158 COCONUT PLANTER'S MANUAL 



over it the above quantity of water, great heat being developed by the 

 chemical combination, the rise in temperature being sometimes .sufficient to 

 cause ignition of any organic matter in contact with it. 



When still further exposed to the air for some weeks the slaked lime 

 absorbs carbonic acid gas and is re-converted into carbonate of lime, the 

 same chemical compound as the original coral, but in a more perfect state 

 of division than any grinding machinery could effect. 



As re-carbonating goes on simultaneously with slaking when quicklime 

 is merely exposed to the air, slaked lime usually consists of a mixture of 

 luild carbonate of lime and hydrate of lime. 



Limk a Plant Food. 

 Lime is of universal occurrence in soils, and its salts are no doubt 

 necessary constituents of all plants. 



Lime and Nitrification. 

 The nitrification of the organic nitrogen of soils, or of tlie various forms 

 of organic nitrogen in manures, is brought about by the agency of various 

 bacteria, some of which transform the ammonia compounds into nitrites and 

 others, which oxidise the nitrites into nitrates. 



It is this nitrification process which renders the nitrogen of the soil 

 available to the roots of plants, and it can only go on in slightly alkaline 

 soils ; the nitrous and nitric acids produced by these processes must therefore 

 combine with a base as soon as formed, otherwise nitrification ceases and 

 the plant cannot obtain the necessary supplies of nitrogen. Many Ceylon 

 soils are somewhat deficient in lime and show a slightly acid reaction, in 

 which case nitrification can only take place slowly. 



Lime Liberates Potash. 

 Lime by powerful chemical action liberates the mineral reserves of 

 soils, especially potash. This potash occuis in Ceylon soils in combination 

 as double silicates of alumina and potash, and these are decomposed by the 

 lime with the liberation of potash. 



Lime and Phosphoric Acid. 

 The action of lime on the phosphates of the soil is equally marked ; this 

 solving action is of some value, since the phosphoric acid in Ceylon soils is 

 only available in traces to the roots of the tea plant. 



Quantity to Apply. 

 As lime itself is only in a limited sense a direct food to the plant, bat 

 sets principally in action the dormant constituents of the soil, its con- 



