CONTENTS 



Biographical In'trodictiox 



xxi 



CHAPTER I 

 The Sources of the Nitrogen of Vegetation 



CHAPTER II 



Meteorological Observations 



15 



CHAPTER III 



The Composition of the Rothamsted Soil 



24 



II. 

 III. 



CHAPTER IV 



E.XPERIMENTS UPON WhEAT 



The Continuous Growth of Wheat, Broadbalk Field . . ."^l 



A. Maintenance of the Yield under Continuous Wheat Grow- 



ing on the same Land ..... 36 



B. Effect of Nitrogenous Manures .... 42 



C. Effect of the Mineral Constituents . . . . 4S 



D. Retention of Manures by the Soil .... bO 



E. Character of the Crop as affected by Manuring and Season 54 

 Wheat after Fallow, and in Rotation .... IL' 

 Trials of Varieties of Wheat . . . . .66 

 Practical Conclusions and References . . . . 6S 



CHAPTER V 

 Experiments upon Barley 

 I. The Continuous Growth of Barley upon the same Land, Hoos Field 



A. Maintenance of Yield under the Continuous (irowth of 



Barley on the same Land 



B. Effect of Nitrogenous Manures 



C. Effect of Mineral Manures . 



D. Character of the Crop as affected by Manuring 

 II. Barley Grown in Rotation, Agdell Field . 



Practical Conclusions and References 



76 

 .SO 

 i<3 

 88 

 90 



