With Western drought as a backdrop, an OSU project grows crops without irrigation
By Eric Mortenson
CORVALLIS, Ore. — The squash plants’ leaves are wilted and crinkled in the mid-day heat, and look like they desperately need water. But unless it rains, they won’t get any.
In fact, they’ve never been irrigated since they were planted this spring. Neither have the zucchini, dry beans, potatoes, melons and tomatoes growing alongside them.
The vegetables are part of a dry farming demonstration project at Oregon State University’s Oak Creek Center for Urban Horticulture. In three 10-foot-by-100-foot plots, OSU Extension instructor Amy Garrett is examining the possibilities of growing food crops without irrigation.
It’s a topic under serious review as drought grips the West.
Hold the water
Irrigators throughout the Pacific Northwest and California have been restricted or shut off entirely this summer, the mountain snowpack that feeds streams in late season has already melted and many storage reservoirs are at alarmingly low levels.
Climatologists believe longer, hotter, drier summers and winter precipitation that falls as rain rather than snow is the “new normal.”
Beatrice Van Horne, director of the USDA’s Northwest Regional Climate Hub in Corvallis, said that will be the trend for the coming decades, although individual years may vary. “Those are pretty clear results” of climate modeling, she said.
Faced with that reality, some farmers and ranchers are thinking about making changes.
About 100 people attended a dry farming field day that Garrett hosted at her OSU demonstration plots in early August. She’d expected that 30 people might show up.
What they saw may have surprised them. Garrett is growing four varieties of dry beans, her Yukon Gold potatoes are producing about four pounds per plant and the squash, despite looking withered, have produced nice-looking Stella Blue and Blue Hokkaido varieties.
Then there are the Dark Star zucchini, which look as vigorous as if they’d been irrigated all summer. Planted May 27, they were in full production by early July. Garrett said she’s picked lots of “zukes” in recent weeks.
“It’s like a machine, a zucchini machine,” she said with an admiring glance.
The hit of Garrett’s field day, however, were the small, striped Little Baby Flower watermelons, which easily won a taste test.
“Across the board, they preferred the flavor, sweetness and texture of the dry farmed melon over an irrigated one of the same variety,” Garrett said.
Dry farming is not new, of course. Mediterranean growers have been raising wine grapes and olives without irrigation for centuries. Some California growers do the same, and the term “old vine Zinfandel” often refers to dry-farmed vineyards that are more than 75 years old, according to the California Agricultural Water Stewardship Initiative.
Other California crops that are sometimes dry-farmed include tomatoes, cantaloupes, garbanzos, apricots, apples, squash and potatoes, according to the group.
Pacific Northwest producers grow wheat and other grains without irrigation, but Garrett wants to see what else can be grown that way.
Many of the farmers interested in the project are relatively new to the profession or are just now venturing into commercial production. In some cases, they’ve leased or bought land, then discovered it did not come with water rights, or they are in a state-declared groundwater limited area and can’t sink a new well.
It’s not easy
Dry farming is not an easy option. Without irrigation, yield and size are almost certainly reduced, although quality remains good.
It requires altered techniques, revised expectations and the right conditions, starting with the soil. A layer of clay in the soil, common in Oregon’s Willamette Valley, holds moisture that plants can access during the summer. Dry farming is less likely to work on soil that’s sandy and porous.
Soil preparation, seed selection and the timing and method of planting are critical, Garrett said. Many of the seeds she planted come from varieties that are dry-farmed elsewhere. The Stella Blue and Blue Hokkaido squash come from a line originally developed by a Veneta, Ore., farmer who has been dry-farming vegetables for 40 years.
Dry farming calls for deeper planting and more space between plants to reduce competition for water. When planting, some farmers step on the seeded area to compress the soil and force water up from the clay level to germinate the seed. Garrett said she planted bean seeds four to six inches deep and transplanted tomatoes into holes up to a foot deep.
The technique can work, and small farms could certainly feed themselves with dry farming methods, but it’s not clear whether it can pay off commercially.
Dave Runsten, policy director with Community Alliance with Family Farmers, based in Davis, Calif., said the practice “flies in the face” of what supermarkets want and what agricultural universities have taught.
Big yields of big fruit and vegetables are favored by the market and researched at universities, Runsten said. Dry-farmed crops are smaller in both regards.
A place for dry
But he said there’s a place for it. Some California growers are tearing out avocado and orange groves because water is so expensive, he said, and dry-farmed wine grapes may replace them.
The practice may work in Western Oregon and Washington, which get plentiful winter and spring rain that could sustain some crops through a dry summer, he said.
Garrett, the OSU instructor, said it’s an open question whether dry-farming producers can break even.
“That’s the kind of research I’d like to do,” she said. “Does it make economic sense to grow things this way?”
The work is partially funded by the National Institutes of Food and Agriculture under its Beginning Farmer and Rancher Development Program. Oregon State’s Center for Small Farms administers the grant.