Chalk (Marne) 



chalk is that which disintegrates most thoroughly 

 and is reduced to the finest particles. 



To use it one lets the chalk disintegrate in the 

 heap on the ground to be treated. When it is ready, 

 it is distributed over the surface of the ground in 

 little heaps about 8 yards apart, like lime. It should 

 be spread for preference in autumn. When necessary, 

 before ploughing in, it can be reduced by the har- 

 row. One should sow in the following spring. 



It is really a mixture of clay and of limestone, 

 and it often contains dolomite or sand which is given 

 them. 



The lower chalk does not contain flint beds, and is 

 less white ; the soil derived from it is more tenacious, 

 as though containing more clay. A dressing of 

 sand is sometimes useful. It yields excellent crops 

 when it receives manure at the same time as 

 humus. The whitest chalk contains the most lime, 

 it is then called calcareous. It disintegrates easily 

 and is especially suitable for clayey and damp soils 

 rich in humus. It contains more than 50 per cent, 

 carbonate of lime and forms a paste with water. 



One can apply this in alternate layers, like gas 

 lime, with farm manure or vegetable debris, such as 

 twitch, potato-tops, leaves and waste of crops 

 generally. After some time the heap is turned and 

 used when the chalk is completely disintegrated. 

 The chalking ought to be renewed more or less 

 frequently according to the quantity of chalk em- 

 ployed, and to the quantity of carbonate of calcium 

 it contains. The average applications are i to 20 

 cubic yards to the acre, renewed every ten years. 



145 L 



