72 



EXPERIMENTS UPON BAELEY 



TABLE XXIX. Experiments on Barley, Hoos Field. Produce of Grain 

 and Straw per acre. Averages over 60 years (1852-1911), and over 

 10 years (1902-1911). Also Produce in 1911. 



* Average 48 years (1864-1911). 



t Average, 41 years (1872-1911). 



A. Maintenance of Yield under the Continuous Growth 

 of Barley on the same Land. 



One of the plots, 1 O, has been without manure since the 

 beginning of the experiments. Under the continuous barley- 

 growing the decline in production has been much more marked 

 than on the wheat plot similarly treated, the average crop having 

 been only 9*3 bushels for the ten years 1902-1911, against an 

 average of more than 12 bushels for the whole period. The 

 continual fall of crop from decade to decade would seem to 

 show a progressive exhaustion of the soil, without reaching the 

 comparatively stable condition of the continuously unmanured 



