FERTILITY OF LAND NOT DUE TO ITS NITROGEN. 289 



which was not true for manures could not possibly hold 

 good for land. 



Every one who is acquainted with chemical analysis 

 knows that among the constituents of the soil none can 

 be approximately determined with greater accuracy than 

 nitrogen. In an exhausted soil at Weihenstephan and 

 Bogenhausen, nitrogen was determined by the usual 

 method, and calculated to a depth of 10 inches. 



The field contained, per hectare, 



Bogenhausen. Weihenstephan. 

 kilogr. kilogr. 



Nitrogen 5145 5801 



On both fields summer barley was cultivated in 

 1857, and the following returns were obtained, per hec- 

 tare : 



Bogenhausen. Weihenstephan. 

 kilogr. kilogr. 



Corn 413 1604 



Straw 1115 2580 



1528 . 4184 



Thus, the field at "Weihenstephan, containing about 

 the same amount of nitrogen, yielded almost four times 

 as much corn, and more than twice as much straw, as 

 the field at Bogenhausen. 



In 1858, these experiments were repeated at Weihen- 

 stephan with winter wheat, and at Schleissheim with 

 winter rye ; the result was : 



Nitrogen contained to the depth of 10 inches, per hectare, 



Schleissheim. Weihenstephan. 



kilogr. kilogr. 



2787 5801 



Crop. 



Corn 115 1699 



Straw 282-6 3030 



397-6 4729 



The amount of nitrogen in the field at Schleissheim, 

 as compared with that at Weihenstephan, bears the 



13 



