280 EARTHY PHOSPHATES. 



Increase of produce over the unmanured field (see page 190). 



The field at Kotitz got 50 per cent, more bone-dust 

 than the Cunnersdorf field ; yet its produce of all the 

 crops was lower than that of the latter. The field at 

 Oberbobritzsch got, in 1851, twice the quantity of manure 

 that was apphed to the Cunnersdorf field ; the result 

 was, in the first year, an increase of corn of 250 per 

 cent., and of straw of 66 per cent, more on the former 

 than on tlie latter. In the third year, however, the 

 increase of produce of oats, both in grain and straw, 

 was considerably larger at Cunnersdorf than at Ober- 

 bobritzsch. 



The most curious part of the results is the great difi'er- 

 ence in the increase of the produce of clover on the 

 several fields ; from the field at Oberbobritzsch nearly 

 six times as much clover was obtained as fi:om that at 

 Kotitz, although the former had received only one-fourth 

 more bone-dust than the latter. 



A glance at the table shows that in the exjDeriments at 

 Cunnersdorf, Kotitz, and Oberbobritzsch, the quantities 

 of bone-dust severally apphed as manure were as 

 1 : 1^ : 2. A comparison of the increase of produce 



