94 CHAPTER VI 



The Manures Employed in Sugar Cultivation. 



Artificial Manures. — This term is employed to denote manufactured 

 products as opposed to farmyard or pen manure considered as a " natural " 

 manure. For convenience of reference their properties and composition 

 are briefly mentioned here. 



Sulphate of Ammonia. — The pure body contains 21-21 per cent, nitrogen 

 and as found on the market contains about 20 per cent, nitrogen. 



Nitrate of Soda. — This material is extremely hygroscopic. The pure 

 body contains 16*5 per cent, nitrogen, the commercial body containing about 

 4 per cent, of impurities ; these impurities are in English commerce grouped 

 together under the peculiar term of refraction. 



Nitrate of Potash. — The pure body contains 13-8 per cent, nitrogen, and 

 46 '5 per cent, of potash ; it is but seldom used as a manure, the supply being 

 devoted to other purposes ; in an impure form it however finds its way to 

 Mauritius from India, and being of local occurrence is used to a certain 

 extent in Egypt. 



Seed Cake Manures. — The refuse of seeds, etc., that have been crushed 



for oil, comes into the market in large quantities as manure. The plants that 



most largely contribute are cotton, flax, castor oil, coconut ; their composition 



of course varies with the origin. In general these manures can be used only 



in the country of their origin, drawbacks of freight prohibiting their more 



extended use. Some analyses of these materials, collected from various 



sources, are given below :— 



Nitrogen per cent. 



Ground nut {Arachis hypogcBo) .. .. 4*06 — 7*94 



Kapok meal (Eriodendron anfractuosum) .. 4 '40 



Castor cake (Ricinus communis) .. .. 4*20 



Coconut meal {Cocos nucifera) .. .. 3*62 



Cotton-seed meal [Gossypium sp.) .. .. 7-00 



Soja cake {Soja hispida) .. .. .. 6-12 



Dried blood, as it comes on the market, contains from. 10 per cent, to 16 

 per cent, of nitrogen. 



Fish scrap is of very variable composition, containing from 5 per cent, 

 to 8 per cent, nitrogen, and from 5 per cent, to 7 per cent, phosphoric acid. 



Tankage is the residue from meat packing houses, and is of variable 

 composition ; as it contains considerable quantities of bone it is also a 

 phosphatic manure. It is similar in action and composition to fish scrap. 



Guano. — The original Peruvian guano has long been exhausted, and the 

 guanos now on the market are of recent origin. They differ much in com- 

 position from those of long accumulation. Some bat guanos contain an 

 extraordinarily high amount of nitrogen, reaching up to 30 per cent. 



Cyanamide is a synthetic compound of the formula CaCNg ; it is sold 

 under the name lime nitrogen, German nitrate, or even as lime nitrate, from 

 which it must be carefully distinguished ; as it appears in commerce it con- 

 tains about 20 per cent, of nitrogen. 



Nitrate of lime is manufactured and put on the market as a basic nitrate 

 of composition Ca (OH) NO3. It contains about 12 per cent, of nitrogen. 



