A gricultural Cliemistry — Turnips. 



505 



ditions of exhaustion most favourable to an investigation into the 

 effects of suiphj for the growth of the turnip, were not so promi- 

 nent in the first season as afterwards, when the unaided yield was 

 little more than a weed, so that the entire produce under manures 

 could then be attributed either to their agency or their supply. 



The following selected results, showing the average weight of 

 bulbs and numljer of plants per acre, yielded by manures which, 

 compared with each other, are respectively mineral, nitrogenous, or 

 carbonaceous, will point to some of the conditions which it is essen- 

 tial to provide for the healthy and rapid growth of the turnip : — 



Selected Results. 



Plot 

 jNos. 



Description of Manures. 



Number 



of 

 Plants 

 per Acre. 



Average 

 Weiglit of 



Bulbs 

 in lbs. and 



tenths. 



2 





17.910 



0-52 



3 





17,043 



1-OS 



7 







1-03 



16 



3j cwts. superpliospb. lime, l-Jcwt. phos. of magn, manure 



19,975 



1-39 



17 



, , J , , , 150 lbs. phos. potass, manure 



19,228 



1'36 



18 



, , , , , , 84 lbs. phos. mag. 75 lbs. phos. 









pot. manure .... 



19,642 



1-35 



22 





18,446 



1-47 



The figures in the first column show a great destruction of 

 plants under direct ammoniacal supply, as well as considerable 

 depreciation where rape-cake was used ; and common experience 

 teaches us that, however useful rape-cake and ammoniacal salts, 

 or guanos containing much ammonia, may be as manures for 

 turnips, substances of their description are never safely applied 

 near to the seed. Other instances than those quoted above from 

 the table at page 503 distinctly show the injurious mfluence of 

 organic manures when drilled with the seed ; indeed, it may be 

 laid down as a general rule that, especially for all spring crops, 

 it is much more safe to apply such matters broadcast, and incorpo- 

 rate them well with the soil. The conflicting accounts which are 

 given of the effects of guano and ammoniacal salts when they are 

 supplied to spring corn crops, and of these manures and rape- 

 cake when used for turnips, are, it is believed, mainly attributable 

 to differences in the manner of their application ; and whilst with 

 a very wet season no injury, or perhaps benefit, may arise from the 

 use of the manure drill in such cases, by far the safest course is 

 to sow broadcast. 



The second column of the selected results shows for this season 

 of 1843 a considerable superiority in point of development, as well 

 as numher, of surviving plants, under purely mineral by the side 

 of organic manures; and, compared with the uninanured plot, 



