1016 THE COMPLETE GRAZIER. BOOK XI. 



soil, and, as regards their feeding or exhausting value, there is no 

 difference between them, except that sulphate of ammonia tends to 

 exhaust the lime on soils poor in that constituent. 



SULPHATE OF AMMONIA. This manure may, perhaps, be called the 

 great rival of nitrate of soda, as it is a fertiliser equally soluble and even 

 more concentrated, containing as much as from 24|- to 25 1 per cent, 

 of ammonia. It is produced in very large quantities from the refuse 

 " liquor " of gas-works, and lately even from the gases of blast- 

 furnaces, its source being the organic nitrogen existing in the coal, 

 which is mainly converted into ammonia when the coal is distilled for 

 gas or burned as fuel. This ammonia, combined with oil of vitriol, 

 forms the useful salt to which we are referring. 



Sulphate of ammonia may be used for practically all purposes for 

 which nitrate of soda is to be recommended, the chief difference being 

 that it should be applied somewhat earlier, because its ammonia 

 cannot act until it has undergone in the soil the process known as 

 nitrification. In dry weather, nitrate of soda acts more quickly than 

 sulphate of ammonia, or other manures in which the nitrogen exists in 

 the form of either ammonia or organic matter. In wet weather, the 

 difference in speed of action is not so great indeed if the weather 

 should be exceptionally wet the ammonia salt, on a freety draining 

 soil, is even preferable to nitrate, as the latter is in danger of being 

 washed away into the drains before the crop can get hold of it. The 

 general result, however, of experiments on the question is that, on the 

 whole, nitrate of soda is the more economical manure as long as it can 

 be purchased below the price per ton of sulphate of ammonia. 



This manure should not be continuously used on soil poor in lime ; 

 but the deficiency can be easily supplied by liming or chalking. 



DRIED BLOOD, SHODDY, HOOFS AND HORNS, &c. These are 

 organic manures manures, that is to say, consisting almost wholly 

 of organic matter, containing nitrogen which is gradually converted in 

 the soil into ammonia and nitrates. Dried blood contains nitrogen 

 equal to from about 10 or 12 per cent, up to 16 per cent, of ammonia. 

 Hoofs and horns are sometimes even richer. Shoddy varies in value 

 according to the quantity of wool it contains, cotton, dirt, grease, &c., 

 being usually present. It generally yields from 3 or 4 per cent, up to 

 8 or 10 per cent, of ammonia. 



Of these manures, the most quickly acting is dried blood, which 

 decomposes more rapidly than the others. Hoofs and horns are the 

 slowest of all in action, unless they are prepared by highly drying and 

 grinding to powder, when they decay more rapidly. These are 

 chiefly used in market-gardening and for hops, for which last-mentioned 

 crop most of the shoddy sold to farmers is employed. 



EAPE-DUST, &c. A large quantity of the rape-cake, produced in 

 the process of crushing rape-seed to obtain its oil, is too much 

 contaminated with wild mustard-seed (charlock) to allow of its being 



