TABLE OF CONTENTS 



XV11 



Utilization of humus compounds by plants, 419 

 Sodium nitrate, 420 Ammonium sulfate, 421 Ferti- 

 lizers containing atmospheric nitrogen, 422 Cyanamid, 

 423 Composition of cyanamid, 424 Changes of cal- 

 cium cyanamid in the soil, 425 The use of cyanamid, 

 426 Calcium nitrate, 427 Organic nitrogen in ferti- 

 lizers, 428 Availability of organic nitrogenous ferti- 

 lizers, 429. 



Fertilizers Used for their Phosphorus. 



Bone phosphate, 430 Mineral phosphates, 431 

 Superphosphate fertilizers, 432 Reverted phosphoric 

 acid, 433 Relative availability of phosphate fertilizers, 

 434 Changes that occur when superphosphate is added 

 to soils, 435 Other factors influencing the availability 

 of tricalcium phosphate, 436 Effect of plants on the 

 availability of tricalcium phosphate, 437 Effect of 

 basicity on tricalcium phosphate, 438 Influence of fer- 

 menting organic matter, 439 Influence of other salts, 

 440. 

 Fertilizers Used for their Potassium. 



Stassfurt salts, 441 Wood ashes, 442 Insoluble 

 potassium fertilizers, 443. 

 Sulfur and Sulfates as Fertilizers. 



The use of free sulfur, 444 Sulfur as sulfate, 445. 

 Catalytic Fertilizers. 



Nature of catalytic action, 446 Catalytic action of 

 soils, 447 Substances used as catalytic fertilizers, 448 



Manganese, 449 Physiological role of manganese, 

 450 Action of manganese as a fertilizer, 451 Forms 

 of manganese and response of soils, 452. 



CHAPTER XXIV 



SOIL AMENDMENTS ; 



Salts of calcium, 453 Effect on tilth and bacterial 

 action, 454 Liberation of plant food materials, 455 

 Influence of lime on the formation of nitrates in soil, 456 

 Effect on toxic substances and plant diseases, 457 



534-545 



