Gypsum is one of those rare materials that perform in all three categories of soil treatment: an amendment, conditioner and fertilizer. It is a fast release source of sulfur and calcium. When dissolved it releases an equal proportion of calcium and sulfate. Gypsum is 100% more soluble than lime! It increases calcium without effecting pH. Low in dust and easy to apply either by hand or lawn spreader, pelleted gypsum is the right choice because it doesn't have to be worked into the soil, it can be applied directly to the surface. Just water it in after application to dissolve the pellets quickly. Gypsum loosens clay and compacted soil, improving the structure. Gypsum helps aerate compost allowing fungi and bacteria to do their work quicker and reducing unpleasant smells. Gypsum also raises the compost's nitrogen content, for, in the presence of gypsum, the ammonia released by bacteria converts to ammonium sulphate (a fertilizer) instead of being lost to the air