Abstract: Abstract: Tillage practice is one of the energy-consumed links in agricultural production, while the energy can be saved through proper management of blade geometry. In case of rotary tillage, the geometry of sidelong edge, lengthwise edge and transition edge plays a pivotal role in the energy consumption and working performance in the field. The continuous development of the conservation tillage puts forward higher requirements for the performance of rotary blade. In order to manage the rotary tillage process reasonably, the power consumption and working performance of blade should be better understood. In this paper, the sidelong edge and lengthwise edge of the national standard blade were designed as serrated ones and the bionic-shape transition edge was devised according to the arrangement of mole's toes, and later the power consumption and working performances of the bionic serrated blade and the national standard blade were investigated in the field. Meanwhile, the performances of both blades were also studied in soil with and without straw covered via discrete element method (DEM) simulation. A torque sensor was installed between the PTO (power take-off) shaft of tractor and the cardan of straw returning machine to measure the power consumption, while the straw burying rate, the soil crashing rate and the proportion with straw length ≤15 cm were used to evaluate the working performance of blade. Both simulation and experiment were performed with the rotational speed of 300-350 r/min and a constant forward speed of 0.5 m/s. The simulation was performed under 2 conditions with 0% and 100% straw covered, and the results showed that the horizontal and vertical force both increased from 0 to the maximum value and then decreased to 0, while the side force nearly remained constant in one tillage cycle. The directions of horizontal force and side force were the opposites of the working direction of blade and the blade edge, respectively, and the vertical force would change its direction when the maximum tilling depth was reached. It was also observed that the forces and torques of blade in soil with 100% straw covered were larger than those in soil without straw covered because of the extrusion and shear effects between the blade and straw. The field experiments were conducted under 3 soil conditions with kilogram of 0, 0.375 and 0.75 kg (0%, 50% and 100%) on field surface with 0.5 m×0.5 m. The torque and power consumption of the bionic serrated blade and the national standard blade were 404.05 and 389.27 N·m, 20.08 and 18.52 kW with 0% straw covered, 438.33 and 443.79 N·m with 50% straw covered, and 557.92 and 507.34 N·m with 100% straw covered, respectively. The working performances of both blades showed that the performances of bionic serrated blade were better than those of national standard blade in the straw burying rate, the soil crashing rate and the proportion with straw length ≤15 cm under all straw covered conditions. Both simulation results and experimental results revealed that the torques of bionic serrated blade were larger than those of national standard blade with 0% and 100% straw covered. Although the torque and power consumption of the bionic serrated blade appeared better than those of national standard blade only with 50% straw covered, the working qualities after the bionic serrated tillage were always better under all 3 soil conditions. It can be inferred that the bionic serrated blade will perform well with some straw removed from field to compensate for the disadvantages of higher torque and power consumption. The study provides a reference to achieve soil-rototilling and stubble-shattering by using one kind of blade.