THE SOIL OF THE FARM. 403 



son why " rest " restores land, and a clear difference between the active 

 and the as yet dormant constituents of a soil. 



TKNACITY. A degree of tenacity is essential to a soil Where it does 

 not exist in sufficient strength, the entire mass is liable to be gradually 

 blown away. On the other hand, too great a tenacity causes a soil to be 

 expensive and critical to cultivate, and unfits it for the growth of turnips, 

 mangel, and other crops suitable for the winter feeding of stock. The 

 tenacity of a soil is due to the presence of clay. 



SLOPE OR INCLINATION. The slope of land is well known to influence 



its productive power, and that in more than one way. Slope to a great 



nt controls the drainage of water, and this alone must be allowed to 



be of first importance. It also admits of a greater or less intensity of 



light and heat upon a given area of the surface. 



1 1 is from this cause that the north side of valleys, or those which enjoy 

 a sunny or southern slope, are the most productive. It is upon such slopes 

 that the finest wine is grown. 



COLOUR. Even colour influences the fertility of a soil, although to only 

 a sli-_dit d.-_rree. A white soil, like white cloth, snow, or any pther white 

 substance, throws off the heat. On the other hand, dark-coloured sub- 

 stances absorb it. 



A familiar illustration of this is seen in the fact that snow immediately 

 underlying a piece of black cloth soon melts, while the surrounding 

 \v, protected by its own whiteness, remains unaffected at the same 

 erature. 



-MIL. A soil may be well stocked with plant food, and be of good 



physical character, but before it can be productive it must be provided 



with a pruj i.- il. The reason of this is obvious, for upon the subsoil 



the drainage of the surface soiL A tenacious clay subsoil is hv 



idered bad, but it will generally ivijuiiv to be thor- 



ily drained by artificial means before the superficial soil ran grow 



ndant rrnj-. A light sandy or gravelly subsoil sennvs tin- natural 



Ira'. face, but is likely to it to burn h in 



r. The eH'.-rt of a POCky subsoil upmi the cult i\ at ed Mir- 



he nature of tie- rock. A fissured dry rock lib 

 o dry a soil, while a cool porous stone, like that of the 

 its an opjM.dt-- eil'rct. A rocky sui 



argues a thin 1 a low standard of fertility. 



term Subsoil ma, 1 bO exprett the stratum which underlies 



.il earths ; its depth beneath the 



and in this case we mi- k of a soil six feet thick underlaid by 



