In addition to Dave Robison's reply, and applying Ca in one form or another: I have added oak leaves to garden beds, with the intention of eliminating a snail and slug problem , but which also resulted in increased friability (as would be expected) of the high clay (>45%) soil which I was working with at that stage. The interesting realisation for me now is that this improved friability lasted for at least another 8 years, compared to shorter term benefits from applying compost only. My take on this now is that possibly the high concentration of Ca added through the oak leaves had the effect that Dave has described, compared to more diluted Ca through compost.
The feasibility of this route depends of course on the scale of operation. Stephen Barrow
