Chinese History and Statistics -- Page 8
Chang Jiang Lowland
The third low-elevation sub-region is the southeastern upland, which occupies all of eastern China south of the Chang Jiang lowland and consists mostly of low mountains. The Guangzhou (Canton) plain is the largest lowland in the southeastern upland.
China's most productive soils for agriculture are alluvial soils, chernozems, and brown and chestnut-brown soils. The alluvial soils are found mainly in the lowlands of the North China plain, the Chang Jiang valley and delta, the Guangzhou plain, and most other flood-prone valleys. They are well-suited to rice and wheat cultivation. The small chernozem belt is located mainly in the northern area of the Manchurian plain and along the southern border of Inner Mongolia. Chernozems are fertile, black soils that are rich in humus and plant nutrients and excellent for grain cultivation. Somewhat less productive agriculturally are brown and chestnut-brown soils, which are found on the drier margins of the chernozem zone. Although they are moderately fertile, especially when irrigated, these soils are used mainly for pasture owing to the limited rainfall areas where they occur. Where developed on loess (as in Shanxi, Shaanxi, and Henan provinces), the brown soils are fertile, but they are also subject to heavy erosion.
Less productive agriculturally are podzols and gray-brown forest soils and gray desert, saline, and lateritic soils. The podzols and gray-brown forest soils develop in temperate climates under forests; they are associated with coniferous forests in northeastern Manchuria, the Qin Ling Mountains, and other central uplands. The gray desert soils, low in humus, are formed in semiarid regions and occur widely in Inner Mongolia and Xinjiang. They are used mainly as pasturage. Saline soils are found both in the inland desert basins and along the seacoasts. After removal of the salt, the maritime saline soils are fertile for cotton or rice cultivation. The lateritic red and yellow soils in the subtropical areas of southern China are used for growing rice, tea, and mulberry trees.