Posts Tagged: pollution
UC Davis Researchers Link Vehicle Pollution to Elevated Insect Damage to Street Trees
Trees planted near streets and highways are subject to elevated insect damage due to the adverse...
Vehicle pollution is associated with elevated insect damage to street trees, UC Davis researchers said in their paper published in the Journal of Applied Ecology. They studied insect damage to native oak trees.
UC Davis lab experiments showed that caterpillars preferred the native oak leaves from the nearby streets and highways.
Growing cereal crops with less fertilizer
Discovery could reduce nitrogen pollution, save farmers billions
Researchers at the University of California, Davis, have found a way to reduce the amount of nitrogen fertilizers needed to grow cereal crops. The discovery could save farmers in the United States billions of dollars annually in fertilizer costs while also benefiting the environment.
The research comes out of the lab of Eduardo Blumwald, a distinguished professor of plant sciences, who has found a new pathway for cereals to capture the nitrogen they need to grow.
The discovery could also help the environment by reducing nitrogen pollution, which can lead to contaminated water resources, increased greenhouse gas emissions and human health issues. The study was published in the journal Plant Biotechnology.
Nitrogen is key to plant growth, and agricultural operations depend on chemical fertilizers to increase productivity. But much of what is applied is lost, leaching into soils and groundwater. Blumwald's research could create a sustainable alternative.
“Nitrogen fertilizers are very, very expensive,” Blumwald said. “Anything you can do to eliminate that cost is important. The problem is money on one side, but there are also the harmful effects of nitrogen on the environment.”
A new pathway to natural fertilizer
Blumwald's research centers on increasing the conversion of nitrogen gas in the air into ammonium by soil bacteria — a process known as nitrogen fixation.
Legumes such as peanuts and soybeans have root nodules that can use nitrogen-fixing bacteria to provide ammonium to the plants. Cereal plants like rice and wheat don't have that capability and must rely on taking in inorganic nitrogen, such as ammonia and nitrate, from fertilizers in the soil.
“If a plant can produce chemicals that make soil bacteria fix atmospheric nitrogen gas, we could modify the plants to produce more of these chemicals,” Blumwald said. “These chemicals will induce soil bacterial nitrogen fixation and the plants will use the ammonium formed, reducing the amount of fertilizer used.”
Blumwald's team used chemical screening and genomics to identify compounds in rice plants that enhanced the nitrogen-fixing activity of the bacteria.
Then they identified the pathways generating the chemicals and used gene editing technology to increase the production of compounds that stimulated the formation of biofilms. Those biofilms contain bacteria that enhanced nitrogen conversion. As a result, nitrogen-fixing activity of the bacteria increased, as did the amount of ammonium in the soil for the plants.
“Plants are incredible chemical factories,” he said. “What this could do is provide a sustainable alternative agricultural practice that reduces the use of excessive nitrogen fertilizers.”
The pathway could also be used by other plants. A patent application on the technique has been filed by the University of California and is pending.
Dawei Yan, Hiromi Tajima, Howard-Yana Shapiro, Reedmond Fong and Javier Ottaviani from UC Davis contributed to the research paper, as did Lauren Cline from Bayer Crop Science. Ottaviani is also a research associate at Mars Edge.
The research was funded by the Will W. Lester Endowment. Bayer Crop Science is supporting further research on the topic.
Editor's note: Blumwald is affiliated with UC Agriculture and Natural Resources through the Agricultural Experiment Station at UC Davis.
/h3>/h3>Sustainable landscaping can garner big results and savings!
For those of us who have lived in Stanislaus County for many years, can you remember what...
Decreases in air pollution boost corn and soybean yield
Faced with growing global food demand, one solution to increasing productivity is cutting air pollution, reported Ohio's Country Journal.
MIT Sloan School of Management visiting professor Konstantinos Metaxoglou and UC Davis ag economics professor Aaron Smith quantified crop yield increases attributed to recent reduction in the emissions of NOx from power plants in the U.S. They found that the average corn yield increased by 2.5% and soybeen yield by 1.6% from 2003 to 2011.
The increased yield led to an increase in the two crops' total annual surplus.
“While farmers are worse off and consumers are better off, the economy on the whole benefits because the gain for consumers outweighs the loss for producers,” Metaxoglou said. “Our findings show that reducing NOx and other harmful emissions from power plants is beneficial not only for human health, but also for agriculture production.”
Falling levels of air pollution drove decline in California’s tule fog
Reposted from the UC Berkeley News
The Central Valley's heavy wintertime tule fog – known for snarling traffic and closing schools — has been on the decline over the past 30 years, and falling levels of air pollution are the cause, says a new study by scientists at the University of California, Berkeley.
Tule fog, named for a sedge grass that populates California's wetlands, is a thick ground fog that periodically blankets the Central Valley during the winter months.
To find out why the fog is fading, the researchers analyzed meteorological and air pollution data from the Central Valley reaching back to 1930. They found that while yearly fluctuations in fog frequency could be explained by changes in annual weather patterns, the long-term trends matched those of pollutants in the air.
The results help explain the puzzling decades-long rise and fall in the number of “fog days” affecting the region, which increased 85 percent between 1930 to 1970 and then decreased 76 percent between 1980 to 2016. This up-and-down pattern follows trends in air pollution in the valley, which rose during the first half of the century, when the region was increasingly farmed and industrialized, and then dropped off after the enactment of air pollution regulations in the 1970s.
“That increase and then decrease in fog frequency can't be explained by the rising temperatures due to climate change that we've seen in recent decades, and that's what really motivated our interest in looking at trends in air pollution,” said Ellyn Gray, a graduate student in environmental science, policy and management at UC Berkeley and first author on the paper, which appears online in The Journal of Geophysical Research: Atmospheres. “When we looked at the long-term trends, we found a strong correlation between the trend in fog frequency and the trend in air pollutant emissions.”
The link between air pollution and fog also explains why southern parts of the valley — where higher temperatures should suppress the formation of fog — actually have a higher occurrence of fog than northern parts of the valley.
“We have a lot more fog in the southern part of the valley, which is also where we have the highest air pollution concentrations,” Gray said.
And it makes sense, given what we know about how clouds and fog form, Gray says. Oxides of nitrogen (NOx) react with ammonia to form ammonium nitrate particles, which help trigger water vapor to condense into small fog droplets. Emissions of NOx have declined dramatically since the 1980s, resulting in a decrease in ammonium nitrate aerosols and fog.
“In order to get fog to form, not only do you need the temperature to go down, but there has to be some sort of seed for water to condense around, similar to how you would have a cloud seed in the atmosphere,” Gray said. “Ammonium nitrate happens to make very good fog seeds — water is very attracted to it.”
As a next step, the team plans to take a close look at the association between air pollution, tule fog and traffic safety in the valley.
“When I was growing up in California in the 1970s and early 1980s, tule fog was a major story that we would hear about on the nightly news,” said Allen Goldstein, a professor in the Department of Environmental Science, Policy, and Management, and in the Department of Civil and Environmental Engineering at UC Berkeley and senior author on the paper. “These tule fogs were associated with very damaging multi-vehicle accidents on freeways in the Central Valley resulting from the low visibility. Today, those kind of fog events and associated major accidents are comparatively rare.”
Co-authors of the paper include S. Gilardoni and Maria Cristina Facchini of the Institute of Atmospheric Sciences and Climate in Italy; Dennis Baldocchi of UC Berkeley, and Brian C. McDonald of the University of Colorado, Boulder, and the NOAA Earth System Research Laboratory in Boulder.
This research was supported by a National Science Foundation (NSF) Graduate Fellowship, the California Agricultural Experiment Station and McIntire-Stennis Cooperative Forestry Program of the U.S. Department of Agriculture, and the National Research Council of Italy.
/span>