CONTENTS x iii 



PAGE 



How "the Plant Gets Its Food 64 



Root-Hairs, p. 64; Osmosis, p. 65; Importance of Water, 

 p. 67; How the Plant Gets Its Food from the Air, p. 67. 



The Manufacture of Food Materials 68 



Carbohydrates, p. 68; Fats, p. 68; Protein, p. 69; Plants 

 the Only Source of These Foods, p. 69. 



Stored Food 69 



Periods in the Life of a Plant, p. 69; Effect of Time of Har- 

 vesting on Composition, p. 71. 



Questions 71 



Laboratory Exercises 72 



Collateral Reading 74 



CHAPTER V 



THE SOIL 75-108 



What Soil Is ' 75 



Rock Particles of the Soil 76 



Amounts of Mineral Matter, p. 76; How the Size of Particles 

 Is Determined, p. 76; How Soils Are Named, p. 78; Impor- 

 tance of the Size of Particles, p. 79; Relation of the Size of 

 Particles to Water, p. 79; Relation of the Size of Particles to 

 Plant Food, p. 81; Size of Particles and Air, p. 81; Size of 

 Particles and Temperature, p. 81 ; Size of Particles and 

 Crop Adaptation, p. 82; Relation of Labor and Soil, p. 82; 

 The Best Soils, p. 83; Flocculation, p. 83. 



Soil Water ' 84 



Importance of Soil Water, p. 84; Movement of Water in the 

 Soil, p. 85; Conservation of Moisture, p. 85; Dry Land Fann- 

 ing, p. 87. 



Irrigation 88 



Areas Requiring Irrigation, p. 88; Storage Reservoirs, p. 89; 

 Seepage from Canals, p. 90; Over-Irrigation, p. 90; Alkali, 

 p. 90. 



Drainage 91 



Best Amount of Water for Crops, p. 91; Harmful Effects 

 of Too Much Water, p. 91; All Soils Require Drainage, p. 91; 

 Effects of Tile Drainage During Drought, p. 92; Kinds of 

 Drains, p. 93; laying Tile Drains, p. 93; Drainage as a 

 Government Problem, p. 94. 



