Agricultural Chemistry — Turnips. 



549 



the animal will be as different as, in the cases of the two plants, 

 is attained by more directly varying the supply, and the peculiar 

 habits of life and growth will be developed accordingly. 



The following results further show how truly dependent is the 

 composition of the turnip-bulb upon the provision by manure : — - 



Percentages of Nitrogen in the Dry Matter of Turnip Bulbs^ the produce of different 



Manures. 



Plot Numljers. 



Conditions of Standard Manuring. 



Standard 

 Manures 

 only. 



Standard 

 Manures, 

 and Top- 

 dressing of 

 Rape cake. 



Standard 

 Manures, 

 and Top- 

 diessin;; of 

 Amra.Salt. 



standard 

 Manures, 

 aiui Top- 

 dressing of 

 Rape -cake 



and 

 A mm. Salt. 



1 



12 tons farm-yard dung .... 



l-o6 





2-54 





2 





3-31 



2-17 



2-98 



2-o3 



3 



8 cwts. rape-cake 



2-23 



2-79 



2-SO 



3-00 



We see that the percentage of nitrogen by farm-yard dung is 

 1*56, which differs litde from either the results obtained by 

 mineral manures alone, when all the organic supply was derived 

 from normal sources, or from the number observed by Bous- 

 singault, which was IvO. The addition of sulphate of ammonia 

 to the farm-yard dung, raises the percentage of nitrogen in the 

 bulb from 1*56 to 2-54, or by two-thirds of the usually observed 

 amount. Here, however, we have in the manure a large pro- 

 vision of carbonaceous matter, and, as before noticed, a coinci- 

 dently less percentage of nitrogen than when there was ammo- 

 niacal salt alone. 



In the second line of the table we have some most interesting 

 results, consistent with what have gone before, and, further, afford- 

 ing a new and significant illustration of the office of the turnip as 

 a fallow-crop. 



It will be recollected that the average weight of the bulbs on 

 the unmanured plot was in this season of 1845 less than 2 oz., 

 and that the entire produce was only \o\ cwts. per acre. We 

 find, however, that these stunted bulbs give a percentage of 

 nitrogen higher than any in our series, even than those which had 

 an unusually excessive supply by manure, and twice as high as 

 the amount supposed generally to exist in the cultivated bulb. 

 We may reasonably infer that, under the influence of season and 

 a soil reduced to the lowest conceivable state of exhaustion, as 

 regards its fitness for the growth of the cultivated turnip, the 

 natural supply of nitrogen was, in proportion to that of other con- 

 stituents, abundantly available to the special accumulative powers 

 of the plant. In the same line w^e find, in the second column, 



VOL. VIII. 2 o 



