Looking at the good and bad of glyphosate
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A newly publicized study by researchers with the University of Saskatchewan confirms what many farmers already knew.
Glyphosate, one of the world’s most widely used herbicides, and crops that are genetically modified to tolerate the herbicide have contributed to better soil management through reduced tillage.
The researchers with the university’s agricultural and resource economics department set out to quantify the net increases in carbon sequestration due to the virtual elimination of summerfallow practices, reductions in tillage and the use of herbicide-tolerant crops over three decades. Based on a 1,000-hectare farm, it equates with the emissions from 432 cars.
In the early 1990s, a 1,000-hectare farm under conventional tillage of the time released 15 times more carbon than the average car each year. Two decades later, in the period between 2016 to 2019, that same farm would sequester the equivalent of emissions from 95 cars due to the adoption of reduced tillage.
“Similarly, the annual increase in soil organic carbon from this farm in 1991 to 1994 from the reduction in summerfallow practices would be equivalent to the emissions from 27 cars, and by 2016 to 2019, equivalent to the emissions from 337 cars,” the researchers report.
In short, these technologies enabled farmers to transition their soils from being net carbon emitters into carbon sinks over three decades.
The researchers based their findings on an online survey of Saskatchewan farmers who also outlined how hard it would be to maintain sustainable farming practices without access to glyphosate and herbicide-tolerant crops.
The results indicated there could be a 54 per cent increase in tillage and a 37 per cent decrease in yield and profitability, an increase in chemical use, and a 14 per cent increase in summerfallow. Four per cent of respondents said they would stop farming altogether.
“This research confirms the essential contributions to improving agriculture’s sustainability made by genetically modified crops and glyphosate, providing insights into the challenges facing jurisdictions that anticipate increased carbon sequestration without either technology or certainly significant restrictions on each technology,” they conclude.
“Saskatchewan farmers have confirmed just how crucial the use of glyphosate is with the complementary technology of herbicide crops for the ability to continuously maintain sustainable land management practices. Removing or restricting either or both of these technologies would have adverse impacts on sustainability.”
The research appears focused on creating a more positive aura around the herbicide, which is in some campaigners’ eyes symbolic of everything bad about modern agriculture. Some blame it for cancer. Some buyers refuse to buy grains treated with it pre-harvest for fear of residues, and some jurisdictions are moving to restrict or ban its use altogether.
“Countries that ban genetically modified crops and are enacting legislation restricting glyphosate use are implementing policies that Canadian farm evidence indicates will not contribute to increasing agricultural sustainability,” they write.
Not discussed in this research is the distinct possibility that natural forces will force farmers to reduce their glyphosate use because the weeds they are trying to control have evolved to become resistant to it. There are now 45 species of plants that it can’t kill.
And while glyphosate and GM crops have enabled reduced tillage and continuous cropping practices, they also perpetuate farmers’ reliance on monoculture at a time when increased biodiversity is seen as essential to improving the sector’s sustainability.
A newly released meta-analysis of research published in the Proceedings of the National Academy of Sciences looked at how regenerative agricultural practices affect soil carbon levels. It found that no-till practices increased soil organic carbon in topsoil by 11.3 per cent compared to conventional tillage, and planting cover crops increased levels by 12.4 per cent. Meanwhile, no-till practices, combined with crop and livestock integration, led to a 29.9 per cent increase in soil organic carbon compared to conventional approaches.
The point is that glyphosate is a valuable tool for farmers, but they will likely use less of it in the future due to a combination of market forces, regulatory pressures and evolutionary biology.
Based on the Saskatchewan farmer survey, it’s going to be a tough row to hoe.
Laura Rance is vice-president of content for Glacier FarmMedia. She can be reached at email@example.com
Laura Rance is editorial director at Farm Business Communications.