202 SOILS AND MANURES 



3. On stiff soils- 

 Basic slag .... 5 ozs. per square yard 

 Sulphate of potash . . . 2 ,, ,, 



Sulphate of ammonia . .1 ,, ,, 



The dressings suitable for old trees might prove in- 

 jurious to younger plants, and it is recommended that 

 only about half quantities should be given until the 

 trees are at least five years old, after which the quantities 

 may be gradually increased. Some authorities recom- 

 mend the addition of considerable quantities of calcium 

 carbonate on all except the naturally limey soils. 



The requirements of flowers are very various, but in 

 general they are similar to those of fruits, i.e., mainly 

 phosphates and potash with small quantities of nitrogenous 

 compounds. 



The composition of some mixed manures sold for 

 garden purposes is given on p. 288. 



CLASSIFICATION OF MANURES. 



Artificial and Natural Manures. The term " artificial 

 manure " is, by common consent, applied in a general 

 way to all kinds of manufactured and prepared articles 

 used for fertilising purposes. It is popularly under- 

 stood and has been used in that sense in preceding, 

 pages. If used for purposes of classification, it almost 

 necessarily involves the adoption of the expression 

 " natural manures " for other substances. Such a dis- 

 tinction, however, is purely arbitrary ; it is often highly 

 inconvenient and is apt to be misleading. No acceptable 

 definition of the terms has been formulated and no 

 general agreement as to their application has ever been 

 reached. Farmyard manure is almost the only fer- 

 tilising substance that has not been treated by some 

 writers as artificial manure; guanos, bones, sludge and 



