366 NATUEB AND PEOPBRTIES OF SOILS 



Table LXXI 



Form of Lime 



NUMBEK 

 OF 



Samples 



CaO 



% 



MgO 



Insolu- 



BI.K 



Matter 



Burned lime (low mg.) . . . 

 Burned lime (high mg.) . . 



Slaked lime (low mg.) 



Slaked lime (high mg.) . . 



Pulverized limestone 



Pulverized oyster shell .... 

 Artificial carbonate . 



Marl 



• 



59 

 4 



242 

 107 



161 

 4 



72 

 22 



70.01 

 52.23 



64.26 



48.87 



47.83 

 47.60 

 50.70 

 46.75 



2.97 

 33.07 



3.73 

 28.07 



3.19 



.85 



2.52 



1.00 



6.19 

 2.81 



3.17 



1.58 



6.82 

 8.78 

 1.29 

 5.90 



The first point to be determined in deciding whether or 

 not lime should be applied is in regard to the acidity and its 

 degree. The litmus or zinc sulfide test will supply this in- 

 formation, although a q,uantitative determination may be 

 made.^ The general degree of acidity, unless it is very high, 

 is not sufficient, however, in deciding whether it would be 

 wise to lime the soil. The nature of the crops is a , factor, 

 as well as the ty^e of the rotation, the fertilizer to be used, 

 and to what extent farm manure and green-crops are utilized. 

 Often special considerations are involved, such as scab on 

 potatoes, which is encouraged by liming. All of the factors 

 mentioned, as well as the experiences of the community with 

 lime, should be considered in deciding whether liming would 

 pay. If the increased crops that will probably result from 

 an application of lime will not pay a good interest on the 

 investment, then liming is not to be advised. An application 

 sufficient to make possible the production of good crops of 

 clover or alfalfa is probably all that can be used profitably. 



* The tests are discussed in Chapter XVIII. 



