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.In this study,penetrating performances of two punching-opener with different duck-rostra were compared.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.The existence of front angle enlarged the soil hol...