PARA RUBBER, 45 



Composition of Artificial Manures, 



The following table shows the constituents of common artificial 

 manures obtainable from local firms, and the compositions here 

 quoted are those guaranteed by various firms in Colombo :— 



Green Manuring for Para Rubber Trees. 



It is a fortunate coincidence that the climatic conditions favourable 

 to the cultivation of Para rubber in the young stage are identical 

 with those required for the plants of value as green manure. When 

 estates are planted with rubber alone one must either elect to allow 

 the soil to be exposed to the sun and rain and to be thereby 

 impoverished, or decide to protect it by a green crop and in- 

 crease the organic matter and mineral constituents for the future 

 benefit of the growing rubber. 



It is hardly necessary to point out the advantages of green manur- 

 ing, seeing that the system is adopted in European as well as tropical 

 countries. One great advantage attending the use of the plants men- 

 tioned below lies in the fact that they are able, in virtue of the bac- 

 teria associated with the nodules on the root, to absorb nitrogen 

 direct from the air, a capacity not possessed by most of the plants 

 under cultivation. 



The points to be considered are during what stage in the life 

 of a rubber plantation green manures can be cultivated, and which 

 plants are best suited for the purpose. It is unnecessary to explain 

 that after a good rubber estate is six to eight years old green manur- 

 ing must practically cease. But dining the first few years il is pos- 

 sible to keep a green cover over those parts of the land not affected 

 by the rubber plants. 



