Effectiveness of sand-fixing measures on desert land restoration in Kerqin Sandy Land, northern China

摘要

In the semi-arid Kerqin Sandy Land of north China, land desertification and frequent sand storms in the spring strongly affect the growth of grassland vegetation and crops, and give rise to large reductions in yield as a result of wind erosion and sand dune movement. To bring desertification under control and reduce its influence on grassland and farmlands, many measures have been developed and implemented for stabilizing mobile sand dunes and restoring desertified grasslands. This study was conducted from 1996 to 2003 to evaluate the effectiveness of desert land restoration after implementation of sand-fixing measures. The results showed that construction of straw checkerboards and planting of shrub seedlings significantly enhances topsoil development on the dune surface, increasing silt and clay content and facilitating accumulation of soil carbon and total N, as well as accelerating an increase in plant diversity, vegetation cover and plant density. These findings suggest that using straw checkerboards and planting shrubs are successful methods for mobile sand dune stabilization and desertified grassland restoration in semiarid regions. The mechanism creating these changes is a reduction in wind erosion and improvement of the soil environment for plants. In addition, our results showed that construction of straw checkerboards was slightly more effective in vegetation and soil restoration in comparison with planting shrub seedlings, especially at the primary stage.