On a stormy March morning, gusts of wind lifted walls of dust hundreds of feet high from the bare ground south of Coolidge. It involved 23 cars and was responsible for a traffic accident.
The source of the hazard was an unplanted fine-grained patch of soil that stretched for half a mile along California Route 87. That day, as the machine operator was preparing to clear 160 acres of land for planting season, a gust of wind blew the dirt away. The victim of the accident sued the farmer and won a settlement of $400,000.
Nearly 20 years after the accident, serious concerns about seasonal sandstorms and fallow lands continue. Dust storms are his second leading cause of traffic accidents in Arizona, and thousands of people fall ill each year from deadly fungal infections transmitted by the wind. Recent water outages have increased the number of dry, unplanted plots in Pinal County, potentially exacerbating the problem.
Some researchers believe they are on the verge of a new solution. A team at Arizona State University is testing a way to regenerate the “skin” of desert soil. This is a thin, living natural layer that prevents the wind from scooping up dust.
By monitoring dust sources and unique weather phenomena, and evaluating two bio-inspired methods to grow new soil crusts, the team offers new solutions for immediate and long-term dust control. Aiming to be
The method is nothing new. Biological crust repair and enzymatic carbonate precipitation have been studied for over a decade. However, applied research on this scale is still rare for biocrusts, and so far neither method has had commercial applications for dust control.
“The best technology available for transient dust control, such as on a construction site, is to run water trucks. You can
“We wanted to find a better way, a more sustainable way.”
This research project $4.5 million in grants over three years The Arizona Board of Trustees also supports research at Northern Arizona University and the University of Arizona. There, scientists study the growth patterns and transmission of Coccidioides fungal spores and work to track fungal hotspots.
Polluted air:Summer storms are spectacular, but the dust in them is harmful to health
Build a new desert skin
On January 25, Pinal County announced that the west side of the county will implement new, stricter dust control rules in June, based on Environmental Protection Agency guidelines.
In 2012, the EPA determined that the area did not meet national air quality standards for PM-10 (airborne dust and smoke particles less than 10 micrometers in diameter). This has designated the West Pinal area as a PM-10 “unfinished” area. In 2020, EPA reclassified it as a “significant underachievement.”
Arizona has missed a deadline and must prove that West Pinal County is reducing PM-10 emissions by 5% each year.
This situation is similar to what Maricopa County experienced several years ago. If the 5% reduction is not achieved in western Pinal County, the government could freeze federal transportation funding, putting new projects on hold until a new dust control plan is submitted and approved by the EPA. There is a nature.
The penalties will be punitive on a large scale, according to Timothy Frankist, environmental director of the Maricopa Government Association, the government agency leading efforts to create a new state plan for West Pinal County. Pinal County The situation in is different from that in Maricopa, mainly due to the scale of the problem.
“It’s a low-risk situation because we’ve identified control measures,” Frankist said.
Countermeasures can be very expensive. Most important is the pavement of dirt roads, which accounts for 67% of his total PM-10 emissions, according to the latest 2017 inventory. Other procedures include watering, costly measures in the desert, and treatment of both construction sites and miles. Roads with dust suppressants.
Synthetic polymers and a variety of other products are frequently used for dust protection on roads and construction sites. Annual treatment costs are approximately $10,000 per mile. However, some of them can be toxic and are not suitable for large ground areas such as fallow.
A more sustainable solution to keeping dust in the ground is to build a new soil crust for immediate and long-term relief, according to ASU researchers.
Biocrust restoration restores and accelerates the growth of naturally occurring microbial communities in desert soils, creating a living layer that protects the soil from wind erosion. Enzyme-induced carbonate precipitation (EICP) uses enzymes extracted from beans to precipitate calcium carbonate into the soil (the main component of limestone regularly used in agriculture), creating an artificial crust, a bio-based method. Inspired technology.
The idea is that biocrust restoration can be used as a long-term solution for plots that may be left unattended indefinitely, while calcium carbonate crusts serve as a treatment for areas in need of immediate dust suppression. It means that there is a possibility to
Matthew Fraser and Pierre Herckes, also on the ASU team, continue to monitor windblown dust with 14 sensors deployed across the region to identify extreme weather events and agricultural activity and track dust sources. to measure the effect of treatment.
Land remediation:How researchers hope to preserve and restore the ‘biocrust’, the protective skin of the desert
Biocrust research is growing
Biocrust restoration research has exploded over the past decade, and land managers are increasingly investing in protecting biocrust as a vital resource, says Sasha Reed, an ecologist with the U.S. Geological Survey. says Mr. .
For fallow land that cannot be planted indefinitely, this can be a long-term solution. Mighty microbes are ‘ecosystem engineers’ who can improve the habitats of other species and withstand extreme weather events, but they’ll be crushed to death under tractor tires.
“It’s a self-perpetuating ecosystem. It’s a natural way for deserts to maintain their soil,” says Ferran Garcia, a biological soil crust scientist and Regent grant researcher. – said Pichel.
Biocrust restoration on this scale has never been done before. ASU’s one-acre plot experiment is one of the largest that has been attempted. A large-scale restoration project was attempted in Utah, “it was the largest in the world and probably the only one in the world. biocrust farm According to Reid of the USGS who participated in the project, the biocrust died when it was taken out of the breeding grounds into the wild.
The ASU team faces similar hurdles. In the field, the biocrust is not growing as fast as it should. In natural conditions, it can take decades to repopulate an area.
“Of course, that’s not enough,” says Brian Scott, an academic conducting ASU field trials in Pinal County. “We need to grow the biocrust in incubation chambers each season so that it can be transplanted into the field.”
Reid believes, with USGS, that this is exactly the scale that science needs to be done today. We have a wealth of research and management experience to support biocrust restoration, which is needed so that more tools for dryland restoration in the West are readily available.
“We need to know these things now so managers have a choice,” she said.
dry land:ADEQ Treats Soil Along I-10 in Pinal County to Reduce Sandstorm Risk
Agricultural dust management is one small piece of the puzzle
A holistic approach is needed to reduce PM-10 emissions by 5% annually in western Pinal County. New rules for construction sites went into effect in June, requiring cities in the county to expand road paving starting next year.
Farmers are also expected to adopt more best management practices, such as leaving crop residues in the fields for long periods, establishing perennial crops, and planting windbreaks.
Farmland is not a major source of dust in western Pinal District. According to his inventory of PM-10 sources in 2017, 67% of all dust came from his 5,897 miles of dirt roads. A wide variety of users stir the dust every day. Harvesting and tilling practices accounted for only one-tenth of total daily dust levels.
However, tillage, laser grading, and harvesting of land can still pose significant road visibility problems and health hazards.
Since 2006, the Arizona Department of Environmental Quality, which oversees agricultural best management practices, has received 81 complaints about dust from farms.
“Agricultural equipment is stirring up dirt and huge clouds are covering the Skyline Ranch subdivision and the entire surrounding area,” one complainant wrote in 2019. area. This has been going on for years. ”
Since 2012, when the area was declared a non-compliance zone, authorities have carried out 132 inspections.
Another source of controversy is how extreme weather exacerbates the dust problem. Farmer Paul Ollerton, who was sued for a dust cloud incident nearly 20 years ago, now chairs a committee within ADEQ that oversees dust control methods for agriculture.
In his view, most farmers follow best practices, do what they can to avoid dust, plow only when necessary, and run water trucks when leveling the ground. He said there is a need for a more thorough analysis of impacts and local soil types.
An operator at the Ollerton farm was running a water tanker to settle the dust while the land was being cleared when the accident occurred, he said.
“It was out of my control. We used our financial capabilities and knowledge to the best of our ability to prevent it,” he said.
As Maricopa County fought to reach PM-10, officials classified the sources of air pollution as “exceptional occurrences,” arguing that much of the dust level problem was out of control. EPA agreed.
Ollerton frankly opposes some of the EPA’s calls for farmers to adopt better management practices. He also provided the agency with more information and records on their activities.
The increase in fallow land is a cause for concern, and farmers will need help finding new and better ways to deal with dust on their farmlands.
“A lot of our[best management practices]are based on, you know, water use, water use, water use,” he said. “And the water, it’s not there anymore.”
Clara Migoya is responsible for environmental affairs for the Republic of Arizona and azcentral.Submit a tip or question clara.migoya@arizonarepublic.com.
Environmental coverage at azcentral.com and in the Republic of Arizona was supported by a grant from the Nina Mason Pulliam Charitable Trust. For the Republic’s Environmental Reporting Team, follow @azcenvironment on Facebook, Twitter, and Instagram at environment.azcentral.com.
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