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What’s in healthy soil?

Do the best yields come from the healthiest soil? Not necessarily. But new research suggests farm management practices can impact soil health – and improve a crop’s chance of thriving when times get tough.

Dr. Amanda Diochon, a professor in the Department of Geology at Lakehead University, is part of a multi-partner research study that aims to develop an improved soil health test for Ontario.

The project focuses on how different management practices impact soil health from four Ontario sites – in Ottawa, Delhi, Elora and Ridgetown. For Diochon’s part, she’s tracking how components of organic matter change over time.

“It’s possible for a farmer to optimize fertilizer levels and optimize yield, but that doesn’t necessarily mean soil will be healthy,” Diochon says. “And sometimes yields may be consistent across seasons or crop locations, but soil health in different fields can be variable.”

So if it’s possible to produce a high-yielding crop with less-than ideal soil, why does soil health matter? Diochon says the answer is simple: insurance. Healthy soil will be more productive when conditions are less than ideal.

Healthy soil is more resilient and can deal with stressors brought on by a changing climate. For example, soil with healthy levels of good quality organic matter will hold on to more moisture when climate is dry. And soil with a more diverse and productive microbial community is better able to buffer change.

Diochon is evaluating the effects of crop rotation and tillage on the different properties of organic matter. The key, she says, is in finding indicators in organic matter that are sensitive to change.

“We know what soil health is, but can we measure it? Nobody has that nugget yet,” Diochon says.

Her research team has zoned in on seven key indicators that she says will respond over time. Together, the indicators allow her to measure the physical, biological and chemical properties in soil.

“It’s hard to detect change by measuring organic matter or organic carbon,” Diochon says. “But by looking at certain attributes in organic matter, such as light fraction or sand fraction, we see they are sensitive to change.”

By examining soil samples from four sites in Ontario, Diochon says researchers will have a more comprehensive understanding of how organic matter responds across location and soil type.

“The hope is this research will identify best management practices to maintain or enhance soil health,” Diochon says. “We want to make it as profitable as possible for farmers while minimizing the impact on the environment – and ultimately enhance the resiliency of the entire system.”

This research is funded by the Ontario Ministry of Agriculture, Food and Rural Affairs and Grain Farmers of Ontario.

October 11, 2016  By Lisa McLean for AgInnovation Ontario