At a time when fertilizer is playing a more prominent role on the global stage, a new study out of the University of Waterloo compares the greenhouse gas emissions of nitrogen-based fertilizers with biobased residues like compost, and found that compost emits less greenhouse gas during spring thaw than nitrogen fertilizer.
The study analyzed how different soil amendments impact the amount of greenhouse gases released into the air during a spring freeze-thaw event in a typical agricultural field.
Researchers compared nitrogen fertilizer, composted food waste, hydrolyzed biosolids, and anaerobic digestate and found that fertilizer released the most greenhouse gases with approximately 127 kg of CO2 equivalent (a measure that amalgamates the total effect of all the released greenhouse gasses) per hectare. Compost, biosolids and digestates all produced less than approximately 100 kilograms of CO2 equivalent per hectare.
Fertilizer is a hot topic right now. Recent and ongoing farm protests in Sri Lanka and Holland are both connected to the enforced reduction of nitrogen fertilizer.
The federal government’s recent 35-per-cent tariff on Russian-sourced fertilizer – applied in response to the Ukraine invasion – has made sourcing fertilizer more difficult for Ontario’s farmers this year as well. According to Grain Farmers of Ontario, producers in Ontario, Quebec, and Atlantic Canada import 660,000 to 680,000 tonnes of nitrogen fertilizer from Russia each year, and this represents 85 to 90 per cent of all the fertilizer used in this region.
At the end of 2020, the Canadian federal government announced a target to reduce fertilizer emissions to 30 per cent below 2020 levels by 2030.
It’s a topic of interest to Mark Reusser, vice-president of the Waterloo County Federation of Agriculture and vice-president of the Ontario Federation of Agriculture.
“I think that there’s a lot of discussion currently about the fact that we import so much of our fertilizer. Is that a wise thing to do?” he said. “And I think that many private companies and farmers in particular are looking at the wisdom of being able to produce a greater percentage of the fertilizer that we use domestically. Can it be done? Can it be done commercially? I think there is a lot of discussion in boardrooms across Canada. What can we do to be more self-sufficient in the future and avoid issues like this one that we’re currently having with Russia?”
Emmanuel Badewa, the study’s lead, thinks that bio based fertilizer alternatives could be a viable way for farmers to augment soil fertility by using the organic byproducts (organic material from fields, food waste, and human and animal waste and the like) of our society.
“Yes, looking at the bigger picture, I think you will notice the major option that farmers always look at is nitrogen fertilizer,” Badewa said. “But with our research, we’ve seen that there are other products that are sustainable, that can serve as alternatives to nitrogen fertilizer. And in terms of cost too, most of these materials are readily available in different localities. All that needs to be done is to locate the feedstock of the organic waste in different localities, regardless of the country, regardless of the location,” he said.
“All the organic wastes that were used in this study were gotten within the locality. So I will say actually that in terms of product improvement, then farmers should know that they have alternatives to use for nitrogen fertilizer.”
Reusser says most farmers rely on commercial products, as not every farmer has access to their own manure. “If there was more compost available at an appropriate price, I think many more farmers would be interested in utilizing it,” he said.
“We recognize the need for further research as to how to deal with emissions, and how to generate the most food possible, probably from the least amount of inputs. That only makes sense. And if we don’t have the answers, we need to look for them. I think farmers absolutely support research,” he said.
He continued: “There is a lot of pressure on agriculture to become more efficient. In other words, produce more food. There is no more land being made. So we have to feed a growing population on a land base that’s actually shrinking as it becomes urbanized and changed to other uses. So farmers have to deal with that, and they also have to deal with the fact that if less food is produced, the price goes up and society really doesn’t take kindly to food prices increasing. So it’s in our best interest I guess, to hold food prices, you know, and not short the market and cause prices to rise. Because society doesn’t like that.
“On the other hand, we’re being told to attempt to reduce emissions and nitrous oxide, though we really need nitrogen to grow more food. So it’s a difficult puzzle to try and figure out. Yeah, it’s not simple. Not at all simple. We’re being pushed from both sides.”
Badewa was clear to say this study was not focused on crop productivity, but he is working on another study expected to be published in the next few months that addresses this question. Even so, “I can actually tell you that from our study, we’ve never really seen any difference (in crop productivity),” he said.
“We hope that farmers too will be able to see that there are other alternatives they can use,” he said.