THE PRACTICAL SIGNIFICANCE OF THE 



ILLINOIS SYSTEM OF PERMANENT 



AGRICULTURE 



By EALPH ALLEN 



Member of the University Soil Advisory Committee 



TO help us realize the magnitude of Doctor Hopkins' work 

 in investigation, let us make a little comparison. Before 

 his time the great source of agricultural knowledge was at 

 Rothamsted ; and when we consider that here the soil investi- 

 gation was virtually confined to one farm of less than sixty 

 acres, that before this time investigations had been practically 

 limited to two or three men, that the Rothamsted investigation 

 was in one place and in one climate, and yet produced results 

 which changed agricultural thought and agricultural advance- 

 ment ; and then when we consider the scope of Doctor Hop- 

 kins' researches, that they involved not the soils of a farm but 

 of a great state, of a varied climate, that they included the 

 soils of almost the extremes in type, from sand to peat and 

 from the rich, black soils found in the corn belt of this state 

 to the other extreme of what are known as the post-oak soils 

 of the south almost devoid of fertility, that his researches cov- 

 ered the physical as well as the chemical and even the biolog- 

 ical phases of the soil, that his fields of investigation were 

 located on lands so eroded that they were practically aban- 

 doned for agriculture, that they involved soils which were 

 almost impossible of drainage, and from those extremes to the 

 very best land of Illinois — then we find the great range of the 

 research within which Doctor Hopkins' fields brought him. 



Doctor Hopkins not only covered this wide field, but he 

 undertook what no other man had attempted — he undertook 

 to show the farmer how he could make practical use of all 

 that had been learned from the study of soils. He taught 

 him the various elements of fertility of the soil and how some 

 of them are found in the air, and some in the soil upon his 



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