Building Better Nutrient Knowledge

New spectrometers streamline soil research at University of Saskatchewan

The University of Saskatchewan’s Department of Soil Science already sets the international standard for isotope tracing methods – a process used in agricultural research to trace and track the pathways of key soil nutrients to help inform and improve crop production practices. Thanks to funding from the Western Grain Research Foundation (WGRF) and the Canadian Foundation for Innovation (CFI), two new stable isotope mass spectrometers have been added to the research capacity for the department, and the College of Agriculture and Bioresources. Funding for the project totaled nearly $1.19 million, with WGRF contributing $818,000.

Dr. Bobbi Helgason, Associate Professor in the department led the funding application process, along with colleagues Drs. Melissa Arcand and Kate Congreves. “We have a long reputation of using stable isotopes for environmental and agronomic research, and these new systems are a fantastic addition to our research capacity and will support our department, the college and external users,” says Helgason.

Studying how carbon and nitrogen move through the soil often means measuring small amounts and small flows of nutrients, and it can be difficult to know where the nutrients are coming from and where they are ending up. Stable isotopes are heavier versions of nutrients like carbon and nitrogen that naturally exist in the environment – and they are the compounds the new systems can trace and analyze. Tracing is key as researchers continue to understand how and where carbon is stored in the soil for carbon sequestration and soil health, or how much nitrogen is being fixed by a pulse crop that informs how much fertilizer is required.

“We can use this equipment to understand the dynamics of carbon and nitrogen with a level of detail we wouldn’t be able to see without using the stable isotopes,” says Helgason. “We can tell which pathways carbon and nitrogen have taken throughout the cropping ecosystem.”

The first of the two new spectrometers – what Helgason calls the “workhorse” – was funded through WGRF and updates an existing system for the department. “We were spending a lot of time keeping our old system up and running, and this new bulk analysis system streamlines and automates the sample analysis with more precision and efficiency,” she says. The new workhorse is up and running and available to researchers at the University of Saskatchewan, as well as external users.

The second system, the Cadillac, is brand new to the department, the only one of its kind in Canada and was jointly funded by WGRF and CFI. It provides a more precise level of analysis and information on carbon and nitrogen in specific compounds, allowing researchers to conduct more sophisticated tracing throughout the crop production cycle.

“Not all soil carbon is made the same – some is very stable and some is unstable and more susceptible to decomposition,” explains Helgason. “The workhorse gives us the quantity of isotope in a whole sample, but the Cadillac can give us isotopic quantity of a variety of forms from within that same sample. In that way, the compound specific system can help us peer into the different pools of carbon in the soil and understand the forms of carbon that result from a particular way of managing our soil ecosystem.”

To bring this technology to a practical, on-farm level, Helgason points to tracking crop residue decomposition. “We struggle to figure out how much nitrogen a crop will take from the soil and decomposing residue from the previous crop vs. how much needs to be added as fertilizer. Using stable isotopes, we can trace nutrients in different crop residues to see how they impact soil fertility for upcoming crops, and quantify the amount of nutrients that will be provided by the crop residue.”

With this type of information, researchers will be able to more reliably quantify and predict fertilizer requirements, helping producers improve on-farm environmental and economic performance.

Other applications for the information available using the stable isotope system would be adjusting management practices to improve nitrogen use efficiency and reduce greenhouse gas emissions, improve soil carbon sequestration and understand which pulse varieties are more successful at fixing nitrogen.

Increasing overall research capacity with leading-edge equipment like these stable isotope mass spectrometers also simplifies the human capacity required for research analysis. “Our most important resource in research is human capacity,” says Helgason. “This new more user-friendly equipment will also allow us to increase sample throughput and enhance our training of the next generation of agricultural researchers.”

In total, twenty-four Phase 2 Capacity Initiative applications were approved by WGRF. Additional Capacity funding announcements will be made in the coming months.