I've been successful at growing in 90+% organic material(compost).
A very thin layer(1/2") of clay on top of the will help the process, hold moisture, so plants don't topple over as much.
See the permaculture forum....hugelkulter beds.
If anything was added, it was most likely urea. This is done with things like mushroom compost to get the N higher and pile cooking quicker.JaRoHe wrote: Someone had told me they add some chemical to the pile to get it cooking but I couldn't substantiate that claim, the Solid Waste Agency assured me they don't add anything to activate the pile.
If there are problems in my experience with 100% compost, it is roughly the same as with 100% peat moss in beds. Once wet, it stays wet. Once dry it stays dry.
Its August here in SE-OH and has been a bit dry. A dried out bed filled with all compost can be quite hydrophobic, and a real pain in the asterisk to get the bed to take water in.
If I have a long term reccomendation it is compost will continue to break down and it will loose its fertility. Establishing a composting system close to your beds to add mostly, but not quite completely composted yard waste will make your garden and resulting crops better.
Even if no urea was added, mechanically made compost tends to collect salts and just doesn't give back the tilth I think you want. Those little bits of lignin and other high carbon bits are the fodder of micro-herd you want to keep pooping back into your garden.
if you scoop up some dirt, how many worms are in each shovel full? There should be some. Will dirt ball up? the absence of either (or both) is an obvious showing of lack of tilth.
I'd fill beds built about now for next year with leaves or spoiled hay. let providence cold compost it to dirt over the winter.