222 SOILS ;AND MANUEES 



which are at least moderately well supplied with lime, 

 and in its absence the residual value of the manure will 

 probably be considerably diminished. 



Superphosphate is pre-eminently suitable for the growth 

 of root crops and especially of turnips and swedes. It 

 may be used for pastures, leguminous crops or cereals if 

 required. The strongly acid character of the manure has 

 a tendency to promote the development of " linger and toe " 

 in turnips, to discourage the growth of clover in pastures, 

 and to render it harmful, rather than beneficial to all 

 leguminous crops. The tendency to produce such effects 

 is more marked in the more concentrated varieties, and 

 is, of course, much greater when large quantities of the 

 manure are used. It is not noticeable at all except in 

 soils that are deficient in lime. 



In general, superphosphate is the best kind of phos- 

 phatic manure for the lighter class of soils. It is cer- 

 tainly by far the best for those that are inclined to 

 dryness. It is commonly applied at the rate of from 

 2 to 5 cwt. per acre. Sometimes larger dressings are 

 used, but the smaller quantity is, as a rule, sufficient. 

 It is sometimes applied in the back end of the year, but 

 for most purposes better results are obtained by spring 

 sowing. 



Effects of Mixing Superphosphates with other Manures. 

 For the reasons given above it is inadvisable to mix 

 superphosphates with any form of lime, basic slag, wood 

 ashes, salt, or in short, any substance which can react 

 with the monocalcic phosphate and cause precipitation. 

 Above all, it should not be mixed with nitrate of soda or 

 similar salts. To do so may not only spoil both manures, 

 but also bring about results of a highly dangerous 

 character. Heat is developed by the reaction, noxious 

 fumes (oxide of nitrogen) are given off, and may become 

 a menace both to life and property. 



