Agricultural lime, also called aglime, agricultural limestone, garden lime or liming, is a soil additive made from pulverized limestone or chalk. The primary active component is calcium carbonate. Additional chemicals vary depending on the mineral source and may include calcium oxide. Unlike the types of lime called quicklime (calcium oxide) and slaked lime (calcium hydroxide), powdered limestone does not require lime burning in a lime kiln; it only requires milling. All of these types of lime are sometimes used as soil conditioners, with a common theme of providing a base to correct acidity, but lime for farm fields today is often crushed limestone. Historically, liming of farm fields in centuries past was often done with burnt lime; the difference is at least partially explained by the fact that affordable mass-production-scale fine milling of stone and ore relies on technologies developed since the mid-19th century. Some effects of agricultural lime on soil are: it increases the pH of acidic soil, reducing soil acidity and increasing alkalinity it provides a source of calcium for plants it improves water penetration for acidic soils it improves the uptake of major plant nutrients (nitrogen, phosphorus, and potassium) of plants growing on acid soils. Other forms of lime have common applications in agriculture and gardening, including dolomitic lime and hydrated lime. Dolomitic lime may be used as a soil input to provide similar effects as agricultural lime, while supplying magnesium in addition to calcium. In livestock farming, hydrated lime can be used as a disinfectant measure, producing a dry and alkaline environment in which bacteria do not readily multiply. In horticultural farming it can be used as an insect repellent, without causing harm to the pest or plant. Spinner-style lime spreaders are generally used to spread agricultural lime on fields. Agricultural lime is injected into coal burners at power plants to reduce the pollutants such as NO2 and SO2 from the emissions. Determining the need for agricultural lime Lime can improve crop yield and the root system of plants and grass where soils are acidic. It does this by making the soil more basic, allowing the plants to absorb more nutrients. Lime is not a fertilizer but can be used in combination with fertilizers. Soils become acidic in several ways. Locations that have high rainfall levels become acidic through leaching. Land used for crop and livestock purposes loses minerals over time by crop removal and becomes