Assessing the impact of conservation tillage
Assessing the impact of conservation tillage: to plough or not to plough?
The Soil Association’s new policy briefing, To Plough Or Not To Plough: Tillage and soil carbon sequestration, challenges the assumption that min-till and no-till systems offer a guaranteed method of cutting farming’s greenhouse gas emissions.
In the quest to protect and improve soils, conservation tillage practices (also known as ‘min-till’ or ‘no-till’) have gained increasing popularity among policymakers on the basis that these approaches minimise soil disturbance and sequester additional soil carbon over time.
But when it comes to minimising farming's environmental impact does conservation tillage really provide all the answers?
Key findings from the report:
- Scientific research shows that min or no-till methods do not guarantee a reduction in greenhouse gas emissions
- Min or no-till is not the only way to increase soil carbon. Many farming practices—particularly those that are part of organic farming systems—can contribute to raising the levels of soil organic matter and soil carbon
- Min and no-till practices bring other benefits to soils, including a greater concentration of organic matter near the soil surface and better soil structure. However, other practices—including farming practices inherent in organic farming but available to all farmers—will bring similar results
- Despite the use of ploughing on most organic farms, organically-farmed soils have been found to have on average 21% higher levels of soil organic matter than non-organic soils
- Recent research found that shallow non-inversion tillage resulted in no significant reductions in yield relative to deep ploughing, with significantly higher earthworm populations and better weed control
No 'silver bullet' solution
What is clear is that there is no ‘silver bullet solution’ for soil health and there are no shortcuts for building soil carbon. Whether using inversion tillage, min or no-till systems, all farmers should take special care to disturb as little of the top layer of their soils as possible.