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 



