Dry Farming for a Drought Resilient Future

Plus, a Carbon Capture Bonus

 It is a rainy time of year to be thinking about drought. But, as most Northwesterners know, there are wet winters and dry summers here. As climate change revs up, our summers are becoming increasingly drought-prone, triggering urgency to develop new ways for our communities to adapt.

Abnormally Dry
Statewide, precipitation was reported at 85 percent of normal in the Oregon Water Resources Department’s monthly Water Conditions Report released on February 11. The report also stated that stream flows for the month were up to 100 percent of normal, after December’s alarming statistic of 53 percent of normal. In addition, the most recent update to the US Drought Monitor now indicates that almost 90 percent of the state is experiencing abnormally dry conditions, with almost 23 percent listed as in moderate drought.

Drought can be defined as any time there is insufficient water supply to meet the demands of human and natural systems. For many, the summer of 2015 stands out. This drought was caused due to an unusually warm winter where more rain fell than snow, followed by an unusually warm and dry summer. In western Oregon, snowpack was 60 to 90 percent below normal, and since so little fell, it didn’t take long for it to melt.

Usually, May and June are periods of time with significant increases in streamflow due to snowmelt, but in 2015, streams were at their baseflows as early as April and May.

Statewide, 25 of the 36 counties in Oregon made emergency drought declarations. Locally, Benton and Linn County agricultural communities were greatly impacted. Fruit crops struggled and were damaged by sun-scalding, while junior water right holders had their irrigation shut off early in the growing season to conserve water for those with senior rights – generally impacting smaller growers more than the older, larger operations.

The challenges posed to food producers during the growing season were often overwhelming. With heat wave after heat wave, many were surprised to learn that research trials had begun in Oregon State University Extension Services’ Small Farms Program that were purposefully growing crops without any irrigation at all.

OSU’s No Irrigation Experiment
“If I had known that in April or May, when I was planning [this experiment], I would’ve thought, ‘I’m not going to [do] that this year, maybe I’ll wait until next year’,” recalls Amy Garrett of the Small Farms Program in Benton, Linn and Lane Counties.

She had been working up to get this study going in the Willamette Valley after at least two years of conducting case studies of California farmers who grow produce without the use of irrigation. With no way of knowing how bad the growing season would be, 2015 had been penciled in as the year to test these techniques locally. “Even though that was our first year doing it,” she says, “we actually had crops [survive] to look at in August.”

That month, Garrett and her team hosted a demonstration at their research plots at Oak Creek. “I anticipated maybe 20 or 30 people to come to that field day, but more than 100 did,” Garrett says. “The drought year startled people and made them curious… Even people with water rights were thinking ‘okay, how do we adapt and how do we continue to be viable economically, to still grow food for our families, with the uncertainty of climate change?’”

According to Garret, the biggest question participants had at that first demonstration day was, “’So how are these crops growing without water?’”

“And the answer is they’re not growing without water, they’re growing without irrigation, and we’re using these practices to conserve moisture from the winter rain for summer crop growth.” This is the crux of dry farming: that food can successfully be grown without the additions of water that our society is so accustomed to.

“I think it’s kind of mysterious to people what’s below ground,” Garrett says. “They can’t really see the plant roots accessing water. They can see that the surface is dry, but they can’t really see what the roots are doing. That’s what we’re hoping to demystify in our research.”

Intro to Dry Farming
As Garrett described, dry farming is a technique in which water in the soil, stored from winter rains, is utilized to produce crops during the summer dry season. This method is generally considered doable in any region that receives 20 inches or more of annual rainfall.

Thinking in historic terms, this is how most farming has always occurred. “Before the rise of dams and aquifer pumping, this is how people farmed,” says Garrett. “People that had been living on land historically were farming within the constraints of their natural environment.”

While it is believed that agriculture developed at multiple times in multiple areas, irrigation is often credited first to the Sumerians, who lived in the southeastern corner of the Fertile Crescent (present-day Iraq), and began more intensive forms of agriculture around 5,000 BCE that wouldn’t look unfamiliar to us today.

However, even after irrigation practices began, some crops continued to be dry farmed. For example, in the Mediterranean region, crops such as olives and grapes are commonly dry farmed, and in some regions of Europe, it is illegal to irrigate wine grapes during the growing season – the idea being that adding water dilutes the quality of the grapes.

While dry farming is not a yield maximization strategy, the improved quality of the crop can be attested to. The famous California wines that won the 1976 Paris Wine Tasting were all dry farmed.

Plus, for newer farmers with junior or no water rights, any yield is better than nothing.

Unique Techniques
For non-irrigators, it is extremely important to grow crops and crop varieties with a known history of being successfully dry farmed. With this in mind, Garrett’s research is focused on potatoes, tomatoes, squash, beans, corn, and melons.

Perhaps not coincidentally, these crops also have a history in the development of agriculture in the Americas. Along with maize (corn), it is thought that many of these plants were first domesticated around 3,000 BCE, with no known irrigation in place.

Garrett explains, “We’re not dry farming lettuce or broccoli.” Instead, crops and varieties of crops being planted “have a physiological trigger that allows them to go a little dormant — they kind of lay low in these extreme events instead of wither and die.”

The dry farming growing season could be said to start with the preparation that begins right after last year’s harvest. In the fall, cover crops such as grasses, grains, legumes, and brassicas are planted to prevent erosion during winter storms and to add nutrients back into the soil. In the spring, these are mowed down after reaching about knee height.

In comparison, most irrigators will let their cover crops grow as much as four feet high before mowing to get the most nutritional benefit to the soil, but at that height, the crops suck out a lot more water from the soil.

Once the ground is dry enough, the clippings from the cover crop are worked into the soil to add organic matter. In May, planting begins, with wider spacing than is used with irrigation in order to decrease plant roots’ competition for water.

If it gets hot and dry early on in the season, further thinning may take place to lessen this competition even more. Another option for farmers during early season droughts is to apply mulch to the soil surface to prevent water from leaving, or to utilize shade cloth. All these are tools that “comfort [the plants] in their time of stress,” says Garrett.

After planting and any management needed to respond to changing environmental conditions, dry farming is somewhat hands-off compared to other forms of farming. Because irrigation is not used, lines don’t need to be set up and maintained, and weeds are often less of a nuisance. A lot of the labor expenses happen up front while the plants are getting established, then at the end of the season when harvest begins around August.

Then it’s back to site preparation, which cannot be emphasized enough.

Carbon Storage
Some sites simply won’t be successful with dry farming if the soil is not conducive to holding water. The best soils for dry farming are silty loams, whereas sandy soils drain water. While over time soils can be made more amenable to dry farming, it requires long-term, thoughtful planning.

In addition to cover cropping, another option to add organic matter that helps the soil store more water is to rotate crops with livestock. Also important to building up high quality soil is minimizing its disturbance – for example, the number of times a field is run over by farm machinery, or how often it is tilled.

The strong focus dry farming requires on maintaining soil health to improve water storage has other valuable benefits, one of which is carbon storage. In the light of climate change, this agricultural method has the ability to lessen the demand on water resources expected to decrease in availability, as well as to mitigate other negative impacts to come.

OSU Research
At the core of the OSU Extension’s research into dry farming is the goal of aiding local farmers who are interested in taking up the method on their own land.

One way this is being done is through the variety trial process itself.

“We’re engaging lots of growers, mostly farmers, but some gardeners, in participating in variety trials across [about] 30 soil types,” Garrett says. “Then we compile our data and can see ‘okay this variety did good on 8 of the 10 sites,’ or ‘this variety didn’t do good on any but this one site.’ So over time we can understand that in our region it looks like this shorter list of varieties has a history of successfully being dry farmed on the sites that we’re trialing on.”

The clearest result gleaned so far is not just that some crops and crop varieties do better than others, but that success in dry farming is very site specific.

“Different soils, different microclimates, different management systems, different scales — all these things effect how well things do,” says Garrett. “What works on one farm doesn’t necessarily work as well on another farm, but… based on their markets, their customers, and their specific area, [each farm] is identifying in the trials we’re working on [with them] which things they want to expand on”

In a more focused site suitability study, soil moisture sensors are deployed, five feet long soil cores are taken, and crop yield is measured at a range of locations on OSU and farmers’ properties across the state. In the end, the results will allow for evidence-based counsel to be given to growers new to dry farming on whether or not their site may be successful using the technique.

In another study by Alex Stone, dry farmed winter squash storage rates are compared to irrigated winter squash, with the findings showing that dry farmed winter squash stores longer. These results are persuasive for farmers on the fence with trying dry farming; in addition to the water and labor expenses they won’t have to pay for when dry farming more of their acreage, they may also be able to tap into a new market in the winter when less produce is generally available.

When all of these and other research trials wrap up, the leftover crops are used in outreach efforts such as comparative tastings, are sold as a means to fundraise to buy next year’s dry-farm specific seed varieties to test, and are provided to community members who rely on the food bank.

The Dry Farming Collaborative
Following the success of the 2015 dry farming demonstration, the Dry Farming Collaborative was established in 2016 as another means for locals to explore the method.

DFC operates through annual winter meeting and growing season demonstration days, and through informal communication via their website and Facebook pages. In all settings, the goal is to share and learn about members’ approaches to dry farming on their own properties, whether they are taking part in official research trials with OSU Extension or experimenting at their own pace.

“A lot of people… hesitate to participate in a formal research project that’s maybe too much of a commitment,” Garrett says, “but they can still attend the winter meeting or come to a field day, or ask questions to the Facebook group. We’re just trying to provide platforms for knowledge exchange.”

In addition to commercial growers, DFC members include non-commercial or hobby farmers, home gardeners, school garden managers, and agricultural professionals. In taking an inclusive, bottom-up approach, Garret explains that the DFC strives to “engage people at different parts of the food system to learn how we may collectively adapt to less water.”

Whether it be a grower that took part in official research trials or not, “a lot of people that are interested in dry farming, and are continuing to dry farm, don’t mind experimenting, don’t mind failing,” Garrett explains. “They aren’t risking a huge amount by, say, dedicating a quarter-acre of their 10-acre farm [to] trialing some of these things.”

This kind of innovative attitude and hands-on approach of the DFC has inspired another offshoot: the Dry Farming Institute, established in September of 2019. This new non-profit strives to build upon and expand DFC’s efforts.

How to Dry Garden
Home gardeners who wish to take on the practice of dry farming can do so if they are aware of several key points.

Since it is important to decrease competition with other plant roots, plants must be spaced more widely than is typical in the standard veggie plot. In addition, the use of raised beds won’t work well, since they have a greater surface area exposed to air that dries the soil out.

While these may be downfalls, results from the OSU Extension 2016-2018 variety trials are available online, and are one of many great resources that can aid in determining how to maximize limited gardening space without using irrigation. The varieties tested and their seed sources are all included in this report, so that readers may easily order their own dry farming seeds via referenced catalogs or other means of seed distribution.

“If people want to base their decisions off of productivity,” says Garret, “they can say ‘okay, looks like [the variety] Early Girl was a good fit, I’m going to try one tomato dry farmed this year, and it looks like North Georgia Candy Roaster was the highest yielding squash, so I think I’ll try a couple of those, and Dark Starred Zucchini is definitely a high yielder too.’”

While this may sound like a list of nicknames rather than hard data, these results and their availability to the public make dry gardening in your own backyard an accessible endeavor.

How to Support Dry-farmed Produce
While not everyone is graced with a green thumb or has the space and time required to grow their own food without irrigation, there are many other ways to support this water-saving practice.

In the future, The Dry Farming Institute will have a directory of dry farmed produce on their website. “In the meantime, look for dry farmed produce at your local markets and inquire about dry farmed produce with your local farmers and markets,” Garrett advises.

“The Dry Farming Collaborative Facebook group is open to the public and could also be a place to inquire about dry farmed produce,” Garrett continues. “For example, ‘I live in Portland and am looking for 50 pounds of dry farmed tomatoes.’ This kind of inquiry would get multiple responses in late summer.”

As the rain continues to pour in these winter months, keeping these tips in mind for another dry season or potential drought may help our community build resilience in the face of climate change.
By Ari Blatt

Do you have a story for The Advocate? Email editor@corvallisadvocate.com