Here is a link to a simple test one can do to find out if gypsum is compatible with your soil. Before spending any money that you might not need too, read this and do the test. It works. There are many variations of it, but they all are similar in principle.

One thing I do know about gypsum is to not over apply it. 2000#/a is plenty. 500# is better applied more often.  The sulfur in gypsum will react with nutrients in your soil and knock them off the clay particle creating energy. Energy is what makes your crops grow, not any one nutrient alone. It's the interaction of nutrients which gives off energy which makes things grow. It's not the actual nitrogen that makes your corn grow, it's the reaction with other nutrients in the soil which create energy and heat.     Too much gypsum and you knock loose too many minerals and they will leach out, essentially mining your soil. A little is good, a lot is not better.

JAR TEST