Using a rented no-till seeder and tractor (a Case-IH 685 -- a very nice tractor with a wheel under each corner and a low center of gravity), I planted the turnips and kale on July 28. The turnips are on one side of the field, and the kale on the other, with a strip of Italian ryegrass in the middle. The ryegrass will serve to provide fiber and a more familiar source of energy while the lambs adjust to the brassicas (also known as a "runback" area -- the lambs can run back to familiar feed while learning about eating their turnips and kale).
The no-till seeder didn't do a great job. It frequently clogged up with trash from the oats and peas that were harvested earlier this month, so I had to slow down and lift the seeder out of the ground to allow it to empty out. This leaves a combination of unplanted areas and big piles of straw. The seeder wasn't equipped with coulters, which would have sliced the trash into shorter pieces that could have slipped through the seeder points.
As always, pics to follow.