528 



Agricultural Chemistry— Turnips. 



ing a complete network to a considerable distance around tlie 

 plants and throwing innumerable m.oulhs to the surface. The ex- 

 tent and direction of the underground range of the turnip are at 

 the same time very much dependent on the mechanical condition 

 of the soil ; and it is universally known that tilth is of the highest 

 importance to the favourable formation of hulh. We know that 

 the best relation of bulb to leafj and, in fact, the best acreage 

 produce of bulbs is in the lighter soils^ where there is compara- 

 tively little obstruction to the development of fibrous root, and it 

 is in these that the special eflScacy of superphosphate of lime has 

 been most observable. We believe that, if the turnip is to be 

 valued for its hulh-formation, the aim of our culture must be, not 

 to increase the aboveground organs of collection (the leaves), but 

 the underground Jihrous roots. 



We shall now consider the effects of organic vianures " upon 

 the production of turnip bulb ; and the facts that will come before 

 us will tend to confirm the views just maintained regarding the 

 essential development of rootlet rather than leaf accumulation, as 

 a means of obtaining the turnip in agricultural quantity and 

 quality. 



The results collected below will illustrate some of the effects 

 of "organic manures " upon the growth of the turnip : — 



Description of Mineral Manures. 



manures ......... 



Mean of four experiments with alkaline 

 supply «... 



Mean of three experiments with superphos- 

 phate of lime 



Mineral 

 Manures 

 only. 



1 Mineral i Mineral 

 j Manures, Manures, 

 ;and 10 cwt. and 3 cwt. 

 j Rape-cake Sulph.Am. 

 j per Acre. ^ per Acre. 



Mineral 

 Manures, 

 10 cwt. 

 Eape-caJie 

 and 3 cwt. 

 Sulph. Am. 

 per Acre. 



M6 



i i 



I'M 



MO 



MO 



1 1-33 1 



1 



1-17 



1-15 



1-21 



! 1.37 1 



1-18 



M3 



"We may explain that the results in the first column were ob- 

 tained by means of mineral manures alone^ and that, the previous 

 crops having been entirely removed from the land, the organic 

 supplies must have been chiefly derived from the atmosphere. 

 The development of leaf was less in these than in any of the other 

 cases. In column 2 there was, besides these same mineral ma- 

 nures, 10 cwts. rape-cake, which may be estimated to provide 

 perhaps 50 lbs. of nitrogen. It was, however, employed in these 

 experiments as supplying a large amount of carbonaceous matter, 

 in which it abounds. In the 3rd column the effects are due to 

 the addition of 3 cwts. of sulphate of ammonia to the mineral 

 manures. In these cases about 60 lbs. of nitrogen is supplied^ 



