| Desertification is one of the main ecological environment problems in the world,it will bring to the huge losses for the social economic benefits and has a serious threat to human survival and sustainable development.Due to the destruction of the ecological environment,China is one of the most serious countries suffering from land desertification disaster in the world.Therefore,it has important theoretical and practical significance to research the new type of the sand-fixation material to prevent and control desertification.Biological soil crusts are organic complexes composed mainly of bacteria,fungi,algae,lichens,mosses,other cryptogams and surface soil,its existence and development has important value to the improvement of the desertification environment.It can improve the capability of soil antierosion,maintain the soil moisture,improve the soil nutrient and create favorable conditions for the recovery of vegetation in desertification area,so it has the important field in desert research,it is highly valued by scholars in home and abroad.Because of the special physical and chemical properties of attapulgite,it had been widely applied in many fields.As attapulgite was modified by acid,there were a lot of active hydroxyl on its surface,it could add different polymer by graft modification and form polymer with certain functional groups.So attapulgite had new performance,it made attapulgite have better water absorption and water retention.Due to wide range of temperature fluctuations of dersert area,the survival rate of simple biological soil crusts fell under dry environment conditions,it affected the sand-fixation effects.When biological soil crusts were mixed sand-fixation polymer material based on attapulgite at different mass ratio,under different environmental conditions,whether it could product a new sand-fixation material,which had no secondary pollution to the environment and was more nutritional sand-fixation material.Therefore,this study intended to use artificial biological soil crusts,functionalization of attapulgite and polymer to determine its biological activity and reproduction ability under different environmental conditions,to explore the optimition of the augmented matrix and control conditions of biological soil crusts by experiment,to determine the optimized polymerization conditions of the functionalization of attapulgite and polymer material.According to the above results,to prepare biological sand-fixation polymer material based on attapulgite with reproduction ability and activity.The main research contents were as followed:To use 5 different culture solutions(MS,Knop,Beneck,BG11 and BBM),cyanobacterial soil crusts and moss soil crusts were cultured 15 days in light incubator.The cell death,damage,the number of pollution and pollution degree were observed by light microscope.Finally,the culture solution of cyanobacterial soil crusts was BBM,and the culture solution of moss soil crusts was MS.To obtain a better culture conditions and the optimum environmental factors for cyanobacterial soil crusts,effects of different time,light intensities(40 ?E·m-2·s-1,120 ?E·m-2·s-1 and 240 ?E·m-2·s-1)and temperatures(15?,20?,25?,30? and 35?)on content of chlorophyll a,content of MDA,soluble protein content and soluble sugar content of cyanobacterial soil crusts were studied under laboratory conditions.The results showed that the optimum environmental factors for the growth of cyanobacterial soil crusts were the temperature 25? and the light intensity 120 ?E·m-2·s-1,under the environmental conditions,cyanobacterial soil crusts could grow fast and had minimum environmental stresses.To obtain a better culture conditions and the optimum environmental factors for moss soil crusts,effects of different time,light intensities(40 ?E·m-2·s-1,120 ?E·.m-2·s-1 and 240 ?E·m-2·s-1)and temperatures(15?,20?,25?,30? and 35?)on content of chlorophyll a,content of MDA,soluble protein content and soluble sugar content of moss soil crusts were studied under laboratory conditions.The results showed that the optimum environmental factors for the growth of moss soil crusts were the temperature 30? and the light intensity 120 ?E·m-2·s-1,under the environmental conditions,moss soil crusts could grow fast and had minimum environmental stresses.Attapulgite was treated by H2SO4(1 mol·L-1,2 mol·L-1,3 mol·L-1,4 mol·L-1,5 mol·L-1 and 6 mol·L-1),water absorption,water retention,the change of p H value,XRD and SEM analysis were studied,the results showed that the attapulgite modified by 4 mol·L-1 H2SO4 had the better water absorption and water retention,the change of the p H value had a better influence on water absorption of attapulgite modified by 4 mol·L-1 H2SO4,the results of XRD and SEM showed that attapulgite modified by 3 mol·L-1and 4 mol·L-1 H2SO4 had better adsorption performance.Sand-fixation polymer material based on attapulgite was treated by H2SO4(1 mol·L-1,2 mol·L-1,3 mol·L-1,4 mol·L-1,5 mol·L-1 and 6 mol·L-1),water absorption,water retention,the changes of p H value,XRD and SEM analysis were studied,the results showed that sand-fixation polymer material based on attapulgite,which was modified by 4 mol·L-1 H2SO4,had the better water absorption and water retention,the changes of the p H value had a better influence on water absorption,the results of XRD and SEM showed that sand-fixation polymer material based on attapulgite,which was modified by 3 mol·L-1 and 4 mol·L-1 H2SO4,had better adsorption performance.The biological activity of cyanobacterial soil crusts was studied after cyanobacterial soil crusts were mixed sand-fixation polymer material based on attapulgite at different mass ratio,under certain conditions of temperature and light conditions,the results showed that the optimal ratio of cyanobacterial soil crusts and sand-fixation polymer material based on attapulgite which was modified by 4 mol·L-1 H2SO4 was 3:1 and the state of growth was better.Content of chlorophyll a,content of MDA,soluble protein content and soluble sugar content were analyzed and the amount sprayed was 400 g·m-2 and 500 g·m-2,the results showed that physical properties was good and the amount sprayed was 500 g·m-2,which cyanobacterial soil crusts mixed with sand-fixation polymer material based on attapulgite that was modified by 4 mol·L-1 H2SO4.The biological activity of moss soil crusts was studied after moss soil crusts was mixed sand-fixation polymer material based on attapulgite at different mass ratio,under certain conditions of temperature and light conditions,the results showed that the optimal ratio of moss soil crusts and sand-fixation polymer material based on attapulgite which was modified by 4 mol·L-1 H2SO4 was 1:4 and the state of growth was better.Content of chlorophyll a,content of MDA,soluble protein content and soluble sugar content were analyzed and the amount sprayed was 400 g·m-2 and 500 g·m-2,the results showed that physical properties was good and the amount sprayed was 500 g·m-2,which moss soil crusts mixed with sand-fixation polymer material based on attapulgite that was modified by 4 mol·L-1 H2SO4.By the results of the experiment,the study was to find out a set of optimized preparation method of biological sand-fixation polymer material based on attapulgite,to prepare a new type of cyanobacterial soil crusts and moss soil crusts of biological sand-fixation polymer material based on attapulgite with reproduction ability and activity.And preparation of raw material was abundant,cheap and easy,it had very wide popularization and application prospects. |
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