Fungi love gypsum, and it's often overlooked by people whether they are trying to harness mycorrhizal or saprophytic fungi. It's as easy as having a bag of pelletized gypsum on hand and using it in the garden, compost pile, grinding into flour and watering innoculated logs with, etc..
For example, I have had excellent results starting outdoor garden piles with a simple technique based on lasagna gardening and utilizing gypsum to bring the fungi to life:
1) Break up the sod with a shovel and discard.
2) Spread a handful of gypsum around the area
3) Layer a big pile of wood chips/compost/cardboard/etc. on top.
4) Plant directly into several months later; the fungi will have turned this all into beautiful soil.
Hope that helps