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Century-old soil plots help researchers tackle greenhouse gas emissions

A living time capsule — that’s how Dr. Henry Janzen describes the near century-old soil plots at Agriculture and Agri-Food Canada’s Lethbridge Research Centre that are helping researchers tackle modern issues such as greenhouse gas emissions.

Samples gathered from this land over decades, provide a remarkable document of long-term soil change in the Canadian Prairies, says Janzen. Researchers are using the plots to examine the long-term flux of soil carbon under different farm production systems. This allows them to pinpoint strategies to reduce emissions of carbon — carbon dioxide is a major greenhouse gas — and develop benchmarks to measure those reductions.

“Soils change over decades and centuries,” says Janzen. “To measure those changes, you need a study of at least 15 years. That’s why long-term research is so essential.”

The Lethbridge Research Centre has helped coordinate Agriculture and Agri-Food Canada’s greenhouse gas initiative since it began in 1992. Since then, Janzen and other scientists have studied various ways to reduce emissions from various types of agriculture. The main efforts include reducing carbon dioxide and nitrous oxide emissions from cultivated land, and reducing methane releases from livestock production.

On the crops side, most agricultural land has traditionally been regarded as a carbon source because of management methods that deplete organic matter, releasing carbon into the atmosphere, says Janzen. But research shows that various new cropping systems can significantly increase soil organic matter, essentially collecting carbon out of the atmosphere and storing it in the soil.

The good news is that what’s good for greenhouse gas reductions is also good for farming, he says. The land management practices that favor carbon storage are often the same ones that prevent erosion, increase yields and reduce production costs. This includes growing perennial crops, reducing tillage intensity and applying organic amendments.

“Living organisms are the links between the atmosphere and the land,” says Janzen. “Plants, by photosynthesis, convert carbon dioxide into green plant material, which becomes organic carbon in the soil when the plants die. So the key is to encourage that process.”

There is still a lot of uncertainty about the global effect of increased concentrations of greenhouse gases, says Janzen.

“We cannot yet predict all the global effects of increasing greenhouse emissions,” he says. “But there is a lot of incentive to try to reduce agricultural emissions as best we can, and improve our industry at the same time.”

Agriculture and Agri-Food Canada’s Lethbridge Research Centre has a mandate to promote innovation for growth, maintain security of the food system and protect the health of the environment.

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