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WSU’s Green Times- Bioasphalt, Fungi, Soil

Posted by | February 19, 2014

Paving the way with fryer oil

The heat, the petroleum fumes…  No one likes to be stuck behind an asphalt paving truck on a sweltering summer day. But, for the last 100 years, asphalt has played an integral role in building a strong American economy, keeping us all connected via our sprawling, easily accessible web of national roadways. So, imagine the relief and celebration if hot asphalt instead served up the aroma of French fries or deep-fried shrimp, won tons, or corndogs.

Asphalt is going green. In the near future, Washington motorists may be the first in the nation to drive on streets and highways paved with waste cooking oil-based asphalt. A scientist at Washington State University has developed the technology to substitute restaurant cooking oil for crude oil in the production of a sustainable “bioasphalt” that looks and handles just like its petroleum-based predecessor.

Professor Haifang Wen shows a can of his cooking oil-based bioasphalt.
Professor Haifang Wen shows a can of his cooking oil-based bioasphalt.

“We are shooting for summer 2014 to construct a trial road—probably at least a quarter mile long,” says Haifang Wen, assistant professor in the WSU Department of Civil and Environmental Engineering.

Faced with rising petroleum prices, new environmental regulations, and changes to the crude oil refining process, asphalt has become a scarce and costly commodity. Made from the residue left behind after production of gasoline, plastics, and other materials, lowly asphalt still commands $700-800 per ton, or half the price of gasoline at $1500 per ton, estimates Wen.

Haifang Wen in his laboratory holding a small can of cooking oil-based bioasphalt and a sample of the final hot mix asphalt (HMA).
Haifang Wen in his laboratory holding a small can of cooking oil-based bioasphalt and a sample of the final hot mix asphalt (HMA).

“Every year in the U.S., we use about 30 million tons of asphalt binder for roads,” he says. “More if you include roofing shingles. It’s easily a multi-billion dollar business.” But, it’s an old-school business that hasn’t done much sustainable thinking, Wen adds. “Only in the last decade has the green asphalt industry started coming together.

It’s slowly picking up—more slowly than I wish.” In Iowa, for example, scientists are making a corn-based bioasphalt from residue left after the production of ethanol. In North Carolina, swine manure is being incorporated as a paving substitute.

“Building roads is a big expenditure of taxpayer money,” says Wen. “In general, a one-mile road in a rural area costs at least a million dollars to build. With the waste cooking oil technology, we can reduce the cost of asphalt binder to under $200 per ton, making road building much cheaper.”

Laboratory compression test for Haifang Wen's cooking oil-based bioasphalt. "Can it take the pressure?"
Laboratory compression test for Haifang Wen’s cooking oil-based bioasphalt. “Can it take the pressure?”

Asphalt binder, the sticky “glue” that holds crushed stone and sand together to form pavement, only accounts for about five percent of the final hot mix asphalt (HMA) that is steamrolled into glossy new lanes and boulevards.

HMA has to be tough and reliable, able to withstand the ravages of heavy trucks as well as the extremes of Mother Nature. In Wen’s lab, each component of his bioasphalt is subjected to a series of rigorous stress tests such as intense heat, freezing temperatures, compression, and loading.

After four years of working with a chemist and “adjusting the recipe,” Wen is confident that his green, sustainable asphalt “is as good as the old-school petroleum asphalt.
I am very excited to have patented a solid technology,” he says.

All of which has the undivided attention of both federal and state highway agencies. Wen has been collaborating with both and says the industry is “very interested and eagerly awaiting the roll out of (his) product.”

Nationwide, it’s an industry that supports more than 300,000 Americans in about 4,000 asphalt plants — one in every congressional district, according to the National Asphalt Pavement Association.

Wen’s waste cooking oil asphalt study also fits with President Obama’s 2012 Moving Ahead for Progress in the 21st Century Act (MAP-21) — where Congress is addressing the need for sustainability in the national infrastructure system, including surface transportation.

-Becky Phillips

Exploring environmentally-friendly veggie grafting

A team of Washington State University vegetable horticulture researchers travels to China next month to present their research findings as part of a global effort to increase environmentally friendly vegetable production through grafting. Their efforts may stimulate a new market for vegetable production in Western Washington.

WSU vegetable horticulture scientist Carol Miles (left) and graduate student Jesse Wimer (right) will share the results of their latests research in China next month. Photo by Kim Binczewski, WSU.
WSU vegetable horticulture scientist Carol Miles (left) and graduate student Jesse Wimer (right) will share the results of their latest research in China next month. Photo by Kim Binczewski, WSU.

WSU Mount Vernon’s Vegetable Horticulture Program Leader Carol Miles and graduate student Jesse Wimer will give presentations in Wuhan, China, at the International Symposium on Vegetable Grafting, March 17-21, sponsored by the International Society for Horticultural Science.

Miles and Wimer are among the 200 guests–including researchers, company managers, and growers–who were invited to this inaugural event being held at Huazhong Agricultural University to promote communication and cooperation among vegetable grafting professionals around the world.

“Attending this symposium gives us the opportunity to share our Washington results with the international vegetable grafting science community and to learn from scientists and professionals where vegetable grafting has been practiced for decades,” said Miles, who is a faculty member at the WSU Mount Vernon Northwestern Washington Research and Extension Center and also serves as advisor to Wimer, an M.S. student in the vegetable horticulture program there.

The theme of this inaugural symposium is environmentally-friendly production of vegetables via grafting. The five-day event includes such topics as grafted seedling production, rootstock breeding, grafting and stresses, rootstock-soil interactions, and rootstock-mediated effects on yield and fruit quality. Read more.

-Carol Miles

Growing interest in soil quality spurs discussion

Interest in “soil quality,” or soil health, has grown rapidly over the past decade, regardless of agricultural production system or geographical region. While there have been focused efforts on soil conservation in the past, there seems to be a growing consensus that agriculture at large has historically undervalued the important role that soils can play in improving sustainability. Some of these roles or functions include disease suppression, nutrient cycling, and water management.

In Washington State, numerous educational workshops, research experiments and publications have been popping up that have some relevancy to the larger questions of defining and managing for improved soil quality. The interest has been so high that many of these workshops have been at capacity or standing-room-only events.

The Center for Sustaining Agriculture and Natural Resources (CSANR) at Washington State University is no stranger to many of these activities and discussions – and our Advisory Committee has long advocated for more research investment focused on soil quality – which we are doing. In fact, we prioritized soil quality in the FY14 BIOAg Grant Program: “Special consideration will be given for proposals in FY14 related to valuation (such as, economic, ecosystem services, etc.), increasing understanding, and management for soil quality.” We will be funding several research proposals in this area.

Chad Kruger, CSNAR Director
Chad Kruger, CSANR Director

The challenge that we’ve faced thus far, though, is how to prioritize our fairly limited investment power in an area as broad as soil quality to maximize the impact we can have for agriculture in our region. With that question in mind, we convened the CSANR Advisory Committee in January to provide guidance into how we prioritize soil quality research.

The Advisory Committee (AC) proposed nearly 100 different possible soil quality topics that could be categorized into about 15 themes. The AC further winnowed these lists through discussion and ranking, and presented their top three research priorities. In spite of the distribution of agricultural system perspectives across groups, a few key priority areas did emerge. Across all four groups there was universal agreement on two priorities:

  1. The role of soil biology and disease management. (To be fair, while disease suppression seemed to be the most easily identified function, there was general agreement that this priority should be about more than “just disease suppression”.)
  2. The economics of farming for improved soil quality.

More than one group also identified the following priorities:

  1. Understanding the role of soils in water management (both supply and quality).
  2. Developing soil quality indicators that farmers can use as a management tool.

Obviously, these are still relatively broad areas of inquiry, but they do provide a useful lens through which to evaluate and prioritize future research investments. The good news is that some of the current research underway does address these priorities and will help kick-start our efforts. I will be charging a task force of faculty and Advisory Committee members to further explore this topic and help us refine our research investment strategies for the next five years.

If you have any specific ideas or research questions that you think would be interesting to add to this discussion, please leave them in the comments field via the link below and the task force will take them into consideration.

This article was originally posted on the WSU Center for Sustaining Agriculture and Natural resources blog and can be viewed along with other posts and comments, here.

-Chad Kruger

Can good fungi restore bad soil?

Tarah Sullivan is fascinated by fungi, especially the ones in agricultural soils that offer hope for mitigating toxicity issues by transforming harmful metals.

Tarah Sullivan and Geoff Gadd. Photo by Shelly Hanks, WSU.
Tarah Sullivan and Geoff Gadd. Photo by Shelly Hanks, WSU.

As a new assistant professor of soil microbiology in the WSU Department of Crop and Soil Sciences, Sullivan is busy setting up her laboratory to study how soil microbes can transform toxic metals like lead, aluminum, and cadmium into less toxic forms, and how they can help plants more effectively take up essential micronutrients like iron, zinc and copper.

“One idea that gets people excited is the possibility that beneficial fungi could help address the increasing soil acidification and aluminum toxicity problems found in the Palouse,” Sullivan said.

In the last 50 years, soil acidity has increased due to the use of nitrogen fertilizers. The bad news is that soil acidity can cause dramatic decreases in yields– in many locations up to 50 percent or more for sensitive crops, such as garbanzos, lentils, wheat, and barley, according to Sullivan. Soil acidity transforms naturally occurring aluminum into a soluble form that is more available to plants, but which damages their roots. A common, though costly, solution to aluminum toxicity is to reduce soil acidity by applying lime to the soil. But the effects are often short lived.

The good news is that fungi are plentiful and tolerant of acidic soils, and many are even well-suited for remediation of metals. According to Sullivan, as soils become more acidic, fungi can comprise more than 75 percent of soil microbes by mass– and most are the “good guys.”

“There are hundreds of billions of microbes in one gram of soil. An extremely small proportion of them are pathogens. The vast majority of soil microbes are beneficial and we don’t fully understand those,” Sullivan said.

Many species of fungi associated with plant roots, called mycorrhizal fungi, have been shown to decrease aluminum toxicity in plants. Sullivan wants to know how we can enhance these beneficial soil fungi populations in the field and how we can promote their metal-detoxifying activities.

Fungi on the surface of lead shot transform lead minerals into a less toxic form. Photo by Geoff Gadd.
Fungi on the surface of lead shot transform lead minerals into a less toxic form. Photo by Geoff Gadd.

Sullivan hopes to identify specific fungi that have the aluminum buffering qualities, and then see if it’s possible to inoculate the soil with them to extend the benefits of liming. She also hopes to discover whether it’s possible to create soil conditions that favor the beneficial fungi by adding soil amendments such as compost or straw.

Ultimately, Sullivan believes her research will contribute to a sustainable approach to mitigating soil acidification problems in the Palouse, providing a more environmentally friendly and economically viable long-term strategy.

Sullivan holds a doctorate in soil microbiology from Cornell University and comes to WSU following postdoctoral research at Oak Ridge National Laboratory where she focused on soil fungal communities in a lead-contaminated military site. She recently hosted a WSU Department of Crop and Soil Sciences seminar presented by Geoffrey Michael Gadd, an internationally known geomycologist from the University of Dundee in Scotland who studies how fungi transform the chemical composition of rocks and minerals.

Learn more about mycology and crop and soil sciences at

-Sylvia Kantor