Abstract: Studies on the effects of no-tillage on root growth and yields of crops and soil physical properties could provide basic information for the development of no-tillage practices. Here, we conducted a meta-analysis to evaluate the responses of soil physical properties and root morphological traits and yields of maize to no-tillage. The results showed that no-tillage significantly reduced root length, root length density, and root surface area density by 13.8%, 15.7% and 22.8%, respectively, but did not affect root biomass, root biomass density (RMD) and specific root length. No tillage significantly reduced maize yield by 8.4%, such negative effect being significant at sites of soil pH<7.0 (P<0.05) but not at sites of soil pH≥7.0. Notillage significantly increased soil bulk density and penetration resistance by 3.5% and 13.0%, respectively, while it decreased soil water content. Across the soil profile, no-tillage significantly reduced RMD (10-20 cm, -22.2%), increased RMD (30-40 cm, 33.3%), but did not affect RMD in the topsoil (0-10 cm) and subsoil (20-30 cm) as well as its horizontal distribution. No-tillage significantly increased soil bulk density (0-20 cm) and penetration resistance (0-10 cm). Our results highlight the negative effects of no-tillage on yield and soil physical properties. Future studies need to better understand the long-term responses of crop root traits to no-tillage. Improved no-tillage with additional system modifications (residue retention) is necessary to optimizing no-tillage performance and contributing to food production goals.

Key words: no-tillage, root morphological trait, soil physical environment, corn yield, meta-analysis.