Soil microbes left behind during decades of corn breeding

UNIVERSITY OF ILLINOIS COLLEGE OF AGRICULTURAL, CONSUMER AND ENVIRONMENTAL SCIENCES

Research News

 

IMAGE: USING A CHRONOSEQUENCE OF CORN LINES, UNIVERSITY OF ILLINOIS RESEARCHERS FOUND DECADES OF BREEDING AND RELIANCE ON CHEMICAL FERTILIZERS PREVENTS MODERN CORN FROM RECRUITING NITROGEN-FIXING MICROBES. view more 

CREDIT: ALONSO FAVELA, UNIVERSITY OF ILLINOIS.

URBANA, Ill. - Corn didn't start out as the powerhouse crop it is today. No, for most of the thousands of years it was undergoing domestication and improvement, corn grew humbly within the limits of what the environment and smallholder farmers could provide.

For its fertilizer needs, early corn made friends with nitrogen-fixing soil microbes by leaking an enticing sugary cocktail from its roots. The genetic recipe for this cocktail was handed down from parent to offspring to ensure just the right microbes came out to play.

But then the Green Revolution changed everything. Breeding tools improved dramatically, leading to faster-growing, higher-yielding hybrids than the world had ever seen. And synthetic fertilizer application became de rigueur.

That's the moment corn left its old microbe friends behind, according to new research from the University of Illinois. And it hasn't gone back.

"Increasing selection for aboveground traits, in a soil setting where we removed all reliance on microbial functions, degraded microbial sustainability traits. In other words, over the course of half a century, corn breeding altered its microbiome in unsustainable ways," says Angela Kent, professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois and co-author of a new study in the International Society of Microbial Ecology Journal.

Kent, along with co-authors Alonso Favela and Martin Bohn, found modern corn varieties recruit fewer "good" microbes - the ones that fix nitrogen in the soil and make it available for crops to take up - than earlier varieties. Instead, throughout the last several decades of crop improvement, corn has been increasingly recruiting "bad" microbes. These are the ones that help synthetic nitrogen fertilizers and other sources of nitrogen escape the soil, either as potent greenhouse gases or in water-soluble forms that eventually end up in the Gulf of Mexico and contribute to oxygen-starved "dead zones."

"When I was first analyzing our results, I got a little disheartened," says Favela, a doctoral student in the Program in Ecology, Evolution, and Conservation Biology at Illinois and first author on the study. "I was kind of sad we had such a huge effect on this plant and the whole ecosystem, and we had no idea we were even doing it. We disrupted the very root of the plant."

To figure out how the corn microbiome has changed, Favela recreated the history of corn breeding from 1949 to 1986 by planting a chronological sequence of 20 off-patent maize lines in a greenhouse.

"We have access to expired patent-protected lines that were created during different time periods and environmental conditions. We used that understanding to travel back in time and look at how the associated microbiome was changing chronologically," he says.

As a source of microbes, Favela inoculated the pots with soil from a local ag field that hadn't been planted with corn or soybeans for at least two years. Once the plants were 36 days old, he sequenced the microbial DNA he collected from soil adhering to the roots.

"We characterized the microbiome and microbial functional genes related to transformations that occur in the nitrogen cycle: nitrogen fixation, nitrification, and denitrification," he says. "We found more recently developed maize lines recruited fewer microbial groups capable of sustainable nitrogen provisioning and more microbes that contribute to nitrogen losses."

Kent says breeding focused on aboveground traits, especially in a soil context flooded with synthetic nitrogen fertilizers, may have tweaked the sugary cocktail roots exude to attract microbes.

"Through that time period, breeders weren't selecting for maintenance of microbial functions like nitrogen fixation and nitrogen mineralization because we had replaced all those functions with agronomic management. As we started selecting for aboveground features like yield and other traits, we were inadvertently selecting against microbial sustainability and even actively selecting for unsustainable microbiome features such as nitrification and denitrification," she says.

Now that it's clear something has changed, can breeders bring good microbes back in corn hybrids of the future?

Bohn, corn breeder and associate professor in the Department of Crop Sciences at Illinois, thinks it's very possible to "rewild" the corn microbiome. For him, the answer lies in teosinte, a wild grass most people would have to squint pretty hard at to imagine as the parent of modern corn.

Like wild things everywhere, teosinte evolved in the rich context of an entire ecosystem, forming close relationships with other organisms, including soil microbes that made soil nutrients easier for the plant to access. Bohn thinks it should be possible to find teosinte genes responsible for creating the root cocktail that attracts nitrogen-fixing microbes. Then, it's just a matter of introducing those genes into novel corn hybrids.

"I never thought we would go back to teosinte because it's so far removed from what we want in our current agricultural landscape. But it may hold the key not only for encouraging these microbial associations; it also may help corn withstand climate change and other stresses," Bohn says. "We actually need to go back to teosinte and start investigating what we left behind so we can bring back these important functions."

Bringing back the ability for corn to recruit its own nitrogen fixation system would allow producers to apply less nitrogen fertilizer, leading to less nitrogen loss from the system overall.

"Farmers don't always know how much nitrogen they will need, so, historically, they've dumped as much as possible onto the fields. If we bring these characteristics back into corn, it might be easier for them to start rethinking the way they manage nitrogen," Bohn says.

Kent adds that a little change could go a long way.

"If we could reduce nitrogen losses by even 10% across the growing region of the Midwest, that would have huge consequences for the environmental conditions in the Gulf of Mexico," she says.

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The article, "Maize germplasm chronosequence shows crop breeding history impacts recruitment of the rhizosphere microbiome," is published in the International Journal of Microbial Ecology Journal.

The Department of Natural Resources and Environmental Sciences and the Department of Crop Sciences are in the College of Agricultural, Consumer and Environmental Sciences at the University of Illinois.

MOONSHINE

Corn ethanol reduces carbon footprint, greenhouse gases

DOE/ARGONNE NATIONAL LABORATORY

Research News

 

A study conducted by researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory reveals that the use of corn ethanol is reducing the carbon footprint and diminishing greenhouse gases.

The study, recently published in Biofuels, Bioproducts and Biorefining, analyzes corn ethanol production in the United States from 2005 to 2019, when production more than quadrupled. Scientists assessed corn ethanol's greenhouse gas (GHG) emission intensity (sometimes known as carbon intensity, or CI) during that period and found a 23% reduction in CI.

According to Argonne scientists, corn ethanol production increased over the period, from 1.6 to 15 billion gallons (6.1 to 57 billion liters). Supportive biofuel policies -- such as the Environmental Protection Agency's Renewable Fuel Standard and California's Low-Carbon Fuel Standard -- helped generate the increase. Both of those federal and state programs evaluate the life-cycle GHG emissions of fuel production pathways to calculate the benefits of using renewable fuels.

To assess emissions, scientists use a process called life-cycle analysis, or LCA -- the standard method for comparing relative GHG emission impacts among different fuel production pathways.

"Since the late 1990s, LCA studies have demonstrated the GHG emission reduction benefits of corn ethanol as a gasoline alternative," noted Argonne senior scientist Michael Wang, who leads the Systems Assessment Center in the laboratory's Energy Systems division and is one of the study's principal investigators. "This new study shows the continuous downtrend of corn ethanol GHG emissions."

"The corn ethanol production pathway -- both in terms of corn farming and biorefineries -- has evolved greatly since 2005," observed Argonne analyst Uisung Lee, first author of the study. Lee pointed out that the study relied on comprehensive statistics of corn farming from the U.S. Department of Agriculture and of corn ethanol production from industry benchmark data.

Hoyoung Kwon, a coauthor, stated that U.S. corn grain yields improved by 15%, reaching 168 bushels per acre despite fertilizer inputs remaining constant and resulting in a decreased intensity in fertilizer input per bushel of corn harvested: reductions of 7% in nitrogen use and 18% in potash use.

May Wu, another co-author, added that ethanol yields increased 6.5%, with a 24% reduction in ethanol plant energy use.

"With the increased total volume and the reduced CI values of corn ethanol between 2005 and 2019, corn ethanol has resulted in a total GHG reduction of more than 500 million tons between 2005 and 2019," Wang emphasized. "For the United States, biofuels like corn ethanol can play a critical role in reducing our carbon footprint."

The Argonne team used Argonne's GREET® model for this study. Argonne developed GREET (the Greenhouse gases, Regulated Emissions, and Energy use in Technologies) model, a one-of-a-kind LCA analytical tool that simulates the energy use and emissions output of various vehicle and fuel combinations. Government, industry, and other researchers worldwide use GREET® for LCA modeling of corn ethanol and other biofuels.

###

The work is funded by DOE's Vehicle Technologies Office in the Office of Energy Efficiency and Renewable Energy.

The Office of Energy Efficiency and Renewable Energy supports early-stage research and development of energy efficiency and renewable energy technologies to strengthen U.S. economic growth, energy security, and environmental quality.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.

The future of US corn, soybean and wheat production depends on sustainable groundwater use

Peer-Reviewed Publication

DARTMOUTH COLLEGE

 

IMAGE: SPATIAL DISTRIBUTION OF PRODUCTION LOSS BY AGRICULTURAL DISTRICT FROM SUSTAINABLE GROUNDWATER SCENARIOS WITH VARYING RECHARGE RATES FOR CORN (TOP MAP), SOYBEAN (MIDDLE MAP), AND WINTER WHEAT (BOTTOM MAP). RED, ORANGE, YELLOW, AND CHARTREUSE DOTS SHOW PRODUCTION LOST BY AGRICULTURAL DISTRICT FOR SUSTAINABLE GROUNDWATER USE SCENARIOS BASED ON 100% RECHARGE, 75% – 100% RECHARGE, 50% – 75% RECHARGE, AND 25% – 50% RECHARGE, RESPECTIVELY. GREEN DOTS SHOW SUSTAINABLE PRODUCTION. view more 

CREDIT: FIGURE BY J. LOPEZ ET AL. AND J. CHIPMAN.

In the U.S., 52% of irrigated land is used for corn, soybean and winter wheat production. Corn and soybean are two of the country’s most important crops, with 17% of corn production and 12% of soybean production coming from irrigated areas. However, the water used for this irrigation is often unsustainably pumped groundwater.  According to a recent Dartmouth-led study published in Earth’s Future, using groundwater sustainably for agriculture in the U.S. could dramatically reduce the production of corn, soybean and winter wheat. 

Irrigation relies on extracting groundwater from aquifers, which also serve as a source of drinking water and are essential to lakes, rivers and ecosystems. Aquifers are naturally recharged, as rainfall, snowmelt and other water infiltrate the soil, and are collected in a porous layer underground. If groundwater use, however, exceeds aquifer recharge rates, this reduces the amount of groundwater that is available in the aquifer, including for growing crops.

“Our findings underscore how corn, soybean and winter wheat production could be affected if we chose to stop depleting aquifers across the United States,” says co-lead author Jonathan Winter, an associate professor of geography and principal investigator of the Applied Hydroclimatology Group at Dartmouth. “However, future precipitation, which affects groundwater resources, is difficult to predict, and improved irrigation technology, more water-efficient crops, and better agricultural water management could reduce the production losses from a transition to sustainable groundwater use.”

To analyze the impacts of sustainable groundwater use for irrigated corn, soybean and winter wheat, researchers used a crop model to simulate irrigated agriculture from 2008 to 2012. The crop model uses information about daily weather, soil properties, farm management and crop varieties, and was compared to survey data from the U.S. Department of Agriculture to confirm its accuracy.

Crop production was simulated under four different groundwater use scenarios, ranging from most optimistic to pessimistic. The most optimistic scenario assumes that the maximum amount of recharge can be used for irrigation. The less optimistic scenarios, which are based on safe aquifer yield, assume that only a fraction of the recharge goes into the aquifer and just that restricted amount of water can be used for irrigation.  The less optimistic scenarios account for uncertainty in groundwater availability as well as preserving some water to maintain healthy ecosystems.  The four sustainable groundwater use scenarios are based on safe aquifer yields of 100%, 75%, 50%, and 25%.

Under the most optimistic sustainable groundwater use scenario, U.S. irrigated production of corn, soybean and winter wheat is reduced by 20%, 6% and 25%, respectively. Under the most pessimistic scenario, corn, soybean and winter wheat production is reduced by 45%, 37% and 36%, respectively.

“Our findings underscore how corn, soybean and winter wheat production could be affected if we chose to stop depleting aquifers across the United States,” says co-lead author Jonathan Winter, an associate professor of geography and principal investigator of the Applied Hydroclimatology Group at Dartmouth. “However, future precipitation, which affects groundwater resources, is difficult to predict, and improved irrigation technology, more water-efficient crops, and better agricultural water management could reduce the production losses from a transition to sustainable groundwater use.”

The findings show that Nebraska, Kansas, and Texas, which rely on groundwater from the High Plains Aquifer (also known as the Ogallala Aquifer) to grow corn, soybeans and winter wheat, would experience some of the greatest production losses as a result of sustainable groundwater use. This region is particularly vulnerable due to its lack of rainfall, which limits rainfed agriculture and groundwater recharge. Prior research found that the High Plains extracts three times as much groundwater as its aquifer’s recharge rate.

Central California, which relies on the Central Valley Aquifer, would also have large production losses in corn and winter wheat from sustainable groundwater use, but production losses of corn and winter wheat in California are limited due to the dominance of specialty crops, such as almonds, grapes and lettuce, which limit the amount of land used to grow corn and winter wheat.

In contrast, the Mississippi Valley, a significant corn and soybean region, would experience relatively few production losses, as groundwater extraction is typically less than recharge over the region. The Midwest would also experience minimal corn and soybean production losses because the region is humid and relies mainly on rain-fed rather than irrigated agriculture.

“Sustainable groundwater use is critical to maintaining irrigated agricultural production, especially in a global food system that is already taxed by climate change, population growth and shifting dietary demands,” says co-lead author Jose R. Lopez, a former postdoctoral researcher in geography at Dartmouth. “We need to expand the implementation of water conservation strategies and technologies we have now and develop more tools that can stabilize the nation's groundwater supply while preserving crop yields and farmer livelihoods.”

###

Winter is available for comment at: Jonathan.M.Winter@dartmouth.edu. In addition to Winter and Lopez, Joshua Elliott at the University of Chicago, Alex Ruane at NASA Goddard Institute for Space Studies, Cheryl Porter and Gerrit Hoogenboom at the University of Florida, Martha Anderson at the USDA ARS, and Christopher Hain at NASA Marshall Space Flight Center, also served as co-authors of the study.

---

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Sustainable Use of Groundwater May Dramatically Reduce Irrigated Production of Maize, Soybean, and Wheat

ARTICLE PUBLICATION DATE

8-Dec-2021

México’s tortilla bakeries hit hard by high inflation

US CORN FEEDSTOCKS FOR METHANOL E15 WILL RESULT IN CORN SHORTAGES

Pedro Pablo Cortes
Wed, May 4, 2022,

México’s highest inflation rate in 21 years is exacting a particularly steep toll on tortillerias (tortilla bakeries) and their customers, who are facing a spike in corn prices triggered in part by the ongoing war in Ukraine.

Case in point is La Morena, which is based in northern México City’s Pensil Sur neighborhood and is a traditional seller of that thin flat bread made from unleavened cornmeal.

Carmen Hernández, an employee at that establishment, she hasn’t seen another similar rapid increase in prices since she started working there 12 years ago.

“(Customers) get angry, of course. In fact, people think that the (higher prices) are our doing, but it’s really not. It’s the increase in (the price of) corn that’s making us raise the (price per) kilo of tortilla,” said Hernández.

The prices of corn tortillas rose at an annual clip of 17.42 percent in the first half of April, or more than double México’s overall inflation rate of 7.72 percent (a 21-year high).

Isaac Sánchez, La Morena’s manager, said the price of tortillas had long remained unchanged but has risen between 20-25 percent over the past two years.

A kilo of tortillas cost 15 pesos (around $0.75) in 2020 but has since climbed to 20 pesos, meaning that a family now receives between 10 and 12 fewer tortillas for the same amount of money spent, he said.

The climate crisis has spurred droughts, lower crop yields and higher prices, while Russia’s invasion of Ukraine has roiled the global grain trade and made matters even worse, according to Sánchez, who said he expects additional price hikes going forward.

A worker packs corn dough that is used for making corn tortillas. Tortilla makers in México have been hit by inflation and a shortage of corn.

La Morena has not laid off any of its 16 employees despite the crisis and currently produces 1,800 kilos (4,000 pounds) of tortillas per day.

According to the Inegi national statistics office, that establishment is one of more than 110,000 bakeries in México that make tortillas either from traditional corn dough or nixtamal meal, which is prepared through a process known as nixtamalization in which corn kernels are cooked and steeped overnight in water mixed with limestone.

Sánchez said the price situation is largely out of the tortilla bakers’ hands and that all they can do is try to reason with their frustrated customers.

“There’s no doubt whatsoever that we’re selling a little less because people also are consuming less. Perhaps we could offer them other alternatives, but at the end of the day nothing can replace the tortilla,” he added.

In response, Mexican President Andrés Manuel López Obrador on Wednesday announced that his administration will unveil an inflation control plan on May 4 that will offer “price guarantees” for 24 staple products, including corn and tortillas, and negotiated agreements with business leaders.

He also is urging small farmers to plant more corn and beans to reduce shortages and bring down inflation.

But Blanca Mejía, representative of the Traditional Mexican Tortilla Governing Council that comprises tortilla and tortilla dough makers, expressed skepticism about the plan.

“We’re very nervous in the industrial sector because we don’t know what measures they’re going to take. We’re very afraid of price controls,” she said, adding that producers need freely fluctuating tortilla prices to face the price-hike situation.

Mejía said the main challenge facing tortilla makers is the price-per-ton of corn, which has risen from 6,900 pesos ($345) in early January, prior to the war in Ukraine, to 8,900 pesos at present.

Higher prices of corn are a major bread-and-butter issue in a country where 98 percent of the population consumes tortillas and per-capita consumption of that flat bread stands at around 75 kg per year, according to the Institute of Ecology, a public strategic research institute.

But even if consumption falls in the short term, Sánchez said he is convinced Mexicans will remain loyal to corn tortillas, which accompany most Mexican dishes and are a basic ingredient for making a variety of traditional foods such as tacos, tostadas and enchiladas.

“We could say that without tortillas you practically can’t eat. The Mexican diet needs them,” he added.

Mexican official says US refuses to cooperate on GM corn studies

“Their science is the Word of God. That is not science, that is ideology,” 


Mexico has repeatedly called on the US to work together on scientific studies amid a conflict over the Latin American country’s plans to limit the use of GM corn. Mexico buys about US$5 billion (RM22.8 billion) worth of corn from its trade partner annually, most of which is GM yellow corn used for livestock feed. — AFP pic

Thursday, 03 Aug 2023 

MEXICO CITY, Aug 3 — The United States has denied a request by Mexico to jointly conduct scientific research on the health impact of genetically-modified corn, a Mexican government official said, a sign the two sides could be inching closer to a formal trade dispute.

Mexico has repeatedly called on the US to work together on scientific studies amid a conflict over the Latin American country’s plans to limit the use of GM corn. Mexico buys about US$5 billion (RM22.8 billion) worth of corn from its trade partner annually, most of which is GM yellow corn used for livestock feed.

The US, however, denied this request and made it clear it will not participate in new scientific studies with Mexico, Mexican Deputy Agriculture Minister Victor Suarez said in an interview with Reuters.

The two countries discussed Mexico’s request, including during a visit by US Agriculture Secretary Tom Vilsack, but the US will not oblige, Suarez said.

“They did not want to establish a period in which the two parties agree to carry out impact studies on animal health and human health,” Suarez said at his office on Wednesday.

“Their science is the Word of God. That is not science, that is ideology,” he added.

When asked to comment on what Suarez said, the US Department of Agriculture referred Reuters to previous remarks by Vilsack stating that the US “fundamentally disagrees” with Mexico’s position on biotechnology.

Mexico wants to ban GM corn for human consumption in the food staple tortilla, which is mostly made of white corn, and eventually replace GM yellow corn used for livestock feed, arguing that biotech corn harms native varieties and may have adverse health effects.

The US has argued that Mexico’s plan is not based on science and will hurt US farmers.

In June, Washington requested a new round of trade dispute settlement consultations with Mexico under the US-Mexico-Canada Agreement (USMCA), which are underway. If the two sides cannot resolve the conflict within 75 days, which falls on Aug. 16, the US can request a dispute settlement panel to decide the case. Canada also joined the consultations.

Suarez said the US does not have the evidence to support its argument in a panel, but that Mexico would be ready.

“If they establish the panel, we will defend ourselves. And if we defend ourselves, we think we are going to win,” Suarez said, adding that Mexico’s policy has no commercial impact on the United States.

Suarez estimated that between 10 per cent and 15 per cent of foreign corn purchases could be substituted by domestic production by the end of President Andres Manuel Lopez Obrador’s mandate in 2024.

The government is buying 1.5 million metric tons of white corn from producers in Sinaloa state at 6,965 pesos per ton ($409) after the country saw major unrest in the sector prompted by a drop in international grains prices. The state government will also buy half a million metric tons at that price.

Suarez said the price is based on a calculation of production costs and seeks to revalue the Mexican white grain and separate it from the “commodity” price of yellow corn on the Chicago grains exchange.

“This breaks the price link with Chicago,” Suarez said, adding that the program would soon expand to other states. — Reuters

Mexico to fight US dispute over GM corn after formal consultations fail

A worker holds GMO yellow corn imported from the U.S., in Tepexpan

Story by By Cassandra Garrison • Yesterday 

MEXICO CITY (Reuters) -Mexico said on Friday it would counter U.S. arguments over agriculture biotech measures, including plans to limit its use of genetically modified (GM) corn, in trade dispute settlement consultations requested by Washington earlier in the day.

The consultation request comes as the North American neighbors inch toward a full-blown trade dispute under the U.S.-Mexico-Canada Agreement (USMCA) over Mexico's policies to limit the use of GM corn, which it imports from the U.S.

If the consultations fail to resolve disagreements within 75 days, Washington can request a dispute settlement panel to decide the case.

Mexico said it was committed to "constructive dialogue" regarding U.S. concerns and to "reach a mutually satisfactory agreement."

Asked if Canada would take similar action to the U.S., a spokesperson for the Trade Ministry said Canada is "considering its next steps" and would be "guided by what is in the best interest of our farmers and the Canadian agriculture sector."

The United States requested formal trade consultations in March over objections to Mexico's plans to limit imports of GM corn and other agricultural biotechnology products. Those consultations took place, but failed to resolve the matter, senior officials of the U.S. Trade Representative's office said.

Mexico's agriculture ministry declined to comment, but the minister this week expressed confidence that the dispute with the U.S. would not escalate to a dispute settlement panel.

The conflict comes amid other disagreements between the U.S. and Mexico, most notably over energy in which the U.S. has argued that Mexico's nationalist policy prejudices foreign companies.

Despite February changes to Mexico's decree on GM corn, the U.S. said the Latin American country's policies are not based on science and appear inconsistent with its commitment under the USMCA.

The new decree eliminated a deadline to ban GM corn for animal feed and industrial use, by far the bulk of its $5 billion worth of U.S. corn imports, but maintained a ban on GM corn used in dough or tortillas.

Mexico argued on Friday the ban will not affect trade with the U.S., as Mexico produces more than enough white corn used for tortillas.

A senior Mexican executive, speaking before consultations were requested, said that because Mexico is not formally preventing sale of U.S. GM corn, any dispute panel would likely find little material damage had been done to U.S. business.

Mexican President Andres Manuel Lopez Obrador has also said GM seeds can contaminate Mexico's age-old native varieties and has questioned their impact on human health.

February's revised "decree does call for a gradual substitution and eventual banning of biotech corn, and this part of the measure itself is not science-based," said a senior USTR official.

The consultations will also address Mexico's rejection of new biotech seeds for products like soybeans, cotton and canola, U.S. officials said.

Mexico argued on Friday that the decree "encourages Mexico to preserve planting with native seeds, which is done in compliance with the USMCA's environmental regulations."

Some sector experts have expressed concern that the move could set a precedent among other countries, which would disrupt the global corn trade.

The National Corn Growers Association, which represents U.S. farmers, praised the U.S.' move.

"Mexico's actions, which are not based on sound science, have threatened the financial wellbeing of corn growers and our nation's rural communities," association President Tom Haag said in a statement.

(Reporting by Cassandra Garrison; Additonal reporting by Adriana Barrera, Kylie Madry and Dave Graham in Mexico City and Ismail Shakil in Ottawa; Editing by Leslie Adler and William Mallard)

 

Laser scarecrows make birds see red

Peer-Reviewed Publication

SOCIETY OF CHEMICAL INDUSTRY

 

IMAGE: 

LASER SCARECROWS SET UP IN EXPERIMENTAL FLIGHT PEN IN GAINESVILLE, FLORIDA, US, 

view more 

CREDIT: UNIVERSITY OF FLORIDA

Damage to crops caused by birds costs millions of dollars each year. Now, researchers from the University of Florida and the University of Rhode Island in the US are investigating the effectiveness of laser scarecrows – a high-tech solution using light to deter birds.

In a new study published in Pest Management Science, they presented captive flocks of European Starlings with fresh ears of sweetcorn and demonstrated that devices emitting a moving laser beam can significantly mitigate damage to the crop, up to 20m from the laser device.

Kathryn Sieving, Professor of Wildlife Ecology and Conservation at the University of Florida and corresponding author of the research explained that more and more growers are seeking inexpensive and portable laser units, like the ones tested in the research.

‘Growers need big effects for affordable prices, and if they can spend $300-$500 each for lasers to protect large fields for 1-3 weeks instead of more expensive options such as hiring people to patrol with dogs, falcons, or rifles, then lasers would be beneficial’, she said.

One reason why lasers provide a particularly effective solution for the protection of sweet corn is the short timeframe before harvest in which birds would target the crop, known as the ‘vulnerability window’. This short window reduces the risk of birds becoming desensitised to the lasers.

Sieving explained, ‘Lasers are being explored widely for crops with short vulnerability windows, like sweet corn. They seem to be performing very well and especially when different non-lethal deterrents are combined (e.g., lasers with loud noises). Birds only attack sweet corn during the brief ripening phase (called the milking stage) and it lasts only 5-10 days. So, as soon as it ripens, harvest begins. Therefore, in sweet corn, the protection does not need to last very long, and lasers seem to be working well – surprising birds such that they leave fields with lasers, and this reduces damage during milking stages by far more than 20%.’ 

The study involved two types of trials: Stick Trials, where fresh sweet corn ears were mounted on sticks at varying distances from laser units, and Natural Trials, where birds foraged on ripe corn grown from seed in a flight pen. Laser and control treatments were alternated each day over five days, allowing the researchers to assess the birds' response to repeated laser exposure.

‘We designed the stick trials to increase the sample size for more robust results. Natural corn matures over several weeks but then is only attractive to birds for two weeks – so our planted crop was not going to give us enough sample size. With the stick corn experiments we could study small scale effects and amp up the sample sizes,’ said Sieving.

The results showed that lasers reduced sweet corn damage marginally in Stick Trials and dramatically in Natural Trials. Explaining this difference in effectiveness, Sieving noted ‘the sticks we presented corn on were sturdy and the birds likely could perch and feed on corn while avoiding the laser layer sometimes. Natural corn stalks are flimsy though and the birds would be bouncing in and out of the laser layer with no control. Thus, just as in larger fields it seems that natural corn makes lasers quite effective.’

The researchers also examined how distance from the lasers affected the amount of damage to the sweetcorn. They found that there was effective deterrence up to 20m from the laser source however beyond this distance, damage to the crop increased, with little to no deterrence at 30m. Sieving notes, ‘The data showing that relationship with distance is really the only data of its kind and was possible to get because we did the work with captive birds.’

However, she explained that in true field settings, this effect seems to be unimportant. ‘In open fields, birds will simply leave a field that has detectable laser protection, and they fly far out of its influence. It seems that just one laser per field can often do the trick to keep birds mostly out of a field. So, the fine scale spatial effects might only apply if birds were overly committed to feeding a small area – then a grower may need to add a couple of laser units with overlapping ranges.’

Sieving hopes that laser scarecrows can offer a sustainable solution for the protection of crops with short vulnerability windows.

‘Lasers are silent, unlike acoustic deterrents (loud bangs, other noises occurring several times per hour) which can be very disturbing to neighbours and workers. Lethal deterrents require permits and time and labour to apply and the potentially toxic secondary effects on wildlife, soil and water are often unacceptable.’

Wooden stake presenting corn during the Stick Trials

Planted corn rows in one of the test plots

European starling (Sturnus vulgaris)

European starling (Sturnus vulgaris) feeding on corn ear in Stick Trial

CREDIT

University of Florida

JOURNAL

Pest Management Science

DOI

10.1002/ps.7888 

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Experimental assessment of laser scarecrows for reducing avian damage to sweet corn

COI STATEMENT

All authors reported there were no conflicts of interest to disclose.

Leafhopper Swarms Threaten Argentina Crops and Economic Recovery

Jonathan Gilbert
Wed, Apr 17, 2024


(Bloomberg) -- Argentina corn farmers had high hopes for this season’s harvest after near-perfect weather conditions ended years of drought. A record crop would also bode well for President Javier Milei’s plan to turn around the nation’s embattled economy

Now a bug is getting in the way.

Corn farmers are seeing their fields ravaged by a plague of leafhopper insects. The infestation is slashing production potential for the world’s third-largest exporter of corn just as harvesting gathers speed.

Swarms of the tiny insects — spreading a disease on plants called spiroplasma — have grown so vast across the Pampas crop belt that analysts at the Rosario Board of Trade will likely continue to trim their output estimate.

“There’s concern that the damage will keep increasing as the crop cycle progresses,” they wrote in a report, after calling the widespread impact of the pest “unprecedented.”

It’s a severe setback for a country still recovering from the worst drought in living memory. Farming is a huge component of Argentina’s economic activity, and its central bank desperately needs crop export dollars in the second quarter to boost its reserves of hard currency in order to scrap money controls.

The controls were designed to protect the peso, but they’re counterproductive for the broader economy. Milei, who’s served as president since December, has vowed to ditch them as he moves to free up business and lure investment.

Argentina’s corn and soybean harvests are just getting started. Prospects earlier in the year were for a record corn crop of 56.5 million metric tons, but that forecast has since plunged 12% to 49.5 million, according to the Buenos Aires Grain Exchange.

There are also some problems for soy: Rains have been hampering field work, and delays to the harvest could reduce the quality of the crop, with subsequent discounts to prices paid by traders.

“If the forecast for more rains is right, the harvest pace will slow,” said Bruno Ferrari, a researcher at the Rosario bourse. “We’ll see damage from excess moisture, affecting quality, and potentially a cut to our national production estimate.”

Argentina is the world’s biggest supplier of soy meal and soy oil.

Deformed Corn

Meanwhile, attacks by leafhoppers are choking the internal workings of corn plants, causing deformities and ultimately reducing the number and size of corn kernels that farmers truck to ports.

In the prime swath of farmland, known as zona nucleo, average corn yields are expected to plunge by roughly a third, to six metric tons a hectare. Before the leafhopper plague, they were due to be around nine tons.

In powerhouse farming province Cordoba, production is now seen 26% lower than last month and is expected to keep falling, with month-on-month cash losses exceeding $1.1 billion, according to the regional grain exchange.

In the northern province of Santiago del Estero, German Esponda, an agronomist from the town of Bandera, said the full extent of the damage hasn’t been computed. “This movie isn’t over yet,” he said.

Late-planted corn, which isn’t yet ready for harvest, is most affected. That’s bad news since two thirds of Argentine corn acreage is now late-planted, a strategy that’s developed to combat drier weather.

“My latest corn, planted in January, was younger and weaker when the leafhoppers came, so those yields could fall by half,” said Daniel Calaon, a farmer in Serodino in the zona nucelo.

Calaon is also struggling to collect his soybeans because of the rains. “It’s too wet to get tractors in the field,” he said. “We may lose some acreage and it’s very likely we’ll see quality losses.”

For Argentina, these curbs to production are compounding low global prices for both corn and soy. The combination will be detrimental to export revenue, with $4.5 billion wiped from the estimated value of Argentine crop shipments from December to March, according to Rosario. The revenue losses have grown in recent weeks as the leafhopper swarms intensified, said researcher Ferrari.

To be sure, smaller corn harvests in Argentina and neighboring Brazil haven’t yet been fully factored in at the US Department of Agriculture. When they are, it could fuel an uptick in corn prices that are trading at three-year lows, although demand is soft.

Further out, Milei’s plans to open up the economy could see headwinds from a La Nina climate pattern that’s forming in the Pacific Ocean. La Nina usually brings drought to Argentina and could shrink the 2025 harvest.

 Bloomberg Businessweek

 

Corn reduces arsenic toxicity in soil 

UNIVERSITY OF BASEL

 

IMAGE: 

CORN PLANTS IN A FIELD EXPERIMENT NEAR LIESBERG, BASELLAND, SWITZERLAND.

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CREDIT: UNIVERSITY OF BASEL, VERONICA CAGGÌA

When crops grow in arsenic-contaminated soil, this toxic element accumulates in the food chain. A study involving the University of Basel has now discovered a mechanism used by corn plants to reduce arsenic uptake: the key factor is a special substance released into the soil by the roots.

Arsenic is a toxic metalloid of natural origin. Arsenic-contaminated soils and waters are found all over the world, especially in southeastern Asian countries like Bangladesh, Vietnam, and China. Also, Switzerland has a few natural hot spots where arsenic is found in above-average concentrations. An example is soil at Liesberg in the canton of Baselland.

“The particular problem for plants is that arsenic behaves chemically similar to phosphorus,” says Professor Klaus Schlaeppi of the Department of Environmental Sciences at the University of Basel. Phosphorus is an important nutrient that plants take up through special transport channels in their roots. “The arsenic enters the plants through these channels.” As a result, more and more of the toxic substance accumulates in the biomass and gets into the food chain. On the long run, this negatively affects human health. High arsenic exposure can cause neurological damage and cancer, for example.

Roots release an antidote
But as Schlaeppi's team has now reported in the scientific journal PNAS, corn reduces arsenic toxicity through compounds known as benzoxazinoids. These substances are produced by most plants in the botanical group of grasses, which also includes corn and wheat. Corn produces particularly large quantities of benzoxazinoids, which are also released into soil through the root system. “There was already some evidence that corn takes up less arsenic than other plant species,” says Schlaeppi.

To test this hypothesis, the researchers grew corn plants in two types of soil: without arsenic and with high levels of arsenic. They performed the same experiment in parallel using corn plants that cannot produce benzoxazinoids because of a genetic defect. Schlaeppi performed these experiments in collaboration with the research groups of Professor Adrien Mestrot and Professor Matthias Erb at the University of Bern.

Mitigating arsenic toxicity
The result was unambiguous: benzoxazinoid-producing corn grew better in the arsenic-containing soil and accumulated significantly less arsenic in its biomass than the corn that did not exude benzoxazinoids. When the researchers mixed benzoxazinoids into the arsenic-containing soil, the mutant plants were also protected from arsenic toxicity. “This provided the proof that the presence of benzoxazinoids in soil reduced arsenic uptake into plants,” says Schlaeppi.

Next, the researchers wanted to find the underlying mechanism causing this effect. Analyses of the root microbiome indicated that bacteria and fungi were not involved. However, chemical soil analyses showed that a particularly toxic form of arsenic disappeared when benzoxazinoids are present. “This indicated that the benzoxazinoids transform arsenic in such a way that it can no longer be taken up through the root.” What chemical processes are involved is currently still unclear.

Further experiments showed that the positive effect of benzoxazinoids in soil persisted for a long time: even a second generation of corn still benefited from the benzoxazinoids discharge of the first generation.

“One application of these findings would be to cultivate at arsenic-contaminated locations plant varieties that release more benzoxazinoids,” says Schlaeppi. Hyper-emitting plants could be generated through classic breeding or targeted genetic modifications. “This way we could be more certain that less arsenic is entering the food chain.”

Seedlings of corn plants in a field experiment near Liesberg. W22 denotes the plants that produce benzoxazinoids. The bx1 corn plants lack the ability to produce these substances.

CREDIT

University of Basel, Veronica Caggìa

First author Veronica Caggìa measures the chlorophyll content of maize leaves. 

These measurements provide an approximation for photosynthesis and plant health.

CREDIT

University of Basel, Antoine Baud

JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2314261121