Desertification land ecological restoration method based on algae-moss composite biological soil crust

Abstract

The invention provides a desertification land ecological restoration method based on algae-moss composite biological soil crust. The method comprises the steps of algae and moss species screening, algae propagation, moss propagation and algae-moss co-culture, resistance domestication treatment, preparation of an algae-moss composite particle inoculant, soil preparation and microtopography optimization, field application of the algae-moss composite particle inoculant and maintenance after inoculation. According to the invention, the crust forming speed and structural stability can be obviously improved, the wind erosion resistance, water retention and nutrient fixation capabilities are enhanced, and long-term stable ecological restoration of the desertification land is realized.

Description

Technical Field

[0001] This invention belongs to the field of ecological restoration and desertification control technology, specifically involving a method for ecological restoration of desertified land based on algae-moss composite biological soil crust. Background Technology

[0002] Desertification and land degradation are serious ecological problems that are prevalent in arid and semi-arid regions around the world. Under natural conditions, biocrusts (or 'biocrusts' for short) are widely developed on the surface of desert and semi-desert soils. They are formed by the cementation of various organisms such as cyanobacteria, green algae, fungi, lichens, and mosses with soil particles and have multiple ecological functions, including sand fixation, water retention, nutrient fixation, and promotion of higher plant colonization.

[0003] Existing technologies include those that utilize cyanobacteria or microalgae inoculation to construct primary biological soil crusts, as well as those that use moss propagation and spraying or paving to stabilize engineering surfaces and localized desert surfaces. These technologies share the following characteristics: 1) Focusing on a single algae or a single moss group, it lacks simulation of the "multi-component synergistic succession" characteristics of natural crust formation; 2) In typical desert environments characterized by extreme drought, high temperature and strong light, and strong winds and sandstorms, the crusts formed by inoculation of a single group often have limited resistance and are prone to structural breakage and functional decline. 3) The inoculation materials are mostly loose algae mud or moss fragments, which are difficult to transport and store. The efficiency of mechanized sowing is limited, and the wind resistance and operability of construction need to be improved.

[0004] Mosses, as typical surface "tidal water plants," possess significant dehydration-rehydration capabilities and a mechanical reinforcement effect on sandy substrates. Cyanobacteria and other microalgae, on the other hand, exhibit rapid colonization, extracellular polysaccharide secretion, and nitrogen fixation capabilities, which can improve soil aggregate structure and surface nutrient conditions. If algae and mosses can be artificially propagated in a synergistic manner and prepared into granular inoculants through adaptive domestication and encapsulation granulation processes, it is expected that ecological functions, stress resistance, and engineering construction efficiency can be simultaneously achieved.

[0005] However, no publicly available literature or patent system has yet disclosed a solution for ecological restoration of desertified land that uses bryophyte species screening as the main method, combined with algae mixed propagation, to form algae-bryophyte composite biomass on artificial substrates. Furthermore, resistance domestication is carried out through methods such as alternating wet and dry conditions, light and temperature gradients, and osmotic pressure gradients. Then, natural polymer binders are used for encapsulation and granulation to obtain granular inoculants suitable for automated mechanical sowing. This solution is accompanied by an integrated technology for ecological restoration of desertified land that includes land preparation, water management, and disturbance control.

[0006] Therefore, it is necessary to provide an algae-moss composite biological soil crust granule inoculant and its application method to improve the crust formation rate and structural stability, enhance wind erosion resistance and water retention capacity, thereby achieving automated and large-scale long-term stable ecological restoration of desertified land. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an ecological restoration method for desertified land based on algae-moss composite biological soil crust, which can significantly improve the formation rate and structural stability of the crust, enhance the ability to resist wind erosion, retain water and fix nutrients, and achieve long-term stable ecological restoration of desertified land.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for ecological restoration of desertified land based on algae-moss composite biological soil crust, the method being as follows: S1. Screening of algae and mosses: S101. Algae Isolation and Screening: Natural crust samples were collected from the target desertification area and similar ecological zone. After being crushed, the samples were inoculated onto the surface of a sponge moistened with BG11 liquid medium. After cultivation, the resulting green filamentous algal colonies were further cultured and their stress resistance was evaluated. Dominant desert algal species were selected as algal inoculum sources. S102. Moss Isolation and Screening: Moss plant samples were collected from the target desertification area and similar ecological zone. After natural air drying, the samples were cut into pieces and sieved to obtain moss fragments. These fragments were then spread on the surface of a sponge soaked in Knop medium and covered with a layer of cellulose paper. After cultivation, moss plants were obtained, and their stress resistance was evaluated. Dominant desert moss species were selected as moss inoculum sources. S2, Algal Proliferation: The algal inoculum obtained in S101 was used to propagate algae on the surface of a sponge moistened with BG11 liquid culture medium to obtain algal mud. S3, moss propagation and algae-moss co-culture: S301, Propagation of Mosses: After the bryophyte inoculum obtained in S102 is air-dried, cut into pieces, and sieved, the resulting bryophyte fragments are propagated on the surface of cellulose paper impregnated with the matrix until the bryophyte coverage reaches more than 60%, and bryophyte bodies are obtained on the matrix surface; the matrix is ​​a mixture of BG11 liquid medium and Knop medium. S302, Algae-Moss Co-culture: The algal mud obtained in S2 is diluted with water to obtain an inoculation solution. The inoculation solution is sprayed onto the moss on the surface of the substrate in S301 for algae-moss co-culture until the biomass coverage reaches more than 80% to obtain an algae-moss-substrate complex. S4. Resistance acclimatization treatment: The algae-bush-matrix complex obtained in S302 was subjected to resistance acclimation treatment to obtain the acclimated algae-bush-matrix complex. The specific acclimation method is as follows: S401, Precipitation Pulse Simulation: After drying the algae-moss-matrix composite obtained in S302 at a relative humidity of 45%±5% for 72 hours, deionized water was sprayed onto the dried algae-moss-matrix composite for replenishment. The drying and replenishment operation was repeated 3 times to simulate intermittent precipitation pulses in desert areas. S402, Temperature and Illumination Gradient: When performing the cycled drying and water replenishment operations in S401, the temperature and light gradient are set as follows: S40201: First cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 23℃±2℃, and photosynthetically active radiation 200µE·m. -2 ·s -1 ~400µE·m -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40202: Second cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 400µE·m. -2 ·s -1 ~1000µE·m -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40203: 3rd cycle: The light treatment and dark treatment were performed alternately. The conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 1800±2000µE·m. -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S403, Nutrient restriction and osmotic regulation substance addition: Starting from the first cycle described in S40201, the mixture of BG11 liquid medium and Knop medium obtained in S302 is no longer added to the algae-moss-matrix complex for nutrient restriction; during the water replenishment operation in the precipitation pulse simulation described in S401, a final concentration of 1 g·L⁻¹ is added to the water. -1 NaCl and a final concentration of 1 g·L -1Trehalose is used to regulate osmotic pressure and salinity tolerance. S5. Preparation of algae-moss composite particle inoculant: S501. Treatment of domesticated algae-moss complexes: The domesticated algae-moss-matrix complex obtained in S4 was pre-dried in a cool and ventilated place until the moisture content was <5%, and then sheared and crushed to obtain algae-moss complex fragments. S502, wet mixing and granulation: After mixing the algae-moss composite fragments obtained in S501 with the auxiliary materials, a mixture is obtained. Then, a binder solution is added until the water content of the mixture is 35%±5% to obtain a wet mixture. After granulation, shaped granules are obtained. The auxiliary material is a mixture of soybean fiber powder, activated carbon powder, ascorbic acid powder and sand; S503. Drying and Sieving: After the shaped particles obtained in S502 are air-dried, they are sieved to retain particles with a particle size of 1 mm to 5 mm, thus obtaining algae-moss composite particle inoculant. S6. Land preparation and micro-topography optimization: The target area is prepared by creating a depression array on the surface soil and setting up sand barriers to obtain a target area with optimized micro-topography. S7. Field application of algae-moss composite granular inoculant: The algae-moss composite particle inoculant obtained in S503 was applied to the target area with optimized micro-topography obtained in S6 to obtain the target area after inoculation. S8. Post-vaccination maintenance: Days 1-2 post-inoculation: The target areas obtained from S7 inoculation were sprayed with water in a mist once daily in the early morning and evening, with a spray volume of 1.5 kg / m² each time. -2 ; Days 3-8 post-inoculation: Every two days, on days 5 and 8 post-inoculation, the target area obtained from S7 was sprayed with a mist of water once, with a spray volume of 1 kg·m³ each time. -2 ; Days 9–21 post-inoculation: Spray water in a mist every 3–5 days, with a spray volume of 0.5 kg·m³ each time. -2 ; Days 22–60 post-vaccination: No regular rehydration is required. In cases of extreme drought or high temperatures, local rehydration may be necessary.

[0009] Preferably, the conditions for culturing the naturally crusted sample described in S101 on the surface of a melamine sponge soaked in BG11 liquid medium are: photosynthetically active radiation of 80 µE·m. -2 ·s -1The temperature was 25℃, the relative humidity was 70%, and the incubation time was 3 days. The conditions for culturing the green filamentous algae colonies on the agar medium were: photosynthetically active radiation of 100 µE·m. -2 ·s -1 The temperature is 25℃±5℃, and the culture time is 5 days; the number of species of algae inoculation source is not less than 2.

[0010] Preferably, the mesh size of the sieve in S102 is 40 mesh; the cultivation conditions are: photosynthetically active radiation of 100 µE·m -2 ·s -1 The temperature is 25℃±5℃, the relative humidity is 80%±10%, the culture time is 14 days, and water is sprayed every 2 to 3 days during the culture period; the number of species of algae inoculation source is not less than one.

[0011] Preferably, the methods for evaluating stress resistance described in S101 and S102 include rehydration recovery tests and stress tests.

[0012] Preferably, the method for algae propagation in S2 is as follows: first, the algae inoculum is inoculated onto the surface of a sponge moistened with BG11 liquid culture medium, and then, under photosynthetically active radiation of 100 µE·m... -2 ·s -1 The algae were cultured for 14 days at a temperature of 27℃±1℃, a relative humidity of 65%±5%, and a shaking speed of 100 r / min to obtain an algal solution. This algal solution was then sprayed onto the surface of a nylon filter membrane impregnated with BG11 and cultured under conditions of 200 µE·m² photosynthetically active radiation. -2 ·s -1 The algae were cultured for 14 days at a temperature of 22℃±2℃ and a relative humidity of 65%±5% to obtain algae mud.

[0013] Preferably, the method for propagating mosses in S301 is as follows: a layer of nylon nonwoven fabric is laid at the bottom of a plastic tray, followed by a layer of cellulose paper, which is then moistened with a substrate. The moss fragments are then evenly spread on the surface of the substrate-moistened cellulose paper. This process is carried out under conditions where the photosynthetically active radiation is 100 µE·m⁻. 2 ·s⁻ 1 The culture was carried out for 30 days at a temperature of 22℃±3℃ and a relative humidity of 60%±5%, with water replenishment during the culture period; the substrate was a mixture of BG11 liquid medium and Knop medium in a volume ratio of 1:1.

[0014] Preferably, the mass ratio of algae sludge to water in the inoculum in S302 is 1:20, and the total inoculum volume is 100 mL / tray; the algae-moss co-culture method in S302 is as follows: under photosynthetically active radiation of 200 µE·m -2 ·s -1The cells were cultured for 20 days at a temperature of 23℃±3℃ and a relative humidity of 65%±5%, with water replenishment during the culture period; the amount of water replenished in S401 each time was 2 mm of precipitation / m. 2 Matrix.

[0015] Preferably, the wet mixture in S502 is composed of the following raw materials in mass fractions: 20% soybean fiber powder, 15% activated carbon powder, 0.1% ascorbic acid powder, 0.7% sand, and the balance being algae-moss composite fragments; the binder solution in S502 is composed of the following raw materials in mass fractions: 1% sodium alginate, 1% gum arabic, and the balance being water; the particle size of the molded particles in S502 is 2.0 mm to 3.0 mm.

[0016] Preferably, the air-drying conditions in S503 are: temperature of 30℃±5℃ and relative humidity of 50%±10%; the water content of the algae-moss composite particle inoculant is ≤5%.

[0017] Preferably, the application rate of the algae-moss composite granular inoculant in step S7 is 5 g / m². 2 .

[0018] Compared with the prior art, the present invention has the following advantages: 1. The purpose of this invention is to overcome the problems of low survival rate, insufficient stress resistance, easily broken crust structure, and difficulty in achieving high-efficiency construction in existing single algae or single moss crust technologies for desertification land restoration. This invention constructs an algae-moss composite biological soil crust through moss species screening and algae propagation; resistance acclimation is carried out during the propagation process; algae-moss composite granular inoculant is obtained by encapsulation with a binder; and an ecological restoration method combining land preparation and micro-topography optimization, field application, and post-inoculation maintenance is employed. This method can significantly improve the crust formation rate and structural stability, enhance wind erosion resistance, water retention, and nutrient fixation capabilities, and achieve long-term stable ecological restoration of desertified land.

[0019] 2. In this invention, algae-moss synergy improves the speed and stability of crust formation.

[0020] Algae possess rapid colonization and extracellular polysaccharide secretion capabilities, enabling them to form primary cementation structures and improve surface nutrient status in a short period. Mosses exhibit superior mechanical reinforcement and dehydration-rehydration abilities, making them suitable as a medium- to long-term stable structural framework. This invention, through the co-cultivation and resistance acclimation of algae and mosses on an artificial substrate, allows them to synergistically construct a stable and multifunctional biocrust after field application. This invention achieves the synergistic construction of the spatial structure and function of algae and mosses during the propagation stage. The rapid coverage and extracellular polysaccharide secretion of algae provide a microenvironment for mosses, while the moss structural framework, in turn, stabilizes the algal layer. Therefore, after field application, it not only rapidly fills degenerated patches but also quickly forms a mature and stable biocrust.

[0021] 3. This invention employs multi-factor progressive resistance acclimatization, which significantly improves the survival rate and stability under extreme environments.

[0022] This invention employs a multi-factor combined acclimatization scheme involving alternating wet and dry conditions, temperature gradients, light gradients, nutrient restriction, and the addition of osmotic regulators. This allows algae-moss complexes to pre-adapt to the combined stress environment of desert conditions characterized by severe drought, intense radiation, and nutrient deficiency under artificial conditions. Compared to techniques that involve direct transplantation after cultivation under conventional conditions, the inoculum prepared by this invention exhibits higher survival rates, photosynthetic recovery capacity, and structural stability in the field.

[0023] 4. The granular encapsulation morphology of the present invention is suitable for engineering and mechanized application. By adding excipients and binder solutions to encapsulate algae-moss composite fragments, a granular inoculum with controllable particle size was prepared. On one hand, it provides skeletal support, bonding reinforcement, and a partial nutrient source; on the other hand, after drying, it forms a three-dimensional network structure, significantly improving the mechanical strength and wind resistance of the particles, avoiding the significant loss during transportation, spreading, and early wind erosion of traditional bulk algae mud or moss fragments. Upon reaching the target surface, the particles absorb water and swell under suitable humidity conditions, allowing algae and moss to expand and colonize from the particle surface into the surrounding substrate, achieving efficient spreading and targeted release.

[0024] 5. This invention is adaptable to various desertified land types, has high construction efficiency, wide applicability, and is easy to operate and promote in the long term.

[0025] The granular inoculant of this invention is flexible in form and offers diverse application methods. It can be adapted to various types of desertified land by adjusting granule size, application rate, and land preparation methods, demonstrating its potential for widespread application. For different desertified surfaces such as mobile dunes and semi-fixed sand dunes, land preparation measures such as porous / strip microstructure construction and small sand barrier installation are proposed, along with manual, mechanical, or drone-based application methods for the granular inoculant, combined with clearly defined application rates and phased water management curves. This allows the technology to be used for both small-scale, precise operations and large-scale, rapid construction using machinery and drones, with controllable water consumption, making it particularly suitable for engineering applications in arid regions with scarce water resources. Furthermore, in the inoculant preparation process, this invention prioritizes the use of algae and mosses themselves and their propagation substrates as the main active ingredients, with sodium alginate and gum arabic as effective components—natural polymer binders—and soybean fiber powder, activated carbon powder, ascorbic acid powder, and sand as auxiliary materials. This avoids the introduction of large amounts of recalcitrant or potentially toxic chemicals, ensuring good ecological safety.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1This refers to the biocrust coverage of desertified land after one year, according to Embodiment 1 and Comparative Examples 1-5 of the present invention.

[0028] Figure 2 The average thickness of the biological crust after one year is the desertification land ecological restoration method of Example 1 and Comparative Examples 1-5 of the present invention.

[0029] Figure 3 This refers to the maximum water holding capacity of the topsoil after one year, as per Embodiment 1 and Comparative Examples 1-5 of the present invention for the ecological restoration of desertified land.

[0030] Figure 4 This refers to the topsoil organic matter content one year after the implementation of the desertification land ecological restoration method of Embodiment 1 and Comparative Examples 1-5 of the present invention.

[0031] Figure 5 This refers to the weight loss rate of the desertified land ecological restoration method of Embodiment 1 and Comparative Examples 1-5 of the present invention after one year of standing for 20 minutes at a wind speed of 20 m / s. Detailed Implementation

[0032] Example 1 The sample collection in this embodiment is as follows: Biological crusts and bryophytes were collected from the distribution area of ​​biological crusts in the Gurbantünggüt Desert, placed in sterile bags, and transported to the laboratory at 4°C.

[0033] The BG11 liquid culture medium used in this embodiment was purchased commercially from Qingdao Haibo Biotechnology Co., Ltd.; the Knop culture medium was purchased commercially from Guangdong Zhongshan Baiwei Microbial Technology Co., Ltd.

[0034] The desertification land ecological restoration method based on algae-moss composite biological soil crust in this embodiment is as follows: S1. Screening of algae and mosses: S101. Algae Isolation and Screening: In the target desertification area and similar ecological zone, specifically the biocrust distribution area of ​​the Gurbantünggüt Desert in this embodiment, natural crust (biocrust) samples were collected, crushed, and inoculated onto the surface of a sponge moistened with BG11 liquid culture medium (the surface was completely moistened but without liquid accumulation). After cultivation, the resulting green filamentous algal colonies were further cultured and their stress resistance was evaluated. Dominant desert algal species were selected as algal inoculum sources. The conditions for culturing the naturally crusted samples on the surface of melamine sponges soaked in BG11 liquid medium were: photosynthetically active radiation of 80 µE·m. -2 ·s -1The temperature was 25℃, the relative humidity was 70%, and the incubation time was 3 days. The conditions for culturing the green filamentous algae colonies on the agar medium were: photosynthetically active radiation of 100 µE·m. -2 ·s -1 The temperature was 25℃±5℃, and the culture time was 5 days; the number of algal inoculum species was not less than 2; the algal inoculum in this embodiment was: Microcoleinae (denoted as A1) and Pseudobranchia javanica (denoted as A2). S102. Moss Isolation and Screening: In the target desertification area and similar ecological zone, specifically the biocrust distribution area of ​​the Gurbantünggüt Desert in this embodiment, bryophyte samples were collected, air-dried, and then chopped and passed through a 40-mesh sieve to obtain bryophyte fragments. These fragments were then spread on the surface of a sponge soaked in Knop medium and covered with a layer of cellulose paper to prevent sample movement. After cultivation, bryophyte plants were obtained, and their stress resistance was evaluated. Dominant desert bryophyte species were selected as bryophyte inoculum sources. The cultivation conditions were: photosynthetically active radiation of 100 µE·m -2 ·s -1 The temperature was 25℃±5℃, the relative humidity was 80%±10%, and the culture time was 14 days. During the culture period, water was sprayed every 2 to 3 days to keep the substrate moist for a long time without water accumulation. The number of algal inoculum species was not less than one. In this example, the algal inoculum was *Bryophytum esculentum* (denoted as B). The methods for evaluating stress resistance described in S101 and S102 include rehydration recovery tests and stress tests, and the specific methods are as follows: Different algal strains and bryophyte plants were collected and subjected to rehydration recovery and multifactor stress tests in small trays: Rehydration test: First, the algae and moss samples were dried to an air-dry state, and then completely soaked in deionized water. The moss unfolding time and the color recovery of the algae were recorded. The chlorophyll fluorescence parameters were measured at 0 h, 4 h and 24 h. Multifactor stress experiment: Dried algae and moss samples were subjected to a temperature of 37±3℃ and photosynthetically active radiation of 1000±200µE·m. -2 ·s -1 The algae were treated for 7 days under the specified conditions, and after rehydration, the survival rate and chlorophyll fluorescence recovery rate were measured. Algal strains were cultured on BG11 medium and BG11 medium supplemented with 50 mM NaCl; bryophyte plants were cultured on Knop medium and Knop medium supplemented with 50 mM NaCl, and their growth status was observed. The results showed that Micrococcus gracilis, which has the ability to rapidly form crust structures, and Pseudobranchia javanica, which has nitrogen-fixing ability, are resistant and can therefore be used as algal inoculum sources; Rhizophora dentata can rapidly restore photosynthesis after rehydration and has excellent stress resistance, and therefore can be used as a moss inoculum source. S2, Algal Proliferation: The algal inoculum obtained in S101 was used to propagate algae on the surface of a sponge moistened with BG11 liquid culture medium to obtain algal mud. The method for algal propagation is as follows: First, the algal inoculum is inoculated onto the surface of a sponge moistened with BG11 liquid culture medium, under a photosynthetically active radiation of 100 µE·m. -2 ·s -1 The algae were cultured for 14 days at a temperature of 27℃±1℃, a relative humidity of 65%±5%, and a shaking speed of 100 r / min to obtain an algal solution. This algal solution was then sprayed onto the surface of a nylon filter membrane impregnated with BG11 and cultured under conditions of 200 µE·m² photosynthetically active radiation. -2 ·s -1 High-biomass algal sludge was obtained by culturing the algae for 14 days at a temperature of 22℃±2℃ and a relative humidity of 65%±5%. S3, moss propagation and algae-moss co-culture: S301, Propagation of Mosses: After the moss inoculum (algal strains A1 and A2) obtained in S102 is air-dried, cut into pieces, and sieved, the resulting moss fragments are propagated on the surface of cellulose paper that has been soaked in the matrix until the moss coverage reaches more than 60% to form a continuous moss layer, and moss bodies are obtained on the surface of the matrix. The method for propagating mosses is as follows: a layer of nylon non-woven fabric is laid at the bottom of a plastic tray, followed by a layer of cellulose paper. This is then moistened with a substrate, and the moss fragments are then distributed at a rate of 5 g / m³. 2 The mixture was evenly spread on the surface of cellulose paper moistened by the matrix, under photosynthetically active radiation of 100 µE·m. -2 ·s -1 The cellulose paper and the material beneath it were cultured for 30 days at a temperature of 22℃±3℃ and a relative humidity of 60%±5%. Water was added during the culture period by adding water to the substrate and spraying water onto the moss to keep the cellulose paper and the material beneath it moist. The substrate was a mixture of BG11 liquid medium and Knop medium in a volume ratio of 1:1. S302, Algae-Moss Co-culture: After diluting the algal mud obtained in S2 with water, an inoculation solution was obtained. The inoculation solution was sprayed onto the moss on the surface of the substrate in S301 at a total volume of 100 mL / tray for algae-moss co-culture. It was observed that a tight algae-moss-substrate complex with algae adhering and moss interspersed was formed on the substrate surface until the biomass coverage reached more than 80%. In this embodiment, the biomass coverage reached 98%, and an algae-moss-substrate complex was obtained. The mass ratio of algae sludge to water in the inoculum is 1:20; the algae-moss co-culture method is as follows: under photosynthetically active radiation of 200 µE·m -2 ·s -1 The cells were cultured for 20 days at a temperature of 23℃±3℃ and a relative humidity of 65%±5%, with water replenishment during the culture period. S4. Resistance acclimatization treatment: The algae-bush-matrix complex obtained in S302 was subjected to resistance acclimation treatment to obtain the acclimated algae-bush-matrix complex. The specific acclimation method is as follows: S401, Precipitation Pulse Simulation: The algae-moss-matrix composite obtained in S302 was transferred to a controlled environment chamber. Water addition and spraying were stopped, and the substrate in the tray was allowed to dry in situ for 72 hours at a relative humidity of 45% ± 5% until the algae-moss-matrix surface was completely dry. Deionized water was then sprayed onto the dried algae-moss-matrix composite for replenishment, with each replenishment amounting to 2 mm of precipitation / m². 2 The substrate was subjected to the same "72 h drying + 2 mm water replenishment" cycle, which was repeated three times to simulate intermittent precipitation pulses in desert areas. S402, Temperature and Illumination Gradient: When performing the alternating dry and wet process in S401 through the cyclical drying and water replenishment operations, the temperature and light gradient are set as follows: S40201: First cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 23℃±2℃, and photosynthetically active radiation 200µE·m. -2 ·s -1 ~400µE·m- 2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40202: Second cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 400µE·m. -2 ·s - 1~1000µE·m -2 ·s -1The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40203: 3rd cycle: The light treatment and dark treatment were performed alternately. The conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 1800±2000µE·m. -2 ·s -1 The conditions for the dark treatment are: temperature 17℃±3℃, 12h, to enhance resistance to strong light; S403, Nutrient restriction and osmotic regulation substance addition: Starting from the first cycle described in S40201, the mixture of BG11 liquid medium and Knop medium obtained in S302 is no longer added to the algae-moss-matrix complex for nutrient restriction; during the water replenishment operation in the precipitation pulse simulation described in S401, a final concentration of 1 g·L⁻¹ is added to the water. -1 NaCl and a final concentration of 1 g·L -1 Trehalose is used to regulate osmotic pressure and salinity tolerance. At the end of the entire resistance acclimatization treatment, the coverage of the algae-moss-matrix complex in the tray was still above 86%, and the color of the algae and moss turned yellow, but there were no visible large areas of necrotic patches. S5. Preparation of algae-moss composite particle inoculant: S501. Treatment of domesticated algae-moss complexes: The domesticated algae-moss-matrix complex obtained in S4 was pre-dried in a cool and ventilated place until the moisture content was <5%, and then cut and broken into irregular pieces of 1-2 mm to obtain algae-moss complex fragments. S502, wet mixing and granulation: After mixing the algae-moss composite fragments obtained in S501 with the auxiliary materials, a mixture is obtained. Then, a binder solution is added until the water content of the mixture is 35%±5% to obtain a wet mixture. After granulation, shaped particles with a particle size of 2.0mm to 3.0mm are obtained. The auxiliary materials are a mixture of soybean fiber powder (800 mesh), activated carbon powder (3000 mesh), ascorbic acid powder and sand; The wet mixture is composed of the following raw materials in the following mass fractions: 20% soybean fiber powder, 15% activated carbon powder, 0.1% ascorbic acid powder, 0.7% sand, and the remainder is algae-moss composite fragments; the binder solution in S502 is composed of the following raw materials in the following mass fractions: 1% sodium alginate, 1% gum arabic, and the remainder is water; S503. Drying and Sieving: The shaped granules obtained in S502 were air-dried at a temperature of 30℃±5℃ and a relative humidity of 50%±10%, and then sieved to retain granules with a particle size of 1mm to 5mm, resulting in algae-moss composite granule inoculant with a moisture content of ≤5%. Microscopic observation and activity testing showed that the algae and moss inside the granules still had good activity. S6. Land preparation and micro-topography optimization (surface treatment): The target area is prepared by creating a series of depressions in the surface soil and then sand barriers are installed to obtain a micro-topographically optimized target area. The specific method is as follows: A selection was made on the slope of the sand dunes in the Gurbantünggüt Desert, with a total area of ​​approximately 200m². 2 The bare sandy area was used as the test area (shared with Control Examples 1-5). Multiple treatment plots were divided within the test area, each plot measuring 10 m². 2 (Including areas of Control Examples 1-5). In some small sample plots, the sand surface was manually leveled and lightly compacted using a tamping hammer. Subsequently, in other small sample plots, a pressure plate with protrusions (2cm in length, width, and height, spaced 2cm apart) was used to press a perforated array of depressions into the leveled surface to improve surface conditions. In some areas, straw checkerboard sand barriers with a height of 20-30cm were set up to form a perforated-strip-shaped combined microstructure. S7. Field application of algae-moss composite granular inoculant: The algae-moss composite particle inoculant obtained from S503 was used in an environment with a wind speed of less than 4 m / s. -1 During the specified time period, a backpack spreader was used to evenly spread the seeds on a portion of the small sample plots at a rate of 5 g / m². 2 Inoculation was applied to the target area with micro-topography optimization obtained in S6, so that the particles fell as much as possible into the strip-shaped shallow ditches and grass squares to reduce the risk of wind erosion, thus obtaining the target area after inoculation; the blank control area was only prepared and no particles were sown. S8. Post-vaccination maintenance: Days 1-2 post-inoculation: The target areas obtained from S7 inoculation were sprayed with water in a mist once daily in the early morning and evening, with a spray volume of 1.5 kg / m² each time. -2 ; Days 3-8 post-inoculation: Every two days, on days 5 and 8 post-inoculation, the target area obtained from S7 was sprayed with a mist of water once, with a spray volume of 1 kg·m³ each time. -2 ; Days 9–21 post-inoculation: Apply a mist spray of water once every 3–5 days, with each application using a spray volume of 0.5 kg·m³. -2 ; Days 22–60 post-vaccination: No regular rehydration is required; local rehydration is only necessary in cases of extreme drought or high temperatures.

[0035] Compare with Example 1 The desertification land ecological restoration method in this comparative example is the same as that in Example 1, except that no surface treatment is performed (no land preparation or micro-topography optimization is carried out), no inoculant is applied, and only water replenishment maintenance is performed (the same as the water replenishment maintenance in step S8 of Example 1).

[0036] Compare with Example 2 The surface treatment is the same as the land preparation and micro-topography optimization in step S6, without the application of any inoculant, but water replenishment maintenance is performed (same as the water replenishment maintenance in step S8 of Example 1).

[0037] Compare with Example 3 The ecological restoration method for desertified land in this comparative example is as follows: The algae mud obtained in step S2 of Example 1 was diluted with water to prepare an algae inoculation solution (the mass ratio of algae mud to water was 1:20). The solution was sprayed on the target area after micro-topography optimization (the surface treatment method was the same as the land preparation and micro-topography optimization in step S6 of Example 1, and the application method and amount were the same as in step S7 of Example 1). The maintenance after inoculation was the same as in step S8 of Example 1.

[0038] The steps of moss propagation, algae-moss co-culture, resistance acclimatization treatment, and preparation of algae-moss composite particle inoculant using wet mixing granulation, drying and sieving methods, as described in Example 1, are not employed.

[0039] Compare with Example 4 The ecological restoration method for desertified land in this comparative example is as follows: In Example 1, the algae-moss-matrix complex in step S302 is applied directly without resistance cycling and granulation. Instead, the algae-moss-matrix complex in step S302 is crushed and then directly broadcast. The land preparation and micro-topography optimization are the same as in step S6 of Example 1. The application method and amount are the same as in step S7 of Example 1. Post-inoculation maintenance is the same as in step S8 of Example 1.

[0040] The algae-moss-matrix complex in this comparative example was applied directly without resistance domestication or granulation, and did not employ the multi-factor resistance domestication and encapsulation granulation steps of this invention.

[0041] Compare with Example 5 The desertification land ecological restoration method in this comparative example is the same as that in Example 1, except that there is no surface treatment in this comparative example (i.e., no land preparation and micro-topography optimization in step S6 of Example 1).

[0042] For Example 1 and Control Examples 1-5, the recovery of biocrust in each small plot was monitored at 1, 3, 5 and 12 months after application. The main indicators included: biocrust coverage (grid method), maximum crust thickness (measured by excavating samples), maximum water holding capacity of surface soil (saturated drying method), organic matter content (burning method), and wind erosion resistance (calculated based on the mass loss of the wind erosion box).

[0043] Monitoring results showed that Example 1 formed a bio-soil crust with significantly higher continuity than the control within 5 months. After 1 year, the crust coverage reached 70% to 90%, with a thickness of 1 mm to 3 mm. The wind erosion mass loss was significantly lower than that of the control. The maximum water holding capacity and organic matter content of the soil were significantly higher than those of the control, and there was a clearly visible and extensive bryophyte cover.

[0044] In control plots 1 and 2, almost no biocrusts formed after one year (coverage ≤10%), and no moss plants were visible.

[0045] In Control Example 3, after the application of the inoculant: In the first two months, a thin layer of algal film was visible in localized areas, but it was significantly affected by wind erosion and dryness, and the film easily detached in flakes; from the third to the sixth month, the overall surface was still mainly bare sand, with algae concentrated in shallow gullies and depressions, exhibiting poor continuity; by the twelfth month, although some natural crusts had sporadically developed, the overall crust coverage and thickness were significantly lower than in Example 3, and no moss plants were clearly visible. Compared to the algae-moss composite particle inoculant treatment in Example 1, this algae-only spraying control example was significantly inferior in terms of crust formation speed, crust structure stability, and wind erosion resistance, and no moss plant coverage was formed, verifying that algae inoculation alone is insufficient to form a long-term stable biological crust in harsh desert environments.

[0046] For Example 4, one month after application, some moss fragments germinated in shallow trenches and depressions. However, due to the lack of artificial substrate and binder support, a large number of fragments were displaced by wind or buried by sand. Algae were also concentrated in localized moist micro-sites. From the 3rd to the 6th month, thin algal-moss crust patches could form in small areas, but the spatial distribution was uneven, the overall continuity was poor, and the crust thickness was thin, making it easily destroyed in wind erosion tests. By the 12th month, although some local crust patches had expanded, the overall crust coverage was significantly lower than in Example 1, and the surface structure was loose. In summary, the simple algal-moss mixed sowing method, which did not undergo propagation and co-cultivation on an artificial substrate, multi-factor resistance acclimatization, or granular encapsulation, is unlikely to form a continuous, dense, and stable biological soil crust in desert environments with strong wind erosion and large fluctuations in moisture levels. Its recovery effect is significantly inferior to that of the embodiments of the present invention.

[0047] In Comparative Example 5, during the first two months, due to the smooth and loose surface, lack of shallow ditches, porous structures, and sand barriers that retain and shield the soil, the inoculated particles were prone to rolling, migrating, and accumulating in depressions under the influence of wind and slope runoff. Only in local depressions could a small amount of algae-moss inoculated bodies be rehydrated and form a thin crust, while higher areas were mostly bare sand. During the third to sixth months, due to poor soil infiltration and water retention, and the difficulty of water retention in local areas after replenishment, only a few micro-depressions maintained small patchy crusts, with low overall crust coverage and a patchy and fragmented spatial distribution. By the twelfth month, although a small amount of crust developed locally, it was still mainly in the form of scattered small patches, and large-area continuous and complete algae-moss composite crusts failed to form. Compared with the treatment in Example 1 where algae-moss composite granular inoculant was applied on the basis of land preparation, this control example was significantly inferior in terms of uniformity of inoculation spatial distribution, water use efficiency, and the rate and continuity of crust formation. This verifies that even with the application of algae-moss inoculant, it is difficult to construct a long-term stable biological soil crust in a harsh desert environment without surface preparation and micro-topography optimization.

[0048] The results show that after one year, the biocrust coverage of Example 1 was 86.0%, while the biocrust coverage of Control Examples 1-5 was 1.1%, 5.8%, 38.2%, 45.2%, and 48.1%, respectively. Figure 1 One year later, the average thickness of the biocrust in Example 1 was 12.1 mm, while the average thicknesses of the biocrusts in Control Examples 1-5 were 0.9 mm, 1.1 mm, 2.1 mm, 6.8 mm, and 6.0 mm, respectively. Figure 2 One year later, the maximum water holding capacity of the topsoil in Example 1 was 38.3 g H2O·100 g. -1 The maximum water holding capacity of soil in comparison examples 1-5 was 9.1 g H₂O·100 g, respectively. -1 11.2gH2O·100g -1 15.2gH2O·100g -1 21.2gH2O·100g -1 20.1gH2O·100g -1 ( Figure 3 One year later, the topsoil organic matter content of Example 1 was 98.4 gC·kg⁻¹. -1 The topsoil organic matter content of control examples 1-5 was 3.2 gC·kg⁻¹, respectively. -1 2.3 gC·kg -1 14.6 gC·kg -1 31.2 gC·kg -1 33.5 gC·kg -1 ( Figure 4One year later, the weight loss rate of Example 1 after standing for 20 minutes at a wind speed of 20 m / s was 7.1%, while the weight loss rates of Control Examples 1-5 were 72.1%, 72.0%, 48.1%, 45.2%, and 39.1%, respectively. Figure 5 ).Depend on Figure 1-5 It can be seen that the data results of Example 1 are significantly better than those of Control Examples 1-5.

[0049] In summary, this invention achieves a complete technical route from inoculum source screening and indoor propagation to field application through a set of processes including "algae-moss synergy + resistance acclimatization + granulated formulation + land preparation and micro-topography optimization". Example 1 shows that a stable biocrust with a coverage of 50%-80%, a thickness of 1mm-3mm, and extensive moss coverage can be formed within 3-5 months. The soil's maximum water holding capacity, organic matter content, and wind erosion resistance are significantly better than the controls. Controls 1 and 2 showed almost no biocrust formation, Control 3 had only a thin algal film without moss coverage, Control 4 had a scattered and weak biocrust, and Control 5 had a patchy and broken biocrust, all of which were difficult to obtain a long-term stable biocrust structure. The results demonstrate that this invention is not only significantly different from traditional single algae or simple algae-moss dispersal schemes in terms of technical approach, but also has outstanding innovation and practical value in shortening recovery time, improving structural stability, and engineering operability.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for ecological restoration of desertified land based on algae-moss composite biological soil crust, characterized in that, The method is as follows: S1. Screening of algae and mosses: S101. Algae Isolation and Screening: Natural crust samples were collected from the target desertification area and similar ecological zone. After being crushed, the samples were inoculated onto the surface of a sponge moistened with BG11 liquid medium. After cultivation, the resulting green filamentous algal colonies were further cultured and their stress resistance was evaluated. Dominant desert algal species were selected as algal inoculum sources. S102. Moss Isolation and Screening: Moss plant samples were collected from the target desertification area and similar ecological zone. After natural air drying, the samples were cut into pieces and sieved to obtain moss fragments. These fragments were then spread on the surface of a sponge soaked in Knop medium and covered with a layer of cellulose paper. After cultivation, moss plants were obtained, and their stress resistance was evaluated. Dominant desert moss species were selected as moss inoculum sources. S2, Algal Proliferation: The algal inoculum obtained in S101 was used to propagate algae on the surface of a sponge moistened with BG11 liquid culture medium to obtain algal mud. S3, moss propagation and algae-moss co-culture: S301, Propagation of Mosses: After the bryophyte inoculum obtained in S102 is air-dried, cut into pieces, and sieved, the resulting bryophyte fragments are propagated on the surface of cellulose paper impregnated with the matrix until the bryophyte coverage reaches more than 60%, and bryophyte bodies are obtained on the matrix surface; the matrix is ​​a mixture of BG11 liquid medium and Knop medium. S302, Algae-Moss Co-culture: The algal mud obtained in S2 is diluted with water to obtain an inoculation solution. The inoculation solution is sprayed onto the moss on the surface of the substrate in S301 for algae-moss co-culture until the biomass coverage reaches more than 80% to obtain an algae-moss-substrate complex. S4. Resistance acclimatization treatment: The algae-bush-matrix complex obtained in S302 was subjected to resistance acclimation treatment to obtain the acclimated algae-bush-matrix complex. The specific acclimation method is as follows: S401, Precipitation Pulse Simulation: After drying the algae-moss-matrix composite obtained in S302 at a relative humidity of 45%±5% for 72 hours, deionized water was sprayed onto the dried algae-moss-matrix composite for replenishment. The drying and replenishment operation was repeated 3 times to simulate intermittent precipitation pulses in desert areas. S402, Temperature and Illumination Gradient: When performing the cycled drying and water replenishment operations in S401, the temperature and light gradient are set as follows: S40201: First cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 23℃±2℃, and photosynthetically active radiation 200µE·m. -2 ·s -1 ~400µE·m -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40202: Second cycle: The light treatment and dark treatment were performed alternately; the conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 400µE·m. -2 ·s -1 ~1000µE·m -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S40203: 3rd cycle: The light treatment and dark treatment were performed alternately. The conditions for the light treatment were: temperature 30℃±5℃, and photosynthetically active radiation 1800±2000µE·m. -2 ·s -1 The conditions for the dark treatment were: temperature 17℃±3℃, 12h; S403, Nutrient restriction and osmotic regulation substance addition: Starting from the first cycle described in S40201, the mixture of BG11 liquid medium and Knop medium obtained in S302 is no longer added to the algae-moss-matrix complex for nutrient restriction; during the water replenishment operation in the precipitation pulse simulation described in S401, a final concentration of 1 g·L⁻¹ is added to the water. -1 NaCl and a final concentration of 1 g·L -1 Trehalose is used to regulate osmotic pressure and salinity tolerance. S5. Preparation of algae-moss composite particle inoculant: S501. Treatment of domesticated algae-moss complexes: The domesticated algae-moss-matrix complex obtained in S4 was pre-dried in a cool and ventilated place until the moisture content was <5%, and then sheared and crushed to obtain algae-moss complex fragments. S502, wet mixing and granulation: After mixing the algae-moss composite fragments obtained in S501 with the auxiliary materials, a mixture is obtained. Then, a binder solution is added until the water content of the mixture is 35%±5% to obtain a wet mixture. After granulation, shaped granules are obtained. The auxiliary material is a mixture of soybean fiber powder, activated carbon powder, ascorbic acid powder and sand; S503. Drying and Sieving: After the shaped particles obtained in S502 are air-dried, they are sieved to retain particles with a particle size of 1 mm to 5 mm, thus obtaining algae-moss composite particle inoculant. S6. Land preparation and micro-topography optimization: The target area is prepared by creating a depression array on the surface soil and setting up sand barriers to obtain a target area with optimized micro-topography. S7. Field application of algae-moss composite granular inoculant: The algae-moss composite particle inoculant obtained in S503 was applied to the target area with optimized micro-topography obtained in S6 to obtain the target area after inoculation. S8. Post-vaccination maintenance: Days 1-2 post-inoculation: The target areas obtained from S7 inoculation were sprayed with water in a mist once daily in the early morning and evening, with a spray volume of 1.5 kg / m² each time. -2 ; Days 3-8 post-inoculation: Every two days, on days 5 and 8 post-inoculation, the target area obtained from S7 was sprayed with a mist of water once, with a spray volume of 1 kg·m³ each time. -2 ; Days 9–21 post-inoculation: Spray water in a mist every 3–5 days, with a spray volume of 0.5 kg·m³ each time. -2 ; Days 22–60 post-vaccination: No regular rehydration is required. In cases of extreme drought or high temperatures, local rehydration may be necessary.

2. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The conditions for culturing the naturally crusted samples described in S101 on the surface of melamine sponges soaked in BG11 liquid medium were: photosynthetically active radiation of 80 µE·m. -2 ·s -1 The temperature was 25℃, the relative humidity was 70%, and the incubation time was 3 days. The conditions for culturing the green filamentous algae colonies on the agar medium were: photosynthetically active radiation of 100 µE·m. -2 ·s -1 The temperature is 25℃±5℃, and the culture time is 5 days; the number of species of algae inoculation source is not less than 2.

3. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The sieve size described in S102 is 40 mesh; the cultivation conditions are: photosynthetically active radiation of 100 µE·m -2 ·s -1 The temperature is 25℃±5℃, the relative humidity is 80%±10%, the culture time is 14 days, and water is sprayed every 2 to 3 days during the culture period; the number of species of algae inoculation source is not less than one.

4. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The methods for evaluating stress resistance described in S101 and S102 include rehydration recovery tests and stress tests.

5. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The method for algal propagation described in S2 is as follows: First, the algal inoculum is inoculated onto the surface of a sponge moistened with BG11 liquid culture medium, under photosynthetically active radiation of 100 µE·m. -2 ·s -1 The algae were cultured for 14 days at a temperature of 27℃±1℃, a relative humidity of 65%±5%, and a shaking speed of 100 r / min to obtain an algal solution. This algal solution was then sprayed onto the surface of a nylon filter membrane impregnated with BG11 and cultured under conditions of 200 µE·m² photosynthetically active radiation. -2 ·s -1 The algae were cultured for 14 days at a temperature of 22℃±2℃ and a relative humidity of 65%±5% to obtain algae mud.

6. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The method for propagating mosses described in S301 is as follows: A layer of nylon nonwoven fabric is laid at the bottom of a plastic tray, followed by a layer of cellulose paper. This is then moistened with a substrate. The moss fragments are then evenly spread on the surface of the moistened cellulose paper. The propagation is carried out under conditions where the photosynthetically active radiation is 100 µE·m. -2 ·s -1 The culture was carried out for 30 days at a temperature of 22℃±3℃ and a relative humidity of 60%±5%, with water replenishment during the culture period; the substrate was a mixture of BG11 liquid medium and Knop medium in a volume ratio of 1:

1.

7. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The inoculum in S302 contains an algae-moss co-culture solution with a mass ratio of algae sludge to water of 1:20, and a total inoculum volume of 100 mL / tray. The algae-moss co-culture method described in S302 is as follows: under photosynthetically active radiation of 200 µE·m⁻ 2 ·s⁻ 1 The cells were cultured for 20 days at a temperature of 23℃±3℃ and a relative humidity of 65%±5%, with water replenishment during the culture period; the amount of water replenished in S401 each time was 2 mm of precipitation / m. 2 Matrix.

8. The method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The wet mixture described in S502 consists of the following raw materials in the following mass fractions: 20% soybean fiber powder, 15% activated carbon powder, 0.1% ascorbic acid powder, 0.7% sand, and the remainder is algae-moss composite fragments; The binder solution described in S502 is composed of the following raw materials in the indicated mass fractions: 1% sodium alginate, 1% gum arabic, and the remainder being water; the particle size of the molded particles described in S502 is 2.0 mm to 3.0 mm.

9. A method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The air-drying conditions described in S503 are: temperature of 30℃±5℃ and relative humidity of 50%±10%; the water content of the algae-moss composite particle inoculant is ≤5%.

10. A method for ecological restoration of desertified land based on algae-moss composite biological soil crust according to claim 1, characterized in that, The application rate of the algae-moss composite granular inoculant described in S7 is 5 g / m³. 2 .

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