THE SOIL OF THE FARM. 405 



is a good combination, as such soils are naturally drained. Here also 

 mixing the surface soil and subsoil may be attended with good effects. 



SUBSOILS WHICH KXKUT AX iNJi'iimrs KFFECT ON THE SURFACE SOIL. 

 All "pans" from whatever cause are injurious and require to be 

 broken up. Open gravelly, or rubbly subsoils are apt to allow fertiliz- 

 ing matter applied to the land to work through beyond the reach of 

 the roots of plants. They are also liable to suffer from drought in hot 



->ns. Such land should never be manured in the autumn, but as 

 much as possible during the period of active vegetation. 



A rocky subsoil is usually objectionable, as preventing deep cultivation, 

 and facilitating the escape of moisture too rapidly. Soils resting on the 

 rock seldom carry heavy crops, but they are well adapted for sheep, and 

 are usually farmed with a view to folding sheep in winter in temperate 

 climates, and for growing barley. 



5. CLASSIFICATION OF SOILS. 



Sinking for a time the important consideration of chemical composition, 

 the relative fertility of soils is largely due to the proportion in which the 

 already described proximate constituents are combined. It is upon this 

 principle that agriculturists classify soils, speaking of them as argillace- 

 ous, silicious, calcareous, or vegetable, according to the predominance of 

 one or other of these substances. 



The following classification was proposed nearly forty years ago by 



il.ler, and may be adopted as giving a method of distinguishing the 



various kinds of land. The terms usually employed by farmers in de- 



ini: diti'.'ivnt soils are numerous, but unfortunately either local in 



tin ii .significance, or the same term is made to convey a verv different 



iin-4 in districts remote from each other. 



Sehuhl'-r followed tin- method adopted by naturalists in dividing soils 

 bto classes, Orders, >p.-ci-s, and varieties. He recognised eight da- 



: 'in'matin-; el.-m.-nt of e;ieh. 



be argillaceous or clay eroup, containing always above .">0 per 

 cent, of clay real or 90 call.- 1, for ch.-mieally pure clay has siii' 

 found to !>* mueli less, than I.y this ehrmi-t. 



Thi 1 int. clays without lime, and clays with from "> 



:. of lime ; and these Wete airaiu divided int.* poor, inter- 

 and rich. Hen.-.- tlp-iv W&tG iv> IVwer than Ul sorts of argilla- 

 ceous soils : ntermediate, and rich, with but little or no lim- -. and 



A ith a hi^lnT p'-n-entaire of lime. 



