By Anne Marshall-Chalmers for Civil Eats.
Broadcast version by Suzanne Potter for California News Service reporting for the Solutions Journalism Network-Public News Service Collaboration

More than 20 years ago, Craig McNamara started planting woody vegetation on his family’s farm, west of Sacramento, California. McNamara was an early organic pioneer in the region, and he prioritized weaving nature into the agricultural landscape at a time when it was far from popular. Native shrubs and trees lined a creek that ran through the walnut farm. Plants became boundaries between orchards and row crops—i.e., hedgerows—and it didn’t take long for the 450-acre organic farm to come “alive,” says Craig’s son, Sean McNamara, who joined the operation in 2014. Bees, owls, ladybugs, and many other creatures still routinely visit the farm. Just a few weeks ago, a bobcat strolled through the bushes along the creek.

These above-ground benefits to hedgerows are easy to spot. But a few years ago, McNamara watched as a soil scientist dug into the dirt surrounding them. She scooped up rich, dark, compacted soil, mycelial strands tangled within. “I think we were in the middle of summer and the soil, even the topsoil, was moist,” he recalls. It was a memorable sight in drought-riddled California.

That scientist, Jessica Chiartas, was studying the soil around hedgerows. She selected a couple dozen farms in the Sacramento Valley, an area with plenty of well-established hedgerows thanks to a campaign initiated more than 20 years ago that sought to bring native vegetation back to local farms.

Chiartas’ study, published in late 2022, found that no matter the soil type, be it loam or clay, the soil below hedgerows stored significantly more carbon than the soil in the adjacent agricultural fields. While most of that carbon remained on the surface layer, an increase in soil carbon was detected down to the depth of 1 meter—where it’s more likely to remain. In fact, the study concludes that installing hedgerows on 50 to 80 percent of California’s farmland would capture so much carbon, it would help the state to reach up to 12 percent of its ambitious greenhouse gas reduction goals.

California farmers, who are contending with drought, flooding, and a long list of pests that can ruin fruits, nuts, and vegetables haven’t fully embraced planting native vegetation adjacent to fields. But as the state encourages and incentivizes climate-friendly agriculture practices, they might just start.

Hedgerows are straightforward strips of shrubs or trees roughly 15 feet wide, but they highlight nature’s complex work, says Chiartas. At the surface of the soil around them, “you have a buildup of litter: leaves, stems, dead insects, feces, whatever organic materials are deposited,” she explains. When it rains, the organic matter dissolves and moves deeper into the soil profile. That “litter layer” also protects soil temperature and moisture, creating a stable, thriving soil food web that pulls organic materials deeper into the ground. “We’re not fighting biology,” she says. “It’s efficient.”

Recognizing that, the USDA’s Natural Resources Conservation Service (NRCS) offers a program to farmers nationwide that provides technical assistance and some funding for hedgerow planting, and Xerces Society for Invertebrate Conservation has also focused on the expansion of pollinator habitat, including hedgerows. Individual states including Minnesota and Iowa have also encouraged the planting of native vegetation in the form of prairie strips.

Chiartas jokes that she’d like to start a campaign to “re-hedge California.” With millions of agricultural acres, she sees potential in otherwise long stretches of empty perimeter. “All these field edges are bare right now,” Chiartas says, adding that because hedgerows stay in place, the carbon benefits would last well into the future. “It’s a proxy for the potential of agroforestry,” she says. “We need shade in California. Not just for carbon sequestration but for farm laborers.”

During her research, growers told Chiartas farmworkers often gravitate toward the rows of native plants, including California redbud, Manzanita, or Blue Elderberry trees for a break. And she, along with others who prioritize conservation, applaud a farm system that can expand its scope beyond merely growing food to creating space for all living things.

A Woody History

Hedgerows have been planted in farming and rural landscapes for thousands of years. According to Sam Earnshaw, a longtime sustainable farming advocate who helps growers establish hedgerows through NRCS, ancient hedgerows drew property lines, confined livestock, created windbreaks, and even provided food and medicine. The industrialization of farmland in Great Britain, though, led to the removal of about 200,000 miles of hedgerows between the late 1940s and early 1990s.

In the U.S., efforts to introduce natural vegetation to agricultural land took a “huge hit,” Earnshaw says, in 2006, the year a serious E. coli outbreak was linked to fresh spinach grown in California’s central coast region. The outbreak sickened more than 200 people and caused three deaths.

“Since then, there has been tons of pressure on growers to do everything they can to keep wildlife off of their fields,” explains Daniel Karp, an associate professor at U.C. Davis in the Department of Wildlife, Fish, and Conservation Biology. “So, that’s meant killing all kinds of wildlife—putting out snap traps and rodenticides along field edges to kill off rodents.” It also often meant removing hedgerows.

Although a USDA investigation wasn’t able to definitively determine how E. coli wound up in bags of baby spinach, the outbreak strain was linked to specific fields where river water, cattle feces, and wild-pig feces all contained the bacteria. A grass-fed cattle operation was located on the ranch, less than a mile from the spinach field.

In the five years following the outbreak, a study found that 13 percent of the plants and trees growing along rivers in one of California’s leading produce-growing regions were eliminated out of fear that they would provide habitat for wildlife carrying pathogens. And a few years later, Karp says, a survey of California produce growers found that 40 percent were still removing habitat even a decade later.

Karp says it’s an understandable, albeit misguided, practice. A 2015 study co-authored by Karp found that, contrary to popular assumptions, the clearing of vegetation has been associated with increased prevalence of foodborne pathogens over time. “Shrubs, grasses, and trees (are) a well-known filter for nutrients and pathogens,” says Karp. “So, you might be able to prevent [pathogens] from getting onto your farm field by having those buffers.”

Karp’s research has also found that smaller, more diverse operations tend to attract species of birds that are less likely to carry foodborne pathogens, unlike monoculture operations that are more likely to have flocking birds that can deposit potentially harmful bacteria on produce.

Karp says many growers he speaks with acknowledge the benefits of hedgerows or riparian habitat, but companies who buy fresh produce often won’t engage with growers who have incorporated plants and wildlife into their operations.

This, says Chiartas, has led to a “scorched earth” mentality for those who grow produce that’s consumed raw. Karp notes, however, that the Food Safety Modernization Act signed into law in 2011 does not advise removing habitat. “The leverage point is definitely going to be big industry buyers and their auditors, and to really convince these folks that the science doesn’t support this idea that habitat removal is effective,” says Karp.

That Bustle in Your Hedgerow? Biodiversity.

About 30 years ago, Rachael Long, a farm advisor with the U.C. Agriculture and Natural Resources (ANR) began preaching the power of hedgerows to farmers in the Sacramento Valley. She eventually followed her own advice and planted a half-mile stretch of redbud, coyote brush, toyon, and other native California species at the edge of her tomato and wheat farm.

Years later, she delights in walking past the various flowering plants. Doves and white-tailed kites sing. Come fall, her coyote bush hums with bees, flies, and other insects. Research shows native vegetation attract critters that can help devour pests harmful to crops. For example, a recent study showed that walnut orchards with hedgerows or riparian edges had more avian predators, like the white-breasted nuthatch and woodpeckers, gobbling up harmful codling moths, than orchards with only weeds growing. The more natural, woody vegetation, the more moth consumption occurred.

Long says that while many farmers have resisted planting hedgerows on their land out of fear the trees and shrubs would only draw harmful pests, studies have shown the opposite to be true. Several years ago, she and other researchers collected bugs in hedgerows during growing seasons over two years and found that 78 percent of the insects were beneficial, while only 22 percent were considered pests. “Hedgerows do bring in more natural enemies like ladybugs and parasitoid wasps that do move into adjacent crops,” she says. Her research has also shown that farmers who have hedgerows don’t have to spray as many insecticides as those farmers who have no habitat around their farm.

Insect biodiversity can also encourage more effective pollination in orchards, Long says, because more wild bees throw honeybees off their vertical, methodical paths. “The honeybee will kind of forget what it’s doing, and it will cross over rows; you get better pollination that way.”

Though establishing hedgerows can cost thousands of dollars, and, at least in the first few years, requires a dedicated water source (a big deal in parched California), Long’s research has found that once the habitat is established, the pollination and pest control that’s provided result in a return on investment that lasts between seven to 16 years.

The Importance of Incentives

In an effort to encourage growers to plant native vegetation, ANR is leading a project that’s exploring the potential for a commercial market for elderberry plants as hedgerows. And the state’s Healthy Soils Program (HSP) offers grants to fund a variety of climate-friendly agricultural practices, including planting hedgerows. Over the last five years, compost application has proven to be the most popular, making up about 70 percent of the incentive grants, while only 16 percent of funding has gone to hedgerows.

Judith Redmond is one several founders of Full Belly Farm, 50 miles northwest of Sacramento; she and her co-founders have been using regenerative, organic farming practices for nearly 40 years. She’d like HSP to push hedgerows as a more attractive option, particularly in terms of carbon sequestration, even though planting them can be more labor intensive in the short-term than applying compost. “Compost has to be trucked around. It might not be as beneficial as hedgerows or cover crops,” she says.

Still, the HSP grants have enticed conventional and organic growers like Don Cameron, vice president and general manager of Terranova Ranch, a large, mostly conventional ag operation outside of Fresno that grows processing tomatoes, carrots, onions, nuts, and other crops, planted a half-mile hedgerow three years ago with an HSP grant.

Cameron has since noticed the presence of wild pollinators, as well as “hummingbirds all year,” he says, and around the hedgerows there’s stability in his otherwise sandy soil. “What we’ve found where we’ve done it is that we have no erosion,” he says. “There’s a lot of erosion without habitat established.”

Since receiving the grant, he’s worked with NRCS and other organizations to plant about two more miles of hedgerows. And he plans to put in another seven miles with funding help from the large companies he sells his produce to, including Nestlé. “We’re seeing major food companies wanting to promote increased sustainability on farms,” he says.

Cameron is well-known in California, particularly for his work around on-farm water recharge. He says that in a stretch of the San Joaquin Valley that is often dusty and void of natural vegetation, his hedgerows have gained attention. Other growers have taken notice and they’re curious about the more than 20 plant varieties that bloom around his crops.

If it works, this type of farmer-to-farmer education may help the state achieve Chiartas’ goal of re-hedging California and pulling more carbon into the soil at the same time. For now, though, Cameron can’t ignore the simple pleasure that comes from simply growing a wider array of plants. Hedgerows are “aesthetically pleasing,” he says. “I like that.”


Anne Marshall-Chalmers wrote this article for Civil Eats.


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Wisconsin is the first state in the country to run its conservation programs by county rather than by district.

One conservation advocate said Wisconsinites may not realize this - or know how it benefits them.

Matt Krueger is executive director of the Wisconsin Land and Water Conservation Association, which represents all 72 counties across the state.

He explained the county conservation model is unique to Wisconsin. It allows for more diverse funding opportunities - and speaks to the state's innovative DNA.

"Wisconsin has a long history of being an innovator in many different topics, you know - politically, but with conservation, too," said Krueger. "Everybody's heard of Aldo Leopold, of course, and John Muir and Gaylord Nelson, and we have this rich history of conservation in the state."

Every county has a Land and Water Conservation Department to help land and business owners, farmers, and waterfront owners solve complex conservation problems and implement effective practices.

In 2025, the state is investing more than $11 million to support staffing for these departments.

Krueger said those staff members are then able to leverage additional funds for conservation projects - unlike district models that are more limited.

He said tapping into funding from state and federal grants and private organizations can often amount to a two-to-one return on investment.

"These professionals, they come in," said Krueger, "they listen to what these private landowners need, they listen to what their management and their business goals are, and they essentially open up this toolbox of conservation tools."

He added those can include project planning, partnership development and connections to additional resources - all to help counties better focus on meeting their own needs, which vary greatly based on size and location.

Consumers are unhappy with increasing food prices and blame inflation. In reality, natural disasters have a direct link to grocery costs, with no end in sight.

Climate change affects Illinois farms, especially drought. The weather extremes lower their livestock's productivity, raising the price of dairy and meat products.

Michael Stromberg, spokesperson for Trace One, a food and beverage regulatory compliance company, said the effects of floods, hurricanes, drought and extreme heat have a nationwide and global impact.

"The price of oranges and the price of orange juice have both steadily increased in recent years due to declining production in Florida caused by large hurricanes," Stromberg outlined. "Grain prices are through the roof in critical agriculture regions like the Midwest. It starts with drought. It affects a huge portion of agriculture in that region that has an aftereffect at the grocery store in terms of your grocery prices."

Illinois ranked 10th in the Trace One study of all 50 states where natural disasters have the biggest impact on the nation's food supply. Losses were mostly due to drought in Henry, Sangamon, Lee, Logan, Bureau and Mason counties.

Stromberg argued innovation is needed to solve these dilemmas. One solution is to develop and
distribute climate-resilient crops capable of withstanding extreme droughts and floods. Other strategies are to implement effective water resource management systems and invest in flood control measures alongside restoring natural buffers. Wetlands and watersheds will act as sponges to help mitigate the dangers of excessive rainfall. He added more answers can take on a scientific tone.

"Farmers can use newer precision agriculture technologies like IOT sensors, drones, advanced analytics that can allow farmers to better monitor weather patterns, things like soil health and their water usage, which can optimize resources better," Stromberg explained.

He urged the public to vote for policies prioritizing renewable energy, water conservation and sustainable agriculture to drive "incremental improvement," and for the public to reduce their food waste. Another Trace One study found Illinoisans lost slightly more than $1,900 per household, or $766 per person from food waste last year.


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By Seth Millstein for Sentient.
Broadcast version by Freda Ross for Texas News Service reporting for the Sentient-Public News Service Collaboration

Another day, another E. coli outbreak. In the last half of 2024 alone, E. coli has been found in ground beef, carrots, onions, walnuts and cheese, causing at least 186 illnesses, one death and several recalls. Why is E. coli popping up left and right — and what do these outbreaks have to do with factory farms?

The answers to these questions, respectively, are “we don’t know” and “a lot.” Harmful E. coli is produced primarily in the guts of ruminant animals, such as cows, sheep, goats and deer, and as a result, it’s often found in beef. It can easily infect other foods as well — but even when it does, beef production and cattle farms are often still the ultimate source of the contamination.

This can play out in several ways, but it’s important to note at the outset that there’s still a lot we don’t know about E. coli transmission. Often, researchers can’t identify with certainty the original source of contamination, and can only speculate on the path it took to reach whatever food it ultimately infected. The bacteria itself also changes and adapts over time, complicating these post-outbreak analyses even further.

“With many of the outbreaks, [investigators] cannot find the source of the infection,” Alfredo Torres, professor of microbiology and immunology at the University of Texas Medical Branch, tells Sentient. “There are all sorts of contaminations that we have no idea where they’re coming from.”

What Is E. Coli?

E. coli, or Escherichia coli, comes in many different varieties. The majority of them are harmless, and some serve important purposes in the human body, but there are six subvarieties of E. coli bacteria — often referred to as “The Big Six” — that can cause illness in humans.

In the United States, most E. coli outbreaks are caused by the strain O157:H7. This strain belongs to a group of E. coli subtypes called Shiga-toxin producing E. coli, or STEC. As the name implies, the STEC varieties of E. coli produce a toxin called Shiga, and when we talk of humans becoming sick with E. coli, it’s usually the Shiga toxin that’s responsible for causing the actual illness.

While there’s a lot that scientists still don’t understand about STEC, it’s believed that the bacteria’s initial development must take place in the intestinal tract of certain non-human animals, namely cows and other ruminants. From there, it can spread to humans in a number of ways, but to the best of scientists’ current understanding, it can’t develop in the first place without a ruminant’s gut.

Humans contract harmful E. coli strains by eating contaminated food and or water, interacting with infected animals or people, or coming into contact with feces with E. coli in it. It can be highly contagious; in 1993, a sixteen month-old boy died from E. coli after coming into contact with the stool of a classmate who had the disease.

Although this was an example of human-to-human transmission of the bacteria, it still began with a cow: The classmate’s mother worked at Jack In The Box, the source of the outbreak.

E. coli can produce a variety of symptoms. When it infects the large intestine, it can result in diarrhea, vomiting, nausea, stomach cramps and loss of appetite; when the bacteria is in the urinary tract, it causes pain during urination, cloudy urine and abdominal or pelvic pain.

Although most people who become sick from E. coli recover within a week or so, some patients develop serious and life-threatening conditions, such as haemolytic uraemic syndrome (HUS) and sepsis. Studies on the mortality rate of E. coli infections have come to a wide range of conclusions, from eight percent on the low end to 35 percent on the high end.

Where Does E. Coli Come From?

E. coli lives in many places, but the “Big Six” subtypes that sicken humans are all found primarily in the bodies of cattle, Torres tells Sentient.

“The bacteria can actually grow in the rectal anal junction of these animals without causing any disease, or any symptoms, or anything,” Torres says. “So when [the cows defecate], the fecal matter is contaminated with this organism, and anything that gets in contact with the manure, or water contaminated with the fecal matter, can get contaminated with the bacteria.”

Historically, E. coli outbreaks in the United States came from tainted beef, Torres says. The O157:H7 strain was first discovered in 1982, when 47 people contracted it after eating contaminated burgers from McDonald’s. The 1992 E. coli outbreak, which killed four people and sickened over 500, also originated from beef patties, this time from Jack In The Box.

The Jack In The Box outbreak received significant media attention and became something of a national scandal. In response, the USDA subsequently implemented a number of regulations to prevent beef from being contaminated with E. coli, and fast food restaurants implemented operational changes, such as separating beef patties with tongs instead of bare hands, in an attempt to accomplish the same.

These changes did reduce the frequency of beef-originated E. coli outbreaks, Torres says, but they didn’t put an end to the outbreaks entirely. The harmful strains of E. coli may originate in a cow’s gut, but they can survive in other environments as well. And thanks to this resilience, E. coli has the ability to infect plenty of foods other than meat.

How Factory Farms Cause E. Coli Outbreaks

Given E. coli’s affinity for cow intestines, it’s no surprise that cattle farms and slaughterhouses are often the source of E. coli outbreaks. Typically, this happens when E. coli in the cow’s gut cross-contaminates the rest of his or her body during the slaughtering process, and ends up in the resulting beef.

But because E. coli is found in manure as well as the body, anything that comes into contact with manure is also liable to be infected. This includes water — and unfortunately, it’s not uncommon for manure from cattle farms to make its way into nearby waterways. (The disease can also spread via human waste in waterways, but only if the human in question had already contracted E. coli).

There’s good reason to believe that this leakage, or runoff, contributes to the spread of E. coli. A 2023 study found that water samples taken from sources within a mile of factory farms had higher concentrations of E. coli than those located more than five miles away from said farms.

This year, an FDA study found that waterways contained a higher prevalence of STEC stains of E. coli in particular when they passed by factory farms. This occurred even when there was no apparent runoff from the farms to the water, leading researchers to speculate that the bacteria latched on to dust from the farms and traveled to the water via the air.

Complicating matters further is the fact that E. coli can also live in the leaves of certain vegetables. This was evident in 2006, when tainted spinach caused a massive nationwide E. coli outbreak that killed three people, sickened over 200, and depressed spinach sales for over a year.

The Spinach Outbreak: a Case Study in Uncertainty

The spinach incident is a good illustration of how E. coli outbreaks occur — and of why even vegetable-based outbreaks can often be traced back to meat production.

“That was the first time we learned that somehow, the bacteria is able to survive in leaves of spinach,” Torres tells Sentient. “If you use a microscope and you look inside of a leaf, there’s an area called the stroma, and you can actually find the bacteria attached to that area.”

The fact that E. coli can survive within the biological structure of spinach itself, as opposed to simply living in water on the surface of spinach, means that washing contaminated spinach isn’t sufficient to rid it of the bacteria.

Subsequent investigations of the 2006 outbreak found that the contaminated spinach originated from a single grower in California, and investigators were even able to trace it back to a specific ranch in San Benito County. That ranch was located next to a cattle farm, and manure and river water from the cattle farm was later found to have the same strain of E. coli that contaminated the spinach.

But incredibly, despite all of these findings, investigators weren’t able to determine precisely how the spinach became infected in the first place. They speculated that tainted river water could have made its way into the well that irrigated the spinach fields, or alternatively, that a wayward cow or pig might have inadvertently transferred the bacteria from the cattle farm to the spinach.

Nevertheless, a spokesperson for the California Department of Health said at the time that “we’ll never be able to make a definitive link” between the cattle farm and the spinach ranch.

The whole episode encapsulates an unfortunate truth about E. coli outbreaks: we often don’t get a full picture of how exactly they unfolded. We know that the disease originates in the stomachs of cows and a few other species, but the path it takes to infect humans is often impossible to fully understand.

Take the recent McDonald’s outbreak. Contaminated onions are believed to be the culprit here — but how did they get contaminated in the first place?

The short answer is that we don’t know. In an interview with Sentient earlier in the year, public health expert Sarah Sorscher said that the onions were “probably being processed in an environment with ground beef or some other high-risk food” that already had E. coli. Torres, meanwhile, suggests that they may have been contaminated via tainted water.

But these are merely guesses — educated guesses, to be sure, but guesses nonetheless. As of this writing, the precise manner in which the onions and carrots became contaminated with E. coli is unknown, and it’s entirely possible that it will never be known. Such is the nature of E. coli outbreaks.

But one thing is for sure: eventually, it always comes back to poop. And factory farms present the perfect opportunity for this poop to make its way into drinking water. Manure from these farms is typically stored in enormous outdoor lagoons, which can — and do — easily leak into nearby waterways.

How Can We Prevent E. Coli Outbreaks?

The federal government has taken a number of steps to lessen the risk of E. coli outbreaks. The Food Safety and Inspection Service (FSIS) of the USDA tests random samples of raw beef for E. coli before they’re sent to restaurants or retailers, and conducts regular inspections of produce farms.

But the government can’t test every piece of spinach or beef before it’s sent out into the world. The ambiguous and confusing nature of E. coli spread means that ultimately, it’s on individual farms to implement and follow best practices that can help stem the prevalence of outbreaks.

Some of these practices are mandated by the government, while others have been developed and voluntarily adopted by producers. Since 1996, the FDA has required meat and poultry producers to implement an inspection system called HACCP, or Hazard Analysis and Critical Control Points, to catch potential contaminations before sending their product to distributors.

But these kinds of rules are only effective if agricultural producers abide by them, and sometimes they don’t. The processor of the tainted spinach behind the 2006 outbreak, for instance, hadn’t been following its own water-inspection policies in the month that the tainted spinach was processed, a subsequent investigation found.

The FDA can warn, fine and even shutter facilities that ignore food safety practices. But much of the time, this only happens after there’s been an outbreak. In 2017, the FDA shut down Dixie Dew Products after discovering numerous food safety violations at its production facility — but only after the company’s soy nut butter gave E. coli to 29 people, nine of whom developed kidney failure as a result.

The Bottom Line

E. coli is something of a moving target. The ways in which it infects food still aren’t fully understood, and the government has at times been slow in implementing policies to reduce the frequency of outbreaks (the FDA only rolled out comprehensive safety rules for produce in 2016, for example). The fact that the bacteria keeps popping up in new foods creates yet another challenge.

One thing is clear, however: Industrial animal agriculture, and cattle farms in particular, are central to the spread of E. coli. While operational and regulatory steps can be taken to reduce the risk, E. coli’s prevalence on cattle farms is an unavoidable and intrinsic consequence of how the cow’s digestive system works. As long as we’re farming cattle for food, we’re going to be dealing with E. coli.


Seth Millstein wrote this article for Sentient.


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