No-till farming has been found to restore soil quality and assist farmers in maintaining healthy crops, but how does it tie in with climate change? It has been proven that no-till not only increases soil quality, crop yield, and prevents soil erosion long term; it can also help us prevent climate change in some interesting ways.
The basic premise of how no-till reduces carbon emissions is through the reduction of soil disturbance, aiming for only 10–40 per cent. By limiting the amount of time the tractor is tilling the earth, the emissions it produces are reduced. There are also natural benefits from the practice over time.
When soil is tilled, it disturbs the natural ecosystem that is present in the top soil, which is the first 20–25 cm of soil. Insects that play a role in fertilizing soil are disturbed when it is tilled, and so the quality of the soil degrades with each tilling. Soil quality affects crop yield as well; as the health of the soil decreases, less will grow.
There is a large amount of carbon in the soil; this is part of a process called carbon sequestration. During this process, carbon from the atmosphere becomes stored in a body of water or the soil. Typically, when farmers are tilling, the first 20–25 cm of soil is turned over. It is during this process that carbon in the tilled soil gets released into the atmosphere.
“Soil CO2 fluxes are the second-largest component of the carbon cycle and in order to mitigate climate change, reducing emissions from soil will be of critical importance.”(1)
In this study conducted by Hannah V. Cooper, she compared crops that were being grown via no-till and conventional tilling. The results ended up being that no-till crops contained considerably more carbon than the ones that were tilled after six to ten years. Conventionally tilled crops also had 13.8 times more carbon emissions then no-till crops. It also affected the carbon content in the first 20 cm of soil. However, anything below this did not see a change.
“The increase in carbon stock in long-term zero tilled soils was attributed to the surface layers 0–10 and 10–20 cm, with no significant difference in carbon content between deeper layers.”(1)
No-till does have a lot of benefits in terms of crop yield and its effects on the carbon cycle, but there are a few things to consider before making the switch. Farmers using no-till would need to keep in mind that weeds would be more likely to grow in untouched soil, mulch may be necessary, and the soil will be much more delicate.
Farmers who decide to use no-till would arguably be doing the environment a favour in the long run, and if done properly, it can increase crop yield. Many farmers in Western Canada have switched over to no-till, and since the early 2000s the practice has seen massive increases in use, as it is utilized on over 50 per cent of Canadian crops.
1 Environmental Research Letters—To Till or Not to Till in a Temperate Ecosystem? Implications for Climate Change Mitigation, 2021