Effects of deep vertical rotary tillage on dry matter accumulation and grain yield of summer maize in the Huang-Huai-Hai Plain of China

No-tillage of summer maize after the harvest of winter wheat is the main agricultural practice on the Huang-Huai-Hai (HHH) Plain of China. However, long-term no-tillage in the absence of deep tillage practices affects soil properties, and this effect is not beneficial for the growth and yield production of summer maize. Field experiments were conducted in 2016 in two agricultural sub-zones (Luancheng and Guoyang) in the HHH Plain. The main objective of this study was to evaluate the effect of deep vertical rotary tillage (DVRT), compared to no-tillage with strip subsoiling (NTSS), on dry matter accumulation (DMA) and yield formation. DVRT significantly reduced the soil bulk density of the top soil layer (0-40 cm), especially for the lime concretion black soil in the Guoyang experimental site. Compared with NTSS, the soil water content in the 20-60 cm soil layer was increased under the condition of DVRT. DVRT also significantly increased root DMA in the 0-30 cm soil layer in Luancheng and in the 0-40 cm soil layer in Guoyang. The total shoot DMA, seed DMA, and harvest index of DVRT were significantly higher than those of NTSS, primarily due to a significant increase in post-anthesis DMA. In addition, DVRT increased the maximum and mean grain filling rate and thus significantly increased the maximum grain weight at harvest. Compared with NTSS, DVRT significantly increased grain yield by 21.3% and 27.8% under the plant density of 6.75 pl m−2 and 9 pl m−2, respectively, in Luancheng and it increased by 12.3% in Guoyang. The present results indicate that DVRT can be used as a deep tillage practice to improve soil properties and grain yield of summer maize, and this may provide guidance regarding the requirements to cope with a diversity of deep tillage machines and develop sustainable agriculture in the HHH Plain of China.