CETAPTER XII 



THE PURCHASE AND USE OF ARTIFICIAL MANURES 



The British farmer has a fairly wide range of fertihsers 

 to select from, and in addition he fertilises his land 

 through the feeding stuffs purchased for his cattle. The 

 supplies are regularised by the various syndicates, never- 

 theless there are market fluctuations of which farmers 

 and co-operative societies should take advantage. Fur- 

 ther, a large number of proprietary manures are on the 

 market, the percentage analysis of which has to be de- 

 clared^, and it is therefore convenient to have a method 

 by which one fertiliser can be compared with another 

 to ascertain which is the cheaper. 



The basis of comparison is the unit value. A unit is 

 1 per cent, per ton ; the unit value is the cost of 1 per 

 cent, per ton, and it is obtained by dividing the cost of 

 the manure by the percentage of nitrogen, potash or 

 phosphate. Thus the unit value of nitrogen in nitrate 

 of soda is obtained as follows : 



Nitrate of soda contains 15 per cent, of nitrogen and 

 cost before the war 11 f.o.r. 



.*. 1 per cent, cost \^ per ton = 145. 8r/. 



and this was the unit price or unit value. So the unit 

 value of nitrogen in sulphate of ammonia was 

 price per ton 13 



percentage of nitrogen 20 



135. 



1 Under the Fertilisers and Feeding Stuffs Act, 1906, full details of 

 which are given in the Journ. Board of Agric, 1906-7, x. 13; and of the. 

 Compound Fertiliser Orders of the Ministry of Munitions. 



