254 THE FARMER OF TO-MORROW 



wished the soils to continue to feed the nation. 

 Pliny also recognized the necessity of adapting 

 the crop to the soil, and in this connection he 

 mentions the benefits to the soil to be had 

 from the growth of legumes, "which are 

 pulled up and not cut in reaping; hence they 

 are called legums because thus gathered." 



Modern Europe early began establishing 

 experiment stations in an effort to determine 

 the exact nature of soil fertility; although it 

 was not until the time of Liebig, about 1840, 

 that active direction was given to these experi- 

 ments. The United States and other younger 

 nations, recognizing soil fertility as a national 

 asset, and the determination of its nature as a 

 national function, developed experiment sta- 

 tions in great numbers. At the present time 

 each State in the Union has such a station 

 supported by federal subsidy under the Hatch 

 Act, and, in addition, stations supported by 

 state subsidy alone, and still others conducted 

 in connection with agricultural colleges. Thus, 

 there is no dearth of data for one who seeks 

 to study the problem of soil fertility in its 

 numerous branches. 



The most classic experiments recorded in 

 the literature of agriculture are those of the 



