SOME GENERAL INFORMATION ON LIME AND ITS USES ANT) 



FUNCTIONS IN SOILS. 



Special Bulletin No. 91 



INT. M. ilCCOOL AND C. E. MILLAR. 



Introduction. 



Lime was used more than three thousand years ago in parts of Europe 

 to improve soils. In some of our eastern states liming has been practiced 

 since the earlier stages of the agricultural development and its use has 

 gradually spread until it is added to the soil to a greater or less extent 

 as far westward as the regions of lighter precipitation. :N[oreover, its 

 need is quite generally recognized in several of the older settled regions 

 west of the Cascade Mountains. In reality all lands in the humid regions 

 will sooner or later become deficient in lime since it is constantly removed 

 from the soil by water that passes through it. and by crops taken away. 



The amount of lime applied to the soil in Michigan is steadily increas- 

 ing from year to year. Although our laboratory and field investigators 

 have not progressed far enough to make possible accurate statements 

 concerning the deficiency of lime in ^Michigan soils, it is conservative to 

 estimate ihat the majority ol" Ihem are in need of it, especially tlie older 

 fields. Moreover, these studies show that this condition is not con- 

 fined to any particular class of soil such as sands, loams and clays :nid 

 mucks, but is more or less common to all, yet the fact should nol lie 

 overlooked that calcareous formations or those high in lime occur in 

 all classes of soil. 



The lime requirement for maximum returns on the investment varies 

 greatly. Many fields require only small quantities in order to obtain 

 satisfact<»ry results from clover nnd alfnlfa, wliile medium to very l;n-ge 



amounts must \)0 applied to utiievs in esj;lblisli tliese (ln]»s ;ni(l prixliicc 



suitable vields of manv others. 



FUXCTIOXS OF r.IMK. 



The benefits derived from applications of lime are the results of 

 chnnges induced in the soil that make them more suitable for plnnt 

 growth. Some of the functions that lime performs are very general 

 in their occurrence, while others are more specific, being confined to 

 a limited number of soils. Inasmuch as several or all of the elTects 

 of liming may be operative at the same time it is indeed com]»lex. and 

 therefore variable results from its use are to be expected. The various 

 functions that lime may perform in the soil nmy be conveniently grouped 

 as follows : 



1. Modification of soil structure or tilth. 



2. Neutralization of acids and other injurious substances. 



3. Meeting the silicate requirements. 



