Effects of Vertical Smashing Rotary Tillage on Root Growth Characteristics and Yield of Broccoli

Most of the soils of the cultivated land in southern China are Ferralsols, which are easily deposited and hardened. To date, rotary tillage (RT) has been the major tillage system used in China. This tillage system results in a shallow soil pan, which reduces broccoli growth and yield. A two-year field experiment was conducted in the Central Zhejiang Basin, China, to compare the effects of vertical smashing rotary tillage (VSRT), RT, and vertical rotary tillage (VRT) on the soil properties, growth characteristics, and yield of broccoli. VSRT reduced the bulk density and penetration resistance of the 0–40 cm soil layer, and increased the soil water content of the 10–40 cm layer. Compared with RT and VRT, VSRT significantly promoted broccoli root length and increased broccoli root dry matter accumulation (DMA). VSRT significantly increased the DMA rate during the growth period, and the size of the broccoli florets was more uniform. In 2020, compared with RT and VRT, VSRT increased yields by 7.8% and 19.5%, respectively; while in 2021, the corresponding increases in yield due to VSRT were 24.8% and 40.5%. Therefore, VSRT, as a deep tillage method, can improve soil characteristics before planting broccoli and ultimately increase broccoli yield.