That s great if you re trying to garden in Arizona. Here in Minnesota, except for a few areas in the Red River Valley, there is not sodic soils, so there is no benefit from incorporating gypsum. It will not change the texture or structure of the clay soils, although it is often sold for that purpose. Gypsum is a good source of calcium and sulfur and can be useful on sandy soils, where it will supply these nutrients. With the exception of sandy soils, most soils in Minnesota contain adequate calcium and sulfur to grow healthy plants.
Lime is calcium carbonate.
It is used to raise the pH of acid soils. This is common practice in the eastern United States, where soils are typically quite acidic. So it s common for gardening books and magazines, many of which are published out east, to recommend liming. Adding lime to these soils will not be beneficial and may even be harmful by making nutrients such as iron less available. Only be having the soil tested.