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Temperature . . 
Relative Humidity . 
Sunshine . . 
Winds . 
Summary of Features . 
Drouth . . . . 
Dry-FaRM SOILS . 
CONTENTS 
CHAPTER V 
The Formation of Soils . < < . 
Physical Agencies 
Chemical Agencies 
Characteristics of Arid 
Clay 
Sand 
Humus 
Soil and Subsoil 
Hardpan 
Leaching 
Alkali Soils 
Soils . a . 
Plant-food Content 
Summary of Characteristics 
Soil Divisions 
Great Plains District 
Columbia River District 
Great Basin District 
Colorado River District 
California District 
The Judging of Soils 
CHAPTER VI 
THe Root-systeMs OF PLANTS . 
Functions of Roots 
Kinds of Roots . 
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