8 VOELCKEK an the Scouring Lands 



a deeper surface-soil resting on a more porous subsoil ; and in the 

 other a less deep soil, with a stiff, impervious subsoil. It is quite 

 a mistake to think that drainage necessarily improves every soil 

 in a high degree. It does so in the great majority of soils. But 

 at the same time we cannot shut our eyes to the fact, that 

 whilst drainage often improves one field greatly and another 

 much less, instances are not wanting in which the benefits 

 resulting from draining are scarcely appreciable. Some people 

 evidently think that drainage is a talisman which converts every 

 unproductive soil into .a fertile one. But a little consideration 

 will show that the radical changes which draining usually pro- 

 duces in the agricultural capabilities of land cannot take place in 

 every instance, and that the general character of scouring land is, 

 in many cases, not affected by drainage. 



Let us look for a moment at two pastures of a similar character 

 in their natural, undrained condition. Both are wet, equally un- 

 productive, and to all appearance there is no difference in the two 

 fields ; probably both scour. But we will suppose that in one field 

 we have only 2 or 3 inches of surface-soil, and, -under it, say 3 or 

 4 feet or more of tenacious lias-clay, whilst in the other the same 

 clay subsoil lies at a depth of 18 inches, or still more remote from 

 the surface. Though perfectly equal in their undrained condition, 

 the greatest difference must be produced in the character of two 

 such fields after draining ; for with the removal of the surface- 

 water in the one field only 2 or 3 inches of soil are improved, and 

 in the other 18 inches or more. We can without difficulty take 

 away the surface-water equally well from both fields, but we cannot 

 in an equal degree change their general character. If scouring 

 were caused by an excessive quantity of water in pasture-land, 

 drainage would remove the evil in every instance ; but as the 

 scouring effects of herbage are most perceptible during dry 

 weather, it follows that the mere presence of surface-water in a 

 field does not account for its scouring properties. 



As drainage produces radical changes in the condition of some 

 soils, and as such changes cannot take place in soils in which 

 a thick impervious clay-bed comes close to the surface, we can 

 understand why drainage cures scouring land in one place and 

 not in another. 



I am unacquainted with a solitary instance in which scour- 

 ing land rests on a porous subsoil, but I know many fields in 

 scouring districts where a deep tenacious blue clay subsoil 

 comes very near to the surface. Wherever this is the case, 

 drainage, I am of opinion, will not remedy the evil ; and in par- 

 ticular cases I can understand that it may even aggravate it. 

 But should newly reclaimed peat-land or clay-soils, in which the 



