Responses of grain yield and water use efficiency of winter wheat to tillage in the North China Plain

Water shortage is a known limiting factor in sustainable wheat production in the North China Plain (NCP). Conservation tillage has the potential to maximize soil water efficiency, and also influence crop growth. The distribution of crop roots plays a vital role in determining water consumption and yield production. A 10-year field experiment was established to study the relationship between soil physicochemical properties and root distribution characteristics and determine grain yield, as well as water use efficiency (WUE) of winter wheat in response to tillage. Three representative tillage practices, no-till (NT), conventional tillage (CT), and rotary tillage (RT) were used. The results indicated that RT increased the spatial and temporal root distribution, enhanced photosynthetic activities at the flowering stage, and achieved higher average grain yield by 12.0 % and 6.7 % from 2008 to 2019 as compared with NT and CT, respectively (P < 0.05). The NT significantly increased root length density, soil organic carbon, and total nitrogen concentrations at the 0–5 cm depth, and mean weight diameter at the 0–20 cm depth compared with CT and RT (P < 0.05). However, NT had higher soil compaction (bulk density and penetration resistance) at the 0–20 cm depth, and inhibited root growth, especially for deeper soil levels, while reducing water consumption by 8.5–17.2 % and 8.6–10.5 % compared with CT and RT, respectively. Thus, NT significantly increased WUE by 16.5–29.1 % compared with CT (P < 0.05), while no significant difference was observed between NT and RT. Overall, long-term NT can increase WUE by reducing distribution and water uptake of the root at deep soil layer, but continuous NT can increase soil compaction thus leading to yield reduction. Thus, RT is an effective strategy to improve grain yield and WUE of winter wheat in the NCP. In the future, the strategic tillage based on NT and RT may be a promising approach to sustain the benefits of NT (e.g., soil quality and water consumption) and RT (e.g., grain yield and WUE).