Tines tend to move pre-emergent chemicals away from the seeded rows and some form of harrow may be required to move some soil back over the seed. Rotary harrows are very effective at incorporating chemicals, particularly as they can handle large amounts of stubble. Press wheels leave any pre-emergent chemical where it is thrown by the soil opener, so they may need following by a harrow to even out the chemical. This ensures the seed is placed in the base of a furrow to harvest water. These furrows are best formed with rows slightly wider than 200 mm.
Narrow furrows tend to be filled in by following tines.