Ammonium sulfate is used most commonly as an artificial fertilizer for alkaline soils. When introduced into damp soil, an ammonium ion is released. This creates a small amount of acid, which lowers the pH balance of the soil. It also contributes nitrogen, which aids in plant growth. It dissolves relatively slowly, which makes it cheaper than some other artificial fertilizers. Ammonium sulfate is also used as an herbicide because it will burn the leaves of plants and either kill them outright or at least weaken them for easy removal.