THE NITROGEN CYCLE 



151 



position of the manure but without any corresponding 

 increase in nitrates. On the other hand, under field con- 

 ditions, manure used in relatively small amounts does 

 not undergo this serious loss. 



The application of twenty tons of farm manure to the 

 acre to sod on a clay loam soil for three consecutive years, 

 at Cornell University, resulted in a larger production 

 of nitrates on the manured soil than on a contiguous plat 

 of similar soil left unmanured. This was true during the 

 third year of the applications, when the land was in sod, 

 and also during the fourth year, when no manure was 

 applied to either plat and when both plats were planted 

 to corn, as may be seen from the following table : — 



Nitrates Produced on Heavily Manured and on Un- 

 manured Soil 



Land in timothy 



April 23 . . 



May 3 . . . 



May 14 . . 



May 30 . . 



June 1 . . . 



June 13 . . . 



June 20 . . 



July 24 .' . 



August 14 . 

 Land in maize 



May 19 . . 



June 22 . . 



July 6 . . . 



July 28 . . 



August 10 



