CULTIVATION. 23 



The three ingredients chlorine, silica, and soda cannot 

 be considered in the light of essentials to tobacco culture ; 

 but the other substances are absolutely indispensable to 

 plant growth, and the absence of any one of these would 

 render a soil incapable of sustaining agricultural vege- 

 tation of any kind. " The variation in the percentage of 

 these ingredients depends somewhat upon the fact that 

 the leaves of diflferent crops are unequally developed, and 

 therefore their nutritive needs are unlike ; but it is, no 

 doubt, chiefly connected with the fact that the plant 

 takes up from a highly fertilized soil more of each or 

 every element than is essential for growth. The nearly 

 certain conclusion is that every one of the crops analysed 

 contains more of some elements than belongs to its 

 nutrition. It is quite certain that the average of the 

 analyses of the New England tobaccos is fully up to the 

 mark as regards the necessities of the crop. It is, indeed, 

 not improbable that the lowest percentages of each in- 

 gredient are quantities sufficient for a perfect crop. Still, 

 it is not proved that lime may not partially take the 

 place of potash, or the reverse. The probability of such 

 a substitution is great upon the face of most of the 

 analyses. As a rule, those which show most potash show 

 least lime and vice versa ; but in one sample both ingre- 

 dients are considerably below the average. The practical 

 issue of these considerations is to give great probability 

 to the view that the tobacco crop is fed unnecessarily 

 (and wastefully ?) high." (Prof. Johnson.) 



Tobacco is usually characterized as a very exhausting 

 crop. This is not true as regards the amount of nutri- 

 ment taken from the soil, for in this respect tobacco is less 



