Improving the Condition of the Soil 



This lime contains from 55 per cent, to 65 per cent, 

 of lime, and about 25 per cent, of magnesia. Lime 

 can also be obtained by burning the shells of 

 molluscs, etc., when they can be found in sufficient 

 quantity. 



Basic slag forms a good source of agricultural 

 lime. It contains, as we have seen, besides phos- 

 phoric acid, about 50 per cent, of lime, of which 

 3 to 5 per cent, are free. In many soils this lime 

 represents a part of the value of the slag. A 

 dressing with slag will give the soil a small dose 

 of lime, but very often quite sufficient. 



Good quicklime should be in blocks as large as 

 possible. It should be white, and ought to be 

 entirely burnt, allowing very little waste when 

 finished. It should be made from the purest lime- 

 stone obtainable. When plunged in water for a 

 couple of minutes and withdrawn it ought to dis- 

 integrate completely and rapidly, throwing off a 

 great deal of vapour and swelling considerably. 

 In large lumps it cannot be slaked during transport, 

 and still less carbonated, in which case it would 

 have lost a great part of its value. 



Lime must therefore always be fresh. The 

 waggons in which it is carted ought to be covered, 

 so as to shelter it from CO2, from rain and atmos- 

 pheric moisture. Slaked lime is easily carbonated. 

 Then it no longer has a caustic action on organic 

 matter, and can no longer directly neutralise the 

 acids in the soil. The two great qualities which 

 make the value of the lime will then be lost. More- 

 over, the finer the lime the more will it be car- 

 bonated, since a greater surface will be exposed 



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