On the loess plateau every little piece of land is being used for farming, usually to the edge of slopes. Jingchuan River is located more or less at the geographical center of China. Part of the ancient Silk Road follows its course. Two thousand years ago the loess plateau in this region was still relatively intact, and Jingchuan River flowed relatively clear. Then, there was an obvious difference in the degrees of muddiness as Jingchuan River merged with Weihe River which was already very muddy. Instead of using the phrase "as clear-cut as black and white," Chinese two millennia ago would say "as distinct as Jing and Wei." This phrase is preserved to the present and still used regularly even though one river is just as muddy as the other nowadays.

In Jingchuan, Gansu, the top of the plateau retains a small piece of flat ground, called tableland or platform land, as indicated by the top edge of the slopes. It is not large enough to support an ever expanding population, and the surrounding slopes are terraced for cultivation. In the second picture the background slopes are cultivated while the foreground slopes are dug with ditches for planting trees.

Picture source: George Leung (1999)