32
Driving speeds must be adapted to conditions. At excessively high driving speeds, the coulters may bounce
and rise from the set sowing depth. Sufficient coulter spring loading will secure the coulters to the ground.
On light and moist terrains, the coulter working depth can be limited by using disc coulters, which are
equipped with a limiting cup on the disc. In light tillage conditions, where managing tillage depth may
already cause problems, disc coulters may also be a suitable choice to prevent excessively deep sowing.
Adequate moisture should be ensured so that the seeds are not planted in a ground layer which is either
too dry or too loose.
Setting the sowing depth
As noted above, the sowing depth is to a major degree determined by tillage depth. Changing the coulter
spring loading can significantly impact the sowing depth. On light grounds and when sowing at shallow
depths, the spring loading should be kept low, and increased on more solid terrain. Correct coulter
weighting must always be ensured under practical conditions and the seed placement in the tillage layer
must be observed.
The coulter spring load can be adjusted either coulter-specifically or by using so-called central adjustment.
Coulter loads against the ground can be adjusted between 2 and 20 kg. The respective operating depth is
dependent on the coulter type, tillage and ground type. Sowing depths should always be checked under
actual conditions, and it should be ensured that the seeds are sown into a moist ground layer.
Sowing depth adjustment can be performed most conveniently by means of the main adjustment screw,
located in the center of the rear of the machine, see Fig. 32. Rotating the crank clockwise will increase the
coulter weighting. The storage location for the adjustment crank is inside the frame tube, see Fig. 5 (arrow).
The sowing depth can also be adjusted coulter-specifically. To do this, move the weighting spring extension
chain on the retaining hook on the front of the machine.
Adjusting the chain, e.g. 1-2 loops tighter, is usually required to compensate for tractor tire tracks. The
coulter springs of TUME drills are designed in such a way that the coulter height has no significant impact
on coulter weighting. Therefore, any change in placement depth will not significantly impact the weighting
of the coulters.
Figure 32. Main adjustment screw.
