生物质结皮制剂在民勤流动沙区恢复植被的作用

利用矿物质材料和生物高分子材料的环境友好和吸湿保水的特性制作形成结皮,对立地条件极端恶劣的流动沙丘进行植被恢复.首先将草籽(黄蒿籽)撒播于目的沙丘表面,然后将与砂土混匀的结皮制剂均匀地撒在沙地表面,最后,洒木质素液使结皮凝固并用围栏封育试验区.通过调查结皮制剂施用后沙丘植物的种类、覆盖度、生长状况等植被恢复指标,分析了生物质结皮制剂在流动沙区植被恢复的效果.研究结果表明:结皮封育区内大量草籽萌发,达1000颗/m2;结皮区植物物种丰富度为13,对照区仅为2,物种多样性和均匀度指数也高于对照区,分别为1.57(Shannon-Weaver index H)、0.41(Simpson index D)和0.81(Pielou index),对照区则分别为0.47、0.40和0.68;结皮区植物生长期较对照延长,2010年早春提前10 d萌发,深秋枯黄延迟约20 d;结皮区植物在干旱季节亦可生长存活;2010年9月,结皮区沙丘植被盖度可达38%,对照区植被盖度仅为4%.研究结果表明该制剂可能在寒区旱区困难立地条件下的植被恢复工作中具有较大的潜在应用价值.

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.