COMPOUND MANURES 187 



times overrated, and that on many fields a portion of the phos- 

 phates in a compound manure might safely be in an insoluble 

 form. It is essential that insoluble manures be finely ground. 

 Compound manures, if produced at definite compositions, 

 fill a useful part in the agricultural industry, but too much 

 attention should not be paid to mere names applied to them. 

 It is not practicable to specify any particular mixture as being 

 specially suited to one or another crop under all conditions. 

 A useful manure for the hay crop of a four-course rotation 

 is given on p. 204. Such a fertilizer might be made by 

 mixing 12 cwt. superphosphate (30 %) with 3 cwt. sulphate 

 of ammonia, i cwt. steamed bone flour and 4 cwt. potash 

 manure salts (30 %), and should be used as explained on the 

 page quoted. 



TABLE 22. 

 FIELD EXPERIMENTS WITH PHOSPHATES UPON TURNIPS, 1911-14. 



Average of 66 experiments. 

 Plot. Tons. Cwts. 



1. No artificial manure .. .. .. .. ..13 17 



2. Sulphate of ammonia, potash manure salts, and super- 



phosphates . . . . . . . . . . 20 12 



3. Sulphate of ammonia, potash manure salts, and basic 



slag . . . . . . . . . . . . . . 20 o 



4. Sulphate of ammonia, potash manure salts, and ground 



mineral phosphate . . . . . . . . 19 10 



5. Sulphate of ammonia, potash manure salts, and steamed 



bone flour . . . . . . . . . . 20 7 



6. Sulphate of ammonia, potash manure salts, and bone 



meal .. .... .. .. .. ..19 n 



7. Sulphate of ammonia, potash manure salts, and dissolved 



bones . . . . . . . . . . . . . . 20 3 



8. Sulphate of ammonia, potash manure salts, and mixture 



of superphosphate and basic slag .. .. ..20 15 



9. Sulphate of ammonia, potash manure salts, and mixture 



of superphosphate and ground mineral phosphate . . 20 



10. Sulphate of ammonia, potash manure salts, and mixture 



of superphosphate and steamed bone flour . . 20 15 



1 1 . Sulphate of ammonia, potash manure salts, and mixture 



of superphosphate and bone meal . . . . 20 n 



REFERENCES TO SECTION VI. 



Robertson, " The Rate of Reversion of Mixtures of Superphosphate with 

 Basic Slag and Rock Phosphates," Journ. Soc. Chem. Ind., 1917, p. 626. 



Fritsch, " The Manufacture of Chemical Manures," pp. 143-150 (Scott, 

 Greenwood). 



" Compound Manures," Journ. Bd. Agric., 1915-16, p. 675. 



Hendrick, " The Phosphate Industry," Journ. Soc. Chem. Ind., 1919, 

 P- 155 R- 



Arnott, " Fertilizers as an Aid to Profitable Farming," p. 23 (McGlashan, 

 Gregory). 



