Afforestation was one of most successful measures to rehabilitate desertified lands and to improve regional eco-environments in the Horqin Sand Land. A field experiment was conducted during 2005 and 2006 in the Horqin Sand Land to investigate the effects of Populus simoniiplantation growth on soilcrust formation and topsoilproperties. The results showed that plantation establishment promoted the development of biologicalsoilcrust and improved properties of topsoil 0–5 cm under the crust in sand dunes. As the plantation aged, soilcrust developed gradually from a physical crust, to a lichen crust and then to a moss crust and crust coverage, thickness, hardness, very fine sand content, clay, silt, organic carbon and nutrients increased significantly. Clay, silt, organic carbon and nutrients in topsoil 0–2.5 cm and 2.5–5.0 cm under the soilcrust increased with plantation age and crustdevelopment, but the magnitude of changes decreased with increasing soil depth. Changes in soil physical and chemical properties in the crust had a significant positive correlation with plantation age, and changes in physical and chemical properties in the 0–5.0 cm layer of topsoil had a significant positive correlation with soilcrustdevelopment and plantation age. Soilcrustdevelopment and changes in topsoilproperties under the soilcrust can be attributed primarily to the reestablishment of vegetation and the duration that the vegetation is in place.

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