100 THE FARMERS' HANDBOOK. 



mixed with lime, under which treatment they swell, become soft, and 

 decompose far more readily. They may also be usefully added to the 

 compost heap. 



The most important and most commonly used of these products are : — 

 Dried blood and dried flesh. — These substances are produced in consider- 

 able quantity in slaughter-houses and boiling-down works, and are dried by 

 means of steam. They are almost identical in chemical composition, and 

 contain on the average 11 to 13 per cent, nitrogen. They are specially 

 beneficial on grass lands (about 30 bushels per acre), for turnips, and in 

 fact all crops that require nitrogenous manures. They are less soluble than 

 such manures as sulphate of ammonia and nitrate of soda, and are more 

 applicable as an autumn manuring than as a top-dressing. With superphos- 

 phate and kainit they form a complete manure, suitable for fruit-trees, 

 vines, potatoes, tobacco, and such crops. 



Sulphate of ammonia is a manure of very great value, and being a waste 

 product in the purification of coal-gas, it can be produced more cheaply than 

 other soluble forms of nitrogen. It is obtained by treating the ammoniacal 

 liquor of the gasworks with lime, which drives off the ammonia. The 

 ammonia is absorbed by sulphuric acid and forms sulphate of ammonia. 

 The ammoniacal liquor is a mixture of different ammonium compounds- 

 produced in the purification of coal-gas. Sulphate of ammonia is a white 

 crystalline powder when pure. It is the most concentrated form of nitrogen 

 we possess, containing about 20 per cent, of this element in combination. 

 It is readily soluble and immediately available, and specially valuable as a 

 top-dressing to the young crop. 



For gardening purposes it may be dissolved in water (about \ oz. to 1 oz. 

 to the gallon), and will be found effective for most pot plants and flowers. It 

 is more pai'ticularly adapted for clay soils. It is stated to be ineffective on 

 strong calcareous soils — that is, soils which contain over 8 or 9 per cent, of 

 carbonate of lime ; but as the cultivated soils of the State average something 

 under 1 per cent., there is not much to be feared on this score. Sulphate 

 of ammonia, or manures containing sulphate of ammonia, should not be 

 mixed with lime, nor applied to land which has been recently limed. A still 

 more effective form of available nitrogen exists in — 



Nitrate of soda, the principal source of which is the nitre-beds of Chili 

 and Peru. Enormous quantities are exported to England and the European 

 continent, and it is largely used both in the imported and locally-made 

 fertilisers. 



It contains about 16 per cent, nitrogen, as against 20 per cent, in 

 the case of sulphate of ammonia, and the unit value for the nitrogen is- 

 higher than in the case of sulphate of ammonia. Its local use is consequently 

 limited. 



Of other forms of nitrogen may be mentioned — 



Soot, which contains from 1 to 2 per cent, of nitrogen, principally in the 

 form of ammonium compounds. It is fairly quick in its action, and at the 

 rate of about 33 bushels per acre will be found useful for grass and. 

 vegetables. 



Calcium cuanamide or Nitrolim is a product obtained by passing nitrogen 

 over calcium carbide at a high temperature. It is lower in nitrogen than 

 sulphate of ammonia, and does not appear to possess any higher manurial 

 value, and it cannot at present compete with the latter locally in cost. It is 

 consequently not on the local market to any extent. 



