Drought-tolerant biological crust accelerant and application thereof in sand stabilization in subsidence area

Abstract

The invention belongs to the technical field of soil ecological restoration, and particularly relates to a drought-enduring biological crust accelerant and application thereof in sand stabilization in a subsidence area. The drought-resistant biological crust accelerant is prepared from the following raw materials in parts by weight: 10 to 20 parts of domestic sludge, 10 to 20 parts of solidified blue-green algae and 20 to 60 parts of bionic fibers, the solidified blue-green algae is obtained by carrying out microorganism solidification treatment on blue-green algae; the bionic fiber is a cellulose grafted copolymer prepared from agricultural waste cellulose and biodegradable macromolecules through a polymerization reaction. The drought-resistant biological crust accelerant is added into the existing artificial biological crust, so that the caking property of the biological crust can be effectively promoted, the crust speed is increased, and the drought-resistant biological crust has higher drought resistance, thereby realizing an effective fixing effect on desertification soil in a subsidence area; meanwhile, nutrient substances such as nitrogen, phosphorus and potassium and decayed organic matter particles can be provided for the soil, and great significance is achieved for improvement of desertification soil.

Description

Technical Field

[0001] This invention belongs to the field of soil ecological restoration technology, specifically, it relates to a drought-resistant biological crusting promoter and its application in sand fixation in subsidence areas. Background Technology

[0002] Large-scale coal mining has led to severe subsidence and related ecological damage in the coal-producing areas of the upper and middle reaches of the Yellow River, ultimately triggering and exacerbating soil erosion in the region. This has resulted in a growing conflict between coal mining and soil and water conservation in the upper and middle reaches of the Yellow River. Coal mining activities have severely impacted the land and ecological environment of mining areas, especially in subsidence zones where land degradation is high, soil quality is poor, desertification is severe, and ecological restoration is difficult. Conventional sand-fixing technologies have been found to have limitations, including the inability to sustain operations for extended periods, long plant growth cycles, high costs, and the potential for secondary pollution. These limitations have compelled researchers to seek new technologies to conduct research on biological crusting for windbreak and sand fixation.

[0003] Biocrusts, as pioneer species for ecological restoration, possess core functions such as sand fixation and water conservation, nitrogen fixation and carbon increase, and improvement of the microenvironment. They can reduce wind erosion in gravity erosion control areas and enhance soil water and fertilizer retention capacity in reclaimed land, forming a closed-loop technology of "erosion resistance-reclamation-ecological enhancement." Therefore, in-depth evaluation of the application effects of biocrusts in the ecological restoration of wind-erosion areas, and research on the integrated ecological utilization system of novel biocrusts encompassing "material research-inoculation technology-application effects," are key research areas and hot topics for promoting high-quality, high-efficiency, and eco-friendly development of ecological restoration in wind-erosion coal mining areas.

[0004] Therefore, one of the current research goals is to develop and screen a new type of biological crust material that has good adhesion, strong planting ability, fast crust formation, is not easy to fall off, and has high drought resistance, in order to address the current problems of severe wind erosion and low water retention rate in sandy areas. Summary of the Invention

[0005] The purpose of this invention is to provide a drought-resistant biological crusting promoter and its application in sand fixation in subsidence areas, so that it can combine the advantages of chemical crusting and biological crusting, and has a good sand fixation effect in subsidence areas.

[0006] Therefore, the present invention provides the following technical solution.

[0007] The first aspect of the present invention provides a drought-resistant biological crusting promoter, which, by weight, comprises: 10-20 parts of domestic sewage sludge, 10-20 parts of solidified cyanobacteria, and 20-60 parts of biomimetic fiber. The solidified cyanobacteria is obtained by microbial solidification treatment of cyanobacteria. The biomimetic fiber is a cellulose graft copolymer made by polymerizing agricultural waste cellulose with biodegradable polymers.

[0008] A second aspect of the present invention provides a method for preparing a drought-resistant biological crusting promoter, the method comprising the following steps: Agricultural waste is pretreated to obtain a cellulose suspension; The biodegradable polymer is dissolved in a solvent to obtain a polymer solution; The cellulose suspension was mixed with a polymer solution, and a hydrophilic monomer and an initiator were added to carry out the reaction. After the reaction was completed, the mixture was allowed to stand and filtered. The resulting solid product was washed and dried to obtain biomimetic fibers. The obtained biomimetic fiber, domestic sewage sludge, and solidified cyanobacteria were mixed and stirred evenly according to the weight proportions to obtain a drought-resistant biological crusting promoter.

[0009] In a preferred embodiment of the present invention, the agricultural waste includes corn stalks, rice husks, rice straw, wheat straw, cotton stalks, bean stalks, and root stubble.

[0010] In a preferred embodiment of the present invention, the pretreatment includes crushing and alkali treatment.

[0011] In a preferred embodiment of the present invention, the crushing is to cut and crush the raw material into granules.

[0012] In a preferred embodiment of the present invention, the alkali treatment is to react with an alkali solution of 2-10% by mass at 70-100°C for 1-3 hours.

[0013] In a preferred embodiment of the present invention, the alkali is selected from one or more of sodium hydroxide and potassium hydroxide.

[0014] In a preferred embodiment of the present invention, the biodegradable polymer is selected from one or more of polylactic acid, polyvinylpyrrolidone, chitosan, polyvinyl alcohol, polyacrylamide, and polyhydroxyalkanoates.

[0015] In a preferred embodiment of the present invention, the solvent is selected from one or more of water, hydrochloric acid, dichloromethane, and N,N-dimethylformamide.

[0016] In a preferred embodiment of the present invention, the mass concentration of the polymer solution is 1-5 wt%.

[0017] In a preferred embodiment of the present invention, the cellulose suspension and the polymer solution are mixed in a volume ratio of 1:5-10.

[0018] In a preferred embodiment of the present invention, the hydrophilic monomer is selected from one or more of N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, butanediol monoacrylate, tert-butylaminoethyl methacrylate, 2-ethoxyethyl acrylate, n-hexyl acrylate, and hydroxypropyl methacrylate.

[0019] In a preferred embodiment of the present invention, the amount of the hydrophilic monomer added is 1-3 times the mass of the polymer.

[0020] In a preferred embodiment of the present invention, the initiator is selected from one or more of benzoyl peroxide, azobisisobutyronitrile, potassium persulfate, ammonium persulfate, and azobisisoheptanenitrile.

[0021] In a preferred embodiment of the present invention, the amount of the initiator added is 0.2-0.5% of the mass of the hydrophilic monomer.

[0022] In a preferred embodiment of the present invention, the solidified cyanobacteria are prepared by the following method: After crushing the cyanobacteria, heat treatment is performed to obtain cyanobacteria slurry; The biological fermentation agent is added to the cyanobacteria slurry for fermentation. After fermentation, the cyanobacteria are dried to obtain solidified cyanobacteria.

[0023] In a preferred embodiment of the present invention, the heat treatment conditions are: temperature 100-150℃, time 20-40min.

[0024] In a preferred embodiment of the present invention, the biological fermentation agent is composed of Lactobacillus plantarum, Bacillus subtilis and Bacillus licheniformis.

[0025] In a preferred embodiment of the present invention, the inoculation ratio of the bio-fermentation agent is 1-5%.

[0026] In a preferred embodiment of the present invention, the fermentation conditions are: temperature 35-45°C, time 12-18 hours.

[0027] A third aspect of the present invention provides a biological crust material comprising, by weight percentage, the following raw material components: (i) Biological crust 80-90%; and (ii) The remainder is the drought-resistant biological crusting promoter as described above or the drought-resistant biological crusting promoter prepared according to the preparation method described above.

[0028] In a preferred embodiment of the present invention, the biological crust is a mixture of artificially cultured algal crust and moss crust in a mass ratio of 1:0.3-0.5.

[0029] A fourth aspect of the present invention provides a method for preparing a biological crust material, the method comprising the following steps: Mixture I is obtained by mixing biocrust and drought-resistant biocrust promoter. Add 10%-20% by weight of deionized water to the obtained mixture I and mix evenly to obtain mixture II; The obtained mixture II was granulated to obtain bio-skin material particles with a particle size between 1 and 3 cm.

[0030] The fifth aspect of the present invention provides the application of the drought-resistant biocrust promoter as described above, the drought-resistant biocrust promoter prepared according to the preparation method as described above, or the biocrust material as described above in sand fixation in subsidence areas.

[0031] By employing the above technical solution, the present invention has at least the following advantages: This invention, by adding a certain amount of drought-resistant biocrust promoter to existing artificial biocrusts, effectively promotes the adhesion of the biocrust, increases the rate of biocrust formation, and exhibits high drought resistance, thereby achieving effective fixation of sandy soil in subsidence areas. The biocrust material prepared by this invention, by incorporating the biocrust promoter, overcomes the limitations of existing artificially inoculated biocrusts in terms of hydrothermal environment and transportation and storage conditions, effectively extending the shelf life of the biocrust material.

[0032] This invention relates to a drought-resistant biocrust promoter using sewage sludge, solidified cyanobacteria, and biomimetic fibers as raw materials. The biomimetic fibers are derived from agricultural waste, such as straw, which undergoes pretreatment and polymer grafting modification to obtain a cellulose graft copolymer. This polymer possesses a three-dimensional fiber network, with hydrophilic groups loaded within or on the surface of the fibers. Through a dual mechanism of physical entanglement and adsorption, the fibers fix the soil, allowing them to tightly adhere to soil particles and resist runoff erosion. When the environment is dry, the viscosity decreases, forming a porous structure that promotes soil aeration and reduces water trapping. The cyanobacteria, after fermentation and solidification, are rich in nutrients such as nitrogen, phosphorus, and potassium, as well as decaying organic matter particles, which facilitates the rapid settlement and community building of algae, mosses, and other microorganisms, further enhancing the ecological function of the artificial biocrust and providing long-term maintenance.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0034] Figure 1 The disintegration rates of different biological crust materials are shown. Detailed Implementation

[0035] To make the technical means, creative features, achieved objectives, and effects of this invention readily understandable, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] Unless otherwise specified, the domestic sewage sludge used in the following examples was taken from the wastewater treatment plant of the Hongshaquan open-pit coal mine in Zhundong County. Its main component is organic matter. To better utilize it, it underwent drying treatment. After drying, the sludge varied in size and irregular in shape, and was grayish-black. *Lactobacillus plantarum* ATCC 8014, *Bacillus subtilis* ATCC 23857, and *Bacillus licheniformis* ATCC 6634 were all purchased from Beijing Bio-Biobio Biotechnology Co., Ltd.

[0037] Example 1: Corn stalks were cut, crushed, and sieved through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 6% sodium hydroxide solution at a mass-to-volume ratio of 1g:15ml and reacted at 85℃ for 2 hours to obtain a cellulose suspension. Polylactic acid was dissolved in dichloromethane to obtain a 3wt% polylactic acid solution. The cellulose suspension and polylactic acid solution were mixed at a volume ratio of 1:7.5, and N,N-dimethylaminoethyl acrylate (twice the mass of polylactic acid) and benzoyl peroxide (0.35% of the mass of N,N-dimethylaminoethyl acrylate) were added. The mixture was reacted at 70℃ for 6 hours. After the reaction, the mixture was allowed to stand, filtered, and the resulting solid product was washed and dried to obtain biomimetic fibers.

[0038] After crushing the cyanobacteria, they were heat-treated at 125℃ for 30 minutes to obtain a cyanobacteria slurry. The fermentation broth (with a live Lactobacillus plantarum concentration of approximately 3 × 10⁻⁶) was then inoculated at a ratio of 3%. 8 CFU / mL, the viable concentration of Bacillus subtilis is approximately 3 × 10⁻⁶ CFU / mL. 8 CFU / mL and the viable concentration of Bacillus licheniformis was approximately 3 × 10⁻⁶. 8 (CFU / mL) was added to the cyanobacteria slurry and fermented at 37°C for 16 hours. After fermentation, the cyanobacteria were dried to obtain solidified cyanobacteria.

[0039] According to the weight proportions, 40 parts of the obtained biomimetic fiber, 15 parts of domestic sewage sludge, and 15 parts of solidified cyanobacteria were mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0040] By weight percentage, 85% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 15% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 15% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0041] Example 2: Corn stalks were cut, crushed, and sieved through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 2% sodium hydroxide solution at a mass-to-volume ratio of 1g:10ml and reacted at 100℃ for 1 hour to obtain a cellulose suspension. Polyvinylpyrrolidone (PVP) was dissolved in water to obtain a 1wt% PPVP solution. The cellulose suspension and PPVP solution were mixed at a volume ratio of 1:10, and N,N-diethylaminoethyl acrylate (added in an amount equal to the mass of PPVP) and azobisisobutyronitrile (added in an amount of 0.2% of the mass of N,N-diethylaminoethyl acrylate) were added. The mixture was reacted at 70℃ for 6 hours. After the reaction, the mixture was allowed to stand, filtered, and the resulting solid product was washed and dried to obtain biomimetic fibers.

[0042] After crushing the cyanobacteria, they were heat-treated at 150℃ for 20 minutes to obtain a cyanobacteria slurry. The fermentation broth (with a live Lactobacillus plantarum concentration of approximately 1×10⁻⁶) was then inoculated at a ratio of 5%. 8 CFU / mL, the viable concentration of Bacillus subtilis is approximately 3 × 10⁻⁶ CFU / mL. 8 CFU / mL and Bacillus licheniformis viable bacterial concentration were approximately 2 × 10⁻⁶. 8 (CFU / mL) was added to the cyanobacteria slurry and fermented at 37°C for 18 hours. After fermentation, the cyanobacteria were dried to obtain solidified cyanobacteria.

[0043] According to the weight proportions, 40 parts of the obtained biomimetic fiber, 20 parts of domestic sewage sludge and 10 parts of solidified cyanobacteria are mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0044] By weight percentage, 90% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 10% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 20% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0045] Example 3: Corn stalks were cut, crushed, and passed through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 10% sodium hydroxide solution at a mass-to-volume ratio of 1g:20ml and reacted at 70℃ for 3 hours to obtain a cellulose suspension. Chitosan was dissolved in a 1% hydrochloric acid solution to obtain a 5wt% chitosan solution. The cellulose suspension and chitosan solution were mixed at a volume ratio of 1:5, and butylene glycol monoacrylate (3 times the mass of chitosan) and azobisisobutyronitrile (0.5% of the mass of butylene glycol monoacrylate) were added. The mixture was reacted at 60℃ for 5 hours. After the reaction, the mixture was allowed to stand, filtered, and the resulting solid product was washed and dried to obtain biomimetic fibers.

[0046] After crushing the cyanobacteria, they were heat-treated at 100℃ for 40 minutes to obtain a cyanobacteria slurry. The fermentation broth (with a live Lactobacillus plantarum concentration of approximately 2 × 10⁻⁶) was then inoculated at a ratio of 1%. 8 CFU / mL, the viable concentration of Bacillus subtilis is approximately 1×10⁻⁶. 8 CFU / mL and the viable concentration of Bacillus licheniformis was approximately 3 × 10⁻⁶. 8 CFU / mL was added to the cyanobacteria slurry and fermented at 37°C for 12 hours. After fermentation, the cyanobacteria were dried to obtain solidified cyanobacteria.

[0047] According to the weight proportions, 50 parts of the obtained biomimetic fiber, 10 parts of domestic sewage sludge, and 10 parts of solidified cyanobacteria are mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0048] By weight percentage, 80% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 20% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 10% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0049] Example 4: Corn stalks were cut, crushed, and passed through an 80-mesh sieve to obtain corn stalk powder. The corn stalk powder was dispersed in a 6% sodium hydroxide solution at a mass-to-volume ratio of 1g:15ml and reacted at 80℃ for 2 hours to obtain a cellulose suspension. Polyvinyl alcohol was dissolved in water to obtain a 3wt% polyvinyl alcohol solution. The cellulose suspension and polyvinyl alcohol solution were mixed at a volume ratio of 1:6, and tert-butylaminoethyl methacrylate (twice the mass of polyvinyl alcohol) and benzoyl peroxide (0.4% of the mass of tert-butylaminoethyl methacrylate) were added. The mixture was reacted at 70℃ for 5 hours. After the reaction, the mixture was allowed to stand, filtered, and the resulting solid product was washed and dried to obtain biomimetic fibers.

[0050] After crushing the cyanobacteria, they were heat-treated at 140℃ for 20 minutes to obtain a cyanobacteria slurry. The fermentation broth (with a live Lactobacillus plantarum concentration of approximately 2 × 10⁻⁶) was then inoculated at a ratio of 2%. 8 CFU / mL, the viable concentration of Bacillus subtilis is approximately 3 × 10⁻⁶ CFU / mL. 8 CFU / mL and Bacillus licheniformis viable bacterial concentration are approximately 1×10⁻⁶. 8 (CFU / mL) was added to the cyanobacteria slurry and fermented at 37°C for 16 hours. After fermentation, the cyanobacteria were dried to obtain solidified cyanobacteria.

[0051] According to the weight proportions, 30 parts of the obtained biomimetic fiber, 20 parts of domestic sewage sludge and 20 parts of solidified cyanobacteria are mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0052] By weight percentage, 85% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 15% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 15% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0053] Comparative Example 1: The difference between this comparative example and the embodiment is that the cyanobacteria were not fermented. Specifically: Corn stalks were cut, crushed, and sieved through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 6% sodium hydroxide solution at a mass-to-volume ratio of 1g:15ml and reacted at 85℃ for 2 hours to obtain a cellulose suspension. Polylactic acid was dissolved in dichloromethane to obtain a 3wt% polylactic acid solution. The cellulose suspension and polylactic acid solution were mixed at a volume ratio of 1:7.5, and N,N-dimethylaminoethyl acrylate (twice the mass of polylactic acid) and benzoyl peroxide (0.35% of the mass of N,N-dimethylaminoethyl acrylate) were added. The mixture was reacted at 70℃ for 6 hours. After the reaction, the mixture was allowed to stand, filtered, and the resulting solid product was washed and dried to obtain biomimetic fibers.

[0054] After crushing the cyanobacteria, the mixture was heat-treated at 125°C for 30 minutes to obtain a cyanobacteria slurry. The obtained cyanobacteria slurry was then dried to obtain solidified cyanobacteria.

[0055] According to the weight proportions, 40 parts of the obtained biomimetic fiber, 15 parts of domestic sewage sludge, and 15 parts of solidified cyanobacteria were mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0056] By weight percentage, 85% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 15% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 15% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0057] Comparative Example 2: The difference between this comparative example and the embodiment is that the corn stalks were not treated with polylactic acid, specifically: Corn stalks were cut, crushed, and passed through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 6% sodium hydroxide solution at a mass-to-volume ratio of 1g:15ml and reacted at 85℃ for 2 hours to obtain a cellulose suspension. The obtained cellulose suspension was allowed to stand and filtered. The resulting solid product was washed and dried to obtain straw fiber.

[0058] After crushing the cyanobacteria, they were heat-treated at 125℃ for 30 minutes to obtain a cyanobacteria slurry. The fermentation broth (with a live Lactobacillus plantarum concentration of approximately 3 × 10⁻⁶) was then inoculated at a ratio of 3%. 8 CFU / mL, the viable concentration of Bacillus subtilis is approximately 3 × 10⁻⁶ CFU / mL. 8 CFU / mL and the viable concentration of Bacillus licheniformis was approximately 3 × 10⁻⁶. 8(CFU / mL) was added to the cyanobacteria slurry and fermented at 37°C for 16 hours. After fermentation, the cyanobacteria were dried to obtain solidified cyanobacteria.

[0059] According to the weight proportions, 40 parts of the obtained straw fiber, 15 parts of domestic sewage sludge and 15 parts of solidified cyanobacteria are mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0060] By weight percentage, 85% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 15% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 15% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0061] Comparative Example 3: The difference between this comparative example and Example 1 is that the cyanobacteria were not fermented and the corn stalks were not treated with polylactic acid. Specifically: Corn stalks were cut, crushed, and passed through an 80-mesh sieve to obtain corn stalk powder. The obtained corn stalk powder was dispersed in a 6% sodium hydroxide solution at a mass-to-volume ratio of 1g:15ml and reacted at 85℃ for 2 hours to obtain a cellulose suspension. The obtained cellulose suspension was allowed to stand and filtered. The resulting solid product was washed and dried to obtain straw fiber.

[0062] After crushing the cyanobacteria, the mixture was heat-treated at 125°C for 30 minutes to obtain a cyanobacteria slurry. The obtained cyanobacteria slurry was then dried to obtain solidified cyanobacteria.

[0063] According to the weight proportions, 40 parts of the obtained straw fiber, 15 parts of domestic sewage sludge and 15 parts of solidified cyanobacteria are mixed and stirred evenly to obtain a drought-resistant biological crusting promoter.

[0064] By weight percentage, 85% of biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and the remainder 15% of drought-resistant biocrust accelerator are mixed to obtain Mixture I. 15% by weight of deionized water is added to Mixture I and mixed thoroughly to obtain Mixture II. Mixture II is then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0065] Comparative Example 4: The difference between this comparative example and Example 1 is that no accelerator was added to the biological crust, specifically: 15% deionized water was added to the biocrust (a mixture of artificially cultivated algal and moss crusts in a mass ratio of 1:0.4) and mixed thoroughly to obtain a mixture. The resulting mixture was then granulated to obtain biocrust material particles with a particle size between 1 and 3 cm.

[0066] Experiment 1: Detection of the skin disintegration rate of biological skin materials Equal amounts of biocrust material particles prepared in Examples 1-4 and Comparative Examples 1-4, with essentially the same particle size, were placed in containers containing a large amount of distilled water. The crust disintegration rate (defined as crust crumbling upon contact) was measured every 1 hour, 2 hours, 3 hours, 5 hours, and 10 hours. The results are shown in Table 1 and [Table data missing]. Figure 1 As shown.

[0067] Table 1. Disintegration rate of bio-skin material particles

[0068] As shown in Table 1 and Figure 1 The results show that, compared with Comparative Examples 1-4, the disintegration rate of the crusting materials prepared in Examples 1-4 of the present invention is significantly reduced. Compared with the crusting material in Comparative Example 4 without the addition of the biological crusting promoter of the present invention, the addition of the biological crusting promoter in Examples 1-4 and Comparative Examples 1-3 effectively reduces the disintegration rate of the material.

[0069] Experiment 2: The Stabilizing Effect of Crust Material on Sandy Soil in Subsidence Areas The test site was located in the sandy soil of the Shendong coal mining subsidence area, and was divided into six equal-sized plots. The bio-skin material particles prepared in Example 1 and Comparative Examples 1-4 were then mixed at a density of 50 g / m³. 2 The biocrust material was inoculated into the soil of each experimental site, except for the control site which was not inoculated. The curing period was 32 days. During the curing period, nitrogen and phosphorus nutrient solution was added every 3 days, with a nitrate:phosphate ratio of 3:1 and a concentration of 0.1 mol / L. The control procedures during the curing period were as follows: from 0 to 14 days after inoculation, 2 L of distilled water was sprayed on the biocrust every 2 days; from 14 to 24 days, 2 L of distilled water was sprayed on the biocrust every 3 days; after 24 days, 2 L of distilled water was sprayed on the biocrust every week. The morphology and physiological characteristics of the biocrust were recorded during the curing period, and the biocrust performance was tested at approximately 32 days of cultivation.

[0070] Performance testing includes: hardness testing, evaporation resistance test, permeability test, wind erosion resistance test, and water erosion resistance test. The specific testing methods are described in the applicant's patent application CN202511042461.X, and will not be repeated here.

[0071] The results are shown in Table 2.

[0072] Table 2 Test results of crust material properties

[0073] As shown in Table 2, compared with the blank control, the addition of bio-crust material significantly improved soil hardness, reduced evaporation rate, decreased wind erosion-resistant soil loss rate, and reduced water erosion-resistant soil loss. This indicates that the addition of bio-crust material can improve the soil stabilization and water retention performance of sandy soil. Compared with Example 1, the cyanobacteria in Comparative Example 1 were not fermented during the preparation of the crusting accelerator, the corn stalks in Comparative Example 3 were not treated with polylactic acid, and the cyanobacteria and corn stalks in Comparative Example 3 were not fermented during the preparation of the crusting accelerator. The resulting crusting accelerators all had a certain impact on soil hardness, evaporation rate, wind erosion-resistant soil loss rate, and water erosion-resistant soil loss, and their effects were worse than those of Example 1. This indicates that the crusting accelerator of the present invention is the best product obtained after multiple experiments and has a significant effect on soil improvement in subsidence areas.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the methods and techniques disclosed above without departing from the scope of the present invention to create equivalent embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A drought-resistant biological skin-forming promoter, characterized in that, Based on parts by weight, its raw material composition includes: 10-20 parts of domestic sewage sludge, 10-20 parts of solidified cyanobacteria, and 20-60 parts of biomimetic fiber. The solidified cyanobacteria is obtained by microbial solidification treatment of cyanobacteria. The biomimetic fiber is a cellulose graft copolymer made by polymerizing agricultural waste cellulose with biodegradable polymers.

2. The preparation method of the drought-resistant biological crusting promoter according to claim 1, characterized in that, The method includes the following steps: Agricultural waste is pretreated to obtain a cellulose suspension; The biodegradable polymer is dissolved in a solvent to obtain a polymer solution; The cellulose suspension was mixed with a polymer solution, and a hydrophilic monomer and an initiator were added to carry out the reaction. After the reaction was completed, the mixture was allowed to stand and filtered. The resulting solid product was washed and dried to obtain biomimetic fibers. The obtained biomimetic fiber, domestic sewage sludge, and solidified cyanobacteria were mixed and stirred evenly according to the weight proportions to obtain a drought-resistant biological crusting promoter.

3. The preparation method according to claim 2, characterized in that, The agricultural waste includes corn stalks, rice husks, rice straw, wheat straw, cotton stalks, bean stalks, and root stubble; The pretreatment includes crushing and alkali treatment.

4. The preparation method according to claim 3, characterized in that, The crushing process involves cutting and crushing the raw materials into granules. The alkaline treatment involves using an alkaline solution with a mass concentration of 2-10% and reacting it at 70-100°C for 1-3 hours. The alkali is selected from one or more of sodium hydroxide and potassium hydroxide.

5. The preparation method according to claim 2, characterized in that, The biodegradable polymer is selected from one or more of polylactic acid, polyvinylpyrrolidone, chitosan, polyvinyl alcohol, polyacrylamide, and polyhydroxyalkanoates; The solvent is selected from one or more of water, hydrochloric acid, dichloromethane, and N,N-dimethylformamide; The polymer solution has a mass concentration of 1-5 wt%.

6. The preparation method according to claim 2, characterized in that, The cellulose suspension and the polymer solution are mixed at a volume ratio of 1:5-10; The hydrophilic monomer is selected from one or more of N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, butanediol monoacrylate, tert-butylaminoethyl methacrylate, 2-ethoxyethyl acrylate, n-hexyl acrylate, and hydroxypropyl methacrylate; the amount of the hydrophilic monomer added is 1-3 times the polymer mass. The initiator is selected from one or more of benzoyl peroxide, azobisisobutyronitrile, potassium persulfate, ammonium persulfate, and azobisisoheptanenitrile; the amount of the initiator added is 0.2-0.5% of the mass of the hydrophilic monomer.

7. The preparation method according to claim 2, characterized in that, The solidified cyanobacteria were prepared according to the following method: After crushing the cyanobacteria, heat treatment is performed to obtain cyanobacteria slurry; The biological fermentation agent is added to the cyanobacteria slurry for fermentation. After fermentation, the cyanobacteria are dried to obtain solidified cyanobacteria.

8. The preparation method according to claim 7, characterized in that, The heat treatment conditions are: temperature 100-150℃, time 20-40min; The biological fermentation agent is composed of Lactobacillus plantarum, Bacillus subtilis, and Bacillus licheniformis; The inoculation ratio of the bio-fermentation agent is 1-5%; The fermentation conditions are: temperature 35-45℃, time 12-18 hours.

9. A biological skin material, characterized in that, By weight percentage, it includes the following raw material components: (i) Biological crust 80-90%; and (ii) The remainder is the drought-resistant biological crusting promoter according to claim 1 or the drought-resistant biological crusting promoter prepared by the preparation method according to any one of claims 2-8; The biological crust is a mixture of artificially cultured algal crust and moss crust in a mass ratio of 1:0.3-0.

5.

10. The application of the drought-resistant biological crusting promoter according to claim 1, the drought-resistant biological crusting promoter prepared by the preparation method according to any one of claims 2-8, or the biological crusting material according to claim 9 in sand fixation in subsidence areas.

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