LIME AND LIMING.* 
L, L. VAN SLYKE. 
THE USE OF LIME COMPOUNDS ON SOILS. 
Numerous inquiries in regard to the use of lime-containing 
materials are constantly coming to the Station. In order to 
answer these inquiries more fully than can be done in in- 
dividual correspondence, this circular has been prepared. 
The different lime compounds to be considered are used for 
the purpose of (1) neutralizing the acidity of soils, (2) pro- 
ducing other changes, chemical, biological and physical, (3) 
supplying phosphorus to plants or (4) furnishing calcium to 
plants. Lime compounds are least often used for the direct 
supply of calcium as plant-food because this element is suf- 
ficiently abundant in most soils to supply crops. For neutraliz- 
ing the acidity of soils there are used lime, slaked lime and 
carbonate of lime. For producing other changes in soils the 
same lime compounds are used and, in addition, sulphate of 
lime (land-plaster). The two materials which will be dis- 
cussed as a source of phosphorus are ground phosphate rock 
(floats) and phosphate slag. The slag also contains lime in 
other forms than phosphate and can be used for neutralizing 
soul acidity, while the rock has little, if any such value. 
COMPOSITION OF LIME COMPOUNDS. 
All lime compounds contain as a characteristic constituent 
the chemical element calcium and in chemistry are known as 
calcium compounds, as explained below. In the different com- 
pounds of lime we find calcium combined with one or more 
other chemical elements. 
* A reprint of Circular No. 10. 
[388] 
