[al78]

Today I emptied 30 bags of well rotted manure on a section of the plot which was previously hard compacted clay soil which I had broken up with a fork. I am considering getting another load of manure, but when I have got all the manure down, would it be a good idea to cover it with cardboard over winter (to reduce nutrient leaching by rain) or should I just leave it uncovered?

[JayG]

Long time since I had a clay soil to deal with, but one of its advantages is that it doesn't easily leach out its nutrients because it's so water-retentive.

You already seem to have done exactly the right things - no need for cardboard, just leave it as it is and then turn it in (conditions permitting) in early spring, but remember that newly manured soil is not ideal for root crops like parsnips and carrots. 

[Kristen]

In the days when I dug hard compacted clay I put the manure "under" it, so to speak, so that there was no "insulation" on top and the frost would break up the clods.   Depends how thick the manure is as to how much insulation it might provide, and if you are planning to rotavate in the Spring I guess it would be even-Stevens?

Be interested to know what other think in terms of letting frost attack clay soil.