SASKATOON — Can large-scale farmers learn about soil management practices from urban gardeners?
Kate Congreves, a University of Saskatchewan researcher who specializes in regenerative cropping systems, thinks so.
“We do all this work on our large-scale field cropping systems, but I think our gardens can also tell us something about soil health and we maybe think to look there last,” Congreves told the Saskatchewan Soil Conservation Association conference in Regina in mid-February.
Congreves and her team recently completed research aiming to address this. To do so, they collected and analyzed soil samples from approximately 64 gardens, mostly in urban Saskatoon but also some rural areas.
When compared with soil samples from field crop systems, there were interesting results, Congreves said.
“What we found is that the soil total carbon, organic carbon, total nitrogen and protein levels, as measured by our techniques and our soil samples in the lab, were much greater in those garden systems than you otherwise would expect in your field crop systems,” she said, adding sometimes organic soil levels were up to two times greater.
She said these findings were also true for other measures of soil health, including active carbon and respiration.
“We saw earlier indicators of soil health in garden scenarios, as opposed to field crop systems,” she said.
The team also found that extractable phosphorus levels were excessively high in garden soils, she said.
These findings can likely be explained by the fact that gardeners are able to apply and trial beneficial soil and cropping practices much more easily in their smaller-scale operations, Congreves says. For example, she says many of the gardens surveyed were:
- Using no-till or reduced tillage practices.
- Applying animal manure and compost.
- Diversifying rotations, often with wild plants.
- Using straw or mulch to cover the soil.
“You can do many more things in your garden than you can in a large field scale,” she said.
Congreves and her team also found that any time a gardener was using two or more soil health management practices at a time, their soil health ranking improved.
“If you just did one, you didn’t quite see that shift, but anytime you did two or three or a combination of the soil health management practices, those soil health rankings went up.”
Overall, she says one of the key takeaways from the project is that it’s possible to improve carbon- and nitrogen-based soil health indicators in garden soil but at the risk of accumulating excessive levels of phosphorus.
“So, if we want to manage and monitor soil health, it’s best done in tandem with some sort of soil fertility measurements.”
She says another key takeaway is that soil health indicators must be considered in context, and that there’s no one-size-fits-all approach to soil health improvements.
In light of this, Congreves and her team recently released an online tool to help producers interpret their soil health test results, based on their specific soil zones within the province.
This tool, .
Congreves believes this type of information will help Saskatchewan producers better understand their soil and the impact of management practices.
“These tools can help contextualize things, and can also move toward improving soil health when we’re attempting to maximize carbon gains by minimizing losses.”
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