CHAPTER XXX 



The Use of Plaster in Agriculture 



Plaster is by no means of the same im- 

 portance in agriculture as lime, but it has 

 an excellent effect on clover, sainfoin and 

 lucerne. It is used in spring by dusting the 

 young leaves when they are still damp with 

 the morning dew. Misty and calm weather 

 is most suitable for this operation. Plaster 

 also has a good effect on colza, flax, buck- 

 wheat and tobacco, but it is useless for cereals. 

 The intelligent husbandman has a further 

 use for plaster. In every heap of manure 

 there is slow combustion and fermentation, 

 producing ammoniacal exhalations, which are 

 dispersed in the air and absolutely wasted. 

 These exhalations should be retained in the 

 manure as far as possible ; for it is the com- 

 pounds of ammonia that supply nitrogen to 

 the plants. To prevent this loss plaster is 

 scattered over the top of the manure ; or 

 sometimes, as the heap is formed, each layer 



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