192 



CKOPS GROWN IN ROTATION 



I. THE UNMANURED PLOTS. 



The various crops as grown in rotation are affected very 

 differently by the absence of manure than the same crops are 

 when grown continuously. In the case of the cereals, the 

 crop is maintained far better on the rotation plots that are 

 unmanured than on the similar plots in Broadbalk and Hoos 

 field, where wheat and barley are grown continuously. The 

 root crop, however, falls to a minimum in the absence of 

 manure, and the mere act of growing in rotation is quite 

 unable to provide sufficient nutriment for the needs of even a 

 small crop. The clover and bean crops also grow very 

 indifferently on the unmanured plots notwithstanding the 

 rotation, though the falling-off is not so marked as in the case 

 of the Swedes. 



Although a rotation of crops, by alternating plants of 

 different requirements and different habits (some deep and 



TABLE LXV. Crops grown in rotation, Agdell Field, Comparison of yield 

 at the beginning of the Experiment, and in later years (1852-1867, 

 1884-1903, and 1904-1911). Average Total Produce per acre of four 

 Unmanured and four Manured Plots. 



* Averages for Plots 1 and 2 Complete Manure, and for Plots 5 and 6 Unmanured. 



some shallow-rooting), is able to utilise more thoroughly the 

 nutriment supplied as manure and the initial resources of the 

 soil, it is evident that it cannot enable the crops to dispense 

 with supplies of manure, but that its value largely depends 

 upon the opportunities it affords for cleaning the land and 

 maintaining a proper system of tillage. Table LXV. shows 



