Organic Manures 



Sometimes these phospho-guanos, from which 

 the organic matter had disappeared, became hard 

 and formed a species of rock ; they were then called 

 crust-guanos or guanorites. 



There are actually on the market preparations 

 called guanos which are made of blood, flesh, the 

 bones of animals or of fishes, and fish refuse. Apart 

 from this there are certain flesh guanos made from 

 the refuse of extracts of meat works ; these are 

 " made in England," and are called blood or fish 

 guanos. Unfortunately, they are generally too 

 dear. 



Farmers appear to have the impression that the 

 strong odour of ammonia given off by some guanos, 

 the moist guanos from Bolivia for example, is a 

 proof of their superior value. On the contrary, it 

 is a sign that they are in the process of losing their 

 ammoniacal riches. Good guano ought to have the 

 brown colour of burnt chicory ; it ought to be easily 

 pulverised and to contain no particles of sand or 

 of gravel, but to be smooth to the touch and with- 

 out a strong odour. 



The composition and value of actual guanos vary 

 considerably, and, owing to their well-established 

 reputation, they are often sold at a price in excess 

 of their value. In order to maintain this reputation, 

 attempts have been made by means of these poor 

 guanos to make a manure as concentrated as the 

 Chincha guano, by mixing it with nitrate, sulphate 

 of ammonia, organic nitrogen, phosphates imder the 

 form of superphosphates, also insoluble phosphates, 

 etc., and of potash — these are called fortified guanos. 

 Their value depends largely upon the form of manure 



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