Sustainable development of the society and economy has inevitably been restricted in the region,so that the de farming and afforestation in the steep cropland become far more significant for the development of the society and economy there.

The inevitability and significance of forbidden cuttivate for restoring forest or grass are discussed in this paper.

Assessing benefits of the conversion of cropland to forest and grassland project in the mountain area of southern Ningxia;

Study on the models of conversion of cropland to forest and grassland in dry hot and arid river valley subregions & hilly ravine subregions of loess plateau.;

The Study on Returning Cultivated Land to Forestland or Grassland and Adjustment of Agriculture Structure;

As an important support to ecological construction in the north transitional agro_pasture area, returning cultivated land to forestland or grassland has exited some problems inevitably.

Application of decision support system based on GIS for returning farmland to forestland or grassland in the loess hill semi-arid region;

The Project of Returning farmland to forestland or grassland is one of important content of western exploitation of China.