1 026 THE COMPLETE GRAZIER. BOOK xi. 



neglected and uncultivated state, and has become sour; in which case, 

 one good application of lime was deemed better than many frequent and 

 repeated scatterings of small quantities. Eecent practice, however, has 

 been in favour of frequent small dressings of lime as a manure, such as 

 5 cwt. to 6 cwt. per acre, instead of heavy applications at wide intervals. 

 Moreover, as lime is speedily converted into carbonate of lime (chalk) 

 after being spread upon the land, its use is being superseded to some 

 extent by chalk, where the latter can be obtained from no great distance. 

 In recent experiments finely ground chalk, If cwt. in place of ^ach cwt. 

 of lime, has proved at least as beneficial as a manure. 



Great crops have often resulted from the first application of quick- 

 lime, and farmers have thus been led into the error of repeating the 

 dressing without the addition of other manure, whereby the land has 

 become exhausted, instead of fertilised. A second liming should, 

 therefore, not be undertaken without full consideration. "Caustic 

 lime," says a celebrated writer, "unites with the half -decomposed 

 fibres of vegetable matter, as straw, heath, and the like : it helps their 

 decomposition and accelerates it. By its means the dead fibres of the 

 roots, which remain in the earth when the plant is removed, become 

 soluble, and their elements entering into new combinations supply 

 materials for the various crops which are grown. So long as there is a 

 store of organic matter in the soil, lime will be an excellent manure. 

 Clayey soils are better able to bear repeated limings than those of a 

 more sandy nature, for the lime tends to loosen the texture of the 

 former, while it often hardens the latter to such a degree as frequently 

 to form large clots of mortar. On damp wet ground its effects are 

 scarcely perceptible. Much of the soil's fertility depends on the gradual 

 transformation of organic nitrogen, first into ammonia and then suc- 

 cessively into nitrites and nitrates. The latter stages of this process, 

 known as nitrification, are produced by micro-organisms which can only 

 work satisfactorily in presence of lime. Hence not a litl^e of the 

 immediate benefit derived from lime on a soil poor in that, substance. 

 Lime also helps the production of ammonia, which precedes nitrification, 

 and improves the mechanical condition of most soils. 



MARL is calcareous clay, tiiat is, clay containing a variable per- 

 centage of carbonate of lime. According to its quality and composi- 

 tion it is variously termed stone-marl, argillaceous or clay-marl, and 

 shell-marl. The first is so denominated from its being harder than 

 the other sorts, on account of the greater or less quantity of sandy 

 particles it contains. Of the second kind, clay is a principal in- 

 gredient; it is of a grey-brown or reddish-brown tinge, sometimes 

 intermixed with blue and yellow. In shell-marl, the chief component 

 is the detritus of shells, blended with a small portion of earthy matter. 

 All these varieties of genuine marl agree in effervescing with acids 

 the best test for examining them, sinking in water, crackling in fire, 

 like salt, and undergoing pulverisation on exposure to the atmosphere. 



The best season for applying marl to land is in autumn and early 

 winter, thus affording opportunity for the lumps to be shattered by 



