PROPERTIES OF MANURES 235 



absorbed by tbe roots — it is nitrogen in an as- 

 similable form. 



The author has shown that nitrate of soda is 

 best applied as the crops require it by fractional 

 top-dressing,^ or in the case of trees and shrubs by 

 watering them from time to time with a liquid 

 manure containing nitrate of soda as already 

 directed in this book. 



Mr. E. W. Bell, in his book on Manures, p. 53, 

 says : " Dr. A. B. Griffiths has most conclusively 

 proved that the most economical way of using 

 nitrate is by top-dressing with several successive 

 quantities of the salt at short intervals." As 

 Shakespeare remarks : " 'Tis not enough to help 

 the feeble up, but to support htm after." ^ 



Nitrate of soda must always be used in pre- 

 ference to sulphate of ammonia on calcareous soils. 



It has been stated that nitrate of soda " exhausts 

 the soil " ! No substance, when applied to the 

 soU, can possibly of itself exhaust the land. It is 

 only by taking out and not replacing that a soU 

 becomes exhausted. 



As a rule, a dry light soU requires more nitrogen 

 than a damp heavy soil. SoUs rich in organic 

 matter require less nitrogen than soUs poor in 



' A. B. Griffiths, A Treatise on Mcmures, p. 204. 

 ^ Timon of Athens, Act I, so. i. 



