不同喷洒浓度沙蒿胶固沙效果试验

为了探究沙蒿胶的固沙效果,采用不同质量分数(0、0.02%、0.05%、0.10%、0.20%和0.50%)的沙蒿胶喷洒试验,对固沙试样的固结层厚度、抗压强度、抗风蚀能力、团聚体水稳定性、渗透性、保水性和沙蒿胶对植物种子萌发及幼苗生长的影响进行测定。结果表明:1)喷洒沙蒿胶后,固沙试样的固结层厚度和抗压强度显著增加,抗风蚀能力明显增强,质量分数0.10%的沙蒿胶处理,其起沙风速均在20 m/s以上;2)沙粒在沙蒿胶的作用下相互胶结,微团聚体质量百分数显著降低,大团聚体百分数显著增加;3)团聚体平均质量直径显著增加,表明沙蒿胶提高了沙样的水稳定性;4)沙面形成的固结层具有良好的渗透性,利于水分的入渗,沙蒿胶良好的吸水性和保水性,能够促进虫实(Corispermum puberulum)和沙蒿(Artemisia sphaerocephala Krasch.)2种固沙先锋植物种子的萌发及幼苗的生长。可见,沙蒿胶具有良好的固沙效果,且固沙成本低,可以作为一种环境友好型固沙剂,与生物固沙结合用于治沙,沙蒿胶喷洒质量分数以0.20%为宜。研究可为沙蒿胶的固沙应用提供理论依据。

Sand fixation experiment of Artemisia sphaerocephala Krasch. gum with different concentrations

Desertification is a global environmental problem, bringing considerable economic, social and environmental problems to the local residents. A sand-fixing agent,Artemisia sphaerocephalaKrasch. gum (ASKG), was introduced in this study to effectively control wind erosion. The ASKG was extracted from seed coat of perennial semi-shrub ofArtemisia sphaerocephalaKrasch. and mainly composed of glucose, galactose, mannose, rhamnose, arabinose and xylose. In order to understand the effect of ASKG on sand fixation, an experiment by spraying different concentrations (0,0.02%, 0.05%, 0.10%, 0.20% and 0.50%) of ASKG on the sand surface was carried out. The crusts thickness, compressive strength, resistance to wind erosion, aggregate water stability, permeability and water retention and the effects of ASKG on plant seed germination and seedling growth were tested. When the ASKG was applied on the sand surface, the crust was formed in surface layer. The sand specimens treated with 0.02%, 0.05%, 0.10%, 0.20% and 0.50% ASKG had produced the crusts with thickness being approximately 1.06, 1.31, 2.24, 2.95, and 4.30 mm and the compressive strength being around 0.10, 0.16, 0.20, 0.38, and 0.72 MPa, respectively. It indicated that the ASKG could remarkably increase the crusts thickness and compressive strength. The ability of anti-erosion was improved greatly with increasing concentration of ASKG. The sand specimens could withstand a strong wind of 20 m/s without wind erosion when the concentration was more than 0.10%. The mass fraction of micro-aggregates decreased and that of large aggregates increased because the sand specimens bonded together under the influence of ASKG. With the concentration of ASKG increased from 0 to 0.50%, the mean weight diameter of soil aggregates ranged from 0.21 to 0.52 mm in fast wetting, 0.20 to 0.73 mm in slow wetting, and 0.20 to 0.51 mm in wetting stirring, respectively. It suggested that the ASKG could notably enhance the soil aggregate water stability. The initial infiltration rate and steady infiltration rate of sand specimens treated with ASKG were 5.78-5.98 mm/min and 4.51-4.77 mm/min, respectively, and there was no significant (P>0.05) difference compared with no ASKG adding treatment with 6.13 and 4.72 mm/min, respectively. The ASKG had excellent water absorption and retention, and could promote the seed germination and seedling growth of the two pioneer sand-fixing plants (Corispermum puberulum andArtemisia sphaerocephala Krasch.). In addition, spraying ASKG on sand by the amount of 3 L/m2, the cost was 0.10-0.45 RMB per square meter. If the expense of labor was taken into consideration, the cost could be controlled to about 0.40-0.90 RMB per square meter. The results indicated that the ASKG as a kind of sand-fixing agent has the characteristics of better sand-fixing, lower cost, and environment-friendly, and can be used to desertification control with vegetation. The effect was optimal with the concentration of 0.20%. This study provides valuable information for ASKG sand-fixation application.