CHAPTKR XII 



Tlir. VALUATKJN AND TURCIIASK OF 

 KKKTILISKRS 



Valuation on the Unit System — The current Market Price of the 

 Unit of Nitrogen, Thospliatc of Lime and Potash — \'ariations 

 in Unit \'alues due to Market Fluctuations — Valuation of 

 Fertilisers before Purchase — The Fertilisers and Feeding; 

 Stuffs Act ; Obligations of the Vendor — Sampling Consign- 

 ments of F'ertilisers — Mixed v. Unmixed t'ertilisers — Incom- 

 palibles— Residues of F"ertilisers after the Growth of one or 

 more Crops - \'aluation of unexhausted Residues derived 

 from the Consumption of purchased Feeding Stuffs. 



In buying fertilisers the farmer will generally have a 

 considerable choice between materials of different origin 

 and composition, but which will so far serve the same 

 purpose that their relative price becomes the most 

 important factor in determining the purchase of one or 

 the other. For example, should an active nitrogenous 

 manure be needed, for many soils and crops it is a 

 matter of indifference whether nitrate of soda or 

 sulphate of ammonia is used ; among phosphatic 

 manures the choice may be between superphosphate, 

 basic slag, and a neutral manure like steamed bone 

 flour ; or, to take a case where even fewer secondary 

 considerations enter, practically nothing but relative 

 cheapness need determine a decision between such 

 materials as fish and meat guanos or rape cake. But 



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