duck bill speculum

The results showed that taper duck-rostra was superior to cuneiform duck-rostra no matter from the difficult degree of entering soil or the size of soil hole.

结果表明:不论是从入土难易程度还是从所成穴孔大小或是动土量多少来看,锥形鸭嘴都要优于楔形鸭嘴;鸭嘴前角的存在,使穴孔增大,鸭嘴后角的大小,影响鸭嘴出土时的动土量,有利于覆土。

The shape of the duck-rostra type punching-opener affects penetrating performance of sowing wheel,there are two shapes of duck-rostra in common use,they are cuneiform duck rostra and taper duck-rostra.

结果表明:不论是从入土难易程度还是从所成穴孔大小或是动土量多少来看,锥形鸭嘴都要优于楔形鸭嘴;鸭嘴前角的存在,使穴孔增大,鸭嘴后角的大小,影响鸭嘴出土时的动土量,有利于覆土。