AgBio graduate explores soil health and legume biodiversity

Healthy soil is more resilience to drought, increases nutritional density of food, fosters biodiversity, absorbs and filters more water, and helps fight climate change by absorbing carbon from the atmosphere. Since soil is a non-renewable resource, it is vital to increase soil health around the world.

For University of Saskatchewan (USask) student Warren McAuley, it is important to research practical ways producers can improve soil health via the crops they plant.

“My research builds upon the Saskatchewan Assessment of Soil Health (Wu and Congreves, 2021) to see how changes in cropping systems and species impact soil health in a one-year period,” said McAuley.

McAuley will officially receive his Master of Science in Soil Science at USask Fall Convocation, taking place on November 8 at Merlis Belsher Place.

In May 2023, he successfully defended his master’s thesis, Effect of Intercropping with Faba Bean on Land Equivalency Ratio and Soil Health in Saskatchewan. McAuley was co-supervised by Dr. Maryse Bourgault (PhD) and Dr. Kate Congreves (PhD). Bourgault is an assistant professor in the Departments of Plant Sciences and Soil Science in the College of Agriculture and Bioresources (AgBio), and the Western Grains Research Foundation Integrated Agronomy Research Chair. Congreves is an associate professor in the Department of Plant Sciences.

McAuley conducted his research over two field seasons at USask Kernen Crop Research Farm. Both intercrops (when multiple crops are grown together such as legume and non-legume) and monocrops (a single crop) were grown. The soil samples from the crops were analyzed in three different labs in AgBio.

“The results of my research showed that intercropping with faba beans can be a viable option for having a land equivalency ratio (LER) greater than one for producers, showing increased productivity over a monocrop,” said McAuley.

LER is a measurement of what the crop yield advantage is for producers to plant intercrops versus monocrops.

McAuley’s research also looked at how intercropping affected soil health indicators. Soil health indicators from the Saskatchewan Assessment of Soil Health include total nitrogen, soil protein, organic carbon, active carbon, and total phosphorus.

“Over a one-year period, the short-term soil health indicator of active carbon increased in the legume over the nonlegume monocrops,” said McAuley. “This is indicative of a greater soil microbial population. The longer-term indicators of soil total nitrogen and organic carbon showed no difference over a one-year period, although both soil protein and active carbon contribute to total nitrogen and organic carbon in the longer-term.”

“The real-world application of this research provides a better understanding of what impacts short-term soil health indicators, and how soil health can be increased via the inclusion of legumes within a cropping system,” said McAuley. “It was very practical to see what changes soil health underwent in a field setting.”

McAuley’s research was funded by Western Grains Research Foundation. McAuley excelled academically and received the following scholarships during his master’s degree: the Natural Sciences and Engineering Research Council of Canada Graduate Scholarship, the Canadian Foundations for Food and Agriculture Education Dr. Karl C. Ivarson Agriculture Scholarship, and the Dollie Hantleman Scholarship and the Education Enhancement Travel Scholarship from AgBio.

Originally from Vermilion, Alta., McAuley chose USask for bachelor’s and master’s degrees in soil science “because it is the most dedicated soil science program in Canada.”

“The College of Agriculture and Bioresources is such a welcoming place. You can knock on any professor’s door, and they are able to lend you some of their vast experience,” said McAuley. “There is a great community of students that you feel accepted by and supported by each other.”

Now that his master’s degree is complete, McAuley is working as the northwest director at the Saskatchewan Association of Watersheds. The organization leads projects and programs to improve and protect ground and surface water resources. McAuley would like to continue to work in the non-profit field in the future.

“I’d like to take the regenerative practices that I’ve learned and be able to teach in the developing world how to improve agricultural practices while focusing on what nature can provide for us within a food production system.”