The Crush - April 2020 - 2

[ FEATURE STORY ]
VINEYARD DESIGN FOR SHEEP GRAZING
Kelly Mulville is a viticulture and grazing consultant
who has worked with vineyard operations in
California, Oregon, Texas, New Zealand and
Australia to integrate livestock (primarily sheep)
grazing into vineyard management. In 2008-2009, he
performed a sheep management trial in an existing
Sonoma County vineyard that demonstrated the
ability to reduce mechanized mowing, tillage and
suckering while improving soil health and carbon
sequestration, increasing biodiversity, reducing
irrigation needs and improving overall economics.
He is now working at the 7,600-acre Paicines
Ranch - a multiple crop farm, rangeland, livestock
and meat production operation near Hollister - to design and
develop a vineyard from the ground up to fully integrate sheep
into operations using an ecosystem approach. The vineyard land
was previously planted in vines until about 1980 for the Almaden
wine brand.
Prior to planting, the vineyard soil was improved over three
years with light applications of compost, sheep grazing to
manage existing weed cover, and planting cover crops that
include oats, barley, rye, triticale, daikon radish, and species to
attract pollinators and beneficial insects such as crimson clover,
vetch and California poppies. No-till management was instituted
before vines were planted. Mulville said these improvements
increased soil organic matter and water holding capacity.
The first 12 1/2 acres of the 25-acre vineyard was planted in
2017 using spacing of 6 feet between vines and 12 feet between
rows. The cordon height is 66 inches above ground level, with
a divided canopy on a V-shaped trellis designed specifically
for sheep integration. The irrigation drip lines are also elevated
to allow sheep to pass under vine rows. The remaining 12 1/2
acres will be planted this year. Planted vines include Rhone and
Iberian varieties on 1103P and 110R rootstocks. The grapes will be
certified organic and sold to outside winemakers.
"The goal is to design a system for ease of management with
grazing animals throughout the year, and also develop it from
an ecosystem perspective with increased biodiversity," Mulville
said. "But it also must be economically viable and practical
for viticulture." Mulville said at least two types of mechanical
harvesters on the market can be used for harvest with this trellis
system, and the goal of the vineyard design and system is to
also be practical for large acreage operations. He noted that
sheep provide onsite fertility with high quality dung and urine
rich in nutrients, reducing the need to bring in outside nutrient
additions.
Vineyard grazing research in the past has looked at methods to
deter animals from eating vine vegetation and grapes to enable
2 / APRIL 2020

Photo: Alicia Arcidiacono

grazing longer into the vine growing season. These include
training sheep for aversion to grapes, and using short stature
"babydoll" sheep that have difficulty reaching higher trellised
vines. Mulville believes the most effective deterrent is stringing
a single electrified "hot wire" on each side of the vine row just
below the fruiting zone, that can easily be added and moved as
needed. The wire discourages browsing in the vine canopy and
prevents fruit damage, while allowing sheep to provide undervine weed removal, trunk suckering and hedging of vine tips.
Paicines Ranch also provides dormant season sheep grazing
services to nearby Calera Wine's vineyards for cover crops and
native vegetation. Mulville said Paicines seeks to increase its herd
and provide grazing services to other vineyards in the area.
RENTING SHEEP GRAZING SERVICES
Lodi-based Vino Farms began experimenting with sheep
grazing for post-harvest weed and ground vegetation cleanup
in vineyards in fall 2019. Viticulturist Chris Storm worked with
Hamilton Brothers Ranch in nearby Rio Vista to provide sheep
for a 400-acre vineyard on Ryer Island in the Delta region.
About 180 sheep were brought in over a three-week period to
knock down Bermudagrass and Johnsongrass that was not well
controlled during the summer, and to clean the berms under the
vines.
"From our perspective, it was easy to deal with," Storm said.
"The shepherd had easy access in and out, provided daily
management of the sheep and brought in portable electric
fencing to keep sheep in and to keep predators out. The sheep
were moved and rotated for as long as it took to clear the
acreage." He estimates the cost of renting sheep was somewhat
less or about the same as the cost of bringing in a vineyard crew
to mow the same acreage. Storm hopes to expand sheep use
to additional acreage, for grazing cover crops in spring, and
grazing Vino Farms managed coastal and hillside vineyards
where mechanized weed control and spraying are difficult due to
erosion concerns.

The Crush - April 2020

Table of Contents for the Digital Edition of The Crush - April 2020