530 



Agricultural Chemistry — Turnips. 



view, but we are not prepared to consider them fully until we 

 have detailed the results of an analytical examination of the 

 crops — a subject which vre shall presently enter upon. Resuming 

 the question in discussion, we see that whilst ammoniacal salts in 

 no degree restored fertility to this exhausted soil, rape-cake gave 

 a sixfold development. In the 4th column^ under an equal 

 amount of rape-cake, we find as usual that the excess of nitro- 

 genous manure has deteriorated the tendency to bulb formation 

 exhibited in column 2. 



The contrast observed in the effects of ammoniacal salts upon 

 wheat and upon turnips is very remarkable, and affords a strikmg 

 illustration of the widely differing requirements and sources of 

 growth of the corn-exporting " white crops " and the home-con- 

 sumed, meat-producing green" or "fallow crops/' of which 

 classes respectively the two plants may be considered as the 

 types. 



Hitherto we have only considered the effects of organic manures 

 upon the formation of turnip hulb^ the amount of which is thought 

 to determine the value of the crop when cultivated for feeding 

 and rotation purposes. It has been seen that a liberal supply 

 of available phosphates and of organic manures abounding in 

 carbonaceous matter are pre-eminently favourable to the desired 

 habit of the plant^ and that nitrogenous supply, so essential to the 

 increased growth of corn, is so here only to a very limited extent. 

 Under the influence of ammoniacal manures, however, the pro- 

 duction of turnip leaf is much enhanced, as the following results 

 will show : — 



Description of Manures. 



Bulb per 



Acre, 



in 



Leaf per Acre, 



in 



Proportion 

 of Leaf to 

 1000 of 

 Bulb. 



Tons. cwts. 

 12 8 





lbs. 



3 



Tons. cwts. 

 4 4 



qrs. 



0 



lbs. 

 14 



326 



13 



4 



2 



20 



5 



12 



0 



21 



421 



11 



18 



1 



2i 



6 



15 



0 



21 



559 



12 



5 



0 



13 



5 



14 



0 



17 



466 



11 



6 



1 



11 



7 



9 



0 



22 



669 



12 



4 



3 



6 



6 



15 



2 



16 



554 



Mean by purely mineral manures. 



Mean of mineral manures, witli) 

 10 cwt. rape-cake added . ./ 



Mean by mineral manures, and) 

 3 cwt. sulphate of ammonia added) 



Mean by mineral manures, and 

 3 cwt. sulphate of_ ammonia 

 (second gathering) .... 



Mean by purely mineral manures, I 

 and both rape-cake and ammo- / 

 niacal salt J 



Mean by purely mineral manures,- 

 and both rape-cake and ammo- , 

 niacal salt (second gathering) . j 



Thus comparing' lines 1 and 3, we find that whilst, by the addi- 

 tion of ammoniacal salt in the latter case^ there is in an equal 



