Study on biomass crust preparation to restore vegetation in drifting sand regions in Minqin

A new kind of crust preparation, which was composed of biopolymer materials and mineral materials, could promote vegetation recovery of moving dunes in Minqin Country, Gansu Province. Minqin County is surrounded by the Tengger and Badain Jaran desert on the East, West and North sides. The average annual rainfall is 113 mm, while the evaporation is up to 2 646 mm, so Minqin Country belongs to the extremely arid continental climate zone. Area of desert and desertification land is up to 1.5× 107 hm2, which is 94.5% of the Minqin land area. The rest, only 5.5%, is the sole oasis area of Minqin Country. The length of the oasis edge is 408km. Minqin Country is a typical agricultural county in sandy areas. The experiment site was located at the frontier of a moving sand area. Crust preparation and seeds of Artemisia scoparia were used in this experiment. Crust preparation (applying for a patent) contained attapulgite, plaster, cellulose, lignin etc. First, the seeds was sown on the surface of a moving dune with a density of 1 000-2 000/m2. Second, the crust components were mixed with sand (crust preparations: sand (V/V)=3:1), and the mixture sprinkled evenly on the sand surface with a shovel. The thickness of the mixture was about 10 mm. Then water was sprayed onto the sand surface to form a crust. The dosage of water was about 2.5 L/m2. Finally, the test area was fenced to prevent access by human and animals. No more manual conservation was implemented later. The thickness of the crust was about 10mm, and its bearing strength was 1-2 kg/cm2 (varied according to the thickness of the crust) after two days. Controlled trials were set in the adjacent moving dune. All the materials and operations were the same, but without the crust preparation. The area of the control trials was approximately 2 200 m2. The project was carried out from August 8-10, 2009. About 10 days after construction, a large number of grass seeds germinated in the crust area, up to 1000 / m2. Compared to the control area plant species, the richness and diversity indices were higher in the crust area. Because plants in the crust area germinated earlier in spring and withered later in autumn than in the control area, they had a longer growing season. In the crust area, many plants could grow and survived through the dry season. In September of the following year, the coverage of the dunes' vegetation was up to 38%. These results indicated that this crust preparation method may have potential value in vegetation restoration in the cold and arid regions.