Dr. Peter Tyedmers (Dalhousie University) leads a team of researchers across Canada trying to estimate the level of greenhouse gas emissions of Canadian organic field crop production systems. In June 2020, Dr. Andrew Hammermeister, Director of the Organic Agriculture Centre of Canada sat down with Dr. Tyedmers to learn more about their research.
What kind of research have you been doing at Dalhousie University?
Much of my work has revolved around food systems through a lens or motivation to understand their material and energy performance, questions like how much fossil fuel energy or electricity are we investing into these food systems? How do investments of material and energy translate into concerns we have around the environment, like eutrophication (the over-delivery of nutrients into ecosystems) or greenhouse gas emissions?
Can you tell us about the project?
The project is part of the Organic Science Cluster 3. In conjunction with two colleagues, Dr. Goretty Dias at the University of Waterloo, and Dr. Nathan Pelletier at UBC in Okanagan, we’re working to understand the net greenhouse gas emissions associated with organic field crop production. We’re trying to gather as much data as we can about many field crops, like corn, soy, canola, wheat and potatoes, and their net greenhouse gas emissions under organic management practices.
It seems like a huge job to assess all the greenhouse gas emissions from a farm; do you start at a whole farm level or start looking at the production system associated with a single crop?
We’re looking for two sets of insights from the farmers. First, we want to meet with farmers to get an understanding about key inputs in their farming operations and the results of these. We want farmers to tell us about their rotation over the last three or four years, average rates of fertilizer inputs, fuel inputs, what energy they’re using to irrigate and other key operating inputs. We’re trying to get as much information about what was invested in inputs this past year, and going back in time to see what resulted from past inputs (such as how much corn, wheat or soy was produced in those years). We want to capture these details for the Life Cycle Analysis (LCA).
Secondly, we need to understand where the farm is located, the nature of the soil profile, the history of the soil… is it near its carbon sequestration capacity? Is it a highly carbon-depleted soil, and then likely to be sequestering more carbon? What is the rate of precipitation? Is it irrigated? … All these factors can influence the relative flux (the relative change) in carbon and nitrous oxide into the atmosphere or into the soil.
If you look at conventional agriculture, we often hear that 40% or even 50% of the energy cost of the farming system, is related to manufacturing nitrogen fertilizers. In organic agriculture, we might be looking at alternative sources such as pelletized poultry manure or compost. Would you be evaluating the amount of pelletized poultry manure or compost being used and assessing potential greenhouse gas costs and emissions from those practices?
That’s right! They are nutrient dense, they have real value, and they support the productivity of a farm. Without them, yields would be far lower. These are critical inputs, but they also don’t appear through magic fairy dust. They are generated through real physical processes somewhere else in the world. They may be on a farm next door, or at a distance away. Their production resulted in greenhouse gas emissions somewhere. We will absolutely be interested in knowing how much of these nutrient carriers were used, and how we’re going to characterize the emissions associated with making poultry manure available.
Clearly, this research depends on the data you collected from the farmers, which leads me to ask, how can farmers get involved in your project?
The best thing is to contact the team by using tinyurl.com/organicsurvey2020.
The farmers would work with us by sharing data about their inputs and outputs. The more detail, the better, but it’s okay if the farmers don’t have complete detailed records. In my experience, farmers and other resource producers, like fishermen, can ballpark pretty well. So even if farmers don’t know how many tonnes of pelletized manure was used, but they know how many truckloads came onto the farm, we can work with that. We will work with any level of detail that farmers are able to make available as long as they are willing to participate.
How do you think your research will impact organic agriculture in Canada?
The benefit of our project will be providing an understanding of how organic field crop practices in Canada contribute to climate change. What is the scale of that contribution? Does it vary tremendously with region, with years of experience or with how long the soil has been in organic management?
We suspect that it may vary with these sorts of phenomena, certainly regionally because of differences of soil type and precipitation. But the benefit, I believe, comes from being better able to be part of the conversation in Canada about what the organic sector represents in terms of where it is now on this globally important issue [of climate change].
If we understand enough about the diversity of organic management practices in Canada, it will ideally highlight the practices that are less emitting than others. That could highlight strategies that might encourage other farmers to adopt such practices.
You can’t change where your farm is located or the broad composition of your soil (except on a more incremental basis through efforts to improve soil fertility). But there are a lot of management practices that are absolutely within the domain of control of the producers. If they are relatively neutral from a revenue perspective [i.e., no net cost], we could point out some really important opportunities for emission reductions.
Thanks Peter! We need to first under- stand these systems and their contribution to greenhouse gas emissions and as a carbon sink before we can start adopting new practices. We are chronically lacking data in the organic sector in Canada that would help inform our decision-making and recommendations to improve practices.
I think that this research is really, really important and will have a big impact on the sector in terms of guiding us down a pathway to greater sustainability, which is what organics is all about. I look forward to talking with you again when we have some more results coming in.
DEFINITIONS
Carbon sequestration – the process of long-term removal of carbon dioxide from the atmosphere and storage in plants, animals, oceans or geological formations. In agricultural systems, carbon would be stored in large molecules of organic materials (such as plants) that are not easily decomposed. Agricultural practices that increase soil organic matter help to sequester carbon, but this carbon may also be released through practices that disturb the soil.
Carbon flux – the balance and flow of carbon between the atmosphere, living organisms and soil or water. In agricultural systems, the soil is a major “pool” of carbon which can be influenced by management practices that add or destroy soil organic matter.
Greenhouse gases – the gases in the atmosphere that absorb and reflect infrared radiation (i.e., heat) back to the earth’s surface. The primary greenhouse gasses associated with agriculture are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).
Life Cycle Assessment (LCA) – a method of assessing the environmental impacts associated with all stages of the life cycle of a product. In Dr. Tyedmers’ research, greenhouse gas emissions are being studied from the energy used to manufacture equipment through to the fuel used to harvest a crop.
To take part in this important research, visit tinyurl.com/organicsurvey2020
Note: Sections of this interview have been removed to accommodate space within the magazine.
To read or listen to the full interview, visit www.dal.ca/oacc/podcasts
(OSC3) Originally published in Organic Science Canada magazine, Issue #3, Spring 2021
