Category Archives: Iowa State University

With a twist, rubbery material goes from flexible to stiff

Stress a muscle and it gets stronger. Mechanically stress a new rubbery material—say with a twist or a bend—and the it automatically stiffens by up to 300 percent, the engineers says.

In lab tests, mechanical stresses transformed a flexible strip of the material into a hard composite that can support 50 times its own weight.

…the new material could be used in medicine to support delicate tissues or in industry to protect valuable sensors.

This new composite material doesn’t need outside energy sources such as heat, light, or electricity to change its properties. And it could be used in a variety of ways, including applications in medicine and industry.

The researchers found a simple, low-cost way to produce particles of undercooled metal—that’s metal that remains liquid even below its melting temperature. Researchers created the tiny particles (they’re just 1 to 20 millionths of a meter across) by exposing droplets of melted metal to oxygen, creating an oxidation layer that coats the droplets and stops the liquid metal from turning solid. They also found ways to mix the liquid-metal particles with a rubbery elastomer material without breaking the particles.

When this hybrid material is subject to mechanical stresses—pushing, twisting, bending, squeezing—the liquid-metal particles break open. The liquid metal flows out of the oxide shell, fuses together, and solidifies.

“You can squeeze these particles just like a balloon,” says lead author Martin Thuo, assistant professor of materials science and engineering at Iowa State University. “When they pop, that’s what makes the metal flow and solidify.”

The result, lead author Michael Bartlett says, is a “metal mesh that forms inside the material.”

Octopus-inspired material morphs from flat to 3D

Thuo and Bartlett, also an assistant professor of materials science and engineering at Iowa State, say the popping point can be tuned to make the liquid metal flow after varying amounts of mechanical stress. Tuning could involve changing the metal used, changing the particle sizes, or changing the soft material.

In this case, the liquid-metal particles contain Field’s metal, an alloy of bismuth, indium, and tin. But Thuo says other metals will work, too.

“The idea is that no matter what metal you can get to undercool, you’ll get the same behavior,” he says.

The engineers say the new material could be used in medicine to support delicate tissues or in industry to protect valuable sensors. There could also be uses in soft and bio-inspired robotics or reconfigurable and wearable electronics.

“A device with this material can flex up to a certain amount of load,” Bartlett says. “But if you continue stressing it, the elastomer will stiffen and stop or slow down these forces.”

Squishy motor lets soft robots crawl over rocks

The researchers describe the material in a paper in the journal Materials Horizons.

The Iowa State University Research Foundation is working to patent the material, which is available for licensing. Iowa State startup funds for Thuo and Bartlett supported development of the new material. Thuo’s faculty fellowship also helped support the project.

Source: Iowa State University

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graphene-ink_740

Graphene ink could lead to washable electronics

New graphene printing technology can produce electronic circuits that are low-cost, flexible, highly conductive and water repellent, researchers report.

The nanotechnology “would lend enormous value to self-cleaning wearable/washable electronics that are resistant to stains, or ice and biofilm formation,” according to the new paper.

graphene ink
Jonathan Claussen and his research group are printing and processing graphene ink to make functional materials. (Credit: Christopher Gannon.)

“We’re taking low-cost, inkjet-printed graphene and tuning it with a laser to make functional materials,” says Jonathan Claussen, an assistant professor of mechanical engineering at Iowa State University, an associate of the US Department of Energy’s Ames Laboratory, and the corresponding author of the paper in the journal Nanoscale.

The wonder material

The paper describes how Claussen and the nanoengineers in his research group use inkjet printing technology to create electric circuits on flexible materials. In this case, the ink is flakes of graphene—the wonder material can be a great conductor of electricity and heat, plus it’s strong, stable, and biocompatible.

“The laser aligns the graphene flakes vertically—like little pyramids stacking up. And that’s what induces the hydrophobicity.”

The printed flakes, however, aren’t highly conductive and have to be processed to remove non-conductive binders and weld the flakes together, boosting conductivity and making them useful for electronics or sensors.

That post-print process typically involves heat or chemicals. But Claussen and his research group developed a rapid-pulse laser process that treats the graphene without damaging the printing surface—even if it’s paper.

And now they’ve found another application of their laser processing technology: taking graphene-printed circuits that can hold water droplets (they’re hydrophilic) and turning them into circuits that repel water (they’re superhydrophobic).

“We’re micro-patterning the surface of the inkjet-printed graphene,” Claussen says. “The laser aligns the graphene flakes vertically—like little pyramids stacking up. And that’s what induces the hydrophobicity.”

Claussen says the energy density of the laser processing can be adjusted to tune the degree of hydrophobicity and conductivity of the printed graphene circuits.

And that opens up all kinds of possibilities for new electronics and sensors, according to the paper.

Electronics everywhere

“One of the things we’d be interested in developing is anti-biofouling materials,” says paper coauthor Loreen Stromberg, an Iowa State postdoctoral research associate in mechanical engineering and at the Virtual Reality Applications Center.

As electronics shrink, add wrinkles to pillared graphene?

“This could eliminate the buildup of biological materials on the surface that would inhibit the optimal performance of devices such as chemical or biological sensors,” Stromberg says.

The technology could also have applications in flexible electronics, washable sensors in textiles, microfluidic technologies, drag reduction, de-icing, electrochemical sensors, and technology that uses graphene structures and electrical simulation to produce stem cells for nerve regeneration.

The researchers wrote that further studies should be done to better understand how the nano- and microsurfaces of the printed graphene creates the water-repelling capabilities.

The Iowa State University Research Foundation is working to patent the technology and has optioned it to an Ames-based startup, NanoSpy Inc., for possible commercialization. NanoSpy, located at the Iowa State University Research Park, is developing sensors to detect salmonella and other pathogens in food processing plants. Claussen and Stromberg are part of the company.

The graphene printing, processing, and tuning technology is turning out to be very useful, Stromberg says. After all, “electronics are being incorporated into everything.”

A bit of white graphene could give ceramics extra powers

Funding for the research came from grants from the National Science Foundation, the US Department of Agriculture’s National Institute of Food and Agriculture, the Roy J. Carver Charitable Trust, plus Iowa State’s College of Engineering and department of mechanical engineering.

Source: Iowa State University

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Plants get sensor ‘tattoos’ that track water

Sensors on tape that attach to plants yield new kinds of data about water use for researchers and farmers.

“With a tool like this, we can begin to breed plants that are more efficient in using water,” says Patrick Schnable, plant scientist at Iowa State University. “That’s exciting. We couldn’t do this before. But, once we can measure something, we can begin to understand it.”

The tool making these water measurements possible is a tiny graphene sensor that can be taped to plants—researchers call it a “plant tattoo sensor.” Graphene is an atom-thick carbon honeycomb. It’s great at conducting electricity and heat, and is strong and stable. The graphene-on-tape technology in this study has also gone into wearable strain and pressure sensors, including sensors for a “smart glove” that measures hand movements.

“You just use tape to manufacture these sensors. The cost is just cents.”

Researchers describe the various sensors and the “simple and versatile method for patterning and transferring graphene-based nanomaterials” to create the flexible sensors in the journal Advanced Materials Technologies.

“We’re trying to make sensors that are cheaper and still high performing,” says lead author Liang Dong, associate professor of electrical and computer engineering.

To do that, the researchers have developed a process for fabricating intricate graphene patterns on tape. Dong says the first step is creating indented patterns on the surface of a polymer block, either with a molding process or with 3D printing. Engineers apply a liquid graphene solution to the block, filling the indented patterns. They use tape to remove the excess graphene. Then they take another strip of tape to pull away the graphene patterns, creating a sensor on the tape.

The process can produce precise patterns as small as 5 millionths of a meter wide–just a twentieth of the diameter of the average human hair. Dong says making the patterns so small increases the sensitivity of the sensors.

“This fabrication process is very simple,” Dong says. “You just use tape to manufacture these sensors. The cost is just cents.”

In the case of plant studies, the sensors are made with graphene oxide, a material very sensitive to water vapor. The presence of water vapor changes the conductivity of the material, and that can be quantified to accurately measure transpiration (the release of water vapor) from a leaf.

The plant sensors have been successfully tested in lab and pilot field experiments, Dong says.

“The most exciting application of the tape-based sensors we’ve tested so far is the plant sensor,” Dong says. “The concept of wearable electronic sensors for plants is brand new. And the plant sensors are so tiny they can detect transpiration from plants, but they won’t affect plant growth or crop production.”

Disposable sensor could say when food isn’t fresh

But that’s not all the sensors can do. The technology could “open a new route” for a wide variety of applications, the authors write in their paper, including sensors for biomedical diagnostics, for checking the structural integrity of buildings, for monitoring the environment, and, after appropriate modifications, for testing crops for diseases or pesticides.

Primary support for the work has come from the Faculty Scholars Program of Iowa State’s Plant Sciences Institute. A grant from the US Department of Agriculture’s Agriculture and Food Research Initiative will support more field testing of water transport in corn plants.

The Iowa State University Research Foundation has applied for a patent on the sensor technology. The research foundation has also granted an option to commercialize the technology to EnGeniousAg—an Ames startup company co-founded by Dong, Schnable, and other collaborators.

Source: Iowa State University

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How young people talk about abstaining from sex

New research determines how college students initiate conversations about their decision to abstain from or delay sex, and the strategies they use to explain this to their partners.

At a time of greater awareness about sexual assault, Tina Coffelt, an assistant professor of English and communication studies at Iowa State University, says it is important to help students navigate these conversations.

Young adults may be reluctant to express these needs because of fear of rejection from their partner, or they may feel it is taboo to talk openly about sexual activity, she says. There are resources available, but many focus on safe sex.

“Our culture assumes that young adults do not want to wait, so the messages are always about how to have safe sex,” Coffelt says. “What about students or emerging adults who don’t want to have sex? There just doesn’t seem to be that much support, especially from a secular perspective.”

Other studies have shown as many as 25 percent of young adults are virgins. Part of Coffelt’s motivation for this study, published in the Western Journal of Communication, was to identify the tactics students use when talking about abstinence or delaying. She says some health centers and websites promote “talking with your partner,” but offer no guidance or explanation of what that means.

Coffelt collected data through online surveys of 192 young adults and interviews with 27. Nearly all participants agreed the conversation should include a reason or explanation for delaying or abstaining. Coffelt says this point struck her because she found no evidence in the existing research of young adults explaining why they were sexually active. However, in her study a majority said some rationale was necessary when abstaining.

Three themes

Asserting or enforcing an individual right was the most frequently stated goal—43 percent—for study participants. Coffelt identified three distinct themes or ways they engaged in conversations to delay or abstain:

  • A personal choice that reflected independence and an expectation the choice be respected;
  • A joint decision or collaboration as a couple to reach an agreement about sexual activity;
  • An individual demand for no sexual intercourse, but presented as a joint decision.

In the study, 94 percent of participants said they did not have sex on the day they had this conversation. Coffelt says this shows their partners respected and honored their wishes. The conversations often began as sexual activity escalated. Participants told their partner “no” or used a nonverbal distancing cue to stop the activity, which was followed by a conversation later. Some conversations were initiated well before any sexual activity occurred, the study finds.

Why young men have sex they don’t actually want

Given that some young adults avoid these conversations because of fear of rejection, Coffelt hopes this study will lessen those concerns.

“Young adults have the right to assert their sexual goals,” she says. “If those goals are to abstain or delay, those messages will likely be respected and adhered to.”

Get specific

People have different definitions of abstinence, Coffelt says, and delaying sex has a variety of meanings. For example, several study participants who said they were delaying were willing to engage in sexual activity once they reached a pivotal moment—not necessarily marriage—in the relationship. Coffelt says it is important for young adults to clearly define what they mean to help their partner understand their wishes, rather than assume.

Many study participants said their parents or religion were also strong motivations for abstaining. While families and religious organizations can help young adults initiate these conversations, Coffelt wants to see the Centers for Disease Control and Prevention and student health centers take a more active role. She recommends providing a dialogue that individuals can have if they want to abstain or delay.

Source: Iowa State University

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These genes could save soybeans from sudden death

Researchers have found a gene in the plant Arabidopsis that could protect soybeans from diseases, like sudden death syndrome, that plague the plant.

“We think we may find that multiple genes working together will build the resistance levels…”

Madan Bhattacharyya, a professor of agronomy at Iowa State University and lead author of the study, says his current research points toward several Arabidopsis genes that could act in concert to help soybeans fight off sudden death syndrome, a disease that has caused millions of dollars in crop losses for Iowa farmers.

“We’ve started to map many of these genes, and we think there are many different mechanisms that work together to create resistance of Arabidopsis against two soybean pathogens,” Bhattacharyya says. “We’re testing a hypothesis that putting a combination of these Arabidopsis genes into soybeans confers a high level of disease resistance.”

Bhattacharyya says all complex organisms, whether plants or animals, demonstrate resistance to most of the potential pathogens they encounter in their environment. Arabidopsis, a small flowering plant that serves as a good model plant in experimental settings, shows resistance to two soybean pathogens that cause sudden death syndrome and root rot, respectively.

So Bhattacharyya and his colleagues have spent years combing the genome of Arabidopsis to identify genes that might contribute to that resistance. He then uses transgenic techniques to insert likely genes into soybean plants at Iowa State’s Plant Transformation Facility.

The study identifies one of those genes, called PSS1, as a means of improving soybean resistance. The transgenic soybean plants carrying this gene showed enhanced SDS resistance in two consecutive years under field conditions, Bhattacharyya says. The SDS resistance encoded by this gene will complement the natural SDS resistance, which is encoded by 40 or so genes each conditioning small amounts of resistance.

Soybean farmers face a new foe: early aphids

He expects incorporation of additional PSS genes together with natural SDS-resistance genes will provide soybeans robust and durable resistance. Finding the optimal combination of those genes is the current research goal of his lab, he says.

“We’re hoping in the next few years to test how combinations of PSS genes affect SDS resistance,” Bhattacharyya says. “We think we may find that multiple genes working together will build the resistance levels.”

The Iowa Soybean Association and Consortium of Plant Biotechnology Research funded much of the early research dating as far back as 2004, Bhattacharyya says. Currently, a grant through the Agriculture and Food Research Initiative from the US Department of Agriculture’s National Institutes of Food and Agriculture, as well as the United Soybean Board and the Iowa State agronomy department, provide funding.

The researchers report their findings in the journal Plant Physiology.

Source: Iowa State University

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These ‘at-risk’ preschoolers beat expectations

Dual-language learners in Head Start show significant growth in cognitive and academic areas, report researchers. Once they gained basic English proficiency, the dual-language learners eventually outperformed students who only spoke English.

Not all dual-language learners (DLLs) are at risk academically, but as a group, they are often labeled that way.

As reported in Early Childhood Research Quarterly, researchers analyzed data measuring inhibitory control (the ability to pay attention and control natural, but unnecessary thoughts or behaviors) and math achievement for low-income students in Head Start through kindergarten.

The data, collected through the Head Start Family and Child Experiences Survey (FACES) 2009, included 825 children—whose home language was English or Spanish—at 59 Head Start programs across the country.

Instead of treating DLLs as a homogenous group, researchers created two categories—Spanish-English bilinguals, who can function in both languages; and DLLs with limited English skills—based on their ability entering Head Start.

The findings identified stark differences between the DLL groups and English-only students over the course of the study. Entering Head Start, bilingual students had higher inhibitory control, but lower math scores, than English-only students did. DLLs with limited English skills lagged behind both groups.

“When these students do not have age-appropriate English skills they are more at risk, but once they achieve those skills they actually excel.”

However, over the course of 18 months, bilingual students outperformed English-only students with higher scores in math and inhibitory control, despite having lower baseline scores for math at the beginning of the study.

DLLs with limited English skills—students considered at risk when they entered Head Start—also made significant progress. These students outpaced bilingual and English-only students in the rate of gains for inhibitory control skills.

While their scores had not caught up with the other two groups by the midpoint of kindergarten (the final point of analysis for the study), researchers expect with more time DLLs with limited English skills would eventually match or even outperform English-only peers as they learn more English and become bilingual.

“Recognizing that dual-language learners can do better than we expected has huge implications. When these students do not have age-appropriate English skills they are more at risk, but once they achieve those skills they actually excel,” says Ji-Young Choi, an assistant professor of human development and family studies at Iowa State University. “This study also confirms that there is a cognitive benefit for bilingual students.”

Do bilingual homes raise better communicators?

Bilingual children’s faster growth rate in inhibitory control over time helped explain the significant difference in kindergarten math skills between bilingual children and English-only students. Based on the FACES data, they could not provide a definitive explanation for the faster growth rate in inhibitory control.

However the results lend support to the theory that bilingual students develop stronger inhibitory control skills because of their daily practice toggling between languages to fit the conversation, and inhibiting one language while speaking another.

Inhibitory control encompasses everything from a child’s ability to suppress the impulse to grab a toy away from a friend to inhibiting the impulse to pronounce a “t” sound at the beginning of the, says Christine Lippard, an assistant professor of human development and family studies. It is an important foundational skill for academic growth as well as behavior.

Bilingual babies know when the rules don’t apply

Recognizing skill-level differences is important given that DLLs are in more than 70 percent of Head Start classrooms. All early childhood educators need to understand the developmental strengths of DLLs, and recognize there is no one-size-fits-all approach for teaching these students.

The study makes the case for instructional support to help DLLs become proficient in English while learning or maintaining their home language. One way to achieve that is by giving students the opportunity to engage with linguistically diverse teachers, Lippard says.

“Preschool programs are so full of academic expectations that adding a Spanish lesson time may not be helpful or developmentally appropriate. Learning Spanish by interacting with a native Spanish speaker and experiencing typical preschool activities like singing songs or reading stories in Spanish holds potential benefits for all of the children in the classroom.”

Source: Iowa State University

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Teen smartphone use and lack of sleep may be linked

Teens who spend more than an hour or two on their smartphones each day may not be getting a enough sleep at night, new research suggests.

“The way tech companies develop these algorithms is like making a drug…”

The research is the strongest evidence to date that teens’ increased use of electronic devices in recent years is responsible for similar rises in insufficient sleep.

Researchers analyzed data from two national surveys of more than 360,000 teens, focusing specifically on changes in sleep and smartphone use from 2009 to 2015. They noted an abrupt change in teens’ sleep habits around 2012, the same time smartphones became more prevalent.

According to the study, as time spent on smartphones increased, so did the percentage of teens getting insufficient sleep:

  • Relative to 2009, 17 percent more teens in 2015 reported sleeping fewer than seven hours a night.
  • 35 percent of teens using electronic devices for one hour a day slept fewer than seven hours.
  • 52 percent of teens using electronic devices for five-plus hours slept fewer than seven hours.
  • For comparison, those spending more than five hours were 50 percent more likely to sleep less than those spending an hour a day.

Nine hours a night

Insufficient sleep is one of the many health consequences stemming from an increased dependency on technology, says Zlatan Krizan, an associate professor of psychology at Iowa State University. This is especially concerning for teens who are not getting the recommended nine hours of sleep each night.

“Our body is going to try to meet its sleep needs, which means sleep is going to interfere or shove its nose in other spheres of our lives,” Krizan says. “Teens may catch up with naps on the weekend or they may start falling asleep at school.”

Establishing good sleep habits and setting smartphone limits at an early age helps promote responsible use later in life. Jean Twenge, lead author of the study, San Diego State University professor, and author of the book iGen (Simon and Schuster, 2017), says this study illustrates the need for moderation, particularly for generations of teens now growing up with smartphones.

“Given the importance of sleep for physical and mental health, both teens and adults should consider whether their smartphone use is interfering with their sleep. It’s particularly important not to use screen devices right before bed, as they might interfere with falling asleep,” Twenge says.

Sleepy teens wake at night to check social media

While personal responsibility is an important component, Krizan says that alone is not enough to reverse the trend. The issue is complicated because smartphones are beneficial for work, staying connected with family, and even for emergency notifications, such as Amber Alerts. Electronic devices are so intertwined with our daily activities that if we’re not on our phone, it is always close by.

Unlike other public health concerns, government or social interventions have a limited reach in addressing this issue, Krizan says. Schools have implemented policies and rules regarding smartphone use during class, but parents bear much of the responsibility to restrict use for teens, especially late at night. However, Krizan notes that effective change often comes from social institutions. That is why he says technology companies must be part of the solution.

Silence your phone

“The way tech companies develop these algorithms is like making a drug,” Krizan says. “The software developers want you to make sure you never put your smartphone down. They want you to check in constantly and to like and click as many times as possible. That’s why we get alerts and notifications, all of which make it more and more difficult to put the device down.”

Krizan says we are unlikely to change our behavior without tech companies giving control back to the user. Facebook and Twitter have created social rewards that drive us to check and see if someone liked one of our tweets or shared a photo we posted, he says.

“You may think you’re in control of your smartphone use, but are you? If you are always checking it, then your phone is controlling your behavior,” Krizan says. “It’s the drug of the 21st century.”

Creating a culture without active alerts and protected times when our smartphones are silent will not happen overnight, but Krizan says such steps are likely to have the greatest effect.

Should teens sleep in on school days?

The researchers report their findings in the journal Sleep Medicine.

Source: Iowa State University

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Teamwork is more complex than ‘collective intelligence’

New research casts doubt on the idea of “collective intelligence.”

The concept of collective intelligence is simple—it asserts that if a team performs well on one task, it will repeat that success on other projects, regardless of the scope or focus of the work. While it sounds good in theory, it doesn’t work that way in reality, according to new research.

“While a Marine Corps fire team is great at its job, it’s not going to work well performing surgery.”

Marcus Credé, an assistant professor of psychology at Iowa State University, says unlike individuals, group dynamics are too complex to predict a team’s effectiveness with one general factor, such as intelligence. Instead, there are a variety of factors—leadership, group communication, decision-making skills—that affect a team’s performance, he says.

Anita Woolley’s research supporting collective intelligence quickly gained traction in the business world when it came out in 2010. The attention didn’t surprise Credé. Because organizations rely heavily on group work, managers are always looking for a “silver bullet” to improve team performance, he says.

After re-analyzing the data gathered by Woolley and her colleagues, however, Credé and Garett Howardson, an assistant professor at Hofstra University, found the data didn’t support the basic premise of collective intelligence.

“For decades researchers have looked at what makes a team work well. They’ve typically found that if a team performs well in one area, that is largely unrelated to how the team will perform in a different area,” Credé says. “A team working on a production line requires a fundamentally different set of skills than a team trying to find creative solutions to a problem. While a Marine Corps fire team is great at its job, it’s not going to work well performing surgery.”

Credé notes that of the six studies included in their re-analysis, only one—a 2014 study by researchers at Indiana University—correctly concluded there was no evidence of collective intelligence.

Credé says conflicting data was just one of three major problems he and Howardson discovered. Their analysis found participants in these studies were either unmotivated—which Credé suspects is likely the case—or they were confused by some of the tasks the groups were asked to perform. For example, as part of a brainstorming task, each team had 10 minutes to come up with different uses for a brick. Teams scored a point for each use, regardless of the practicality.

At least one team included in the analysis received a zero on this task. Credé says it’s hard to believe a team could not come up with one use for a brick. In this example, if one group does poorly because of minimal effort, it can artificially inflate correlations between performance across tasks, the researchers explain in the paper.

Groups are often smarter without ‘opinion leaders’

As a result, Credé says Woolley and her team may have misinterpreted the data as an indicator of collective intelligence.

They also did not recognize that teams can exhibit some consistency in performance across tasks, even when the team members barely interact with each other. In other words, the teams may not have functioned collectively. Instead, Credé says individual team members may have developed separate responses that were averaged across the team, rather than true collaboration.

The fact that study participants were college students receiving course credit or community members receiving a stipend also doesn’t reflect how teams form and function within organizations.

“In real organizations, people typically know each other; they work together over time and work on very different tasks than the ones assigned in the study,” Credé says. “A lot of teams are also comprised of members with high-level and different skill sets, and often one member functions as a leader.”

Credé says in one study, Woolley and her team recorded team conversations while each group was completing a task, which offers a better understanding of how team members interact. In some groups, one team member dominated the entire conversation, and in other groups, there were more equal contributions. Credé says team performance generally suffers when one person controls the conversation.

It is possible that team performance on one task may predict its performance on another similar task, Credé says. For researchers to fully understand this relationship, however, their work must mirror team composition and tasks in real organizations. Credé cautions that this may be difficult to replicate in a lab setting.

One ‘dominator’ can damage a group project

The researchers published their work in the Journal of Applied Psychology.

Source: Iowa State University

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Extra fertilizer puts prairie plants off schedule

Excess nitrogen from fertilizers can give an advantage to early-season plants in Midwestern prairies, leading to further changes in prairie ecosystems, new research suggests.

The study shows how excess nutrients from fertilizers that find their way onto prairies tend to alter the composition of those ecosystems, a development that has implications for management practices and wildlife habitat. The nutrients in the fertilizers can end up on nearby prairies when washed away by rain or carried by the wind when fields are plowed.

“When we add fertilizer, we’re changing the composition of the prairie community to species that produce flowers earlier in the season…”

Lead author Lori Biederman, adjunct assistant professor of ecology, evolution, and organismal biology at Iowa State University, says the project drew on data gathered from 11 prairies throughout the Midwest. The study looked at nitrogen, phosphorous, and potassium fertilizers and found that nitrogen added to tall-grass prairies gives an advantage to early-season flowering plants such as brome grass and violets.

The earlier-flowering plants then compete with plants that flower later in the year, such as asters and bluestems. The plants that flower in May and June, fertilized by the excess nutrients, take up more space, water, and sunlight than they would under normal conditions, Biederman says. That makes it more difficult for late-season plants to grow.

“When we add fertilizer, we’re changing the composition of the prairie community to species that produce flowers earlier in the season,” Biederman says. “Nitrogen was the driver of the changes we saw.”

The changes in prairie composition could cause shifts in animal habitat, particularly for pollinating insects that depend on flowering plants, she says.

In the study, researchers added various levels of fertilizer to numerous plots of prairie plants. The researchers then assessed the abundance of each plant species growing in each plot. The research drew on data from a global web of scientists who monitor and share ecological conditions.

Leaving ‘prairie strips’ on farmland pays off

Known as the Nutrient Network, the system has helped scientists at Iowa State and many other institutions by providing valuable datasets at little cost. Iowa State University scientists have participated in the Nutrient Network since 2009, and the network provides data from every continent except Antarctica.

The researchers originally reported their work in the journal PLOS ONE. The Science Journal for Kids, a publication aimed at presenting younger audiences with scientific concepts, also published the paper.

Source: Iowa State University

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Leaving ‘prairie strips’ on farmland pays off

Even a relatively small amount of prairie on certain farmland can deliver major environmental benefits, 10 years of data show.

A group of scientists called STRIPS (Science-based Trials of Rowcrops Integrated with Prairie Strips) is investigating the benefits that may arise from integrating prairie into crop production systems.

“This study puts everything we’ve worked on together,” says Lisa Schulte Moore, a professor of natural resource ecology and management at Iowa State University and lead author of the paper in the Proceedings of the National Academy of Sciences.

“The strips are designed to act as a speed bump to slow water down and give it time to infiltrate the soil.”

The study includes findings from 12 watersheds at the Neal Smith Wildlife Refuge near Prairie City. The experimental areas featured corn and soybean fields with strips of prairie integrated into the land at various positions and percentages on the row-crop landscape.

Each prairie strip contained a diverse range of perennial grass and wildflower species in order to slow the movement of water and ensure that plants would be in bloom the entire growing season to provide habitat to pollinating insects.

The researchers gathered data on dozens of ecosystem performance metrics. The results show prairie strips offer a range of environmental benefits at a lower cost than many other conservation techniques, Schulte Moore says. Social survey results also presented in the paper portray Iowans’ support for agricultural policies that produce outcomes such as those that the prairie strips provide.

The prairie strips reduce soil and nutrient loss from steep ground, provide habitat for wildlife, and improve water infiltration. According to the study, converting as little as 10 percent of the cropped area to prairie conservation strips reduced soil loss by 95 percent, phosphorus losses in surface runoff by 77 percent, nitrate concentrations in groundwater by 72 percent, and total nitrogen losses in surface runoff by 70 percent, compared with all-crop watersheds. Pollinator and bird abundance more than doubled.

“The strips are designed to act as a speed bump to slow water down and give it time to infiltrate the soil,” Schulte Moore says.

The study found that 40 percent of Iowa land currently devoted to row crops could realize significant benefits from growing prairie on approximately 10 percent of the area. Most of the land in question features steep inclines where soil erodes easily.

Paying farmers not to farm saved sage grouse

The study’s economic analysis found the prairie strips cost less than terraces and compare similarly to the cost of planting cover crops. But prairie strips pose different management considerations compared to cover crops, making them more amenable to some farming operations, Schulte Moore says. The study also found that the benefits derived from prairie strips are considerable compared to the land used to support them.

“We found that a little prairie yields big benefits,” Schulte Moore says. “The benefits are disproportionate to the area taken out of crop production.”

The STRIPS project began in the fall of 2003 at the Neal Smith National Wildlife Refuge site. Initiating institutions included Iowa State, the US Fish and Wildlife Service, and the US Department of Agriculture Forest Service. The new paper also includes scientists from the USDA Agricultural Research Service and a private farmer who worked with the team.

Project personnel and collaborators have helped 47 farmers in Iowa, Illinois, Missouri, and Wisconsin install native prairie on their fields, and the team is now working to gather data on a subset of those sites as well. The STRIPS team is planning installations at 11 additional farms in the next few months. The next phase of the project will involve adding new layers to the prairie strip formula, including testing how strips interact with varying soil types and how they work in conjunction with other conservation practices, Schulte Moore says.

Source: Iowa State University

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