Liming

liming (līm`ĭng), application to the soil of calcium in various forms, generally as ground limestone, but also as marl, chalk, shells, or hydrated lime. Lime benefits soil by neutralizing acidity, improving texture, and increasing the activity of soil microorganisms. It enables bacteria on the roots of legumes, e.g., alfalfa and clover, to secure essential nitrogen from the air, increasing soil fertility. It also increases the available phosphorus in soils. The value of liming was recognized in ancient Rome, and it was common in medieval France and England. Some 17 million tons of lime are sold annually in the United States. In 1987, 264,000 United States farms applied lime on 12.5 million acres.

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liming [′līm·iŋ]

(agriculture)

Treating the soil with lime.

(chemical engineering)

Soaking hides and skins in milk of lime and causing them to swell, to facilitate the removal of hair.

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Liming 

in the leather trade, treating a skin or clean raw hide with milk of lime containing sodium sulfide and sometimes other added substances.

Liming is done in frame and other drums, worm apparatus, paddle mixers, and vats. When semifinished products are limed, the connection between hair and dermis is weakened; interfiber protein materials (mucins, mucoids) are removed; sizable structural elements of the dermis (collagen fibers and their clusters) are split into finer ones (fibers and fibrils); and fatty materials of the skin are partly saponified.

The basic factors affecting liming are composition and concentration of the lime liquor, temperature, duration, and mechanical treatment. Liming conditions substantially affect the main properties of the leather. Intensive liming is used to make softer kinds of leather. Without proper precautions, liming can lead to blemishes on the face of the leather.