Assimilability 



are applied, and to give each year the quantities of 

 manure required. 



Besides, in using manure of slow action, how 

 many units will the plants find at their disposal 

 during the first year and during each of the succeed- 

 ing years ? There is no room in modern agriculture 

 for all this waiting and all this uncertainty. Manures 

 of very slow action ought rather to be regarded as 

 improvers and not as manures, and then should be 

 bought at a very low price. 



Yet another manure is one having a more or 

 less progressive action, finishing in a year or there- 

 abouts. The action of these manures depends on 

 their assimilability, which again depends on many 

 factors. There are two especially, of very great 

 importance, first their solubility, and second their 

 fineness. The nature of the soil and the species of 

 vegetation also play an influential part. 



Assimilability. 



The most important point about manures is 

 their assimilability. A non-assimilable matter is 

 not a manure, although it may contain nutritive 

 elements. Certain mineral phosphates are only 

 assimilable with difficulty, or not assimilable at all 

 in ordinary soils, so that they often do not possess 

 any fertilising value. This is why their introduc- 

 tion into more assimilable fertilising matter really 

 constitutes an adulteration of the product. Other 

 manures are more assimilable though not entirely 

 so, and not immediately. These are the manures of 

 more or less slow action. Others, again, are rapidly 

 and immediately assimilable and these are the best 



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