Soil acidity can be ameliorated and the pH of the soil increased by the addition of lime/limestone (calcium carbonate) and similar compounds that have been ground fine for use. Types of lime-like amendments include:
Dolomitic limestone
Quicklime
Hydrated lime
Marl
Chalk
Oystershell
Wood ashes
Fluid lime
Each lime-like amendment has its benefits and drawbacks, such as effectiveness, price, and purity. Lime is most effective at neutralizing acidity when it is incorporated/tilled into the soil to the full depth of the plow layer or root zone.