Authors

Abstract

Novel tillage tools with high working performance are desired in improving degraded natural grassland tillage system. This paper aimed to find the influence of various geometry structures of very narrow tines on related soil disturbance characteristics and tillage resistances. Four shank-type tillage tines with different cutting head shapes, and the test bench were designed and manufactured. Field experiments under different working depths were conducted. The working depth uniformity, soil over-turning rate, cross-section area of disturbed soil layer, and related forces were obtained, analyzed and compared. Results showed that, the working depth uniformities were above 70%, and soil overturning rates did not exceed 5%. Furrows with V-shaped cross-section were formed. The tine with an arc-shaped cutting edge (AT) obtained a lower draft force value, and the tine with chamfer structure (TTD) presented big differences on the draft force and soil disturbance on the grassland compared to the tine with blunt cutting edge (TT). Both the draft force and the area of disturbed soil cross section had a good linear relationship with working depth, and the specific draft force increased with the working depth increasing. Using a very narrow tine with chamfers to split and break the soil layer on the natural grassland without pulling or dragging the roots could be an appropriate tillage method applied for improving degraded natural grassland, but still need further surveys.

Abstract in Chinese

为设计和优化退化草地开沟部件，对具有不同形状结构参数的极窄齿类耕作部件的作业效果展开研究，设计了4种铲尖形状不同的极窄齿类开沟部件，搭建了试验台，进行了草地开沟扰动试验。试验结果表明，在0~15 cm作业深度范围，各部件的开沟深度稳定性系数均在70%以上，造成的地表翻垡率不超过5%，作业后形成具有“V”形扰动截面沟槽的扰动区域。牵引阻力和土层扰动截面积均与作业深度呈良好的线性正相关关系（R2≥0.78），且单位面积牵引力随深度的增加而增大。入土角相同的情况下，铲尖形状对开沟部件的牵引阻力和草地扰动情况影响不显著，但有无刃口对二者具有较大影响；采用具有刃口的极窄齿类开沟部件以切断或割裂土层的方式能够有效打破板结性退化草地土层中的土壤-根系复合体结构，降低地表植被破坏程度，采用凹曲线的铲尖刃线形状可适当降低开沟部件的牵引阻力。