various lime materials that are used in agriculture for soil liming. They eliminate soil acidity, which is harmful to agricultural plants, and enrich the soil with calcium. Lime fertilizers have been used in agriculture since ancient times. As early as the first century A.D., farmers in Gaul and the British Isles were applying marl and chalk to their fields. Beginning in the 16th century liming was used extensively in the countries of Western Europe (Great Britain, Germany, France, and the Netherlands), although the nature of lime’s action was not known until the end of the 19th century. In Russia lime fertilizers were used very little, and only during the years of Soviet power did liming, done over millions of hectares, become one of the most important ways of raising the fertility of acidic soils.
Natural limestones are used as lime fertilizers. Among them are the hard forms, limestone, dolomite, and chalk, which are pulverized or roasted before application; the soft forms, tufa, lake lime (aim), marl, and natural dolomitic meal, which do not require pulverization, are more effective, and act more quickly than, for example, crushed limestone; products of rock processing, such as roasted lime (unslaked ball and crushed lime; slaked lime, or calcium hydroxide); and industrial by-products containing lime, such as defecation slime, shale and peat ash, cement dust, belite meal (a by-product of aluminum production), waste products from pulp and paper combines, and blast slag (see Table 1).
REFERENCESAliamovskii, N.I. Izvestkovye udobreniia v SSSR. Edited by A.V. Peterburgskii and S.G. Shchedrov. Moscow, 1966.
Spravochnaia kniga po khimizatsii sel’skogo khoziaistva. Edited by V.M. Borisov. Moscow, 1969.
M. F. KORNILOV