Authors

Abstract

Unclear soil layer coupling failure characteristics on natural grassland impeded the design and optimization of appropriate tillage tools. The coupling failure characteristics including surface disturbance and profile, disturbed cross-section area, soil over-turning rate, and coupling forces between the soil layer of natural grassland and selected passive subsoiler-type openers were investigated in this paper. Three single-shoot openers (i.e. CO, AO and WAO) and a test unit were designed, and furrow opening experiments under different working depths were conducted. Results showed that, along the passages, U-shaped disturbed cross-sections were usually created with soil-root clods overturned along the furrows. The roots were usually broken in a pulling or dragging way underground. Both disturbed cross-section area and draft force values increased with the working depth increasing linearly (R2≥0.93), contrary to the tendency of the specific draft force with the depth. Winged opener (i.e. WAO) had larger draft forces and disturbed soil layer cross-section areas than no-winged openers (i.e. AO and CO). The soil layer failure processes of the natural grassland were affected by its composite soil layer structure and the geometry parameters of the openers. The results provide original references for designing novel furrow openers applicable to improve degraded natural grassland.

Abstract in Chinese

为研究耕作部件作用下的天然草地耦合失效特性，设计了三种深松铲型开沟部件，通过搭建试验台进行了不同作业深度下的草地开沟失效试验，对草地土层失效过程、扰动情况、扰动截面积、翻垡率和作业阻力进行了分析。试验结果表明，深松铲型开沟部件作业时产生U形扰动截面，同时沿沟易产生翻垡的土壤-根系复合结构土块；开沟部件作业时主要通过拉扯的方式使根系拉断；开沟扰动截面积和水平方向的作业阻力均随着作业深度的增加呈线性增加的趋势（R2≥0.93）；而沟形面积比阻随着作业深度的增加而减少。具有双翼的开沟部件产生较大的牵引阻力和土层扰动截面积，草地土层失效过程受其复合土层结构和开沟部件的形状参数的影响。试验结果为退化草地改良用专用开沟部件的研发和优化设计提供了参考。