soils was declining. At this time the use of bones be- p? od t for 

 came prevalent and this marked the beginning of more 



rational methods of soil treatment. 2 3 r 



The Rise of the Fertilizer Mixing Industry. 



It was not until the second quarter of the nine- 

 teenth century, however, that new and important fer- 

 tilizer materials came into the market. The increasing 

 number of soil and crop analyses had demonstrated the 

 invariable presence of the essential constituents in both 

 soils and plants; while the numerous vegetation experi- 

 ments showed that Nitrogen, phosphoric acid and 

 potash were often present in the soil in amounts too 

 small for profitable yields. 



There then came into being a great fertilizer mix- 

 ing industry. Peruvian guano held for a time a promi- 

 nent place in the agriculture of contemporary Europe. 

 It was not long, however, before the supply of the best 

 grades of guano became depleted, though this did not 

 occur until the chemist pointed the way to new treas- 

 ures of plant-food. Nitrate of Soda, the most valuable 

 source of commercial Nitrogen at present, came to play 

 an increasingly important role after the middle of the 

 nineteenth century. The potash salts of the German 

 mines became a marketable commodity when the last 

 battles of our civil war were being fought; and when 

 the great conflict was over, the phosphate deposits of 

 South Carolina, and subsequently of Florida and Ten- 

 nessee, were ready to supply the third important con- 

 stituent of commercial fertilizers. 



The Make-Up of Commercial Fertilizers. 



The fertilizers sold to American farmers are valu- 

 able in so far as they contain the essential available 

 constituents, — Nitrogen, Phosphoric Acid and Potash. 

 When all are present the fertilizer is said to be complete, 

 otherwise it is incomplete. It is the aim of the fertilizer 

 mixers to supply to farmers both incomplete and com- 

 plete fertilizers, chiefly the latter. Furthermore, usage 

 and state legislation compel them to guarantee that 

 their various brands contain a certain proportion of the 



