Changes in tillage management—such as shifting from conventional tillage to reduced tillage or no-till—produce highly variable SOC sequestration outcomes in Europe (Fohrafellner et al. 2023) because their effectiveness depends on a wide range of environmental and agronomic factors. The impact of conservation tillage on GHG emissions and SOC is influenced by climate (temperature and precipitation), soil texture, soil pH, crop species, microbial activity, and especially the duration of the practice.

Soil properties are a major driver of variation. Clay-rich soils generally show greater SOC gains because clay particles protect organic matter from decomposition, while sandy soils offer limited physical protection and therefore store less carbon. Soils with high microbial diversity and activity can better stabilize organic carbon, but microbial responses differ by soil type and climate. Warmer and wetter regions often show higher SOC sequestration potential under conservation tillage because microbial processes that build stable carbon are more active—although these same conditions can also increase decomposition, adding further variability.

The duration of conservation tillage is equally important: long-term adoption tends to deliver more SOC gain than short-term changes, and results improve when combined with complementary practices like residue retention, diverse rotations, or cover crops. Tillage reductions alone often yield modest or inconsistent gains.

No-till in particular tends to increase SOC mainly in the upper soil layers, while deeper layers often show no change or losses of SOC. This uneven distribution makes the overall SOC impact across the full soil profile very uncertain. Studies such as Haddaway et al. (2017) and Mary et al. (2020) report limited or no long-term SOC increases, although integrating no-till with other carbon-enhancing practices can improve outcomes (Chenu et al. 2019; Dignac et al. 2017).

Because these interacting factors vary widely across Europe’s diverse soils and climates, SOC responses to conservation tillage range from minimal to substantial. As a result, no-till and reduced tillage are often most valuable as measures for reducing erosion and improving climate resilience, with SOC sequestration considered a potential but uncertain secondary benefit (Ogle et al. 2019).