VARIATIONS IN COMPOSITION 



267 



sons. This may be due to the nature of the soil, or 

 to the fertiUzer apphed, though variations in plant 

 composition resulting from soil conditions are com- 

 paratively small. The greater variations are almost 

 wholly the result of varying climate and water supply. 

 As far as it is now known the strongest single factor 

 in changing the composition of plants is the amount 

 of water available to the growing plant. 



Variations due to varying water supply 



The Utah station has conducted numerous ex- 

 periments upon the effect of water upon plant com- 

 position. The method in every case has been to 

 apply different amounts of water throughout the 

 growing season on contiguous plats of uniform land. 

 Some of the early results are shown by the following 

 table : — 



The Effect of Water on the Percentage Composition 

 OF Plant Parts 



Corn Kcrnek 



