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a soil such as we are considering, the root development seems almost 

 as restricted as that of the tea, and it does not seem to have the power 

 to penetrate the stiff layers. Other leguminous trees might do 

 better, as the " Koroi " (Albizzia odotatlssimd] or the "Medeloa" 

 (Dalbergia assamlca], but I have no definite experience. I should like 

 to have these tried on such a soil. Though not leguminous, the Silver 

 Oak (Grevillea robusta) might answer this purpose, especially we 

 know that it does no harm to the tea among which it is grown. 



The last method of influencing and breaking up the subsoil is 

 by means of annual green crops grown among the tea. I am not 

 here going into the question of green manuring, but the value of 

 plants as a means of breaking up of the subsoil should be kept in view 

 in any choice of those suitable for green manuring. At present we 

 have no knowledge of what plants would be suitable. " Mati Kalai " 

 (Phaseolus acomtifolius) only seems, on such heavy soil, to penetrate 

 ten inches deep which is absolutely no good for this purpose and 

 none others have, to my knowledge, yet been tried. Some plant suited 

 to the conditions undoubtedly exists,* and it would well repay 

 experiment to find it Possibly one of the lupins might be found to 

 answer, but it demands trial to find whether under Assam conditions 

 they retain the long subsoil roots which are one of their special 

 features elsewhere. 



INFLUENCE OF THE WATER IN THE SOIL. 



We now come to the relationship of the moisture content of the 

 soil and of the water level in the soil to the luxuriance of the tea. A 

 large amount of water continually present is of course absolutely 

 essential, by far the greatest part of the plant's weight being formed 

 of this substance. Thus green crops as a rule contain 60 to 80 per 

 cent, of water, and including all the woody parts the percentage in a 

 whole tea bush is probably not much below fifty. Practically the 

 whole of this is absorbed through the roots, and the leaves may be said 

 to take no part in providing it, but are, on the other hand, getting 

 rid of it at a great rate through the whole period of growth. The 

 following figures give an idea of the amount actually evaporated by 

 the leaves cf a single crop during its growth. A crop of meadow 

 hay dissipates about 527 tons of water per acre during growth, 



* A wild variety of " Kalai "Phaseolus velutinus has been recently sent to me from 

 Nowgong, whose roots are 3104 feet long. This might possibly prove useful in the above sense. 



