversification strategies, as well as brochures and a website to disseminate research results widely.

    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.