so it wont affect the potatoes if they go into fresh manure then
How are you defining 'fresh' misfit?
Straight from the animal? or
Newly delivered?
Thinking about it; Potatoes could be an exception to planting on fresh manure!
When you think; if you put the seed potato on top of the manure the new tubers doesn't necessarily form at this point.
To explain;
The chits on the seed tuber forms 'haulms (tops) roots emanate from these, and the new tuber forms along the roots so;
1) the new tuber may not be in contact with any of the manure you put in!
2) By the time the new tuber has formed the manure will not be quite as new.
What do you think of my theory folks?