CONTENTS 



PAOBB 



Preface v-vii 



A Letter to the Student ix-xii 



SOILS 



CHAPTER I 

 How Soils are Made and Mixed . ... 1-12 



What the Soil is, 1 — Grinding up the Rocks, 1 — Soil 

 Names, or Types, 4 — Two Sources of Soil Material, 5 — 

 The Part Plant Life plays in making Soils, 7 — The Part 

 Animal Life plays in making and mixing Soils, 8 — Ele- 

 ments in the Soil and Air which Plants must have in 

 Order to make a Healthy Growth, 10. 



CHAPTER n 



The Water in the Soil 13-24 



How the Soil loses Water,, 13 — The Water which 

 runs off the Surface, 13 — The Water which filters down 

 through the Soil and drains away, 16 — How Water en- 

 ters Drain Tile, 18 — Three Kinds of Water in the Soil, 

 19 — How Film Moisture works its Way upward in the 

 Soil, 21 — How the Farmer prevents the Escape of Film 

 Moisture, 23. 



CHAPTER III 



The Air in the Soil 26-29 



Why Air is necessary in the Soil, 2.5 — Why we seek 

 to control the Air Space in the Soil, 26 — How we may 

 get More Air into the Sail, 28. 



xiii 



