CONTENTS. 



CHAPTER PAGE 



I. HISTORICAL AND INTRODUCTORY i 



II. SOIL CONDITIONS AFFECTING PLANT GROWTH - 30 



III. THE COMPOSITION OF THE SOIL - 92 



IV. THE COLLOIDAL .PROPERTIES OF SOIL - 148 

 V. THE CARBON AND NITROGEN CYCLES IN THE SOIL - 175 



VI. THE BIOLOGICAL CONDITIONS IN THE SOIL - 218 



VII. THE MICRO-ORGANIC POPULATION OF THE SOIL AND 



ITS RELATION TO THE GROWTH OF PLANTS - 250 



VIII. THE SOIL IN RELATION TO PLANT GROWTH - - 301 



IX. SOIL ANALYSIS AND ITS INTERPRETATION - - 322 



APPENDICES. 



I. THE METHODS OF SOIL ANALYSIS - - 347 



II. AMOUNTS OF VARIOUS SUBSTANCES ABSORBED FROM 

 THE SOIL BY THE COMMON AGRICULTURAL CROPS 

 OF ENGLAND - -357 



III. A SELECTED BIBLIOGRAPHY OF PAPERS ON SOIL CON- 

 DITIONS AND PLANT GROWTH "- - 359 



AUTHOR INDEX - 387 



SUBJECT INDEX 395 



