270 GKOTJND RAPE-CAKE. 



Oberbobritzsch. 



611 Ibs. guano 8288 Ibs. ground rape-cake 



= 80 Ibs. nitrogen = 157'8 Ibs. nitrogen 



and 74 Ibs. aud 39'5 Ibs. 



phosphoric acid. phosphoric acid. 



1851 and 1853. Rye and oats 4503 Ibs. 2069 Ibs. 



1852. Potatoes 3979 " 691 " 



1854. Clover-hay 4133 " 1194 " 



The one field at Oberbobritzsch received in the ground 

 rape-cake nearly double the quantity of nitrogen that 

 the other got in the guano, and the difference in the prod- 

 uce of the two is in the highest degree striking. 

 In the two experiments 



In the In the 



guano. rape-cake. 



The nitrogen in the manures was as 1 : 2 



In the produce it was : 



" cereals, as 2 : 1 



" potatoes, as 5'7 : 1 



" clover, as 3'4 : 1 



The effect of the nitrogen in the guano was, accord- 

 ingly, in the cereals four times, in the potatoes twelve 

 times, and in the clover seven times, greater than that 

 of the nitrogen in the rape-cake. 



Upon comparing the increase of produce with the 

 amount of phosphoric acid in the two'manures, we find 

 that this increase appears to bear some proportion, 

 though yet by no means a definite one, to the amount 

 of phosphoric acid severally contained in them. 



The general results of the experiments made, in a 

 four years' rotation, on four different fields at Cunners- 

 dorf, Mausegast, Kotitz, and Oberbobritzsch, may be 

 summed up as follows : 



The 48 harvests from the unmanured plots and from 

 those manured severally with bone-dust, guano, and 

 ground rape-cake, gave in rye grain and straw, in po- 

 tatoes, in oats grain and straw, and in clover, by manur- 

 ing with x 



