ACTIVE PLANT FOOD, ETC. 



203 



evident, as the soil under the larger plants contained more water- 

 soluble materials. 



The following table shows the water-soluble material dissolved 

 from several types, according to King's 1 investigations : 



SAI/TS DISSOLVED BY WATER FROM SURFACE FOUR FEET OF SOIL 

 TYPES (POUNDS PER ACRE). 



The average quantity of plant food dissolved from the soil was 

 sufficient to produce the following amounts of clover hay: 2 



Tons 



Potash 7.2 



Lime 24.6 



Nitrogen 2.7 



Phosphoric acid 13.2 



1 Bulletin 26, p. 65, Bureau of Soils. 



2 Bulletin 20, p. 78, Bureau of Soils. 



