250 Bulletin 247. 



applied 320 lbs. of nitrate of soda or 50 pounds of nitrogen and that at 

 harvest there was 2.5 parts of NO3 left in the soil: thus for argument 

 merely it will be assumed that 56.3 parts of NO3 per million of dry soil 

 was taken up by the plant. This is only 13 pounds of nitrogen per 

 million of dry soil. We would have to assume, therefore, that all the 

 water-soluble nitrogen in 3 to 4 million pounds of soil was found and 

 used by the plant. 



Probably no such thing occurs in the soil. When nitrate of soda is 

 added to the soil, as repeatedly shown in the investigations at this station 

 and elsewhere, part of the nitrogen is fixed in the soil and a part of it 

 goes into solution. What probably happens is that as the soil is ex- 

 hausted of its water-soluble nitrogen by the plant, a part of this fixed 

 nitrogen goes into solution. The behavior of nitrate of soda when ap- 

 plied to soils strongly indicates this action. What probably happens is 

 that when nitrate of soda is applied more nitrogen keeps going into solu- 

 tion at jfist the time when the plant is making great demands on the soil 

 for this nitrogen than when nitrate of soda is not added. Thus having 

 water-soluble nitrogen on tap at the right hour and the right place is 

 one of the factors that enabled the Cornell Station to grow three and 

 one-half tons of timothy hay on Dunkirk clay loam when without this 

 artificial help only about one and one-half tons could be raised. 



