GrainsWest Tech 2020

Tech 2020 grainswest.com 19 hile comic book superheroes use X-ray vision to fight crime, a research facility in Saskatoon, SK, is taking sub-surface sleuthing to a whole new level, shining light on new possibilities for agricultural research. The Canadian Light Source (CLS) at the University of Saskatchewan is a national synchrotron research facility that produces a light millions of times brighter than the sun. It is produced using a particle accelerator to generate a high-energy electron beam. Directed through specialized components, this energy can be directed into “beamlines” that use various aspects of the light for imaging. “Light has different forms that we call wavelengths. In simple terms, the synchrotron produces extremely bright light that can be used to study the physical structure of a plant or look at the chemical and elemental composition,” said Chithra Karunakaran, CLS environmental and earth sciences manager. “Hospital X-ray machines are sensitive to high density materials like bones, whereas synchrotron X-rays are very sensitive to small density differences in soft tissues, and that’s where it’s very useful for agricultural applications.” From analyzing soil carbon to reducing sodium content in bread, researchers put the synchrotron to work to address agriculture and food problems that can’t be solved in a conventional lab setting. This oftentimes means projects that require an analysis technique that does not destroy the samples being examined. “We can use X-rays to generate two- or three-dimensional images, so you can see the whole and intact wheat stem and you can get 3D information about living tissues. Then you can go through different layers and see the composition and relate the structure to the function,” said Karunakaran. “People want to see what happens below the ground with the soil and the roots. With the synchrotron systems we can look at root systems intact in soil—not many technologies can do that.” A DEEPER LOOK AT SOIL DYNAMICS Michael Schaefer is part of a research team at the University of California Riverside department of Environmental Sciences that is using the CLS to analyze soil composition. Specifically, the team is studying the short-term impacts of crop rotation on carbon storage in soil. Funded by the university, the project is part of a larger one examining how cover crops help mitigate the effects of drought and can reduce water use by California farmers. “There have been other long-term studies showing that cover crops increase soil carbon and moisture retention, but we were looking at what happens in the short-term, over one season of cover crop, to see if there is any change in how carbon is stored and aggregates are formed in the soil,” said Schaefer. Aggregates are the balls of sand, silt and clay that form in soil. They are held together by organic compounds, specifically carbon. Larger aggregates help the soil hold more water. W The team used the CLS to analyze aggregate samples from a plot that had been planted with a cover crop on one half and no cover crop on the other. Using one of the specialized beamlines, the facility’s high-resolution spherical grating monochromator (SGM), they were able to examine the chemical characteristics and type of carbon present in the samples without destroying them. The SGM beamline allowed the researchers to see where the carbon is in the soil and where it came from. In this case, the research team found that the carbon holding the larger aggregates in the soil together was new carbon that could be traced directly back to the cover crop. “While we didn’t see an increase in the total amount of carbon over a short time in the fields we were studying, with the cover crop we saw a dynamic cycling of carbon into larger aggregates even just within a year,” said Schaefer. The results of this study may indicate that cover crops help speed up the formation of larger aggregates. They help break larger aggregates down through the processes of cultivation and root growth, and then help re-form new, larger aggregates by adding carbon to the soil through the roots that bind smaller aggregates together. In the long-term, these rapid turnarounds may help increase overall soil carbon and aggregation. “Soils are not static, they are really dynamic things,” said Schaefer. The CLS allows researchers to pinpoint the chemical nature of carbon within various soil components giving them a better fundamental understanding of how soils work. “The more understanding you have of something, the more creative you can be in terms of coming up with solutions to problems. CLS allows us to ask questions that we previously wouldn’t have thought to ask because there were no tools to measure them.” “CLS is uniquely supportive of agricultural research across synchrotrons—it’s the premier facility for this kind of work.” —Michael Schaefer