To this point, our discussion has focused on social and cultural changes, but what of changes to the land? In the deep historical past, before China's landscape was radically altered by the hand of man, the North presented the flat but forested horizons of the Central Plain. Beyond the Taihang Mountains that mark the western edge of the Plain lay the broken landscape of the river basins that cut the friable soils called loess. Rainfall across the North is irregular, although in ancient times evidence suggests it was more plentiful than today. Nevertheless, although the soils are fertile and easy to till, the rivers and other water sources could dry up, as they do today. Without irrigation, agriculture is unreliable for crops are likely to wither and die.

In contrast, the South was a land of mountains and forests, riven by valleys marked by free-flowing rivers. Rainfall is abundant, the rivers are broad and the landscape is dotted with lakes, large and small. There was a wide and abundant diversity of plant and animal life: snakes and fish, deer, birds and mammals big and small, even tigers, rhinoceros and elephants. Liu Zongyuan wrote from his exile in the deepest South that the world around him was filled with unfamiliar noises and scents. It was a world that Liu and his colleagues feared. To many, however, the South was both exotic and seductive, so much so that phlegmatic northerners worried that it could captivate and corrupt the unwary, turn them away from the stern moral values on which northern culture was based, and convert them into hedonistic barbarians. As the late eighth-century poet Bao He wrote to a friend about going South as an official:

For those willing to bear its challenges, this was a land filled with opportunity. The verdant bottomlands and coastal plains had rich soils that beckoned to be tilled. Its exotic products: fruits such as oranges, bananas, lychee and longyan, medicinals such as rhino horn and elephant tusk, and exotic meats and herbs, found ready markets in the cities of the North. But it was also filled with dangers, both real and imaginary.