166 



BOARD OF AGRICULTURE. 



distribution from year to year, is of itself a reason wliy you 

 get different crops, everything else remaining perfectly the 

 same. That is a matter always to be taken into consideration 

 in judging of the value or effects of a fertilizer. But it is the 

 effect of nitrogen I am coming at. Dr. Hcllriegel experi- 

 mented with various quantities of nitrogen (in the form of 

 nitrates,) applied also to cereals. The plants grew in the arti- 

 ficial soil, consisting of pure sand, with an admixture of ash 

 ingredients, in such pro^iortions as previous trials had demon- 

 strated to be appropriate. All the conditions of the experi- 

 ments were made as nearly alike as possible, except as regards 

 the amount of nitrogen, which in a series of eight trials ranged 

 from nothing to eighty-four parts in a million parts of soil. 

 The following table gives the results.* 



The maximum crops of wheat and rye were obtained with 

 eighty-four parts of nitrogen to one million parts of this soil, 

 but the maximum oat crop was got with fifty-six parts of 

 nitrogen, at least; the gain between fifty-six and eighty-four 

 parts of nitrogen, in the case of oats, was a mere trifle. Dr. 

 Hellriegel made some other observations, which he has not 

 reported in detail, which led him to conclude that he might 

 have got his best crop of wheat with seventy parts of nitrogen, 

 his best crop of rye with sixty-three parts, and his best crop 

 of oats with fifty-six parts, to a million parts of soil. This 



* See also " How Crops Feed," p. 2S8. 



