CONTENTS. 



CHAPTER PAGE 



I. HISTORICAL AND INTRODUCTORY - - i 



II. THE REQUIREMENTS OF PLANTS - 19 



III. THE CONSTITUTION OF THE SOIL - -51 



IV. THE CARBON AND NITROGEN CYCLES IN THE SOIL - 78 

 V. THE BIOLOGICAL CONDITIONS IN THE SOIL - - 102 



VI. THE SOIL IN RELATION TO PLANT GROWTH - - 120 



VII. SOIL ANALYSIS AND ITS INTERPRETATION - 132 



APPENDIX METHODS OF SOIL ANALYSIS - 149 



A SELECTED BIBLIOGRAPHY OF PAPERS ON SOIL CONDITIONS AND 



PLANT GROWTH - 154 



INDEX - - 167 



viii 



