Subsoiling improves soil physical and microbial properties, and increases yield of winter wheat in the Huang-Huai-Hai Plain of China

Faced with the decline in sustainable farmlands that have resulted from pressure to increase yields, there is a need for science-backed tillage practices that can improve soil ecology and still promote productivity in winter wheat fields. An experiment was performed from 2010 to 2015 under the rotation of summer maize and winter wheat in the Huang-Huai-Hai Plain (3HP) of China, to test how three tillage practices rotary tillage (R), strip rotary tillage (SR), and annual strip rotary tillage with a subsoiling interval of two years (SRS) impact soil physicochemical and microbial indicators. Results showed that soil water content (SWC) under SRS treatment decreased by 10.4% and 13.4% compared with that under R and SR within the 40–60 cm soil layers at maturity. SRS treatment also decreased the mean bulk density (BD), but increased the average soil porosity (SP) within the 0–45 cm soil layer. Furthermore, organic matter (OM) and total nitrogen content (TN) from SRS were significantly higher than those from SR and R at maturity within the 15–45 cm soil layer. Compared with R and SR, soil respiration (SRN) of the 15–45 cm soil layer in SRS was significantly higher at jointing, and the mean soil microbial biomass C (MBC) from SRS increased by 34.9% and 30.6% at 0–30 cm at jointing and maturity, respectively. This increase was likely responsible for suitable soil water, good soil aeration and soil structure in SRS. Average grain yield (GY) and water use efficiency (WUE) were all the highest under SRS at 8997 kg ha−1 and 20.3 kg ha−1 mm−1, respectively. Thus, SRS is the most suitable tillage practice for improving soil physicochemical and microbial properties, and increasing GY and WUE of winter wheat in the Huang-Huai-Hai Plain of China.