Do wider rows cause yield to drop off?
Are there any comments on yields with the wider rows needed for most direct drills?
In terms of row width, the evidence from precision drilled crops on wide row spacing is that you can go to about 30cm in wheat before yield drops off.
However, it can wobble a bit at this spacing so I suggest that 10 ins ( 25cm) is safer.
You also need to bear in mind that this creates a much more open crop structure so you get less weed suppression through crop competition.