LUMP OR BURNT LIME 243 



into lime carbonate again. Air-slaked lime is usually finely divided 

 and can be applied directly to the land. 



Marl IS a name given to earthy deposits, usually more or less 

 friable in character and containing varying amounts of carbonate 

 of lime. Marl beds are usually found in marshes. If a farmer 

 has a deposit of good marl and his soils are acid, he can utilize 

 such a deposit as a source of agricultural lime. Marl should be 

 allowed to air-diy before using (Fig. 8). 



Pulverized kiln-dried marl may be purchased for liming in 

 some sections. 



In New Jersey, the term "maii'' is applied to Greensand 

 material which contains some potassium. Deposits of shells 

 partially disintegrated and more or less cemented together are 

 found in some locahties. Such deposits are commonly called 

 ^^ shell marl.^' 



Waste lime is a by-product from industries, such as lime- 

 kilns, gas works, paper mills, beet sugar factories, tanneries and 

 water-softenmg processes. Some of this material may contain 

 substances that might be injurious to plant growth, and sometimes 

 it is very wet, making its application difficult and transporta- 

 tion unprofitable. 



Pulverized Shells and Coral. — Oyster shells, clam shells, and 

 coral, when cleaned of dirt and organic matter, contain from 

 ninety to ninety-five per cent carbonate of hme. When pulverized 

 these make excellent materials for liming. Shell dust may be 

 secured in some places as a waste product from button and chicken 

 grit factories. 



Marble Dust. — In the East, Hmited amounts of marble dust 

 as waste from marble works are available. This is high-grade 

 liming material. 



Natural chalk is carbonate of lime that has been deposited 

 in much the same way that marl has been. Chalk has been used 

 to a considerable extent in European countries. In this country 

 such deposits are of insufficient extent to be considered a source 

 of agricultural hme. 



Lump or Burnt Lime. — ^This is quick or caustic lime — ^the 

 most concentrated form of hme that may be used. It is produced 

 by heating limestone to a red heat in kilns, thus drivmg out the 

 carbon dioxide gas and leaving the common lump lime. This form 

 of lime can be procured in every town. When used in proper 

 amounts little or no injury can come from its use^ especially on 



