The purpose of this project was to train vineyard managers and sheep producers the practices and techniques of vineyard floor grazing and grape leaf aversion training in sheep, to apply sheep grazing in vineyards and to document feedback from project participants. Three project workshops/field days were held, plus private aversion training sessions on four farms. As a result of this project, approximately 17 vineyards are now using sheep grazing on a regular basis, and four are using averted sheep for spring vineyard floor management. An instructional DVD on vineyard grazing practices is being developed for release in 2012.
Grape production in California requires diligent management of the vineyard floor. This involves weed control practices and may include the use of cover crops. Pre-emergent and/or post-emergent herbicides and cultivation are the primary methods of weed control in the vine rows (the area directly below the vines), while vegetation control in the middles can be accomplished with a combination of mowing and cultivation. Cover cropping in the vineyard middles is a practice often used to reduce soil erosion and to improve soil characteristics. Weeds and cover crops become quite competitive with grapevines beginning in the late spring and early summer. Vineyard floor management practices are used to reduce this competition to ensure healthy vine growth. In addition, a tall plant cover on the vineyard floor increases the risk of spring frost damage to the vines. Developing alternative practices to herbicides, mowing and cultivation can reduce health and environmental risks and may provide savings in vineyard floor vegetation management costs.
Sheep grazing is a cultural practice to manage the vineyard floor that is growing in use and acceptability. Several vineyards in California’s wine growing regions have been experimenting with sheep grazing and have adopted the practice to supplement other floor management practices. Sheep can eliminate the need for herbicides, and they can be used in vineyards rain or shine. Currently, the biggest impediment to their use is the fact that sheep like to browse the spring growth of grapevines. Some vineyards work around this problem by using Babydoll Southdown sheep, which are too short to reach the vines. Vineyard managers are pleased with the results, but the use of these miniature sheep is very limited due to their rarity and consequently high price. Other vineyards are using normal commercial sheep, but only by placing electric fencing around each vine row or by limiting grazing to times of the year when the vines are not susceptible to sheep damage, such as between the time of harvest and the emergence of new spring growth.
This problem can be mitigated by training sheep to have a dietary aversion to grape leaves, which will extend the time sheep can graze in vineyards through the spring months when weed and cover crop vegetation grow most vigorously. Sheep grazing is a reduced risk alternative to herbicide applications and is an attractive option for sustainable, organic and biodynamic grape production programs. The technique used to train a grape leaf aversion in sheep is based on research led by Dr. Fred Provenza at Utah State University. Dr. Provenza demonstrated that lambs acquired aversions to nutritious grains by giving the lambs an oral dose of lithium chloride (LiCl) immediately after eating the grains.
In June 2007, our project team concluded a one-year project demonstrating that sheep with a trained aversion to grape leaves can be used for managing spring vineyard floor vegetation. Sheep were trained with the aversion in June 2006 and were then used for spring vineyard grazing in 2007. Preliminary results show that averted sheep have almost no negative impact on the grapevines due to browsing compared to non-averted sheep that significantly damaged the vines.
The next phase was to apply grazing practices with averted sheep in commercial vineyards in order to better understand the challenges, limitations and improvements to the practices on a larger and commercial scale. This Western SARE grant funded workshops, groundwork and outreach efforts to accomplish this next phase.
The goal of this project is to integrate producers into the Vines and Ovines research program.
The project’s specific objectives are to:
1. Convene a two-day short course to educate and train sheep producers and vineyard managers on the principles of ruminant grazing behavior and techniques to modify grazing behavior.
2. Establish at least five vineyard grazing demonstration sites utilizing sheep with a trained aversion to grape leaves for vineyard floor management during the 2009 growing season.
3. Assist demonstration site producers to apply appropriate grazing practices and monitor the grazing impacts on the vineyard.
4. Develop a set of measurements that the producers can use to evaluate the success of the practices used for training the sheep and for grazing the vineyard floor.
5. Hold at least three field days to demonstrate and extend the practice of using trained sheep for vineyard floor management to sheep producers and vineyard managers.
6. Convene a meeting with all project participants in July 2009 to exchange and record information on the successes, problems and solutions of using trained sheep for vineyard floor management.
The project’s methods were based on practitioner education on vineyard grazing practices, practitioner attainment of vineyard grazing experience and the acquisition of the practitioners’ experiences for further outreach. The project began with one intensive three-day training program for the primary vineyard manager and sheep producer participants. followed by a less intensive one-day field day for other interested participants. Our project team then provided assistance and supplies to trained practitioners for the application of vineyard grazing practices on commercial vineyards. Practitioner experiences were then recorded in written and oral formats and used as main contributions in outreach materials.
The project has successfully increased knowledge and awareness of the potential benefits to using sheep for vegetation management in vineyards, and on the technique used to avert sheep to grape leaves. Our team has presented information on this project to over 240 people at workshops, field days, professional society meetings and commodity group meetings. The applications of the aversion and grazing practices are still being improved with help from the commercial vineyard managers and sheep producer. This understanding is necessary to apply these practices on a larger commercial scale. As a result of this project, we now have factsheets available for distribution to people interested in averting sheep to grape leaves and other plants. These factsheets have been sent to people throughout the United States, and even to people in Spain, France, Australia and New Zealand.
An especially meaningful outcome of this project is the growing acceptance of using sheep for managing vineyard floor vegetation. In California there are at least 17 vineyards grazing 1,550 acres with sheep; three of which are using sheep with a trained grape leaf aversion. Even though the practice of using averted sheep to graze vineyards is the major theme of this project, an even better outcome of this project is the shifting paradigm of integrating livestock with vineyards and the seeking of vineyard management practices and designs that preclude the need for averted sheep.
During the grape leaf aversion training and vineyard grazing in Winters, California, we tested new techniques to train large groups of sheep in approximately one-third the time as former techniques. The new techniques appeared to result in an equally strong aversion to grape leaves. We also discovered that by incorporating non-vineyard areas as part of the vineyard grazing blocks, the sheep appeared more comfortable and able to establish more natural diurnal movements and behavior. A key advantage to this that we observed was a reduction in mischievous behavior that leads to a loss of the grape leaf aversion. As Dr. Fred Provenza often proclaims in his BEHAVE workshops “Variety is the spice of life.”
Educational & Outreach Activities
Two fact sheets were created that provide instructions on training aversions in sheep.
One peer-reviewed UC ANR publication is being written that describes vineyard grazing techniques, practices and considerations.
An educational DVD is being created and due for release in 2012 and will include several modules covering vineyard grazing, aversion training, shepherding techniques and practitioner interviews.
Our team has presented information on this project to over 240 people at workshops, field days, professional society meetings and commodity group meetings.
In July 2008, we held a three-day workshop for 12 project participants. The workshop included a training program with many animal behavior modules from the BEHAVE program (http://www.behave.net/), hands-on aversion training of sheep at UC Davis and fundamental skills required for grazing sheep in a vineyard and averting them to grape leaves.
We held a one-day field day in Mendocino County in August 2008 for approximately 20 people. Mendocino County is a major north coast wine grape growing area just north of Sonoma County and is home to many innovative and early-adopter type farmers and ranchers.
In the spring of 2009, we provided hands-on assistance to four vineyards in Northern California that applied the learned vineyard grazing and grape leaf aversion practices. Two other vineyards in Northern California and one vineyard in Klickitat County, Washington (report attached) applied the grazing and aversion practices without our team’s assistance.
In the spring of 2011, we assisted a new vineyard collaborator in Winters, California in applying the vineyard grazing and aversion practices and established replicated plots to evaluate the weed control of grazing compared to conventional practices. We were also able to test, anecdotally, simplified techniques to avert sheep in groups of 100 rather than groups of 10. At this vineyard we were able to avert sheep and graze a 14-acre vineyard in a manner that most resembled the scale necessary for the commercial application of grape leaf aversion and vineyard grazing practices.
A third field day was held at the vineyard in Winters, California to demonstrate the aversion and grazing practices on a commercial scale. Twelve people participated in the field day, including vineyard managers from prominent Napa County wineries.
Other outreach efforts included the writing of sheep training protocols (see attached documents) and at least six presentations of our project given by both professional and producer cooperators to professional societies and producer groups. We are also creating a DVD that will consist of educational modules covering the various aspects of vineyard grazing, aversion training and collaborator interviews. Each module will be produced into ten-minute videos that will be made available on YouTube.
- Averted sheep grazing a vineyard in Mendocino County. Photo courtesy of Sarah Cahn Bennett.
- Report from the project cooperators in Washington State
- Sheep happily consuming grape leaves before aversion training, July 29, 2008.
- Sheep averted to grape leaves are avoiding grape leaves, July 30, 2008.
- Averted sheep grazing a vineyard in Sonoma County, California, May 2009. Photo courtesy of Colby Eierman.
- Sheep eating grape leaves as part of the aversion training process in Winters, California, May 2011.
- Sheep with trained grape leaf aversion grazing the Winters vineyard in May 2011.
- View of an un-grazed vineyard row on left and a grazed vineyard row on right. Winters, California, May 2011.
- Temporary corral used to for grape leaf aversion training in Winters, California, May 2011.
- Processing sheep during July 2008 workshop.
- Sheep grazing vineyard prior to bud break in Winters, California, March 2011.
- Vineyard grazing field day at Winters vineyard in May 2011.
Vineyard and sheep producers were fully integrated throughout the project’s activities, which resulted in very practical and applicable information that is being made available in outreach material and publications. We feel this producer-oriented approach has resulted in greater acceptance and adoption by other producers after seeing and hearing the vineyard grazing and aversion training practices from our producer-collaborators.
The outcomes of this project are being used to solicit grant funds to conduct larger-scale experiments on crop-livestock integration systems that will incorporate vineyards and additional crops common in California’s Central Valley. We have garnered the interest and collaboration of a UC Davis weed specialist, forage crops specialist and agricultural economics specialist to continue crop-livestock integration research.
There is a growing interest in the practice of integrating livestock back into cropping systems in order to achieve benefits for both the livestock and crop enterprises. This is exemplified by this project and other Western SARE funded research in Montana. Despite these recently completed projects, we are only beginning to understand the correct research questions to address in crop-livestock integrated systems. There are many potential benefits that need to be quantified, and many logistical challenges that must be understood in order to achieve successful crop-livestock integration. Integrating crop and livestock systems has the potential to intensify overall crop production while reducing chemical and carbon inputs, both of which are necessary to achieve greater agricultural sustainability. Our project team recommends that Western SARE continues to fund crop-livestock integration projects and develop research criteria that will encourage future integrated projects.