Hot and cold: Dal researchers examine the effects of freezing and thawing on soil

- February 21, 2013

Student Michelle Erb at work on the soil project. (David Burton photo)
Student Michelle Erb at work on the soil project. (David Burton photo)

Canadians know winter — and certainly the Maritime provinces have been tested this year with colder than normal days, above normal precipitation and wide fluctuations in temperature.  

While we may understand the cold, there is a lot to learn about the impacts of this weather on the environment, particularly when considering the potential impacts of global climate change.

Researchers at Dalhousie’s Faculty of Agriculture, and Agriculture and Agri-Food Canada, are studying the effect of freezing and thawing on soil biological activity and examining the effect they have on the fertility of Nova Scotia soils, as well as their role in the production of nitrous oxide.

Soil is an important resource, providing nutrients for plant growth, decomposing plant residues and animal wastes, and purifying our water. Understanding how freezing and thawing events influence soil function is critical to understanding our soil's long-term sustainability.

David Burton in Dalhousie’s Faculty of Agriculture and Claudia Goyer and Bernie Zebarth at Agriculture and Agri-Food Canada have been studying how the freezing and thawing of soil impacts the composition of soil microbial populations and triggers microbial activity.

The frequency of freezing and thawing events is increasing in Nova Scotia, triggering bursts in microbial activity that can result in the release of plant available mineral nitrogen and the production of significant amounts of the greenhouse gas nitrous oxide.

“Over half of the nitrous oxide produced by soil occurs over the winter period as a result of thaw events,” explained Dr. Burton. “Soil is the primary source of nitrous oxide being released into the environment which ultimately contributes to global warming.”

As Maritimers continue to adjust to climate change and its effects on our Canadian seasons, researchers at the Faculty of Agriculture will continue to investigate the sustainability of our soil.