Spartan scientists are finding solutions to preserve one of the world’s most vital resources—soil.
It may be surprising to many, but soil is one of the planet’s most precious commodities—and it’s deteriorating at an alarming rate.
Unsustainable agricultural practices have led to the degradation of soil around the world, with the World Wildlife Foundation estimating that half of the topsoil on the planet has vanished in the past 150 years.
The United Nations Food and Agriculture Organization, which has dubbed 2015 the “International Year of Soils,” notes that expected growth in global population will require a 60 percent increase in food production, just to keep pace.
With increased demand for food production and one-third of the world’s soil declining in quality, how will growers respond to the challenge? What can be done to reverse negative trends and improve land management?
Michigan State University researchers are working on an international scale to find long-term solutions that help preserve this vital resource.
Laying the foundation
For more than four decades, James Tiedje, a University Distinguished Professor and the director of the MSU Center for Microbial Ecology, has been unlocking soil’s secrets with the development of new technologies and analysis techniques, broadening the scope of understanding for scientists everywhere.
Today Tiedje sequences DNA from soil with the same technology used in human medicine. MSU researchers, including Tiedje, led the largest soil DNA sequencing effort to date, collaborating with scientists at the U.S. Department of Energy Joint Genome Institute and Lawrence Berkeley National Laboratory.
“In the ’90s, it would take us almost four years to sequence one gene in a microbe,’ Tiedje says. “Now we can sequence billions of base pairs a day.”
Tiedje calls soil microbiology the greatest frontier in all of biology because it is the most complex, diverse and unknown. Microbial evolution over nearly 3 billion years has resulted in extremely high genetic diversity in soils. Sequencing efforts have decoded some of the mysteries, but scientists are just scratching the surface of identifying and understanding soil microbes and their impacts on agricultural production, the environment, biotechnology and medicine.
“No one knows how many species of bacteria there are,” Tiedje says. “Any particular gram of soil has about 1 billion bacteria, but no more than 0.1 percent of those microbes would be previously known.”
DNA technology is used in several of Tiedje’s current projects, including one that is part of the Great Lakes Bioenergy Research Center—led by the University of Wisconsin-Madison in partnership with MSU and one of only three national centers funded by the U.S. Department of Energy that focuses on biofuels research.
Tiedje’s group is using new high-capacity DNA sequencing to learn how a plant’s microbiome, or microbial community, can contribute to cost-effective and sustainable biofuel production.
In addition, MSU and other soil microbiologists have found microbes that can degrade environmental pollutants. Tiedje’s team is known for the discovery of bacteria that dechlorinate environmental contaminants, a process used for cleanup of contaminated groundwater and soil.
Lisa Tiemann, assistant professor of soil biology, is working with colleagues to gain a firm understanding of soil organic matter and how sustainable land management methods affect nutrients to increase yield and promote soil health.
“Without healthy soils, we can’t survive,” says Tiemann. “We depend on soils for nearly all of the food we eat.”
Until recently, researchers did not have a full picture of the diversity of organisms within soil. But the technology engineered by Tiedje has revealed a vast ecosystem consisting of thousands of microbial species. One of the keys now, Tiemann says, is to determine the role these species play and the implications they have on humans.
“Over the past 40 years, we’ve doubled the amount of food that we’ve had to produce to keep up with human population growth,” Tiemann says. “In the next 40 years, we have to double it again.”
We’ve gotten to the point now where there’s not a whole lot more land that we can actually use for farming, so what we need to do now is be more productive. My research is trying to understand how we can manage soil sustainably. In order to do that, we have to understand how soil organic matter is formed and how it’s maintained. Soil organic matter is the cornerstone of fertility.”
Through a grant funded by the National Science Foundation’s Science, Engineering and Education for Sustainability initiative, Tiemann’s research has taken her to the central African nation of Uganda, where she is working to understand the causes of soil organic matter decline and soil fertility loss. Running through 2016, the research will provide insight into the land management practices employed by farmers across the country.
A boom in population coupled with a decrease in fertile soil has put significant stress on Uganda’s available farmland. The Uganda National Environment Management Authority estimates the remaining land that could be used for agriculture will be converted to farmland by 2020 or 2025.
“That’s what we are trying to figure out now,” Tiemann says. “Are there things that people are doing elsewhere, cultural practices that would be acceptable for them to adopt that would help to at least maintain the status quo?”
Researchers are stressing the importance of cover crops in helping to increase nitrogen and add other nutrients to the soil as well as increasing the frequency of weeding to improve nutrient uptake for crops. Many of these recommendations are currently being implemented, changing the way Ugandans engage in agriculture with an eye on sustainability. But the work is far from over.
Getting their hands dirty
One of the few applied soil scientists at MSU, Kurt Steinke, assistant professor of soil fertility and nutrient management, works with growers across Michigan through a program he leads called MSU Soil Fertility Research. With the assistance of both graduate and undergraduate students, as well as a research technician, Steinke’s program, which is partially funded by MSU AgBioResearch and Extension, looks to address grower concerns by providing science-based research and extension information that ultimately promotes “greater yield in the field.”
Steinke’s nutrient management methods aim to provide farmers with higher yields and sustainability while improving long-term ecological efficiency. This involves using what’s known as the 4R approach—the right fertilizer source at the right rate, right time and with the right placement—to assist Michigan growers in maximizing their resources while simultaneously giving his students access to industry professionals.
Like Tiemann in Uganda, examining the microbial populations in soil and how management affects them has been a driving force in Steinke’s recent work.
“We’ve partnered with some of the technology that Jim Tiedje has brought into the realm of extracting DNA from the soil,” Steinke says. “Once we extract DNA and see what’s present, then it becomes a bigger question: is a more diverse microbial community better for plant production, or is it functionality rather than diversity? We’ve seen some instances where it may not be about microbial biomass but about getting the right microbes in the right spot at the right time to support a healthy system.”
The shift in thinking from simply growing plants to growing two crops, the microbes and the plants, has been a significant change.
Other technologies have improved accessibility for growers to what were once cost-prohibitive items, such as all-in-one nutrient products and slow-release products that minimize losses to rainfall and other environmental factors.
These improvements in affordable technology, in conjunction with his team’s research, allow Steinke to provide the most appropriate and sustainable recommendations for Michigan growers.
“We’re one of the only unbiased, third-party sources for nutrient response trials and nutrient recommendation,” Steinke says. “That’s the strength of the land-grant university and the strength of MSU AgBioResearch and Extension. We’re trying to make more progressive recommendations that incorporate these newer technologies without forgetting basic agronomic principles and practices. We are there to help growers stay profitable and use long-term management practices that keep their soil productive.”
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