Dolomitic Limestone Apply in fall to raise pH of acidic soils that contain insufficient magnesium. Dolomitic limestone is mined around the world. Gypsum Apply in fall or spring to supply calcium and sulfate, or to improve soils that contain excess sodium. Benefits last 1 to 2 years. Gypsum is mined primarily in the western U.S. Pelletized Calcitic Limestone Apply in fall to raise pH of acidic soils that contain adequate magnesium.
Calcitic limestone is mined in many regions around the world.
Rock Dusts Apply in fall to supply trace nutrients such as aluminum, boron, iron, manganese, silica, and many others. Rock dusts are mined in all regions of the U.S., typically as a by-product of other quarry activities. Benefits are long-lasting, to 5 years or more. Har phosphate is mined in many regions around the world. Mined in Florida, soft-rock phosphate also improves soil moisture retention.