TOBACCO CULTURE IN THE WEST INDIES 31 
POTASH 
While phosphoric acid and nitrogen is needed to grow 
a plant it is principally potash that determines the quality 
of tobacco. 
(x) Dr. Wagner found after many years of experiment- 
ing that the burning quality of a tobacco depends on the 
potash content of the leaf. He also found that the con- 
tent of the leaf depends upon the amount of available pot- 
ash in the soil. Tobacco grown in soils with a low potash 
content contained 0.51% to 0.70% potash in the dry leaf 
which was found to be very poor tobacco. A tobacco grown 
on soil well fertilized but with only a medium potash con- 
tent contained 2:3 % ‘potash in the dried leaves but that, 
was also of poor burning quality. The best burning qual- 
ity was not obtained until the potash content of the dried 
leaves reached 6 % and in order to reach this high percen- 
tage it was necessary to apply 900 pounds of potash per 
acre, equal to 1,800 pounds high grade sulphate of potash, 
which shows that a soil must be fairly saturated with pot- 
ash in order to produce a tobacco of a high combustibility. 
Many different chemical combinations of potash were 
used by Prof. Wagner and he disproved a great many fal- 
lacies regarding the effect of various salts on the tobacco 
plant. The three forms of potash: carbonate, silicate and 
sulphate were carefully compared. A number of experi- 
ments in differents soils and under different conditions 
brought out the fact that they were practically of equal 
value, the sulphate being rather the more desirable. This 
is of great importance to planters and fertilizer manufac- 
(x) Bulletin 138 German Agricultural Society by Prof. Dr. P. 
Wagner, 1908. 
