REVIEW AND CONCLUSION. 365 
while lime is but one-half as much, and the other acids 
and bases are still less abundant. It follows then that if 
71 Ibs. of available potash in 1,000.000 of soil are cnough 
for a barley crop 44 times greater than can ordinarily he 
produced under agricultural conditions, the same quantity 
of phosphoric acid, and less than half that amount of lime, 
ete, must be ample. Calculating on this basis, we give 
in the following statement the quantities required per 
acre, taken to the depth of one foot, to produce the max- 
imum crop of Hellricgel (1), and the quantities needed 
for the average crop of 33 bushels (2). The amounts of 
nitrogen arc those which Hellriegel found adequate to the 
wheat crop. See p. 289. 
1 2 
lbs lbs. 
Potash, 248 55 
Soda, % 17 
Magnesia, %6 17 
Lime, 105 23 
Phosphoric acid, 250 55 
Sulphuric acid, 49 11 
Chiorine, 38 8 
Nitrogen, 245 54 
If now we divide the total quantities of potash, etc., 
found in an acre, or 3,500.000 lbs. of the soil analyzed by 
Baumhauer, by the number of pounds thus estimated to 
be necessarily present in order to produce a maximum 
or an average yield, we have the following quotients, which 
give the number of maximum barley crops and the number 
of average crops, for which the soil can furnish the re- 
spective materials. ; 
The Zuider Zee soil contains enough 
Lime for 1864 naximum and 6138 averaye barley crops, : 
Potash “144 “ “648 “ “ 
Phosphoric acid “65 “ « 992 & “« “ 
Sulphuric a «64 ee ss ORQ « “ 
Nitrogen in ammonia ‘ % ee « 31 tt “ “ 
We give next the composition of one of the excellent 
