AGRICULTURE 91 



The warp area in the southern part of the country and along the banks 

 of the Derwent, Ouse, and Humber contains perhaps the most fertile 

 soil in Yorkshire. Except on the oldest warps, liming is not necessary, 

 and with the new warp several good crops may be obtained without 

 manuring. Along the banks of the Derwent and the Ouse, and especially 

 of the Don, flooding causes serious damage periodically, the land being 

 only 10 to 20 ft. above sea-level. 



In the northern half of the Vale of York, boulder clay and glacial sand 

 and gravels form the chief soils. The sandy soils are very deficient in 

 lime, and until soil sourness is corrected, cropping is confined to oats, rye, 

 and potatoes. When lime is applied, however, it is possible to grow good 

 samples of barley of high malting quality. Good crops of sugar-beet also 

 are possible under these conditions, but the area under this crop is com- 

 paratively small. In these soils, as in the sandy soils south of York, iron 

 pans are common. These pans have developed under forest conditions 

 and occur in hard layers 2 or 3 inches thick at a depth of a foot or 18 inches 

 below the surface. 



The boulder clay of this area is reddish-brown in colour, and although 

 it contains material originating in Scotland and Cumberland, the biggest 

 proportion is of Triassic origin, and has probably been churned up by the 

 glacier from the solid rock beneath. This soil does not contain a very 

 high percentage of the clay fraction, and is amenable to cultivation. It is 

 also fairly well supplied with lime, and is therefore suitable for most crops. 



The mechanical analysis table following illustrates the wide variation 

 in physical composition shown by the soils in the Vale of York : 



Mechanical Analysis of Some Soils in the Vale of York 



(1928 Method).^ 



Key to Soils. 



1 = Glacial sand soil (Thirsk). 



2 = Boulder clay soil (Thirsk). 



3 = Boulder clay soil (Wheldrake). 



4 = Post-Glacial sand (Wheldrake). 



(Nos. 3 and 4 occur in adjacent fields.) 



5 = New warp (artificial). 



6 = Old natural warp. 



1 " Introduction to the Scientific Study of the Soil," 2nd edition, p. 152 

 (N.M. Comber). 



