LOESS PLATEAU

WadeGiles romanization Huang-t'u Kao-yan, Pinyin Huangtu Gaoyuan, highland area in north-central China, covering much of Shansi, north Honan, Shensi, and east Kansu provinces and the middle part of the Huang Ho (Yellow River) basin. Averaging 3,300 feet (1,000 m) in elevation and covering 154,000 square miles (400,000 square km), it is the world's largest loess plateau. The region is overlain by a mantle of fine-grained, wind-deposited, yellowish alluvium known as loess, which is also carried in suspension by the Huang Ho. The loess layers average 165260 feet (5080 m) in thickness and mask the detailed relief of the underlying surfaces. The loess is highly subject to erosion owing to sparse vegetation, heavy concentrations of rainfall in summer, and gullying. There have been government programs to control the denudation by planting trees and terracing on an extensive scale to permit better agricultural use of the land. Grain is the major crop on the plateau.