Zero tillage impacts on soil physical properties but not on crop yield

The adoption of conservation agriculture practices, such as zero-tillage (ZT), is increasingly being promoted to improve soil health and sustainability. However, the impacts of ZT on soil physical properties, root development, and crop productivity remain context-dependent and require further investigation. This study evaluated the effects of conventional tillage (CT) and ZT on soil macroporosity, penetration resistance, root density, and grain yield at two sites: Rothamsted (4 years of ZT, four wheat genotypes) and Sutton Bonington (10 years of ZT, one genotype). Soil cores were analysed using X-ray Computed Tomography (XRCT), revealing reduced macroporosity under ZT compared to CT at 0–10 cm depth, with particularly pronounced decreases from 11% to 3% at Rothamsted and from 19% to 2% at Sutton Bonington in the 0–5 cm layer. ZT also enhanced connected porosity at both sites with prominently more under long-term ZT (10-yr). Additionally, penetration resistance at 0-20 cm depth was 26% greater under ZT at Rothamsted and 109% greater at Sutton Bonington, with significant differences extending down to 20 cm and 45 cm depths at Rothamsted and Sutton Bonington, respectively. Despite these considerable differences in soil physical properties, root density remained largely consistent across both tillage treatments, except for increases in C_egt2_B20 and Rht-B1C genotypes at 40-50 cm depth under ZT, which could be due to an enhanced biopore network observed at this depth. No significant variation in grain yield was observed between CT and ZT treatments for most genotypes, except C_egt2_B20 where ZT decreased yield by 18%. These findings show that under ZT clear differences in soil structure develop, without compromising crop productivity or root development in most genotypes. This study highlights the trade-offs in tillage systems and shows ZT is a sustainable soil management practice that preserves yield potential while enhancing soil structure.