IQ SOILS. 



soaked and afterwards dried, it hardens and cakes into a solid 

 mass, and if quickly brought from a wet to a dry condition it 

 approaches the state of bricks previous to their being burned. 

 Thirdly, when exposed to heat it shrinks and looses consider- 

 able in bulk. Fourthly, it powerfully retards putrefaction by 

 enclosing, as in a case, animal and vegetable remains, by shut- 

 ting out the dissolvent action of the external air. 



Clay soils are tilled with difficulty when too dry, and when 

 too wet this operation has Ihe same effect as the tempering of 

 clay has in the art of making bricks. The tillage of such lands 

 in a proper state, is therefore of the greatest importance; and 

 this is best performed when they are neither too wet nor too 

 dry. They require to fertilize them, a larger proportion of 

 manures than the freer soils; but they retain the effects of the 

 manures for a much longer time. They are better suited to 

 the cultivation of plants with fibrous than with fleshy roots or 

 tubers. Hence it is that wheat, beans, oats, clover, cabbage, 

 grass, &c., do well on clayey soils. 



Clays, like the other soils, approach to their most perfect 

 condition as they advance to that state which is termed loam. 

 The effect of judicious tillage and of the application of manures, 

 is to improve the texture of such soils as well as to enrich them. 

 Thus, clays in the neighbourhood of cities become dark in their 

 colour and less cohesive in their texture, from the mixture of 

 animal and vegetable matter, and thence acquire the properties 

 of the most valued soils of their class. The value of a clayey 

 soil depends essentially on its having an open sub-soil, which 

 renders it more tractable and productive.* 



Clayey soils need only to be properly managed to become 

 the most perfectly fertile and productive of any. It is recom- 

 mended to mix with the soil such substances, mineral and vege- 

 table, as will separate, loosen and mellow it; and to loosen the 

 sub-soil either by the use of the sub-stratum plough,! or other- 

 wise, to a sufficient depth to let the surplus water readily pass 

 beloio the roots of the plants. The proper substances for this 

 purpose are vegetable matter, as straw, rushes, even small 

 bushes, saw-dust, animal manures, sand, anthracite coal ashes, 

 and where the soil does not contain lime, that may be most 

 advantageously applied. Clay, until its very adhesive proper- 

 ties are corrected, is an unpleasant soil to cultivate, especially 

 for hoed crops; and for those which are cultivated solely with 

 the plough, more skill, as well as more labour is requisite for 

 preparing the ground for the proper reception of the seed. 



Where earths have been rendered as dry as they can be by 



* Sir John Sinclair's Code of Agriculture, 

 t See chapter on Agricultural Implements. 



