ROOT-CROPS. 65 



Three plots were selected for investigation, which, with 

 pretty full amounts of produce, would give roots of fairly- 

 good degree of maturation — namely, those manured with 

 rape-cake in addition to various mineral manures. 



In 1878 there were somewhat under-average crops, with a 

 large proportion of leaf — conditions indicative of comparative 

 immaturity. Under these circumstances the percentage of 

 total nitrogen in the roots was not high, but the proportion 

 of the total nitrogen existing as albuminoids was low — 

 namely, 35.5 and 34.2 per cent in two cases, and only 26.2 

 per cent in the third ; but in this last case it was concluded 

 that the determination was too low. 



In the very wet and cold season of 1879 the crops were 

 very small, and the percentage of total nitrogen was low ; 

 the result being doubtless partly due to loss of nitrogen by 

 drainage. Under these circumstances the amounts of the 

 total nitrogen found as albuminoids were 43.2, 45.4, and 

 44.3 per cent, or an average of about 44 per cent. 



In 1880 the crops were much above the average, and the 

 percentage of total nitrogen was low ; and there was again, 

 under the better conditions as to mineral manuring — that is, 

 where potash was applied — more than 47 per cent of the 

 total nitrogen albuminoid. 



The bottom division of the table shows that in the crops Percentage 

 of 1880, in which alone the amides were determined, the of amides. 

 proportion of the nitrogen in that condition was about, or 

 rather less than, 40 per cent of the total nitrogen, and not 

 much less than that of the albuminoid nitrogen. It may 

 be stated that according to results given by Messrs Ivey 

 and Gray, the average composition of eleven New Zea- 

 land specimens of common turnips showed that the propor- 

 tion of the nitrogen reckoned as " amides, &c." (including 

 extractive matter) was 50.1 per cent of the total nitrogen ; 

 which is rather more than was found as albuminoids in the 

 same roots, and more than was found as amides in the 

 Eothamsted mangels. 



In all three cases in 1879, and in two in 1880, the amount mtric 

 of the nitrogen existing as nitric acid was determined. It is acid - 

 seen that, with one exception, in which the nitrogen as nitric 

 acid amounted to only 3.9 per cent of the total nitrogen, it 

 ranged from 10 to 13 per cent of the total. Compared with 

 these amounts, Messrs Ivey and Gray found less than 1 per 

 cent of the total nitrogen of the common turnips to exist as 

 nitric acid, and not much more than 1 per cent as ammonia. 

 It may be added that in some determinations made at Eoth- 

 amsted in swedes the proportion of the total nitrogen as 

 nitric acid was very much less than in the mangels. 



VOL. VII. E 



