To dehydrate turnips, wash your them and then cut off the ends and peel them.
Next using a sharp knife or your mandolin, slice the turnips into slices about 1/4" thick.
At this point, many people will tell you to blanch your turnips but I never do and they still turn out fine. I just place them on my dehydrator trays and turn it on. If your dehydrator has a temperature setting, set it at 125 degrees and turn it on and let them dehydrate for 12 hours. You know they are done with they are brittle but can bend just a little. Store in an airtight container until you are ready to use them.