[collyw]

I am no expert either, but you can make compost pretty easily in far less time. Its good for growing plants.

Could composting on a large scale be a solution?

[thatcat]

No, compost is just organic material. Good top soil has <10%-20% organics by volume. Also, since the organics in compost will break down over time, they will need to be re-applied. Sand and clay are needed for structure and minerals.