Four-course Rotation. 



115 



other constituents are concerned, left much more exhausted 

 for the growth of the barley than without any manure what- 

 ever. With the mixed manure fair crops of turnips were 

 removed in the earlier, but less in the later courses, and 

 (excepting in the first year) there would remain in the land a 

 considerable residue from the manures applied ; and hence it 

 would be left in a higher condition for the barley than after 

 either the unmanured or the superphosphated turnips. Table 

 XXV. shows the total produce (grain and straw) of barley in 

 each of the successive courses, and also the average of the 

 six courses ; for comparison, the top line shows the produce 

 in the same seasons of the unmanured plot in Hoos Field, 

 where barley is grown year after year without manure : 



TABLE XXV. YIELD OP BARLEY UNDER ROTATION. 



Produce (grain and straw) per acre, Ib. 



The apparently anomalous results of the first year are 

 chiefly attributable to the fact that there had been removed 

 from the unmanured plot only about 3j tons of roots, and 

 2J tons of tops, but from the mixed manure plot nearly 

 11 tons of roots, and more than 7| tons of tops; in the 

 manured plot, further, there would be left much less, if any, 

 residue of manurial constituents for the barley of the first 



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