122 BOARD OF AGRICULTURP:. [Pub. Doc. 



fairly be charged with iriditference to, or ignorance of, the 

 more recent developments of science. 



When I first began the study of agricultural science, soil 

 fertilitj' Avas discussed chiefly on a mathematical basis, and 

 the maintenance of fertility was set forth, at least in a pop- 

 ular way, largely as a matter of book-keeping. Let us see 

 how this came about. Our knowledge of plant nutrition, even 

 in its most popular form, had its beginnings in the researches 

 of pure science. The real first teachers of agricultural prin- 

 ciples were not hard-handed tillers of the soil, but such 

 toilers as DeSaussure, Boussingault, Liebig, Way, Knop, 

 Hellriegel and others, who, in their laboratories, animated 

 solely by a love of truth and without thought of material 

 recompense, searched out nature's secrets. What did they 

 learn? They learned, first of all, what are the constituents 

 of the air, soil and plants ; they determined the relation of 

 the plant to its environment of soil and air ; the sources 

 from which plants draw their food ; and the elements Avhich 

 are absolutely necessary to the building of the plant. In 

 the unfoldino; of this knowledoe it was discovered that the 

 greater portion of the dry substance of a plant is drawn from 

 the atmosphere ; but that certain ingredients, especially 

 those which we speak of as the mineral part of the plant, 

 must come from the soil. Moreover, it appeared, from the 

 investigations made as to the com})osition of plants, that ten 

 or more elements are uniformly found in all plants, though 

 in varying proportions, but that the fruit or seed of a par- 

 ticular species has a reasonably constant composition. It 

 was also made very evident that a few of the essential min- 

 eral constituents of })lant growth exist in soils in very small 

 proportions, and that these constituents are constantly sub- 

 ject to waste through the processes of agriculture. More 

 than this, it ^^■as found, in practical agriculture, that when 

 certain compounds containing essential elements of plant 

 food were added to the soil, in many instances a large in- 

 crease of crop followed. By all this knowledge, laboriously 

 wrought out, certain premises seemingly indisputable ap- 

 peared to be established, and pointed to what was regarded 

 as a sound conclusion. The reasoning may fairly ])e stated 



