ILLUSTRATIONS 



PAGE 



Only the Roots Remain Behind 2 



A Bit of Earth's Clothing 5 



Gradually Changing from Rock to Soil 8 



Cover Crop for the Orchard 12 



A Field of Corn Carried Away by a Raging Flood .... 13 



Just after a Flood 15 



Soil Builders at Work 18 



Alfalfa Roots Go Deep into the Soil 20 



A Crop that is Hard on the Soil 24 



Section of Soil Showing Air Spaces and Particles .... 26 



On Two Types of Soil 29 



Crop Adaptation 31 



A Case of Bad Texture 34 



Taking Soil Samples 36 



The Pore-space of the Soil 37 



A Soil that Needs Humus 39 



Circulation of Water in the Soil 40 



Vegetable Matter Aids the Soil in Holding Water .... 42 



Trees in the Prairie Region 43 



How Plant Food Gets into the Soil 44 



The Underside of a Leaf with a Microscope 46 



Oats 47 



Cross-section of Root Hair 48 



Root Hairs 48 



How the Sap Current Moves 49 



The Greater Part of this Wonderful Crop Comes from the Air 55 



Getting Humus into the Soil 59 



Cotton Plant Above and Below the Ground 62 



A Root Hair with Soil Attached 64 



Making Plant Food Available 65 



At Work in the Corn-field 67 



Getting Ready for Cotton 68 



Poor Grass, Poor Cattle 73 



