64 T. LytTLEToN Lyon AND JAMES A. BizzELL 
Estimating the nitrogen in the roots of each crop to amount to one- 
third the quantity in the above-ground part, it will be seen that the nitrogen 
in the oat crop added to the nitrogen in the drainage water from the tanks 
on which that crop grew was less in amount than the nitrogen in the drain- 
age water from the bare tanks for the same period. ‘The same was true 
of barley, but it was not true of maize or, of peas. The excess of nitrogen 
from the pea tanks can doubtless be ascribed to the nitrogen-fixing prop- 
erties of Bacillus radicicola in the nodules of the pea roots. The excess 
nitrogen from the maize tanks must be ascribed to some different phenom- 
enon. It has been suggested? that some plants have the property of 
depressing the formation of nitrates, and that certain plants possess this 
property to a greater degree than do others. The data here presented are 
in line with such an hypothesis. 
REMOVAL OF CALCIUM 
Calcium was removed in the drainage water to a much greater extent 
than was any other of the bases determined, but in relatively small amounts 
by the plants. A comparison of the calcium in the drainage water of the 
Dunkirk and Volusia soils shows that the latter lost more calcium by 
leaching than did the former, in spite of the fact that this soil contained 
only about two-thirds as much of that element as did the Dunkirk soil. 
On the other hand, the crops grown on the Volusia soil contained less 
calcium but the yield of crops was much smaller. The total removal of 
calcium from the Volusia soil, from both planted and unplanted tanks, 
was greater than that from the Dunkirk. 
Effect of plant growth on removal of calcium 
In the experiments with Dunkirk soil it was found that less calcium 
was removed from the planted soil in crop and drainage water combined 
than was found in the drainage alone from the unplanted soil. This is 
true also of the Volusia soil, as may be seen from table 16: 
3 Lyon, T. Lyttleton, and Bizzell, James A. Some relations of certain poe plants to the formation 
of nitrates in soils. Cornell Univ. Agr. Exp. Sta. Memoir 1:1-111. 1913. 
