THE USE OF MANURES 167 



be the case under humid conditions of the 

 atmosphere. A mixture of basic slag and 

 kainit sometimes " sets " very hard, it should 

 therefore be used without delay. It used 

 to be argued that basic slag and super- 

 phosphate of lime should not be mixed 

 together, it being urged that the free lime 

 of the basic slag reacted upon the soluble 

 phosphate of the other manure and caused it 

 to " revert " to an insoluble condition. 

 This, no doubt, is true, but it is doubtful 

 whether reverted phosphate is essentially 

 of less value than water-soluble phosphate, 

 and in any case the mixing of basic slag with 

 superphosphate, or with dissolved bones, 

 will tend to counteract the acid character 

 of these manures ; and for certain purposes, 

 notably for use on the* turnip crop, where 

 finger-and-toe is to be feared, the neutraliza- 

 tion of the acidity is an undoubted advantage. 

 The many field trials carried out during 

 the last twenty years by Agricultural Colleges, 

 and for a much longer period by the leading 

 Agricultural Societies, have shown con- 

 clusively that farmers should not depend 

 too implicitly upon general principles with 

 regard to the use of artificial manures, but 

 should take steps to ascertain the particular 

 requirements of their own farms. This can 



