viii CONTENTS 



PAGES 



soil constituents, 29 Weight of soils, 30 Texture of the soil, 

 32. 



Soil Water 32 



Amount of water used by various crops in producing a ton of 

 dry matter, 32 Mean volume of water held by different soils, 33 

 Water evaporated by growing plants for one part of dry mat- 

 ter produced, 33 Water needed under arid conditions, 34. 



Plant-food in the Soil 34 



Plant-food in surface soil, with calculations to pounds in an acre, 

 34. 



Alkali Lands 35 



The normal condition of arid lands, 35 Percentage composition 

 of alkali, 36 Quantity of gypsum required to neutralize sodium 

 carbonate, 37. 



Tillage, and Soil Management 37 



Objects of tillage, 37 Jordan's rules of fertility, 38. 



CHAPTER III 



CHEMICAL FERTILIZERS ; AND LIME ...... 40-80 



Some of the Sources of Chemical Fertilizers 41 



Composition of materials used as sources of nitrogen, 41 Com- 

 position of materials used as sources of phosphoric acid, 41 

 Marketed production of phosphate rock in United States, 41 

 World's production of phosphate rock, 1905-1907, 42 Average 

 composition of Stassfurt potash salts, 42 Potash salts produced 

 in the United States, 1850 to 1905, 43 Importation of potash 

 salts, 43 Potassic materials produced by the aid of electricity, 

 44 Principal potash material used in United States, 45. 

 Fertilizer Formulas and Guarantees ....... 45 



Methods of Computing Value of Fertilizers 47 



Trade-values of plant-food elements in raw materials and chemi- 

 cals, 1910, 47 Valuation and cost of fertilizers, 48 Valuation, 

 and agricultural value, 48 Rule for calculating approximate 

 commercial valuation of mixed fertilizers, 48 Computing the 

 trade value, 49 How to figure the trade value, in greater detail, 

 50. 

 Home- Mixing of Fertilizers ........ 52 



General advice, 52 Incompatibles in fertilizer mixtures, 53 

 Table for calculating raw materials required per ton by mixtures 

 of given composition, 53. 



