1920.] 



Notes on Manures. 



1015 



1. The greatest care must be taken to avoid waste of such 

 farmyard manure as is available ; methods have been discussed 

 in former notes by which this can be done. 



2. A compost may be made of broken straw, hedge clearings 

 and other suitable materials. Such a compost is not as good 

 as farmyard manure, but it has the merit of supplying organic 

 matter and, therefore, may prove distinctly valuable. 



3. In place of a one-year clover ley a mixture of clover and 

 grass can be substituted and left down for two or three years. 

 Considerable amounts of humus are thus fornled, which, on 

 ploughing in, exert a beneficial effect on the soil. 



Rock Phosphates. — A correspondent has asked whether and if so 

 under what conditions rock phosphates can be used in place of 

 basic slag and superphosphate. This question was raised many 

 years ago by the late Dr. Jamieson, but it soon ceased to be of 

 interest because the suppHes of superphosphate and basic 

 slag were more than adequate for British consumption ; indeed, 

 considerable quantities were exported. In present circum- 

 stances, however, this is no longer the case, and there is now no 

 excess of fertiHsers. The question, therefore, arises, whether 

 rock phosphates can be used direct or whether conversion into 

 superphosphate is really necessary. 



Experimental evidence has been obtained showing that rock 

 phosphates are of value in the north of England and also in 

 Scotland and Wales ; they have not proved successful, however, 

 at Saxmundham in Suffolk. The following table shows the 

 average of some of the field experiments carried out in 

 Scotlanid : — 



Field Experiments with Phosphates upon Turnips, igii-14. 

 (Average of 66 Experiments.) 



Plot. 





Tons cwt. 



I. 



No artificial manure 



Sulphate of ammonia, potash manure salts, and — 



13 





2. 



superphosphate 



20 



12 



3. 



basic slag . . 



20 







4- 



ground mineral phosphate 



19 



10 



5. 



steamed bone flour 



20 



7 



6. 



bone meal . . 



19 



II 



7. 



dissolved bones 



20 



3 



8. mixture of superphosphate and basic slag 



20 



15 



9. 



mixture of superphosphate and ground mineral 









phosphate 



20 



8 



10. 



mixture of superphosphate and steamed bone 









flour 



20 



15 



II. 



mixture of superphosphate and bone meal 



20 



II 



Farmyard manure was applied equally on all plots at the rate 

 of about 12 tons per acre. Sulphate of ammonia and 30 per cent. 



