7Q The soil and the plant 



low — e.g. the northern parts of England— than in the 

 eastern counties where the rainfall is low. 



The difference in water supply, therefore, leads us to 

 expect the following differences between sandy soils and 

 clays or loams : — 



On sandy soils (the water content being small) the 

 wild plants and trees usually have small leaves. Culti- 

 vated plants do not give very heavy crops, but they 

 ripen early. 



On clay soils (the water content being good) wild 

 plants and trees usually have larger leaves. Cultivated 

 plants give good crops, but they ripen rather late. If 

 the water content is too good or the clay is too sticky 

 the land is generally put into grass. 



Plants require to be sufficiently warm. Some like 

 tropical heat and can only be grown in hot houses; 

 others can withstand a certain amount of cold and will 

 grow up on the mountains. Our common cultivated 

 crops come in between and will not grow in too cold or 

 exposed a situation ; thus you find very little cultivated 

 land 800 ft. above sea level, and not usually much above 

 500 ft. At this height it is left as grass land, and higher 

 up as woodland, moor, or waste land. Grass requires less 

 warmth and can therefore grow at greater heights than 

 many other crops. If you start at the top of a hill in 

 Derbyshire, and walk down, you will see that the top is 

 moorland, lower down comes grass land, still lower you 

 may find arable land, and if the valley is damp you will 

 find more grass at the bottom. Figs. 37 and 38 show 

 typical views of the hill slopes further south : they are 

 taken near Harpenden. The top of the hill in each case 

 is over 400 ft. above sea level, and has never been 

 thought worth cultivating, but has always been left as 



