Authors

Abstract

Novel tillage tools causing minimizing surface vegetation deterioration are desired in degraded natural grassland mechanical restoration technology development. This paper attempted to study the effect of tine geometry in its vertical movement on penetration resistance. Four very narrow tines were defined (i.e. rectangle, triangle, crescent and mososeries) based on the geometry of the cutting edge, a special test unit was manufactured as well. Field experiments were conducted on natural grassland. The effects of tine geometry and contact surface area on soil penetration resistance were investigated and surface disturbance obtained. Results indicated that the tendencies of penetration resistance varied with the working depth or contact surface area, and showed differences between the four tines affected by different cutting-edge geometries. The crescent tine obtained the highest penetration resistance as compared to the others, and the mososeries tine got the lowest value. Penetration resistances of all the tines increased with the attack surface area with an exponential function (R2≥0.94) or a power function (R2≥0.95) respectively, depending on the penetration angle equalling 90° or being less than 90°, nonlinear tendency with penetration depth. It could be concluded that penetration resistance was influenced a lot by the tine geometry parameters such as contact surface area and penetration angle. The cutting edge of the tine with continuous acute penetration angle that could obtain lower resistance and stable force variation curve was more suitable for operation on natural grassland.

Abstract in Chinese

为探索适用于退化草地机械化改良作业的关键耕作部件，设计了4种不同形状的极窄刀齿，并搭建了试验台，进行草地贯入失效试验，重点对刀齿的贯入阻力进行分析。结果表明：刀齿贯入阻力随深度和接触面积的变化趋势受刀齿形状的影响而存在差异，新月形刀齿的贯入阻力最大，弦月形刀齿的最小，贯入阻力与贯入深度呈非线性正相关规律，与接触面积呈指数函数或幂函数变化规律（R2≥0.94）。刀齿刃口的入土角度和刀齿与土壤的接触面积均对贯入阻力产生影响，且贯入阻力变化程度受刃口的入土角度的影响，入土角度为直角时，贯入阻力存在急剧变化的阶段，入土角度为锐角时，贯入阻力变化相对稳定，宜选择刃口入土角度为连续锐角的刀齿进行作业。