CH. iv] Distribution of Crops 65 



seed crops that need not fully ripen such as oats, for 

 root crops like mangolds, swedes or potatoes, or for leaf 

 crops like the cabbage tribe. Wet regions are commonly 

 devoted to grass. 



Fig. 17 shows the distribution of rainfall in England 

 and Wales: Fig. 18 shows the distribution of wheat and 

 Fig. 19 that of grass. It will be observed that wheat- 

 growing tends to concentrate in the drier eastern parts 

 of England and grass-growing in the moister west and 

 north. 



The factors that determine the regional distribution 

 of crops operate everyAvhere and many illustrations 

 of their action may be found within very restricted 

 areas. 



Land lying at the bottom of a slope is moister than 

 land lying higher up, because it receives the water that 

 has drained down from above as well as its own share 

 of the rainfall. Sometimes it is so wet that it forms a 

 marsh unsuited for cultivation and therefore left in 

 grass; the land immediately above is then commonly 

 used for general crops. But where the water level is well 

 below the surface of the soil the bottom land is not 

 marshj'- but is on the contrary highly fertile and is more 

 regularly supplied with water than the higher land. 

 Land at the top of a slope may be too exposed or too 

 cold for cultivation, and often if it lies above 700 ft. in 

 England it is left either as grass, wood or waste; the 

 limit is higher in places, e.g., the milder parts of Wales, 

 Cornwall, the Yorksliire Wolds, etc. 



The following is the typical sequence in travelling up 

 a valley or a slope in England. If the bottom is marshy, 

 grass only is grown there ; if it is dry, good crops of roots, 

 cereals or other plants can be obtained ; higher up arable 



K. s. 6 



