66 



EXPERIMENTS UPON WHEAT 



is equally clean and has similarly received a summer fallowing 

 before the wheat crop. In the case of the rotation plot, however, 

 the particular stratum of soil usually occupied by the wheat 

 roots is only drawn upon once in four years, the intermediate 

 crop being the much shallower-rooted barley. 



III. — Trials of Varieties of Wheat. 

 In the eleven years 1871-1881, trials were made of about 

 twenty varieties of wheat under the ordinary conditions of 



Table XXVIIa.— Varieties of Wheat groion at Rothamsted. Produce of 

 Grain 'per acre ihiisheh). Results arranged in order of highest average 

 yield. 



farming, the wheats being grown in a different field each year. 

 Table XXVIIa. shows the results obtained in bushels per 

 acre each year, and Table XXVIIb. the same results 

 reduced each year to the common ratio of the average 



