2 PRINCIPLES OF AGRICULTURAL CHEMISTRY 



edge of the principles of agriculture is largely due to the work of 

 the experiment stations, it is chiefly due, let it be said, to the work 

 of chemists. 



Agricultural Chemistry. Agricultural chemistry is the applica- 

 tion of chemistry and chemical methods of investigation to 

 agricultural problems. It deals, on the one hand, with funda- 

 mental causes of phenomena, and, on the other, with practical ap- 

 plications to agricultural practice. The chemist was the first of 

 the scientists to turn his attention to agriculture, and his results 

 were so fundamental, and practically important, and the science 

 of chemistry was capable of such broad application to agriculture, 

 that for a long time the great body of scientific knowledge re- 

 garding agriculture was known as agricultural chemistry. 

 The chemist has not hesitated to avail himself of the sciences of 

 geology, mineralogy, physics, botany, or such other sciences as 

 were needed in the solution of the problems at hand. Many of the 

 problems of agriculture are complex, and their solution requires 

 the harmonious cooperation of several sciences. Take, for 

 example, the transformation of organic nitrogen to nitrates, a 

 very important process in the soil. This is a chemical change, 

 accomplished by means of micro-organisms, and both chemistry 

 and biology are necessary to give a complete explanation of this 

 phenomenon, though the explanation has been largely worked out 

 by the chemist. 



Scope of the Subject. In a wide sense, agricultural chemistry 

 signifies the study of all the scientific laws involved in plant and 

 animal growth, whatever the several sciences which may be in- 

 volved. We may look at this subject as a fabric in which 

 chemistry is so interwoven in warp and woof that, if removed, 

 the pattern would be destroyed ; if the other sciences were re- 

 moved, the pattern would be very imperfect. 



It shall be our object to deal with the principles ascertained 

 in the application of chemistry to agriculture, taking up the sub- 

 ject from the view-point of the chemist. In particular we shall 

 attempt to indicate the methods which have been followed in 

 securing important results. Agricultural science is founded upon 



