In California’s
hot and dry Napa Valley, grapes grow clustered on loose canopies of vines that
sprawl across valleys and hillsides. Drip irrigation is often necessary here,
where water is scarce during the growing season. Across the country in the northeastern
United States, smaller boutique wineries perch on lush hillslopes in a region
known for its wet summers. With the industry booming and a recent increase in
droughts, however, drip irrigation may soon be a necessity in the Northeast
too.
Without enough water, this Chardonnay
vine’s shoots are stunted and some of the larger leaves at its base are
sunburned. Image courtesy of Alan Lakso.
Agriculturists of all types — working in orchards, small-scale farms and
vineyards — have adopted drip irrigation technology over the past several
decades. Joined together and regulated with water-pressure flow valves and other
connectors, an octopus of plastic tubes brings water directly to apple trees
and grapevines, spouting from punctured holes in the tubes or from complex sprinkler
heads known as emitters. Although their intricacy varies, such systems allow
farmers to control water delivery and to influence the size and flavors of their
fruits.
Wine growers have found that a variety of factors, of which water is key, contribute
to producing a satisfactory wine grape. Too much water accelerates the growth
of leaves, forming a canopy that blocks grapes from the sun. Excess water also
makes grapes too big and therefore less suitable for winemaking (though perhaps
more suitable for table grapes). Less water content in a grape concentrates
the agents that create wine flavors, such as tannins, which tend to gather in
a grape’s skin. A good wine grape can command around $2,000 a ton, as much
as 10 times more than the amount of money per ton for a Concord grape that is
used for juice, according to Bob Pool of Cornell University’s New York
State Agricultural Experiment Station in Geneva, N.Y.
The benefits of drip irrigation when managing vineyards are clear, says Alan
Lakso, Pool’s colleague at the Cornell agricultural station. Such systems
generally use less water than a sprinkler system, he says, which enhances evaporation
and gets water all over plants — setting up conditions for fungal diseases,
which are common in the eastern United States because of humidity. With drip
irrigation, he says, “you can put it right directly under the vine, so
water goes directly to the vine roots.” That system is advantageous because
root systems can vary in size and depth according to soil type, making them
difficult to track.
In water-poor California and other dry grape-growing regions, including Chile,
Israel, South Africa, Australia and Washington State, viticulturists and other
growers adopted drip irrigation in the 1970s. For winemakers, the delivery system
allows them to grow exactly the kind of grape they want to harvest. Such control
in California’s Napa Valley or Central San Joaquin Valley, for example,
is relatively easy, where vineyards might receive less than 5 inches of rainfall
a year and almost no rain at all during the summer growing season.
In comparison to California and elsewhere, the postage-stamp-sized vineyards
of the Northeast may only represent a drop in the bucket for drip-irrigated
acres. The total acreage of Long Island’s vineyards, for example, would
fit into one California vineyard, according to the Long Island Wine Council.
Much of the Northeast’s vineyards, from upstate New York to Long Island,
Connecticut and elsewhere, are in countryside shaped by the Laurentian glaciation,
Pool says. The ice sheet, which stretched to the Atlantic, carved valleys and
dumped a patchwork quilt of soil types that hold different amounts of moisture.
And for this area, where rainfall generally averages 40 inches a year, water
is out of the control of farmers — and the problem is usually one of too
much water.
Nevertheless,
interest from northeastern winegrowers in drip irrigation has increased over
the past decade from “essentially none to quite a bit,” Pool says.
So far, he counts four established wineries in the Finger Lakes region in upstate
New York that have put in drip irrigation; he says that new wineries in that
area, which are increasing vineyard acreage by 20 percent a year, also intend
to use the technology.
Wine growers are now starting to
embrace drip-irrigation technology in the relatively wet northeastern United
States, such as at the Prejean Vineyard in the Finger Lakes region of New York.
Image courtesy Tom Prejean.
Bill Nelson of Wine America says that Northeast wineries can sell up to $70,000
per acre of bottled wine a year, in addition to bringing tourism to economically
depressed regions, and the number of northeastern wineries is exploding. “They
represent a phenomenally important farm product for the local areas,” he
says.
For such an industry, having a little bit of water insurance can pay off big.
In general, Lakso says, the Northeast has a much shorter growing season, with
ample water. Because the region tends to have cool, cloud-covered summers that
keep moisture in soils and plants, the effects of a drought may not be that
bad.
Some estimates, however, of drought severity for the Northeast over the past
century show that the region’s climate may be shifting. The driest historic
periods fell during the Dust Bowl of the 1930s and 1940s, and the 1970s were
abnormally wet. Since then, data over the past 30 years show that “droughts
are increasing, and some of the drought severity is increasing,” Lakso
says. He and his co-workers documented seven droughts with significant effects
on northeastern fruit crops in the past 16 years.
That unexpected
lack of water proved extremely stressful to the region’s grapevines, affecting
the quality of their grapes. Pool, Lakso and their co-workers conducted aerial
surveys of vineyards in the Finger Lakes region over a three-year period, gathering
high-resolution multispectral scans to determine soil nitrogen and moisture
content among other characteristics. They then tracked the wine made from the
harvested grapes.
Alan Lakso of Cornell University’s
New York State Agricultural Experiment Station in Geneva, N.Y., measures the
photosynthesis levels of grapevine leaves, in order to determine whether the
vines are stressed. Image
courtesy of Alan Lakso.
Overly stressed white wine grapevines, they confirmed, either lacking in nitrogen
or water, “produce grapes that initially seem fine. But after six months
to a year, the wines just seem to fall apart,” Lakso says. The wines suffer
from a condition known as atypical aging: “They lose their character, seem
stripped or unfinished, and pick up some off aromas, like furniture polish or
varnish,” he says. “In the worst cases, you end up with dirty dish
rag [aromas].” Stressed red grapes show fewer effects.
To maintain the consistent production of fine wine grapes and avoid extreme
stress, some northeastern wine growers are willing to invest the thousands of
dollars to install drip irrigation systems in their vineyards as protection
against dry times. For the typical hillside vineyard, Pool says, the technology
in the end “is cheaper; you don’t need as much water, and you can
be more precise about applying water.” Drip irrigation tubing might cost
pennies per foot, but installing it with all the emitters and connectors along
hundreds (or thousands) of yards of vines can add up. Some estimates place a
total system’s cost at $500 to $1,500 per acre.
“Wineries will do this because they’re more vulnerable,” Pool
says; without such precautions, they might end up with nothing to sell —
fields of grapes everywhere, without a drop to drink.
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