CONTENTS. 



PAGE 



I. INTRODUCTORY 1 



WHEAT. 



II. EARLY EXPERIMENTS ON WHEAT 6 



1. THE HOLKHAM EXPERIMENTS 6 



2. THE RODMERSHAM EXPERIMENTS 12 



III. EXPERIMENTS ON THE CONTINUOUS GROWTH OF 



WHEAT UPON THE SAME LAND FOR FORTY 



YEARS 18 



PLAN OF THE EXPERIMENTS 19 



INFLUENCE OF SEASON ON THE WHEAT CROP 23 

 EFFECTS OF THE UNEXHAUSTED RESIDUE OF 



MANURES 30 



CONTINUOUS GROWTH OF WHEAT UPON THE 



SAME LAND FOR FORTY YEARS WITHOUT 



MANURE 35 



WITH MINERAL MANURES ALONE 38 



WITH AMMONIA-SALTS ALONE 41 



WITH AMMONIA-SALTS AND MINERAL 



MANURES IN ALTERNATING YEARS ... 43 



COMPARISON BETWEEN AMMONIA-SALTS AND 



NITRATE OF SODA AS SOURCES OF NITROGEN 45 



