Liming is the application (to soil) of calcium- and magnesium-rich materials in various forms, including marl, chalk, limestone, or hydrated lime. In acid soils, these materials react as a base and neutralize soil acidity. This often improves plant growth and increases the activity of soil bacteria, but oversupply may result in harm to plant life.
The degree to which a given amount of lime per unit of soil volume will increase soil pH depends on the buffer capacity of the soil (this is generally related to soil cation exchange capacity or CEC). Soils with low CEC will usually show a more marked pH increase than soils with high CEC. But the low-CEC soils will witness more rapid leaching of the added bases, and so will see a quicker return to original acidity unless additional liming is done.
Most acid soils are saturated with aluminium rather than hydrogen ions. The acidity of the soil is therefore a result of hydrolysis of aluminium. This concept of "corrected lime potential" to define the degree of base saturation in soils became the basis for procedures now used in soil testing laboratories to determine the "lime requirement" of soils.
An agricultural study at the Faculty of Forestry in Freising, Germany that compared tree stocks 2 and 20 years after liming found that liming promotes nitrate leaching and decreases the phosphorus content of some leaves.
- Soil Acidity and Liming (Overview) Archived 2007-05-09 at the Wayback Machine.
- Turner, R.C. and Clark J.S., 1966, Lime potential in acid clay and soil suspensions. Trans. Comm. II & IV Int. Soc. Soil Science, pp. 208-215
- "corrected lime potential (formula)". Sis.agr.gc.ca. 2008-11-27. Retrieved 2010-05-03.
- "One Hundred Harvests Research Branch Agriculture Canada 1886-1986". Historical series / Agriculture Canada - Série historique / Agriculture Canada. Government of Canada. Retrieved 2008-12-22. Note this link loads slowly
- Huber C, Baier R, Gottlein A, Weis W. Changes in soil, seepage water and needle chemistry between 1984 and 2004 after liming an N-saturated Norway spruce stand at the Höglwald, Germany. Forest Ecology and Management, 2006; 233; 11-20.