Experimental Research On The Sand-fixing Effect Of The Joint Of Artemisia Sphaerocephala Krasch. Gum And Microalgae

China is one of the most severely damaged countries in the world.Land desertification is not only a serious threat to ecological security,but also a serious constraint to the sustainable development of social economy.The governance of desertification is imminent and it is urgent to intensify the prevention and control of land desertification.The current domestic and foreign research on sand fixation is mainly limited to a single sand fixation,whose performance is not ideal.As a single form of sand fixation measures cann’t meet the needs of sand control,it is imperative to look for an efficient and economical way.This paper studies the effect of sand fixation of microalgae combined with Artemisia sphaerocephala krasch.Gum(ASKG).Microalgae are widely distributed and widely known as "pioneer".In order to obtain enough algae,the first experiment of the paper is to recovery cultivate Microcoleus vaginatus Gom.and Scytonema javanicum and expand them,and then different concentrations(10mg/L、20mg/L and 30mg/L)of microalgae mixed solution of the volume ratio of 4:1 are prepared for subsequent test.Secondly,an operation spraying successively and evenly different volume ratios(10:0,9:1,7:3,3:7,1:9,0:10)of different concentrations(0.05%,0.10%,0.20%)of ASKG and different concentrations(0.05%,0.10%,0.20%)of microalgae mixed solution on the sand tray is done.After the formation of biological crust(or consolidation layer),the optimal concentration combination of ASKG and microalgae solution is determined by measuring the biomass which is expressed as the concentration of chlorophyll a and the compressive strength of the biological crust.Thirdly,through the sand tray erosion experiment,the starting wind and wind erosion rate at different winds(10m/s、15m/s and 20m/s)of different volume ratio(10: 0,9: 1,7: 3,5: 5,3: 7,1: 9 and 0:10)under the optimal combination are measured to determine the optimal volume ratio under the optimal combination.Finally,the effect of the mixed solution on the germination time,germination rate and seedling height of Festuca sinensis Keng is observed,and the optimal ratio of the combined sand-fixation effect was further verified.(1)When the resistance to wind erosion of the mass fraction of 0.10% of ASKG and the concentration of 20mg/L microalgae solution in accordance with the different volume ratio is determined,it is found than the starting wind speed increases first and then decreases,and the difference of the wind erosion rates at 10m/s and 15m/s is significant,but keep a low level,the wind erosion rate 20m/s shows a tendency to decrease first and then increase,along with the volume ratio 10: 0,9 : 1: 7: 3,5: 5,3: 7,1: 9 and 0: 10.(2)When ASKG and microalgae are used in sand-fixation,the volume ratio of 3:7 of ASKG and the microalgae solution concentration of 20 mg/L is considered to be the optimal proportion.(3)Comparing the seeds sprayed the ASKG(0.10%)alone,there is a significant difference of less than 0.05% in the germination rate and seeding height sprayed the optimal mixed solution.Comparing the seeds sprayed the microalgae(20mg/L)alone,the germination rate and seeding height sprayed the optimal mixed solution show the opposite trend.