Effects of vertical rotary tillage on wheat yield and soil compaction during wheat growing seasons

To explore the effects of vertical rotary tillage(VR)on soil compaction during the wheat growth periods, the effects of VR(30 cm±5 cm)and traditional rotary tillage(TR,12 cm±5 cm)under no fertilization(nF)and fertilization(F)levels, respectively, on wheat grain yields, nitrogen use efficiency, and soil compactions during two consecutive seasons(2017-2018 and 2018-2019)were studied. The results showed that VR increased wheat yield, improved nitrogen use efficiency, decreased soil compaction, and improved soil productivity compared to TR. Compared with nFTR treatment, FVR and FTR treatment related grain yield increased by 50.16% and 36.28%, respectively, in 2018 and by 42.91% and 34.79%, respectively, in 2019. Nitrogen agronomic efficiency of FVR increased by 38.29% in 2018 and 23.35% in 2019 compared with FTR. Partial factor productivity of nitrogen for FVR treatment increased by 10.15% in 2018 and 6.02% in 2019. Compared to TR, VR significantly reduced soil compaction in the 10 cm soil layer depth at the elongation stage and filling stage in the first season. However, there were no significant differences between the two tillages in the following season. VR tillage could also reduce soil compactions in the 20 cm soil layer depth at the elongation stage, and significantly reduced soil compaction under fertilizer conditions. Additionally, there were no significant differences between the two tillage for soil compactions in the 5 cm soil depth layers. VR could effectively decrease soil compaction in the 10 cm soil layer depth at the wheat elongation and filling stages, constructed better soil structures, and increased wheat grain yields and nitrogen agronomic efficiency.