The land use changes and its relationship with topographic factors in the Jing river catchment on the Loess Plateau of China.

A series of soil conservation measures have been carried out to reduce soil loss on the Loess Plateau of China since 1950s, and the biologic measures were implemented according to topographic factors such as slope and elevation; therefore, the changes in topographic factors of land use can indicate the effects of the biologic measures. The objectives of this study were to (i) analyze the land use changes in the Jing River catchment during 1986-2000 and to (ii) examine the effects of biologic measures through relating land use changes with topographic factors. During 1986-2000, the dominant land use types were farmland and grassland (88% of the whole catchment). Compared with 1986, farmland and forest decreased while grassland and construction land increased with little changes in water and unused land. Three main conversion types occurred, i.e. the mutual conversion between forest and grassland, the mutual conversion between farmland and grassland, and farmland converted to other types. The elevation of farmland, forest, construction land and water increased, while that of grassland and unused land decreased. The mean slope gradient of each land use type changed little except for unused land. The above results suggested farmland has greatly decreased on tableland region due to the increase in construction land, forest has moved to gully region while grassland has increased despite elevation and slope. The land use in the Jing River catchment during 1986-2000 was changing to a more reasonable spatial pattern.