104 HUMUS AND THE DEFERT1LIZATION 



thing that has protected them so far has been the large num- 

 bers of inferior trees which do not repay the cost of re- 

 moval. Koomaree cultivation, however, if it extends much, 

 will finally effect this, except on the very steepest ridges. 



Forest fires, rain- I have explained the manner in which earthworms im- 

 fall and the action i -i i i i i 



of animals. prove the soil and cover up stones and gravel by their cast- 



ings. These castings are hard and clayey in nature, and not 

 easily dissolved by rainfall, however heavy. In grass lands 

 which are fired annually by village herdsmen, these nodules 

 of insect-formed clay are partly calcined by the action of 

 fire and then fully exposed to the united action of sun and 

 rain, which tends to pulverise them. When the young grass 

 has sprouted, large herds of cattle are driven up from the 

 plains to graze on the tender and succulent green shoots. 

 They trample on and reduce the clay nodules to dust. Heavy 

 storms follow in April and May, and the finely pulverised 

 soil is washed down the steep slopes into streams and lost. 

 Cattle also by continually treading on the humus and worm- 

 castings in forests trample the soil (where level) into a hard 

 compact mass, which the delicate radicles of seeds cannot 

 penetrate. Reproduction is, therefore, seriously interfered 

 with. 



Kestoration of The only possible way in which soils exhausted by koom- 



exhansted soils. aree cu jtivation can be restored is to put an entire stop to it. 

 If the mischief has proceeded so far that reboisement is 

 necessary it should be taken in hand at once, and the areas 

 requiring it planted up with such descriptions of trees as 

 suit the climate and locality, and are likely to bind the soil 

 with their roots. For high elevations the Acacia deal- 

 bata answers excellently for this purpose. Some species 

 of ficus are also very good, especially those that throw 

 out an abundance of aerial roots such are suited for 

 low elevations. It may be contended that the abori- 

 ginal tribes have practised the koomaree system of cul- 

 tivation from time immemorial that it is impossible to 

 put a stop to it. There is considerable truth in this ; bub 

 the word impossible in this instance should form no part 



