Beyond Reductive Tillage Categories: Quantifying Tillage Intensity to Assess Soil Disturbance in Arable Systems

ABSTRACT

Tillage is commonly described using qualitative labels such as ‘conventional’, ‘reduced’, or ‘no‐till’, but these categories mask large differences in soil disturbance intensity. This study presents the Soil Tillage Intensity Rating (STIR), developed by the United States Department of Agriculture (USDA), a quantitative tillage indicator based on the physical parameters of individual field operations, and demonstrates its applicability across diverse research contexts. A systematic literature review showed that few quantitative tillage intensity indicators exist in peer‐reviewed literature, and that while STIR is widely used by US extension services, its uptake in European peer‐reviewed research is still limited, though increasing. Among the studies that applied STIR analytically, significant relationships with soil organic carbon, biological indicators, weed biomass and crop yield were reported, though not consistently across contexts. Three Swiss case studies further illustrate STIR's versatility: in a 44‐year‐long‐term experiment it discriminated among tillage treatments and captured historical changes in practice better than categorical labels; in an on‐farm survey it characterised tillage intensity across conventional, no‐till and organic systems; and in participatory workshops with farmers it supported the quantitative comparison of tillage strategies and the discussion of soil‐friendly rotations. Despite limitations including data requirements for individual operations, sensitivity to implement speed, and limited validation across pedoclimatic contexts, STIR proved to be a versatile tool to describe cropping systems and potentially link tillage intensity to soil management outcomes. Broader adoption could improve comparability among studies and promote a more transparent assessment of tillage intensity and its impact on the environment.