4 
LysIMETER EXPERIMENTS —II] 65 
TABLE 16. Averace ANNUAL REMOVAL OF CALCIUM FROM PLANTED AND FROM UNPLANTED 
TANKS 
(In pounds per acre) 
Calcium removed in T 
otal 
Tanks Soil treatment | calcium 
: removed 
Drainage Crops 
water 
HS ios cod oattos ) ones See one Rlanted separ 256.4 8.7 265.1 
14. 1G. s ee pieeibdicto Bec ae ae eee Barer: eshte Sole AT ete ete 351.4 
@alcinumuconsenved aby Cropping. 256 2... cee eles see eee oh sate seek 86.3 
The process of cropping conserves the calcium in the soil even when the 
entire crop is removed. The reason for the greater removal of calcium 
from the uncropped soil may be found, in part at least, in the large for- 
mation and leaching of nitrates when plants are not present. In table 17 
are shown the average quantities of nitrates found annually in the drainage 
water of the planted and the unplanted tanks. 
TABLE 17. Average ANNUAL REMOVAL OF NITRATES IN DRAINAGE WATER FROM PLANTED 
AND FROM UNPLANTED TANKS 
Nitrates 
Tanks Soil treatment removed 
(pounds 
per acre) 
13 WS 5.6.6 oc.0':6 ee Cc eS Ie ee Cane Planted Ser ne ain oe AT 
eal GPP Ty ie hat cose seis shes oes IBALG eee te yanwin cee see ieee 231.7 
The nitrates in the drainage water from the cropped soil would account 
for only about 11.5 pounds of calcium, while the nitrates from the unplanted 
soil correspond to about 56.5 pounds of calcium which might be removed 
in the form of nitrate. This would still leave about 245 pounds of calcium 
that had been removed in the drainage water from the planted soil in some 
form other than nitrate, and about 285 pounds from the unplanted soil. 
