The most common material used for liming soils is ground limestone. Limestones range from pure calcium carbonate to mixtures of calcium carbonate and calcium-magnesium carbonate (dolomitic limestone). Lower grade materials may contain shale, chert, sandstone or clay, none of which has any neutralizing value. Byproducts from industry such as sugar-refuse lime, lime sludge from boilers and acetylene plants, and stack dust from cement plants may be available locally in limited quantities. Burned lime and hydrated lime are excellent liming materials but may require special application equipment. Generally these resources are not economically available in Nebraska.
Table 4.4 shows the neutralizing value of lime from pure forms of various lime material.
|Form of lime||Molecular weight||Neutralizing value, %||Pounds equivalent to 1 ton pure CaCO3|
Table 4.4. Equivalent neutralizing value of various liming materials