Irrational land use is the major force of the severe soil erosion and loss occurred in the Loess Plateau.Taking Majiagou catchment in Ansai county as an example

the characteristics and trends of land use/cover change were analyzed based on the first national land use survey maps in 1990(obtained from the Bureau of Landuse Survery of Ansai County)and the 2008land use map(mapped by field survey).In Arc-GIS

two types of land use maps were overlaid and the dynamic changes were analyzed.The results show that

from 1990to 2008

farmland and grassland decreased by 11.88%and 1.58% of the total area of the catchment

respectively.At the same time

forest

orchard and residential lands increased by 11.61%

1.73%and 0.01%of the catchment area

respectively.The areal ratio of farmland

forest and grassland was changed from 3:1:6to 2:2:6during this period.The major transferring patterns among the land use system are grassland to forest

farmland to grassland

farmland to forest

and farm-land to orchard.Forest

orchard and farmland have relatively high changing rates of 8.06%

2.41%

-2.43%

respectively.Although the forestry area has increased over the past20years

it remains as an artificial ecosystem with the nature of instability and non-sustainability.The deployment of the national policy of“Grain for Green”since 1999and the substitution of farmers'operating strategies can be contributed to the increase of forest and orchard areas in the studied region.