INCREASE OF PRODUCE BY GUANO. 257 



the same amount of guano as the Kotitz field, both, 

 accordingly, the same quantity of nitrogen and phos- 

 phoric acid ; yet in cereals and potatoes the increase of 

 produce was twice as great, and in clover much greater 

 in the former than in the latter. 



How very little the crops will enable us to draw 

 comparisons between the effects of the several constitu- 

 ents of one and the same manuring agent, may be 

 clearly seen from the results of the experiments at 

 Cunnersdorf and Oberbobritzsch. 



At Cunnersdorf, 100 Ibs. of guano gave an increase 

 of produce in cereals, potatoes, and clover, containing 



Phosphoric 

 Nitrogen. Potash. acid. Lime. 



Ibs. Ibs. Ibs. Ibs. 



Increase of produce ... 9'2 16'1 3'5 3'6 

 The guano contained . . 13'0 2'0 12'0 12'0 



More in the. manure. . 3-8 S'5 8 '4 less in the crops. 

 Less in the manure ... 14-1 more in the crops. 



At Oberbobritzsch, 100 Ibs. of guano gave an increase 

 of produce, containing 



Phosphoric 

 Nitrogen. Potash. acid. Lime. 



Ibs. Ibs. Ibs. Ibs. 



Increase of produce ... 23'0 15'5 6'1 16'9 

 The guano contained . . 13'0 2'0 12'0 12'0 



More in the manure. . . 5 % 9 less in the crops. 

 Less in the manure , . . 10-0 13'5 4-9 more in the crops. 



The difference in the effect produced by the guano 

 on the two fields is most strikingly exhibited by these 

 tables. At Cunnersdorf the produce reaped contained 

 30 per cent, less, at Oberbobritzsch 77 per cent, more 

 nitrogen than the manure applied. 



