228 THE RUBBER TREE BOOK 



up in the sub-soil. These facts have their bearing on the 

 successful cultivation of rubber also, and although ignored by 

 most rubber-growers, can scarcely be too much or too often 

 emphasized. 



As pointed out elsewhere, chemical analyses may show that 

 all the necessary chemical ingredients for fertility are present in 

 the soil ; but if they are in a locked-up, insoluble form they do 

 not lend their assistance to the growth of plants. "Availability " 

 is the crux of the matter. 



Cultivation has the greatest possible influence in render- 

 ing " available " the useful constituents of the soil. This is 

 not only because forking, chankolling or ploughing turns up 

 fresh mineral food from the sub-soil and the roots get hold of it. 

 It is also because the aeration of the soil revivifies and stimulates 

 the activities of bacterial life. Were the bacteria all to die out 

 of the soil no amount of expensive fertilizers would be able to 

 keep vegetation long alive. Every chemical ingredient might 

 be present in ideal quantities in the soil, and yet plants and trees 

 would speedily starve to death. 



Mr Alma Baker, in the India-rubber Journal, 5th September, 

 1910, strongly advocated chankolling everything once every 

 three months from the time of planting. " The system has," 

 Mr Baker states, " the following advantages: 



"i. It prevents all surface wash from the beginning. 



"2. It enables the land to retain more moisture. 



"3. The land does not only retain all the plant food it origi- 

 nally had, but has in addition the humus derived from 

 the vegetable matter turned in four times a year. 

 Also, the turning up of the under-soil renders readily 

 available, through exposure to the atmosphere, a 

 portion of the otherwise unavailable salts. 



"4. It forces the tree, by cutting the small surface laterals, 

 to root firmer and lower and to take its nourishment 

 from cooler, damper and richer soil. 



"5. It greatly helps in the eradication of Fomes and white 

 ants, as it clears the land of all small pieces of timber, 

 at the same time opening up the soil for the air and 

 sunlight to penetrate." 



