144 CONTINUOUS CROPPING 



in gardens. As previously stated it contains nitrogen, 

 potash, and phosphates, as do also, generally speaking, 

 special or compound manures. 



Regarding these latter manures, they are simply 

 mixtures of the raw ingredients mentioned in the 

 above table. As a rule they are sold at a price far 

 exceeding their value, and the practical farmer, speak- 

 ing generally, would be well advised to have nothing 

 to do with them but to blend his own manures accord- 

 ing to the kind of land he wishes to manure and the 

 kind of crop he wishes to grow. 



We can also classify manures according to whether 

 they are acid, alkaline, or neutral, that is, neither acid 

 nor alkaline. This classification is of importance, 

 especially as regards the phosphatic manures, because, 

 as previously indicated, acid manures on an acid soil, 

 i.e. one deficient in lime, will give poor results, and in 

 extreme cases will do more harm than good. On the 

 other hand, acid manures on an alkaline soil, i.e. one 

 containing Hme, will invariably give a more economical 

 return than alkaline manures. 



Regarding this, one cannot, however, dogmatise, as 

 the writer amongst others has obtained extremely 

 good results by applying such an alkahne manure as 

 basic slag on pure limestone or chalk pasture. Never- 

 theless the principle of alkahne manures on acid soils 

 should always be followed and also the contrary, acid 

 manures on alkahne soils, except when experiments 

 prove that alkahne manures in the latter case are 

 more profitable. 



As to the neutral manures they will give good 

 results on either type of soils, but, with the exception 

 of rock phosphate, better results on alkahne than on 

 acid soils. In short, if a soil is acid, that is, deficient 

 in lime, the best thing to do is to lime it and make 

 it alkaline. 



