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CHAPTER XII. 



mineral manures or amendments, 

 (ameliorators.) 



Practice has preceded science in the appli- 

 cation of mineral manures, for we know not 

 yet, clearly, what is their mode of action, and 

 hence the necessity of a careful study of the 

 subject. 



Lime. Lime is used as a manure, both in 

 a caustic state and as carbonate. Magnesian 

 lime is injurious to vegetation, and its use 

 should be avoided. Caustic or calcined lime 

 is an useful ameliorator, especially in the cul- 

 ture of the cereals. Its application to calca- 

 reous lands is superfluous. Quick lime, says 

 Liebig, acts apparently in rendering the 

 earthy substances assimilable by the plants. 



In the vicinity of Dunkirk they use fort}^ 

 five bushels per acre, and the effect of this 

 proportion is perceptible for 10 or 12 years. 

 The quantity recommended by Puvis (4 

 bushels per acre, annually^ is more than 

 sufficient. 



Though the lime, applied to the soil while 



