232 THE SYSTEM OF FARM-YARD MANURING. 



Oberbobritzsch in the third stage, of cultivation by fanii- 

 yard manuring, to wliich we have referred. 



At Cunnersdorf the arable soil exhausted by the pre- 

 ceding cultivation becomes with every new rotation 

 richer in the conditions required for the production of 

 grain ; not only does the clover replace the loss sustained 

 by the removal of the corn-crops, but a remarkable 

 excess of aU nutritive substances will gradually accumu- 

 late in the arable soil ; and, after a series of years, with 

 the same system of cultivation by farm-yard manuring, 

 the field will be brought to the condition of the land at 

 Mausegast ; which means, that the arable soil will 

 acquire a high productive power for corn and other 

 crops, while the produce of clover will decrease. The 

 fields at Kotitz and Oberbobritzsch most probably were 

 in former times in the same condition as the Mausegast 

 field is at present; not that they ever yielded crops 

 as large as the latter gives, but merely that the unma- 

 nured plots have, at some antecedent period, given better 

 crops than in the year 1851. Without an additional 

 supply of mineral elements derived from meadows or 

 other fields not included in the rotation, the produce 

 must go on continually decreasing, as the supply of 

 mineral constituents brought up by the clover from the 

 subsoil, in these two places, is far from sufficient to make 

 up for what is taken away m the corn-crops. 



In the following calculation it has been assumed that 

 of the crops obtained, rye and oats were actually re- 

 moved, and of potatoes and clover one-tenth was carried 

 away in the form of cattle.* 



* The amount of phosphoric acid and potash is estimated in the 

 calculation as follows : — 



