Contents 



vn 



Mineral Phosphates South Carolina rock phosphates 



Florida phosphates Canadian apatite Tennessee 

 phosphate Recent discoveries in western states Basic 

 slag Manufactured phosphates Artificial basic- 

 slag meal Wiborgh phosphate Wolter phosphate 

 Palmaer phosphate Phosphatic guanos . . . 68-76 



Phosphates as Sources of Phosphoric Acid to Plants 



The influence of source of phosphate upon availability 



Influence of fineness of division The character of 

 soil as a factor influencing availability Influence of 



the kind of crop General considerations . . . 75-80 



CHAPTER V 



SUPERPHOSPHATES POTASH 81-101 



Insoluble Phosphoric Acid 81-82 



Soluble Phosphoric Acid 82 



Reverted Phosphoric Acid 82-83 



How Superphosphates are Made The difference in 

 the superphosphates made from the different materials 

 Soluble phosphoric acid chemically identical, from 



whatever source derived 83-85 



Phosphates and Superphosphates are not Identical . 85-89 



Double Superphosphates 89-90 



Chemical Composition of Superphosphates Well- 

 made superphosphates contain no free acid Phosphoric 

 acid remains in the soil until taken out by plants . . 90-93 



Potash Salts The importance of potash as a con- 

 stituent of fertilizers Forms of potash Kainit 

 Hardsalt Carnallit Muriate of potash High-grade 

 sulf ate of potash Double manure salt Potash manure 

 salt Double carbonate of potash and magnesia Po- 

 tassium carbonate Potassium nitrate Feldspar and 

 other minerals as a source of potash Seaweeds as a 

 source of potash Fixation of potash .... 93-101 



CHAPTER VI 



MISCELLANEOUS FERTILIZING MATERIALS .... 



Tobacco Stems and Stalks Tobacco salts Crude 



fish scrap Wool and hair waste Sewage Muck and 



102-118 



