144 



Fertilisers 



[PT. Ill 



It simply means that the soluble pho-phate present 

 would amount to 30 per cent, ij it were there as tricalcic 

 phosphate. But it is not. and the only justihcation tor 

 this rather cumbersome method of expression is that all 



4Cpl^ 



T 



Plot 1 3 5 



Fig. 30. Effect of fertilisers on swedes (Agdell field. 

 Rothamsted, 1912.) 



Plot 1. Complete manure phosphates, potash and nitrogen 

 compounds. 



3. Incomplete manure phosphates and potash but no 



nitrogen compounds. 

 5. No manure. 



manures are worked out on the same basis, to which 

 everybody has become accustomed. The more concen- 

 trated grades save freight; the others supply a larger 

 amount of gypsum which under some circumstances has 

 distinct manurial value. 



