204 DR. DAUBENY ON THE ROTATION OF CROPS, ETC. 



The following curve will show the variations in the yearly produce. 



Oats. 



Years. 



50' 



40 



30 



20 



10 



>lbs. 



\2. Beta vulgaris. 



In the case also of the beet, the length of time during which the ground was cropped 

 seems insufficient to lead to any decisive results, especially as the matters extracted 

 from the soil by this plant are, compared to its bulk, inconsiderable. 



The average of the shifting and permanent crops, it will be seen, does not vary 

 materially, and what difference there is, seems in favour of the latter. 



