37 



times 9 inches, or 27 inches. Nitrogen determinations 

 (by soda-lime) have been made in the mixed samples 

 from the 3 holes, in each case ; and the nitrogen as 

 nitric acid has been determined in the soils and subsoils 

 of 6 of the plots. 



In the winter of 1883-84, samples were again taken 

 from each of the 12 plots, from 4 places on each plot ; 

 and in the case of 2 of the 4 holes only to the depth of 

 9 inches, but in that of the other 2, to the depth of 12 

 times 9 inches, or 108 inches in each case. Nitrogen 

 determinations have been made (by soda-lime), in the 

 surface soils, in the mixture from the 4 holes, in a mix- 

 ture from the 2nd and 3rd holes, and in that from the 

 1st and 4th holes ; also in the subsoils, at each of the 

 11 lower depths, in the mixture from the 2 holes in 

 each case. In the case of 4 of the 12 plots, the nitrogen 

 as nitric acid has been determined in the mixed sample 

 from the 2 holes, for each of the 12 depths ; and in the 

 case of each of the 12 plots, in the mixed samples of 

 the 12th depth ; also in a few individual cases. In a 

 few cases the chlorine was also determined. 



In the case of these experiments on rotation, it is pre- 

 eminently essential to have the means of tracing the 

 chemical history of the plots, both so far as the crops, 

 and the soils, are concerned. To this end, it is desirable 

 to take samples for dry matter, ash, and nitrogen of the 

 roots and of the leaves, of each of the 12 plots when 

 under turnips ; of the corn and of the straw, of each of 

 the 12 plots when under barley ; of each cutting, of 

 each of the 6 plots, when under clover ; of the corn and 

 of the straw, of each of the 6 plots when under beans ; 

 and of the corn and of the straw, of each of the 12, 

 when under wheat. But, for actual determinations of 

 nitrogen, or for ash-analyses, "mixed-year" samples 

 and in some cases "mixed-crop" samples, can be 

 adopted. 



It would, however, be undesirable to curtail the 

 system of collection and preservation of samples, until 

 the proposed systematic report on the Rotation 



