LIME. MARL. 101 



336. Lime mellows clayey land. It is an essential 

 element in most plants and is valuable therefore for 

 itself. It is a very important element in toba,cco, pota 

 toes, pease, the clovers, and turnips. It corrects the 

 acidity of soils, particularly of that of bogs and swamps. 

 An examination of the mineral ingredients of our soils 

 shows that it is never wanting. 



337. Yet, in most parts of New England, it is so diffi 

 cult to obtain and so dear that it cannot often be largely 

 applied. In small quantities, it produces, when needed, 

 most important effects. In England, large quantities are 

 often applied to land in the shape of chalk. 



338. Limestone rocks often contain magnesia, which is 

 acted upon in a lime-kiln just as lime is. This dimin 

 ishes the value of the lime, as does the mixture of clay 

 and of sand, with which it is sometimes adulterated. 

 Wherever oyster shells or any other shells can be readily 

 got, they may be burned on heaps of brush, or other fuel 

 of little value, and will be converted into a lime which is 

 of greater value for agricultural purposes, than that 

 formed from limestone rocks, because it contains a small 

 quantity of phosphoric acid. The having already formed 

 a part of an organized being seems also to prepare it 

 for a similar service. 



339. Marl is a mixture of lime and clay, or lime and 

 sand, sometimes, but not often, found in New England, 

 but abundant in some other States. When exposed to 

 the atmosphere, it should crumble easily, as its action is 

 in proportion to its readiness to mix perfectly with the 

 soil. Though less energetic, it has all the permanent 

 effects of lime, and is very valuable as an amendment, 

 clayey marl to sandy soils, and sandy marl to clayey. 



