I have blackgrass and an 8m seedhawk on 520ha and have found 7kmhr to be perfect. If the coulter is following the ground in a steady undulating manner that is perfect, if I go much faster the movements become more pronounced and vicious which basically means I am not packing the seed because there is air between the soil and tyre.If you have black grass and going tine drill do you go slower to reduce soil movement?
Does that mean we should go "American" and have much wider drills running at 7kph rather than the more "European" at least 10kph?
Wear rates drop considerably at these speeds.
There is also a correlation with speed and soil movement. I aim for an unrelenting small bow wave of tilth in front of each tine, speed up and this becomes more erratic with more clod being brought up.