Manures and Manuring 163 



cent of soluble phosphate, costing 3 per ton, the cost per unit of phos- 



3 

 phate would be = = Is. lO^d. Basic slag at 2, 10s. per ton, and contain- 



2 10s 

 ing 40 per cent of phosphate, would represent a unit cost of ' = Is. 3d. 



And ground Algerian phosphate at 2, 10s. per ton, but containing 60 per 



cent of phosphate, would show a unit value of ~ ' = Wd. 



oO 



Insoluble phosphates, although not of such immediate value, are never- 

 theless reckoned in the price of manures, and vary from Is. 4<d. to 2s. 9d. 

 per unit. 



Potash manures are reckoned in the same way as nitrates and phos- 

 phates. Kainit, muriate of potash, and sulphate of potash may be taken 

 as standard potash manures. Thus, in kainit containing 12| per cent of 



2 5s 

 potash, and costing 2, 5s. per ton, the phosphate would cost - ' ' = 3s. Id. 



1*1 

 per unit nearly. Muriate of potash containing 50 per cent of potash at 



9 

 9 per ton costs -^ = 3s. 7d per unit. And sulphate of potash with 50 per 



9 10s 

 cent of potash at 9, 10s. per ton would cost j^. ' = 3s. 9^d. per unit. 



With such manures as nitrate of soda, sulphate of ammonia, basic slag, 

 superphosphate, kainit, muriate of potash, and sulphate of potash, each 

 valuable for a certain ingredient, it is easy enough to calculate the cost 

 of nitrogen, phosphate, and potash per unit; but it is not so easy with 

 manures containing more than one valuable ingredient. Nor must natural 



ra o 



manures like stable or farmyard manure, dried blood, seaweed, &c., be 

 valued on the same basis, because they possess other properties apart 

 from their purely manurial value. If, however, the cultivator has a 

 knowledge of the unit system of valuing artificial manures he will find it 

 advantageous to buy sometimes one kind of nitrate, phosphate, or potash, 

 and sometimes another, and use them as required. 



If we take a complete fertilizer, that is, one containing nitrates, phos- 

 phates, and potash, at the unit values quoted above, we get an example as 



follows: 



s. d. 



Nitrogen, 7 units at 11s. = 3 17 



Phosphate, soluble, 15 units at Is. IGd. = 176 



insoluble, 7 units at Is. Qd. 10 6 



Potash, 5 units at 3s. Id. 17 11 



6 12 11 

 Add 25 per cent for mixing, storing, bags, 



carriage, &c ... ... ... 1 13 



Total cost per ton ......... 8 5 11 



By obtaining a warranty with manures purchased, growers are thus able 

 to arrive at a very fair estimate as to the value of their manures, if they 

 price the percentage of nitrates, phosphates, and potash as given in the 

 above examples. 



