In the Dynasty of The Xia the westerners were involved in nomadic herding while the Southerners( Shaanxi ) were involved in agriculture. This was due to the size of the dynasty and its inexorability to economic unification. The Xia were the first dynasty to irrigate ( thanks to rulers Li Jiqian and Li Deming ). These rulers both aided in irrigation in order to develop agriculture in arid areas. As a crop, China was involved with/produced grain. This grain was then kept in the imperial granaries. Majority of the Chinese/ Xia population were peasants.
http://china.hm68.com/xia.php?cid=1
http://china.hm68.com/xia.php?cid=1