CONTENTS 



PAGE 



BIOGRAPHICAL INTRODUCTION ...... xxi 



CHAPTER I 



THE SOURCES OF THE NITROGEN OF VEGETATION . . . 1 



CHAPTER II 



METEOROLOGICAL OBSERVATIONS . . . . . . 15 



CHAPTER III 



THE COMPOSITION OF THE ROTHAMSTED SOIL .... 24 



CHAPTER IV 



EXPERIMENTS UPON WHEAT 



I. The Continuous Growth of Wheat, Broadbalk Field . . 31 



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 . . . .47 



D. Retention of Manures by the Soil . . . .49 



E. Character of the Crop as affected by Manuring and Season 55 

 II. Wheat after Fallow, and in Rotation .... 62 



III. Trials of Varieties of Wheat ..... 66 



Practical Conclusions ...... 68 



References . . . . . . 69 



CHAPTER V 

 EXPERIMENTS UPON BARLEY 



I. The Continuous Growth of Barley upon the same Land, Hoos Field 70 



A. Maintenance of Yield under the Continuous Growth of 



Barley on the same Land .... 72 



B. Effect of Nitrogenous Manures .... 76 



C. Effect of Minei-al Manures . . . . .80 



D. Character of the Crop as affected by Manuring . . 83 

 II. Barley Grown in Rotation, Agdell Field .... 88 



Practical Conclusions and References . . . .91 



CHAPTER VI 



EXPERIMENTS UPON OATS 



Experiments upon Oats grown continuously upon the same Land, 



Geescroft Field . . . . . .92 



