36 AETIFICIAL MANURES [OH. 



s. d. s. d. s. d. 



When 30 % superphosphate is 400 4100 500 

 Then a high grade basic slag 

 (34% soluble) should be 



about 3 15 450 4 14 



Steamed bone flour and bone 



meal should be about ... 01 10 020 022 per unit of 



Allowing 18 per unit of nitrogen phosphate 



5. Mixed manures and proprietary articles. It is often an 

 advantage to buy the manure ready mixed, but two rules should 

 be observed: 



1. Mixed manures must only be bought from firms of repute, 

 as they allow considerable scope for dishonest practices. 



2. Before purchasing the prices should be compared as shown 

 above with those of the ordinary artificial manures. At present 

 prices one would allow about 20s. for each per cent, of nitrogen, 

 3s. for each per cent, of soluble phosphate, 2s. for each per cent, of 

 insoluble phosphate, and 10s. for each per cent, of potash 1 in the 

 fertiliser. Thus, if a manure is guaranteed to contain 4 per cent, 

 nitrogen, 20 per cent, phosphate, half soluble and half insoluble, 

 and 2 per cent, potash, a fair price at the time of writing would 

 be: 



s. d. 



Nitrogen 4 x 20s 400 



Phosphates 10 at 3s. + 10 at 2s. ... 2 10 

 Potash 2 at 10s 100 



7 10 



Anything in excess of this price would be paid for the con- 

 venience of having the mixture made up. These figures represent 

 top grade materials, but there is nothing to compel the maker 

 to use such good stuff, and nothing to show that he has done so, 

 except the crop results : it would be quite easy to use a mixture 

 of shoddy at about 8s. and sulphate of ammonia at about 17s. 

 per unit of nitrogen, making an average of 12s. per unit. It is 

 to avoid trouble of this sort that farmers have often been recom- 

 mended to make their own mixtures instead of buying them. 



1 War price only; in peace time it was 45. Gd. Potash fertilisers cannot be 

 bought at this price and where they are known to be indispensable the farmer 

 must be prepared to pay more. But in ordinary practice and with the ordinary 

 run of mixed manure I think this is a fair allowance. 



