436 CORRESPONDING SOCIETIES. 



grazing is restricted to summer or winter ; whether tlie land is suitable 

 for breeding ; whether it is commonly used for all animals. In the 

 South-Eastern Counties grassland on the chalk and on the sand is healthy ; 

 though it will not easily fatten animals it is suitable for breeding purposes- 

 and particularly for sheep. But there is the important technical differ- 

 ence, which has many consequences, that the chalk grass is suitable for 

 summer grazing, while the sandy soil grass is suitable only for winter 

 grazing. Marsh land presents a third case ; it is suitable only for summer 

 grazing, and it generally fattens animals. It is wet, however, and 

 encourages certain parasites, liver flukes, and the organisms causing foot 

 rot. These distinctions have far-reaching effects which, however, come 

 more appropriately into an agricultural than into a regional survey. 



The best method of subdividing the arable land is according to the 

 length and character of its rotation. The commonest rotation has four 

 courses : two of corn, one of roots or green crops, and one of rotation 

 grass or clover as shown by the following statistics for England and Wales 

 (1915-1924) :— 



Total area of arable land . . . .11.5 million acres 



Total corn 5.7 (=50%) 



Total roots and other green crops . . 3.4 (=29%) 



Rotation grass and clover . . . 2.4 (=21%) 



But the rotation is modified in many places. In the fertile parts of 

 Lincolnshire, especially the Holland Division, it ig shortened to three 

 courses, the roots being mainly potatoes ; in the chalk districts it is often 

 lengthened to five courses by putting in an additional corn crop, or to six 

 or more courses, two of which are green crops fed to sheep on the land. In 

 the north and west the period in grass is lengthened. The records should 

 show what the corn crops are and whether they are sown in winter or in 

 spring, and the map should show the chief crops. Oats are commonly 

 grown all over the country, occupying about half of the total corn land : 

 we produce about 85 per cent, of what the nation consumes. The fact 

 that an area is marked as arable land almost implies that one of its corn 

 crops is oats ; their absence would certainly need recording on the map. 

 Wheat and barley are more symptomatic. Wheat is in such severe 

 competition with the great continental plains of Canada, the United 

 States, Australia, South America, and Eastern Europe, that it survives 

 only in particularly favourable conditions. It is sown in late autumn, 

 and therefore is not grown in the north where the winters are too severe 

 or in the north-west where they are too wet ; it needs a steady supply of 

 moisture at its roots, and therefore is grown on heavy soils or on such of 

 the lighter soils as are well supplied with moisture. It does not ripen well 

 in wet weather, and therefore is grown only where the summer rainfall is 

 normally low. All these conditions are connoted by the presence of wheat 

 as an important crop. Barley, on the other hand, is usually spring sown ; 

 it is therefore unaffected by the winter weather and is found in the coldest 

 parts of the country. It is commonly found on the lighter soils and it 

 tolerates shallower soil conditions. There are advantages about wheat 

 and barley that induce farmers to grow them ; if they cannot do so success- 

 fully they grow oats in both breaks. 



Of the main root crops, swedes and turnips are the commonest, and are 



