MANURES 



Phosphates 



MANURES AND FERTILISERS 



Rice Husk. 



Phosphates. 



Bones. 



Sulphuric Acid. 



Phosphatic 

 Modules. 



Basic Slag. 



Manure 

 Works. 



Trade. 



Bones. 



be addedias manure if fertility is to be preserved. To the Natives of India 

 potash may be said to be summed up in Pearl Ash (see p. 49). Plant ashes have 

 been for centuries valued for high-class cultivation. The subject is closely 

 akin to robing and jumming (see above, p. 770). The value of wood-ashes 

 as manure will be found discussed in many Indian publications, such as the 

 Indian Forester (1879, iv., 284-5). Rice husk, almost worthless as a cattle 

 food, is of great value as a manure, because of the high percentage of potash 

 it contains. So also the refuse skimmings, in the process of sugar manufacture, 

 are much valued, and indigo refuse is also rich in potash. Recently, however, 

 certain natural minerals have come into the market as special potash-yielding 

 manures. Of this nature is kainit, which contains 13 to 14 per cent, of potash. 

 When calcined it is greatly improved, and may be given at from 2 to 4 cwt. to the 

 acre. It is useful on light lands rather than on clay soils. Large beds of this 

 substance have been discovered in Germany. 



Phosphates and Phosphatic Manures, Basic Slag, etc. The phosphoric acid 

 required by plants is one of the soil ingredients liable to be exhausted by con- 

 tinuous cropping, and must be supplied in the form of manure. It is on this 

 account that pastures are liable to get worn out. The principal manures of 

 this class are bones, superphosphates arid reduced phosphates. Space cannot 

 be afforded to revert to the subject of bones and the special preparations made 

 from them (see p. 169). But it may be here observed that large fossilific deposits 

 have been found in many countries rich in phosphates. Holland (Rev. Min. Prod., 

 in Bee. Qeol. Surv. Ind., 1905, xxxii., 112-4) says of India, "One regretful fea- 

 ture" ..." is the absence, in a country where agriculture is such a prominent 

 industry, of any phosphatic deposits of value, and a further circumstance to be 

 regretted is the continued export of phosphates in the form of bones, due primarily 

 to the fact that, being without means for the manufacture of cheap sulphuric acid, 

 superphosphates are not made in the country, and the little that is used is im- 

 ported from Europe." "Amongst the phosphatic deposits of India, the principal 

 and perhaps the only one worth considering is the deposit of phosphatic nodules 

 of the septarian kind, occurring in the cretaceous beds of the Perarnbulur taluk, 

 Trichinopoly district, Madras Presidency. Dr. H. Warth, in 1893, estimated 

 that to a depth of 200 feet the beds contained phosphates to the amount of 

 about 8 million tons, but the nodules are distributed irregularly through clay, 

 varying, in the different deep excavations made, between 27 and 47 lb. per 100 

 cubic feet, and in some shallow diggings 70 lb. per 100 cubic feet. Analyses 

 of these nodules show them to contain from 56 to 59 per cent, of phosphate, 

 and about 16 per cent, of carbonate of lime, with considerable variations in 

 different nodules. The alumina and oxide of iron vary between 4 and 8 'per 

 cent." Two attempts made to utilise these deposits have proved futile, and 

 it is believed there is no present prospect of mining for export. [Cf. Hooper, 

 Effects of Phos. Man. in Jalap Cult., Pharm. Journ., July 1896 ; Sly, Min. Fertil. 

 in Ind., Agri. Journ. Ind., 1906, i., pt. iii., 243-6; Leather, Mem. Dept. Agri. 

 Ind., 1907, i. (Chem. ser.), 45-57.] 



Basic Slag, a by-product in the manufacture of steel, and until recently a 

 waste product, came into use as a phosphate and lime manure. It is ground 

 to a fine powder, and in soil moisture is at once dissolved and rapidly absorbed 

 by the roots. As it contains much iron it is not suited for soils already rich 

 in that substance. [Cf. Hughes, Journ. Soc. Chem. Indust., 1901, xx., 325 et seq. ; 

 Hooper, Agri. Ledg., 1898, No. 20.] 



Indian Manure Works. It would, perhaps, be invidious to attempt 

 an enumeration of the bone-mills of India (further than has already been 

 given, p. 169), since these by no means represent all the manure works, 

 nor the firms that trade in indigenous and imported manures. 



Trade. The traffic in manures is not an extensive one, and, when 

 bones are eliminated, is hardly worth mentioning. The total exports 

 in 1904-5 were valued at Rs. 43,77,841, of which Rs. 37,51,480 were 

 bones, and in 1906-7 at Rs. 1,01,54,892, of which Rs. 55,45,241 were 

 bones. But one point is worthy of consideration, viz. while the exports 

 of raw bones have been declining steadily for some years past, the exports 

 under the heading of Others (excluding oil-cakes) have been steadily 

 increasing. In 1900-1 the exports of bones were valued at Rs. 58,41,916, 



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