Soil chemical health is strongly related to soil acidity. This acidity consists of acidic cations, hydrogen (H+), aluminum (Al3+), and in some soils, manganese (Mn2+). The acid cations are neutralized by basic anions, carbonate (CO32-), hydroxyl (OH-), and oxide (O2-) provided by materials such as agricultural, hydrated/slaked, and quick/burnt limes, respectively. Lime application rates are based on the amount of acidity measured in your soil sample.