Manures in General 



least quantity. For to obtain the whole of the 

 effect of the given manure, the other manures must 

 be present in the soil in the right proportions. If 

 any one manure is lacking, the addition of other 

 manures, no matter in what quantity, will be 

 incapable of increasing the productivity. 



Let us make this clear by means of an example. 



Imagine any kind of crop. The liquid in the 

 tub illustrated represents the crop. The tub full 

 represents the capacity of the soil. The planks of 

 the tub represent the manures. The planks are of 

 different sizes, because different quantities of each 

 manure are required ; but the height represents the 

 proportions, which ought to be equal. The plank of 

 nitrogen [N] is of the necessary height, but the planks 

 of potash [K2O] and phosphoric acid [P2O5] are 

 too low, the plank of P2O5 coming higher than that 

 of K20- The quantity of KgO, represented by the 

 size of the plank, is, however, larger than the quantity 

 of P2O5 present and of nitrogen [N] necessary. The 

 proportion of these elements, therefore, is not 

 good. 



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