Spatial-temporal distribution of winter wheat (Triticum aestivum L.) roots and water use efficiency under ridge–furrow dual mulching

In dryland agricultural production areas, knowledge on the growth and variation of winter wheat root systems under different mulching methods is important for guiding winter wheat production. We conducted a two-year field trial to explore the effects of different mulching practices on the spatial-temporal distribution of root growth, soil water storage, and grain yield. Four cultivation practices were tested: (i) traditional flat planting (CK), (ii) flat planting with half-film mulching (M1), (iii) ridge–furrow planting with film mulching over ridges only (M2), and (iv) ridge–furrow planting with film mulching over ridges and wheat straw mulching in furrows (M3). The results showed that the root diameter (RD), root length density (RLD), and root surface area density (RSD) of wheat under the four treatments were mainly concentrated in the 0–40 cm soil layer. The mean RLD in the 0–40 cm soil layer accounted for 62.2 %, 61.0 %, 59.3 %, and 55.8 % of the total root length density under M3, M2, M1, and CK, respectively, at maturity in both years. The M3 cultivation method produced the maximum values for RD, RLD, and RSD among all cultivation practices and the highest water storage efficiency after the three precipitation events. The M3 treatment had 11.1 %, 15.4 %, and 38.4 % higher mean grain yields than M2, M1, and CK, respectively, over the two-year study. Soil water storage had positive correlations with RD, RLD, and RSD. The RD, RLD, and RSD in the 0–40 cm soil layer had strong positive correlations with yield components, yield, aboveground biomass, and water use efficiency (WUE). Based on this study, ridge–furrow planting with film mulching over ridges and wheat straw mulching in furrows is an effective, sustainable cultivation method for wheat production in rainfed regions, which can increase the spatial-temporal distribution of root systems and soil water content across the root zones to increase crop production and WUE.