Manures in General 



manures. They are those which most rapidly repay 

 outlay, and their employment is the most advisable. 



I. Mineral Tricalcic Phosphates — Coarse and Inassimi* 



LABLE. 



A. While the crop is growing. 

 A poor crop. 



B. After the crop. 

 It remains unchanged. 



Assimilability is generally in proportion to the 

 solubility. 



Solubility. 



Manures which are soluble in water are, as a 

 rule, regarded as very assimilable. A good example 

 is the Ph. Ac. in superphosphates. 



Then come the manures soluble in weak acids, 

 the chief of which is basic slag, soluble in 2 per cent. 

 of alkaline citrate. These are justly regarded as 

 soluble manures, although less so than the super- 

 phosphates ; while the phosphates soluble in strong 

 acids are justly considered as only slightly assimi- 

 lable. 



Those particularly which are only soluble in 

 strong acids have, however, different degrees of 

 assimilability for the same chemical form. This 



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