Sustainability of reclaimed desertified land in Ningxia, China

Desertification is a severe environmental problem in north-central China, where deserts are expanding at an estimated rate of 2100 km(2) year(-1). The Chinese government approved plans to control 6.66 million ha of desertified land in 10 years. Techniques used include planting of trees, shrubs and grasses; land enclosure; irrigation; extraction of buried soils; and stabilization of dunes with straw checkerboards. These efforts are co-ordinated by the Institute of Desert Research of Academia Sinica (IDRAS). Some of the pioneering work was carried out at Shapotou and Yanchi Research Stations in Ningxia Autonomous Region. Community action is one of the cornerstones of reclamation. In 1978 the Chinese government initiated the Shelterbelt Development Program to form a 'Green Great Wall' of 35 million ha of trees stretching 700 km across northern China. Ar Shapotou, sand dunes irrigated with silt-laden water have developed 30 cm of minero-organic topsoil in 25 years. Using a chronosequence of these reclaimed soils, chemical analysis showed progressive increases in nutrients. These reclaimed areas produce high yields of cereals, vegetables, grapes and deciduous fruits. Use of straw checkerboards and planting of indigenous shrubs have established a stabilized ecosystem on mobile dunes of the Tengger Desert. In the Shabianzi Region 74 families in a resettlement project have worked collectively on sand stabilization and steppe reclamation. Farmers levelled dunes and manually excavated buried soils. A chronosequence of land reclaimed and cultivated between 1983 and 1991 showed sustainable increases in soil nutrients. Soil fertility in these reclaimed desertified lands is sustainable but places high demands on resources. These and other examples show what is achievable, but, unfortunately, desertification rates exceed reclamation rates. (C)1998 Academic Press Limited.