6. Canadian Intercropping Project Research Results video

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• published: 20 Jul 2015
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Trees Can Help Save the World - Chapter 6 Watch complete playlist (Chapters 1-7) https://www.youtube.com/playlist?list=PLeR2DZtnlTQtik4SxT9unDrVP5Gu2aEPb For more information about the Canadian Agricultural Greenhouse Gases Program, visit: http://agr.gc.ca To contact researchers: agordon@uoguelph.ca nthevath@uoguelph.ca Robert.Bradley@USherbrooke.ca Edited Transcript: In the previous chapter of this video series, you saw scientists taking a three-dimensional look at empty spaces in soil, and the role that they play in the dynamics of greenhouse gas emissions. The research is part of a multi-disciplinary project to reduce greenhouse gas emissions from farm fields. Funded by Canada’s Agricultural Greenhouse Gases Program, the research project focuses on tree-based intercropping systems in Ontario and Quebec. Intercropping involves planting trees in rows and planting farm crops in the alleys between the rows of trees. The research project is a collaboration of Canadian scientists and their studies have resulted in some remarkable findings. In this chapter, you’ll learn about the results of their research. At the University of Guelph, Dr. Kari Dunfield and her team took a close look at microorganisms in the soil – microorganisms that contribute to harmful nitrous oxide gas emissions. The research found that soil microorganisms near poplar trees contain a specific gene in their DNA. The gene converts harmful nitrous oxide gas into harmless nitrogen gas. The study also revealed that red oak trees show good potential for reducing nitrous oxide gas emissions. Dr. Marney Isaac and her graduate students from the University of Toronto used ground penetrating radar to non-destructively estimate tree root biomass. They found that red oak and black walnut have deeper roots with greater biomass and therefore higher carbon storage. They also determined that rather than competing with adjacent farm crops for water, trees can take water from lower in the soil profile. Dr. Richard Heck and his team examined the structure of soil from four species of trees at the University of Guelph intercropping site. They used high-resolution X-ray computer tomography. Focusing on empty, void spaces in the soil, their research revealed that soil from poplar trees has more small void spaces. The research indicates that there could be a relationship between these void spaces and low greenhouse gas emissions. Amy Wotherspoon and a team of graduate students excavated five species of trees at the University of Guelph intercropping site. Their goal was to quantify above and below ground carbon pools and fluxes. They found that hybrid poplar sequestered the highest amount of carbon at the system level. That includes carbon in the above and below ground tree components. Hybrid poplar is followed by red oak, black walnut, Norway spruce, and white cedar. In Quebec, their research showed a two-thirds reduction in nitrous oxide emissions. Dr. Robert Bradley heads up the research project at the University of Sherbrooke. Dr. Bradley: You must understand that soils contain about 3 or 4 times more carbon than the atmosphere. Therefore, by increasing soil carbon by only a small percentage, we could decrease the quantity of carbon that is (stored) in the atmosphere by a significant amount. Dr. Bradley: In fact, one of our experiments demonstrated that the conversion of a corn field to an agroforestry system increased the level of soil carbon by 12% over a period of some 20 years, which in my opinion is a very substantial increase in carbon sequestration. Their research also showed a dramatic reduction in nitrous oxide emissions. Dr. Bradley: When nitrate is applied to soils as a fertilizer, it can be reduced by anaerobic bacteria to form N2O gas. Our studies have shown that agroforestry systems could decrease N2O gas emissions by 65% over the course of a growing season, which is a truly considerable reduction. And, one should remember that N2O is a much more powerful greenhouse gas than CO2 for storing heat in earth’s atmosphere. By adopting a tree-based intercropping system, farmers could help to reduce greenhouse gases that contribute to climate change. Dr. Andrew Gordon is the Principle Investigator for the project at the University of Guelph. He says some financial incentives are needed to encourage farmers to plant trees in their fields. Dr. Gordon: So our results have been very positive with respect to the ability of intercropping systems to reduce greenhouse gases and we're hoping that the dissemination of our research results will enhance the dialogue between policy-makers with respect to adopting very forward looking policies that will encourage farmers to adopt intercropping systems.