. . .roduction is comparatively high. Such systems of intensive culture prevail in the more densely populated countries, but the bulk of the world’s wheat supply is grown in thinly populated countries, where the methods of cultivation are extensive. Wheat is sown year after year on the same land, no manure is used, and tillage is reduced to a minimum. This style of cultivation gradually exhausts the fertility of the richest virgin soil, and its cropping capacity falls off. As soon as the crop falls below a certain level it ceases to be profitable. No doubt the fertility of the exhausted soil could be restored by suitable cultivation and manuring, but it is usually the custom to move towards districts which are still unsettled, and to take up more virgin soil. Thus the centre of the area of wheat production in the States has moved nearly 700 miles westward in the last 50 years. 15

CHAPTER II
MARKETING

In the last chapter we have followed the growi. . .