Contents xi 



CHAPTER VII 

 MINERAL NUTRIENTS 



PAGES 



The ash content of plants Composition of the ash Effects of 

 conditions upon ash content Ash content at different ages 



Translocation of mineral substances - - Water cultures 

 Nutrient solutions and water cultures Strength of the 

 nutrient solution The forms of the nutrient compounds 

 Plant nutrients in rock Soil fertility --Nutrients removed 

 by farm crops Nutrients removed by fruit crops Amount 

 of nutrients in soils Availability of the nutrients The 

 solvent action of roots CO 2 excretion and the availability 

 of phosphorus Another view of soil fertility- -The paraf- 

 fined wire basket in nutrition studies Laboratory work 

 References ......... 136-168 



CHAPTER VIII 

 SPECIAL, FUNCTIONS AND RELATIONS OF MINERAL NUTRIENTS . 



TJie roles of mineral nutrients : The nature of the special roles 



The role of phosphorus The role of potassium - - The 

 role of magnesium The role of calcium --Iron Sodium 



Chlorine Sulfur Silicon-- References . . . 169-183 

 Balanced solutions: The injurious action of certain basic nutri- 

 ents The relation of calcium to magnesium Other 

 nutrient bases and antitoxic action Laboratory work - 

 References 184-194 



CHAPTER IX 

 THE INTAKE OF CARBON AND THE MAKING OF ORGANIC FOOD 



The amount of carbon in the plant Carbon dioxid the source 

 of carbon in green plants Chlorophyllous plants -- Re- 

 specting the distribution of chlorophyll - - The nature and 

 properties of chlorophyll The factors essential in photo- 



