STATE BOARD OF AGRICULTURE 169 



nitrogen is applied the herbage becomes almost entirely 

 graminaceous, the leguminosa being killed (not choked) ; 

 where the minerals are used the leguminosae have very much 

 increased. In some instances, as in the case where 275 lb. of 

 nitrate of soda is applied every year, the produce of hay 

 annually is about the same. 



The mean annual produce of hay for 16 years is : 



cwt. 

 Minerals only 35 1/2 



Nitrate of soda only 36 1/2 



The nitrogen in the produce is higher where no nitrogen 

 has been supplied for 16 years than it is where 100 lb. has 

 been supplied annually. An analysis of the soil of these plots 

 would be very interesting if our processes are sufficiently 

 accurate to be trusted. You may possibly have heard that I 

 propose to place my Laboratory, and fields, in trust at my 

 death for the benefit of science, and to endow it with a fund. 

 Yours truly, J. B. Lawes. 



Interest in Professor Johnson's paper on soil 

 exhaustion and rotation of crops — a subject then less 

 familiar to the agriculturist at large than it is today — 

 was shared by the United States Department of Agri- 

 culture. In October 1872, the Honorable Frederick 

 Watts, Commissioner, wrote: 



I have read with much interest and profit your "Soil 

 Exhaustion and Rotation in Crops, ' ' and it induces me to ask 

 you to prepare an article to be published in the next Annual 

 Report of this department on the subject of the different crops 

 and different manures and the relation which they bear to 

 each other. — I do not mean to dictate what shall be the title 

 of any article, but merely to suggest a general subject, leaving 

 you to determine what shall be most practically useful to the 

 agriculturists of the country. 



