Raised Bed Planting Pattern Improves Root Growth and Nitrogen use Efficiency of Post-Rice Wheat

Conventional puddling (rice season) and flat planting (wheat season) deteriorate soil properties and induce high mechanical impedance of roots, while increasing nitrogen (N) loss, affecting the normal development of plants and decreasing the yield of post-rice wheat on the Yangtze River Plain, China. Raised bed planting (RBP) may effectively increase wheat productivity. However, how RBP regulates soil properties, root growth and N use efficiency (NUE) is poorly understood.

We conducted a two-year (2021/22–2022/23) field experiment to evaluate the effects of flat planting (FP) and RBP with or without fertilization on the soil physical properties and nutrient status, root traits and NUE of post-rice wheat.

Compared with the FP pattern, the results demonstrated that the RBP pattern generally decreased the soil penetration resistance and soil bulk density at depths of 0–20 cm. Decreased soil penetration resistance and soil bulk density promoted superior root growth, resulting in a significantly greater root mass density, root surface area, root length, specific root surface area, specific root length, root and shoot biomass, and root to shoot ratio. Moreover, the RBP effectively improved the nitrate N (NO₃⁻-N) concentration in the 0–20 cm soil layer, reduced NO₃⁻-N leaching and infiltration, and enhanced the soil nutrient status. The improved root absorption capacity and increased soil N source contributed to increased N accumulation and NUE under the RBP pattern.

Our results suggest that the key factors that limits post-rice wheat cultivation are soil compaction and waterlogging. This findings suggest that the RBP pattern may be the optimal agricultural practice for sustainable post-rice wheat production in the Yangtze River region, China.