It's the dirt, stupid
It's always good to remember and every once in a blue moon, people realize that the health of a farm depends on the health of its soil ...wmh
'Centers of Insurrection': Central Valley Farmers Reckon With Climate Change
"Reckoning in the Central Valley" is a collaboration between Bay Nature magazine and KQED Science examining how climate change is laying bare the vulnerabilities of California agriculture.
On an average day on the Burroughs farm outside of Denair, about an hour’s drive southeast of Modesto, you might witness the surprising sight of cows wandering amidst the almond trees. Chickens might peck their way by. And most definitely there will be plenty of free-spirited birds and bees and insects flickering across the scene, not to mention flowers and grasses unbound on the ground, making for a thick undermat amidst the rows of trees.
This scene on the eastern edge of the Central Valley in remote Stanislaus County is almost jarring, so unlike any of the other almond groves in the area, which are mostly barren of undergrowth — the telltale sign of herbicides like glyphosate sprayed abundantly in these parts. But here at the Burroughs Family Farm is an outpost of what Nina Ichikawa, director of the Berkeley Food Institute at UC Berkeley, describes as “centers of insurrection” spreading slowly but steadily across the Valley — test cases in how to cope with the instability of climate change.
The climate in the Central Valley is, like that in other food-growing regions of the earth, bouncing on an unpredictable axis — rising temperatures, followed by drought, followed by heavy rains, followed by intense sun, followed by ferocious winds, and then again, though not necessarily in that order. Such volatility presents a particular challenge to the crops that have swept through the Valley over the last decade — namely, almonds and other tree crops.
'Because we’re concentrating on soil health, we’re set up to be much more resilient.'Ward Burroughs, Burroughs Family Farm
In a time of unprecedented changes in growing conditions, trees can’t move. You just can’t pack up an almond orchard and head somewhere with your trees.
“It’s bonkers right now with nuts in the Central Valley,” said Charlie Brummer, director of the Plant Breeding Center at UC Davis. “Two issues: Their genetic diversity is very low and they are less adaptable to climate changes.”
Burroughs and other such centers of insurrection are offering us something like an experiment in real time, to see what kinds of agriculture will survive the accelerating stresses being wrought by disequilibrium in the atmosphere. In the decade before 2017, according to the USDA, the number of acres devoted to organic agriculture nearly doubled, to 58,486 acres, in four of the Valley’s largest counties — Merced, Tulare, San Joaquin and Stanislaus. That’s tiny when compared to the five million-plus acres under cultivation in the Central Valley, but it’s steady and it’s growing.
Rosie and Ward Burroughs, of Burroughs Family Farms in Denair, stand in the cover crops in their organic almond orchard. The cover crops will soon be mowed down in preparation for the harvest. These plants and grasses under the almond grove bring a variety of microbes to the soil, which enhances the health of the soil and growth of the trees. (Lindsey Moore/KQED)
Growing a Stronger Tree
The Burroughs Family Farm supports three generations of Burroughs with a combination of organic almonds, cheese, olive oil, chickens, turkey, beef and pork, and a few vegetable crops.
Ward Burroughs and his wife, Rosie, were farming conventional until about 15 years ago, when they started transitioning to organic. They saw that, as Ward put it, applying the cocktail of chemicals required for conventional almond farming “meant destroying biology someplace, above or below the ground.”
In a test plot, their organic almond trees seemed stronger than the conventional trees, Burroughs told me. He noticed that a troublesome pest, the mite, attacked conventional trees more consistently than organic trees — which he surmised was because pesticides killed the mite’s natural predators. So the couple withdrew several hundred acres from cultivation for three years to cleanse the land of chemicals, and began planting new trees block by block. In 2009, the USDA certified the orchard as organic.
The scene on the Burroughs farm could not contrast more with the almond orchards that surround it, and which spread for miles in every direction. The ground under his trees burst with life — wildflowers and cover crops like radishes and mustard plants (good for bees), and grasses like rye, foxtails and philaree, all of which are excellent sources of nutrients and help sustain microorganisms in the soil.
“When we quit spraying herbicides,” said Burroughs, “the ground just springs up — grow, grow, grow.”
The land serves not only to grow almonds but as habitat for multiple species of birds, small mammals and insects, many of which prey on pests. It is also far more absorbent than it once was, he says, making him less dependent on irrigation or access to groundwater which, soon enough, will be curtailed.
There is, he says, more labor involved with these practices. A yearly ritual on the farm illustrates the difference. A common pest on almond and other nut trees is the naval almond worm, which leaves its young to hatch in discarded nut shells.
Ward Burroughs and Rosie make compost for their farm. They buy cow manure and get onion and garlic skins from a local processing plant, add water and let it sit while microorganisms such as bacteria and fungi turn it into this rich, dark compost. It will be spread throughout his orchards to enhance the health of the soil and growth of his almond trees.
Conventional farmers apply pesticides to kill them before they hatch. But Burroughs, after each harvest, sends a machine through his fields that shakes the trees — that’s how almond trees are harvested — and collects the empty shells, denying the pest a hatching location. “We break the nuts and kill the worms,” he says. That requires several days of time-consuming tree-by-tree labor.
It’s that cover-cropped field 'that is the real disrupter here.'Jeffrey Mitchell, UC Cooperative Extension
Yet Burroughs is convinced that his approach — often referred to broadly as “regenerative agriculture,” because it regenerates rather than depletes the soil — is more than compensated for by his soil’s greater water absorption and the farm’s enhanced ability to withstand the changing water and climate patterns.
“Because we’re concentrating on soil health,” he said, “we’re set up to be much more resilient.”
His yields don’t usually match those of his conventional counterparts, he concedes, but his net revenues are roughly the same because he doesn’t have to buy expensive chemicals or the machines that apply them.
Laying Bare the Vulnerabilities
It could be these methods are just what’s needed as climatic shifts hit the Valley at an unprecedented rate of volatility. Valley temperatures are predicted to rise five to six degrees Fahrenheit by the end of the century, while periods of extreme heat are expected to more than double to 50 days a year or more over that time. Irrigation water is becoming saltier, too, as desperate farmers drilling ever-deeper wells are pumping up ever-saltier water.
During winter, it’s often not cold enough to permit trees’ metabolism to slow down, a process critical to the spring flowering that produces fruits and nuts later in the season. Those all-important tree “chill” hours have declined by as much as 30 percent since 1950, according to the California Department of Food and Agriculture. Which means the tree cannot slow its metabolism and preserve its energy for the spring blooms that deliver fruit and nuts.
“If trees haven’t had that low-chill period when they wake up in the spring,” said Mae Culumber, a UC cooperative extension agent based in Fresno, “it’s like being up all night and then trying to go to work.”
Last year, scientists at UC Merced published a paper in agronomy suggesting that the climatic shifts underway ultimately challenge the Central Valley’s long-term life span as an agricultural powerhouse. The researchers foresaw more heat, drought and flooding. They predicted declines of more than 40 percent in avocado yields, and as much as 20 percent in oranges, grapes, walnuts and almonds. More heat-sensitive crops such as strawberries, grapes and cherries also face shrinking yields.
For the Central Valley, climate change is revealing the vulnerabilities of an industrial agriculture system that relies on predictability — which is rapidly unravelling — and shining a light on alternative growing practices that are potentially far more resilient to the onrushing changes.
The lessons learned, or not learned, here at the Burroughs farm and across the Valley have implications for ag centers from the American Midwest to Central America to North Africa, southern Europe and southwest China — breadbaskets everywhere that are experiencing similar extremes of heat, drought and flood, and the new pests and diseases that follow them.
Cover Crops: ‘The Real Disruptor’
Just off the town of Five Points, on the southern edge of Fresno County, a dusty crossroads at the junction between the single lane highways 145 and 269, I visited what could be characterized as the research hub for those ‘centers of insurrection’ — the West Side Research and Extension Center, a sprawl of fields and a couple of Quonset-like huts used for soil testing.
'It is healthy soil that is the actual source of a field’s fertility.'Renata Brillinger, California Climate and Agriculture Network
Jeffrey Mitchell, an agricultural extension agent with UC Davis, has been experimenting for two decades with different ways of enriching the soil to enhance crop health. I looked out on his narrow test plots, stretching side-by-side for about 100 yards: tilling without cover crops; tilling with cover crops; no-till without cover crops; and no-till with cover crops. No-till farming seeks to avoid disrupting the soil ecosystem and to avoid the loss of valuable topsoil by not running a plow through fields. Cover crops are plants grown to enrich the soil, including mustard, fava beans and radishes.
It’s that cover-cropped field, Mitchell said, “that is the real disrupter here.”
The soil in it, he says, is loaded with far more organic nutrients than soil from the other fields. It absorbs water better and is thus more resilient to drier conditions. The wealth of plant and soil life in that experimental field means it also absorbs more carbon from the atmosphere than conventionally grown fields. That factor alone has become a high priority for the state, which aims to be carbon neutral by 2045.
Conventional agriculture is linked to as much as 18 percent of total global greenhouse gas emissions — farms emit nitrous oxide from fertilizers and other synthetic substances, methane from animal waste and from tilling, and CO2 from the processing and transport of agricultural inputs and food. Twenty percent of the state’s carbon targets could, according to a state climate plan, be accomplished through forestry and agriculture. Soils enriched with organic compost, including cattle waste and other organic material, have the potential to turn farms from greenhouse gas emitters into greenhouse gas sinks.
Mitchell and his colleagues are also finding that fields with cover crops host a higher proportion of micro-organisms that strengthen plants’ immune systems, enabling them to fight off diseases, and of bacteriovores and fungivores — organisms, like those abundant in the undergrowth on the Burroughs farm, that eat the bacteria and fungi that harm crops. This all translates to a reduced need for chemical biocides, and stabilizes soil so it doesn’t blow away as easily in the increasing windstorms.
Crops grown in such soil may also be more nutritious.
“What you see in Five Points,” said Daphne Miller, a physician who studies the links between the health of the foods we eat and the soil in which they’re grown, “is that the plots with the greatest diversity of cover crops had the most diverse microbiome in the soil.”
From 2003 to 2017 — 15 years — an average 2.4 million acre feet of water was coming out of the ground every year without getting replenished.
A recent study in Food Processing and Technology points to beneficial minerals like potassium and antioxidant enzymes in significantly higher concentrations in organic oats, tomatoes and peppers — the latter two of which are prominent veggie crops in the Central Valley — than in their conventional counterparts.
The most immediate benefit of cover crops and no-till may be how they reduce the need for irrigation. To demonstrate, Mitchell filled a long translucent tube with water, then dropped in dirt from the conventional field. In another water-filled tube, he dropped dirt from the no-till, cover-cropped field. Soil from the cover-cropped field congealed into a fist-sized mulch, suggesting that the water was absorbed, while the conventional soil dispersed quickly like so much dust. Healthy soil reduces water evaporation levels by four to five inches annually, Mitchell has found. If widely adopted, these practices could reduce water use throughout the valley by millions of acre-feet per year.
That would be a significant step given the pressures just ahead on the water supply. California’s $17 billion agriculture behemoth and its epic network of dams, pumps and canals were built on fragile assumptions: That the snow would keep falling on the Sierras in the winter and melt in the spring, just in time for the dry season in the south; and that farmers could always pump groundwater from one of the nation’s largest aquifers when those sources went dry.
But the snow has not been falling like it used to, and that groundwater is getting sucked from underground at unsustainable rates. The aquifer, for a time, “buffered farmers from the impacts of climate change,” said Charlie Brummer, at UC Davis. Not any more. Farmers made relentless runs at the aquifer when the aqueduct ran dry. From 2003 to 2017 — 15 years — an average 2.4 million acre-feet of water was coming out of the ground every year without getting replenished.
One of the state's efforts to reverse precipitous groundwater declines is the 2014 Sustainable Groundwater Management Act, an effort to restrict the water taken out of the aquifer. As water allotments for farmers drop, the Public Policy Institute estimates it could mean the loss of at least 500,000 acres of Valley farmland.
The state’s Healthy Soils program is aiming to entice farmers to integrate water conservation practices before that happens. It has awarded farmers some $20 million in subsidies over the last two years to facilitate the adoption of cover crops and other soil-enriching, water-conserving, and carbon-absorbing, practices.
“It’s a different way of thinking about soil,” said Renata Brillinger, executive director of the California Climate and Agriculture Network. The program challenges the common assumption that “soil is just the thing that holds the plant up,” she said. “It is healthy soil that is the actual source of a field’s fertility.”
More Practices for Survival
Although the Valley can appear like one huge monochrome blur seen through a car window while speeding down I-5, it’s actually showing signs of diversity, and ingenious responses to the pressures that are impacting agriculture. You just have to know when to pull off. Fresno County is dotted with small and highly diversified farms, most of them run by immigrant families originally from Laos and Mexico.
“A lot of people think of Fresno as nothing but big-ag, but I see farmers tipping in another direction,” said Aidee Guzman, a Ph.D.-track researcher at UC Berkeley who grew up in the San Joaquin Valley and has been working with Central Valley farm communities.
These farms may have been cultivated as survival strategies for immigrants who knew nothing other than farming when they arrived here from Laos or Mexico, but they are now testing survival strategies for farmers who face accelerating changes in growing conditions.
Thus far, Guzman’s research shows a number of correlations between these working farms and Jeff Mitchell’s findings on his experimental plots: higher populations of bees and other pollinators, and richer microbial activity below the surface. One detail — for plant scientists get deep into the details: Guzman says she’s found higher rates of colonization on crop roots of a fungus that helps plants to obtain nutrients from the soil. It appears the fungi send filaments further into the soil that pick up more nitrogen and phosphorous beyond the reach of roots and pass them along to the plant. They also help the plant to be more resistant to drought by retaining water.
Much of the bounty from these small farms — perhaps a couple of hundred across Fresno county, — comes into the farmers markets of the Bay Area and Sacramento, as well as to local ethnic markets. That includes some fruits like maringa, native to the Philippines and JuJuBe, native to China and Southeast Asia.
The farms appear to be seriously resistant to shortages of water that are becoming ever more common in the southern end of the Valley, says Ruth Dahlquist-Willard, a Fresno-based Small Farms Adviser for the UC Cooperative Extension Service. Many of the farms, she says, have from 40 to 50 different crops on them at a time — including daikon radishes, Asian eggplants, and numerous spices such as turmeric, ginger, and lemongrass.
“They know how to keep these crops going,” she said. “They never grow the same thing on the same piece of ground right after one another. They rotate, one year squash, the next year who knows what it could be.”
Many brought such practices with them from their ancestral homes. And scientists like Guzman and Mitchell, and farmers like the Burroughs, are discovering in these real-time experiments that such principles may actually aid farmers’ ability to ride out and survive the accelerating climate storm.