MANURES MODE OF PLANTING. 339 



be in good condition, and that farmyard manure may 

 always be advantageously applied, as it contains all 

 the mineral ingredients that the plants require, while, at 

 the same time, its organic nature is not likely to exert the 

 same influence on a green crop, like turnips or kohl-rabi, 

 as it sometimes does on our cereal crops. 



If from any deficiency of farmyard dung artificial man- 

 ures are resorted to, it is important to recollect what the 

 requirements of the plant are, so that they may be met as 

 far as possible by the substances contained in the manure 

 used. Chemistry has shown us that all the cultivated plants 

 of this " genus" require large proportions of potash, and 

 also of chloride of sodium (common salt), and if these are 

 not obtainable in sufficient quantities, the plant must suffer 

 more or less in its powers of growth. If either bone-dust 

 or "superphosphate" be used, it is most desirable that the 

 above-named substances be added to them say in the pro- 

 portions of about 2 to 5 cwts. of common salt 1 , and half that 

 quantity of potash salts, to the ton of "superphosphate/' 

 The Peruvian and some of the other better descriptions of 

 guano contain potash salts in small quantities; to these, how- 

 ever, common salt may always be added with advantage. 



One of the great advantages that kohl-rabi offers to the 

 farmer, is that it bears transplantation better than any 

 other of his field crops; and, indeed, this is the way in 

 which it used to be most commonly grown. To this 

 method of cultivation, however, there are objections, which 

 increase every year as we substitute machines for hand- 

 labour, which latter, of course, can only be employed in 



1 Common salt is in. most places to be had at a comparatively small cost ; 

 potash salts, however, are always dear. These vary much, according to their 

 composition, in the proportions of potash they contain, and consequently in 

 their real manurial value. Rough sulphate of potash, the residuum of the 

 tartaric acid manufacture, is generally the best form to buy it in ; the muri- 

 ate of the iodine manufacturers, or the common "pot and pearl ashes " of com- 

 merce, are other forms in which it may usually be obtained at a reasonable 

 price in the markets. 



