628 
Rotation of Crops. 
The clover took up, without manure, little more phosphoric 
acid than the rotation beans ; but, with superphosphate, the 
clover took up more than twice as much as the beans ; and 
with the mixed manure it took up more still, and also more than 
twice as much as the beans grown under the same conditions. 
Taking the average of the six crops of beans and two crops 
of clover grown in the eight courses, there was, both without 
manure and with superphosphate, much less phosphoric acid 
taken up than in either the preceding barley or the succeeding 
wheat ; and even with the mixed manure, which gave the most 
normal crops, the average amount of phosphoric acid taken up 
in the beans and clover was less than in either of the two cereals 
under the same conditions. 
The Phosphoric Acid in the Wheat Crops . — The bottom di- 
vision of Table VIII. shows that the rotation wheat, as did 
the rotation barley, took up very much more phosphoric acid 
without manure than did either of the so-called fallow crops 
— the turnips or the leguminous crops. With superphos- 
phate, again, both the wheat and bai’ley took up more than 
either the turnips or the average of the leguminous crops. 
With the full mixed manure, however, when each of the four 
descriptions of crop grew more normally, the amount of phos- 
phoric acid taken up was more nearly uniform in the four cases ; 
the barley, however, then yielding more than the wheat, more 
than the turnips, more than the average of the leguminous crops, 
but all considerably less than the average of the two years of 
clover. 
Comparing the amounts of phosphoric acid in the total pro- 
duce of the rotation, with those in the continuously grown wheat, 
it is seen that there is, without manure, only about half as much 
taken up in the continuous as in the rotation crops; with super- 
phosphate, again, only about half as much in the continuous as 
in the rotation ; but with the more normal growth, when the 
full mixed manure was annually applied to the continuously 
grown crops, there was, with the fuller produce, proportionally 
much more phosphoric acid taken up — indeed, on the average, 
about three-fourths as much in the continuous as in the rotation 
crops. 
Lastly the figures show, that by far the larger proportion of 
the total phosphoi'ic acid in the wheat crops is stored up in the 
grain, which is assumed to be sold off the farm. Thus, without 
manure more than four-fifths, and with superphosphate nearly 
four-fifths, of the total phosphoric acid of the crops was in the 
grain. With the mixed manure, however, with rather larger 
total amounts taken up than with superphosphate alone, there 
