MJ, if you can, I would place the manure (or compost, green manure, other soil amendments) on the soil and turn it in. If you are leaving your garden (except parsnips and sprout areas) fallow over winter, I would coarsely turn that material into the soil. You can mix more thoroughly when you get closer to planting.
For your parsnips and sprouts, you can also top dress with a soil amendment. For root crops, remember that manure has a bacterial component, be aware of that and judge how close to harvest you want to be applying manure, especially if the manure has not been rotting down for a while.