This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
In the first place the lowlands as compared with the highlands are far more easy to cultivate. For in the plains the surface is more level, and ploughing and kindred operations are less arduous, though the slopes of many uplands, as on the chalk, are often given up to cereals. But on the chalk as on other hilly tracts the soil, owing to denudation, rain wash, etc, is very shallow, and the ground becomes more and more stony the more it is tilled. Hence the lowlands offer better conditions, for almost universally they possess a deep soil.
Another and very important reason is that the lowlands as a rule are more closely connected with the main systems of railway, canals, etc, and transit is easier.
Another reason is the better drainage of the lowlands. River systems form a natural drainage for the plains, and artificial drainage also is more readily applied, being impossible in the uplands, save for the natural fall of the surface waters by gravity, its distribution and direction being difficult on hill slopes, as the occurrence of springs shows. In valleys, too, there is a natural alluvium, and the river gravels, which are especially suited to light and early crops, are made use of by the agriculturist who knows the local geology.