.196 THE CHEMISTRY OF GARDEN CROPS - 



greatly benefited by a free application to them of manure from the 

 stable and cow-byre ; but it would be (generally speaking) like carry- 

 ing coals to Newcastle to dress these soils with lime. Clay may be 

 put on with advantage ; and nothing benefits a hot chalky soil more 

 than a good dose of mud from ponds and ditches, which supplies at 

 once humus, alumina, and silicates. In the manuring of sandy soils, 

 great care is requisite, because of their absorbing power. In the bulb- 

 growing districts of Holland, manure from cow sheds is worth the 

 enormous price of one shilling per barrow-load, for digging into 

 loose sand for a crop of Potatoes, to be followed by bulbs. This 

 is an exceptional case, but it illustrates the subject usefully. As a 

 rule, sandy soils are deficient of phosphates and alkalies, and hence, 

 instead of employing manure, which may often be more advan- 

 tageously bestowed upon the loamy pieces and reserved for special 

 purposes, it will be found that kainit (a rough form of potash) and 

 superphosphate of lime will conjointly produce the best results, more 

 especially in raising Potatoes, Onions, and Carrots, which are par- 

 ticularly well adapted for sandy soils. Probably one of the best 

 fertilisers is genuine farmyard manure from stall-fed cattle, for it 

 contains phosphates, alkalies, and silicates, in available forms and 

 suitable proportions. Artificial manure should be selected by ana- 

 lysis, and with a view both to correct the deficiencies of the soil, 

 and to satisfy the requirements of the crops to be grown on it. 



For the present purpose, the principal garden crops may be 

 grouped in two classes, in accordance with the predominance of 

 certain of their mineral constituents. The figures show the average 

 proportions of the several minerals per cent, in the ashes that are 

 left after burning a sample. 



In Class I. PHOSPHATES and POTASH predominate. This class 

 includes the following : The Pea, containing phosphates, thirty-six ; 

 potash, forty. The Bean : phosphates, thirty ; potash, forty-four. 

 The Potato (tubers only) : phosphates, nineteen ; potash, fifty-nine ; 

 soda, two ; lime, two ; sulphuric acid, six. The Parsnip : phos- 

 phates, eighteen ; potash, thirty-six ; lime, eleven ; salt, five. The 

 Carrot: phosphates, twelve; potash, thirty six ; soda, thirteen; sul- 

 phuric acid, six. The Jerusalem Artichoke : phosphates, sixteen ; 

 potash, sixty-five. 



In Class II. SULPHUR, SODA, and SALT predominate. This class 

 includes the following : The Cabbage : phosphates, sixteen ; potash, 

 forty-eight ; soda, four ; lime, fifteen ; sulphuric acid, eight. The 

 Turnip : phosphates, thirteen ; potash, thirty-nine ; salt, ten ; lime, 



