Ancient China has a diverse geographical landscape: only about 10 percent was arable, or available to farm. The north is mountainous, and the middle is high desert. The eastern part, where most people lived and was flush with rivers, was where food was farmed.
This eastern part of China has two very different landscapes: the north and the south. The North China Plain is high and arid, and the south is quite rainy. However, both of these areas were flush with rivers, such as the Yellow River and the Yangtze River. These different terrains along with usable water sources made it possible to produce a varied food supply.
In the north, grains like millet and wheat were grown. "...the earliest known noodles, which are 4000 years old and were reported by a Chinese team in 2005, were made of millet." (Sciencemag.org) According to a recent report from NPR, "It played a pivotal role in the rise of multi-crop agriculture and settled farming societies."