Sand-fixing method of biological soil crust for photovoltaic power station sandy land

Abstract

This application relates to the field of sand control technology, and particularly to a biological crusting sand fixation method for use in sandy areas near photovoltaic power stations. The biological crusting sand fixation method includes the following steps: dividing the sandy area of ​​the photovoltaic power station into a planting zone, a water collection zone, and a sand fixation zone; the planting zone encompasses the area of ​​the orthographic projection of the photovoltaic panels onto the sandy area; the water collection zone includes the area extending outwards by d3 from the orthographic projection line of the lower side of the photovoltaic panels onto the sandy area, where 10cm≤d3≤30cm; the sand fixation zone includes the area between any two photovoltaic panels that is not part of the water collection zone; performing a first water retention treatment on the planting zone; a second water retention treatment on the water collection zone; a third water retention treatment on the sand fixation zone; inoculating algae seed sources into the sand fixation zone, and after 4-6 weeks of growth, inoculating lichen seed sources into the planting zone. This biological crusting sand fixation method has high sand fixation efficiency, good long-term stability, low water replenishment cost, and a high success rate of biological colonization.

Description

Technical Field

[0001] This application relates to the field of sand control technology, and in particular to a biological crusting sand fixation method for use in sandy areas near photovoltaic power stations. Background Technology

[0002] Constructing large-scale photovoltaic (PV) power plants in arid and cold regions is an important way to utilize desertified land resources. Large-scale PV power plants typically employ an array layout, consisting of multiple rows of regularly arranged PV panels, creating a large area of ​​shaded area (hereinafter referred to as "under the panels") and unshaded exposed area between the panels (hereinafter referred to as "between the panels"). The under-panel area, due to the shading provided by the PV panels, possesses microhabitat characteristics such as reduced summer radiation, suppressed evaporation, winter insulation, and rainwater diversion and collection. The between-panel area, however, is directly exposed to strong radiation, strong winds, and drought. During the operation of a PV power plant, although the PV panels can alter the local microenvironment, large areas of exposed sand remain beneath them and between the arrays. These areas are highly susceptible to wind erosion and soil desertification under strong winds and drought conditions, thus affecting the safe operation and ecological sustainability of the power plant.

[0003] Biological crusts (including cyanobacterial crusts and lichen crusts) play an important role in windbreak and sand fixation and enhancing soil stability. Traditional artificial promotion techniques mainly include artificial inoculation of cyanobacteria and lichens. After inoculation, cyanobacteria can quickly form a crust layer within 4-6 weeks, but its long-term stability is poor, and it is prone to degradation and breakage in extremely dry years, with a lifespan of only 1-3 years. Lichens are highly resistant and can live for decades after inoculation, but their natural growth rate is extremely low (the annual diameter growth of crust-like lichens is <0.8 mm), which cannot meet the needs of rapid sand fixation. In addition, traditional inoculation methods still follow the field construction model of open deserts, which has a high dependence on artificial water replenishment, low water use efficiency, and low success rate of biological colonization. In terms of seed source acquisition, lichens grow slowly naturally, and large-scale collection in the wild will destroy the native ecology. Although cyanobacteria can be propagated, there is a lack of efficient inoculation technology adapted to site conditions.

[0004] Therefore, there is an urgent need in this field to address the shortcomings of traditional biocrust construction technology in terms of sand fixation efficiency and long-term stability, microhabitat adaptability, water replenishment cost and seed source sustainability, and to provide a biocrust construction method suitable for sandy land in photovoltaic power stations in cold and arid regions. Summary of the Invention

[0005] Based on this, one or more embodiments of this application provide a biological crusting sand fixation method for sandy land in photovoltaic power stations. This biological crusting sand fixation method has high sand fixation efficiency, good long-term stability, low water replenishment cost, and high biological colonization success rate.

[0006] The technical solution of this application specifically includes the following:

[0007] The photovoltaic power station of this application is equipped with a photovoltaic panel array on the sandy ground. Each photovoltaic panel in the photovoltaic panel array has a high side and a low side. The height of the high side relative to the ground is d1, and the height of the low side relative to the ground is d2, where d1 > d2. During natural precipitation or when washing the photovoltaic panels, this height difference allows water to flow naturally to the low side.

[0008] The biological crusting sand fixation method for photovoltaic power station sandy land in this application includes the following steps:

[0009] The sandy area of ​​the photovoltaic power station is divided into a planting zone, a water collection zone, and a sand-fixing zone. The planting zone includes the area of ​​the orthographic projection of the photovoltaic panels onto the sandy area of ​​the photovoltaic power station. The water collection zone includes the area extending outward from the orthographic projection line of the lower side of the photovoltaic panels onto the sandy area of ​​the photovoltaic power station by d3, where 10cm≤d3≤30cm. The sand-fixing zone includes the area between any two photovoltaic panels that is not part of the water collection zone.

[0010] The planting zone undergoes a first water retention treatment; the water collection zone undergoes a second water retention treatment; and the sand-fixing zone undergoes a third water retention treatment.

[0011] Algae seed sources were inoculated into the sand-fixing zone, and after 4-6 weeks of growth, lichen seed sources were inoculated into the planting zone.

[0012] In some embodiments, the step of performing a first water-retaining treatment on the planting strip includes: mixing a first water-retaining agent into the sandy soil of the planting strip to a thickness of 3cm-8cm, wherein the mixed sandy soil comprises 0.5%-1.5% of the first water-retaining agent by weight; and / or,

[0013] The second water-retaining treatment of the catchment area includes: mixing a second water-retaining agent and a first saline-alkali soil into the sandy soil of the catchment area, with a mixing thickness of 5cm-10cm. The mixed sandy soil comprises, by weight percentage, 2.5%-3.5% of the second water-retaining agent and 10%-20% of the first saline-alkali soil; and / or,

[0014] The steps for the third water retention treatment of the sand-fixing belt include: mixing the sandy land of the sand-fixing belt with a third water retention agent and second saline-alkali soil, with a mixing thickness of 8cm-12cm. The mixed sandy land includes 1.5%-2.5% of the third water retention agent and 5%-15% of the second saline-alkali soil by weight percentage.

[0015] In some embodiments, the first water-retaining agent, the second water-retaining agent, and the third water-retaining agent are each independently polymer particles;

[0016] Optionally, the polymer particles have a particle size of 0.2 mm to 0.5 mm, an absorption rate of 300 to 500 times for pure water, and an absorption rate of 50 to 80 times for an aqueous solution of sodium chloride; the mass concentration of the aqueous solution of sodium chloride is 0.5% to 1%.

[0017] Optionally, the polymer particles may be made of one or more of the following: polyacrylamide-potassium acrylate crosslinked copolymer, cellulose-grafted acrylamide copolymer, and poly(acrylic acid-co-acrylamide) potassium salt.

[0018] In some embodiments, the first saline-alkali soil and the second saline-alkali soil each independently comprise mineral elements;

[0019] Optionally, the mineral element includes one or more of calcium, magnesium, potassium, and iron.

[0020] In some embodiments, the first saline-alkali soil and the second saline-alkali soil are taken from the saline-alkali soil in the area where the photovoltaic power station is located.

[0021] In some embodiments, the first and second saline-alkali soils can provide the nutrients required by the algal and / or lichen seed sources.

[0022] In some embodiments, the first and second saline-alkali soils can adjust the pH of the sandy land in the photovoltaic power station. In some embodiments, the algal source includes one or more of cyanobacteria, green algae, and diatoms;

[0023] Optionally, the cyanobacteria include one or more of the following: Micrococcus sheathingus, Nostoc, Anabaena, and Cephalotaxus.

[0024] Optionally, the inoculation amount of the algal germplasm into the sand-fixing zone is 1.5 × 10⁻⁶ based on the cell density of the algal germplasm. 8 -2.5×10 9 pcs / m 2 ;

[0025] Optionally, the algal seed source may be inoculated into the sand-fixing zone after the spring snowmelt or during the autumn rainy season.

[0026] In some embodiments, the lichen germplasm is selected from crustacean lichens;

[0027] Optionally, the crust-like lichens include one or more of the genera *Cryptophyte* and *Microsporum*.

[0028] Optionally, the inoculation amount of the lichen seed source into the planting strip is 40 g / m². 2 -60g / m 2 ;

[0029] Optionally, the lichen germplasm is lichen propagule particles with a particle size of 0.1cm-0.5cm.

[0030] In some embodiments, the step of inoculating the sand-fixing zone with algal seed sources includes:

[0031] The algal seed source was diluted with water to prepare an algal solution; the cell density of the algal solution was 1×10⁻⁶. 6 -1×10 7 cells / mL;

[0032] The algal solution was prepared at a rate of 150 mL / m 2 -250mL / m 2 The standard spray is applied to the sand-fixing zone.

[0033] In some embodiments, the step of inoculating the planting strip with lichen seed sources includes:

[0034] The lichen seed source was crushed, and the resulting particles were granulated at a density of 40 g / m³. 2 -60g / m 2 The standard seeding was applied to the planting strip.

[0035] In some embodiments, after the algae seed source is inoculated into the sand-fixing zone, the damaged areas are re-inoculated every year.

[0036] In some embodiments, after the lichen seed source is inoculated into the planting zone, the duration of continuous drought is monitored;

[0037] When the continuous drought lasts for 60 days, the photovoltaic panels are cleaned, and the water used for cleaning is diverted from the lower side of the photovoltaic panels to the water collection belt.

[0038] This application's biological crusting sand-fixing method utilizes the physical shading area and elevation differences of each photovoltaic panel in a photovoltaic array to divide the sandy land into a planting zone, a water collection zone, and a sand-fixing zone. The planting zone is located within the area projected onto the photovoltaic panel and has high moisture retention capabilities. The water collection zone is located 10cm-30cm outward from the projection line on the lower side of the photovoltaic panel. During cleaning of the photovoltaic panels or natural rainfall, water flows from the higher side to the lower side of the photovoltaic panel under gravity and is channeled from the lower side to the corresponding water collection zone. The sand-fixing zone includes areas located between any two photovoltaic panels that are not part of the water collection zone. This division... The three functional zones described above employ a method where algae seed sources are first inoculated into the sand-fixing zone and allowed to grow for 4-6 weeks. Then, lichen seed sources are inoculated into the planting zone. This allows the cyanobacteria to first occupy the sand-fixing zone, rapidly cementing the sand particles and extending towards the water catchment zone, thus completing the initial fixation of the ground surface. Subsequently, the lichens in the planting zone, protected from direct sunlight, can continue to grow and extend towards the water catchment zone. The abundant oxygen-containing functional groups on the surface of the cyanobacteria provide an ideal substrate for the physical climbing of the lichen hyphae, enabling the lichens to gradually extend into the sand-fixing zone. At the same time, the lichen rhizoids can penetrate the cyanobacteria layer, forming a stable composite structure of "cyanobacteria-lichen-water-retaining agent," achieving comprehensive coverage of the sandy land.

[0039] The biological crust sand fixation method proposed in this application utilizes the ecological niche differences between cyanobacteria and lichens to achieve dual complementarity in spatial layout and inoculation timing. The resulting composite biological crust has both rapid formation capability (a continuous crust layer is formed within 4-6 weeks after cyanobacteria inoculation) and long-term structural stability (it can be maintained for more than 15 years after lichen colonization), filling the technical gap in biological combination methods in the field of photovoltaic site ecological restoration.

[0040] The biological crusting sand-fixing method proposed in this application is simple to operate and low in cost. Operationally, it only requires one-time improvement of the sandy substrate, one-time spraying of cyanobacteria, and one-time sowing of lichens. No tedious daily maintenance is needed afterward. It requires minimal professional skills from operators. The materials used, such as sand, water-retaining agents, and saline-alkali soil, are inexpensive and readily available. Cyanobacteria and lichen seed sources can be continuously supplied through indoor propagation. Furthermore, by coupling the natural water-conducting effect of photovoltaic panels (collecting natural rainfall and photovoltaic panel cleaning water) with the water-absorbing-storing-slow-release mechanism of the water-retaining agent, intermittent, short-duration water supply is transformed into a continuous root zone water supply, significantly reducing water composition and labor costs. The irrigation water required for traditional artificial construction of cyanobacterial crusting is only 3-4 L·m³. -2 ·d -1 The biological crusting sand-fixing method of this application provides an economical, sustainable, and easily replicable solution for ecological sand control and afforestation of large-scale photovoltaic power stations, with a water-saving rate of ≥95%. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of any two adjacent photovoltaic panels in a horizontal row of the photovoltaic panel array of this application;

[0043] Figure 2 This is a top view of the photovoltaic panel array of this application;

[0044] Attached diagram labels: 11-planting strip; 12-water collection strip; 13-sand fixation strip; 21-photovoltaic panel; 22-photovoltaic panel support. Detailed Implementation

[0045] The present application is further described below with reference to embodiments and examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the protection scope of the appended claims.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0047] The term "and / or" as used herein includes any one of two or more related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations encompass any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected using "logical AND," and also undoubtedly includes solutions connected using "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, AND / OR, B, AND / OR, C, AND / OR, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0048] In this application, terms such as "optionally" are used to describe the purpose and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0049] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0050] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, optional numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval points to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges may be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0051] In this application, weight can be a well-known unit of mass in the ecological or chemical fields, such as μg, mg, g, or kg.

[0052] The photovoltaic power station of this application is equipped with a photovoltaic panel array on the sandy ground. Each photovoltaic panel in the photovoltaic panel array has a high side and a low side. The height of the high side relative to the ground is d1, and the height of the low side relative to the ground is d2, where d1 > d2. During natural precipitation or when cleaning the photovoltaic panels, this height difference allows water to flow naturally to the low side.

[0053] The biological crusting sand fixation method for photovoltaic power station sandy land in this application includes the following steps:

[0054] The sandy land of the photovoltaic power station is divided into a planting zone, a water catchment zone, and a sand fixation zone. The planting zone includes the area of ​​the orthographic projection of the photovoltaic panels on the sandy land of the photovoltaic power station. The water catchment zone includes the area d3 outward from the orthographic projection line of the lower side of the photovoltaic panels on the sandy land of the photovoltaic power station, where 10cm≤d3≤30cm. The sand fixation zone includes the area between any two photovoltaic panels that is not part of the water catchment zone.

[0055] The planting zone is treated with the first water retention treatment; the water collection zone is treated with the second water retention treatment; and the sand-fixing zone is treated with the third water retention treatment.

[0056] Algae seed sources were inoculated into the sand-fixing zone, and after 4-6 weeks of growth, lichen seed sources were inoculated into the planting zone.

[0057] refer to Figure 1 The photovoltaic panel 21 is supported by the photovoltaic panel support column 22 and has a high side and a low side; the height of the high side relative to the ground is d1, and the height of the low side relative to the ground is d2, where d1 > d2.

[0058] In some embodiments, 110cm≤d1≤120cm, 90cm≤d2≤100cm.

[0059] In some embodiments, d1 is 114cm and d2 is 96cm.

[0060] refer to Figure 1 and Figure 2 The planting zone 11 includes the area of ​​the orthographic projection of the photovoltaic panel 21 onto the sandy land of the photovoltaic power station; the water collection zone 12 includes the area d3 outward from the orthographic projection line of the lower side of the photovoltaic panel (the side with a height of d2 relative to the ground) onto the sandy land of the photovoltaic power station, where 10cm≤d3≤30cm; the sand stabilization zone 13 includes the area between any two photovoltaic panels that does not belong to the water collection zone 12.

[0061] In some embodiments, d3 can be selected from any value between 10cm and 30cm, such as 10cm, 15cm, 20cm, 25cm, 30cm, etc.

[0062] refer to Figure 1 and Figure 2 The area of ​​the photovoltaic panel's orthographic projection on the sandy ground of the photovoltaic power station is rectangular, with a length of d4 and a width of d5.

[0063] In some embodiments, 200cm≤d4≤250cm, 100cm≤d5≤150cm.

[0064] In some embodiments, d4 can be selected from any value between 200cm and 250cm, such as 200cm, 210cm, 220cm, 230cm, 240cm, 250cm, etc., and d5 can be selected from any value between 100cm and 150cm, such as 100cm, 110cm, 120cm, 130cm, 140cm, 150cm, etc.

[0065] refer to Figure 1 and Figure 2 The area d3 outward from the lower side of the photovoltaic panel (the side with a height of d2 relative to the ground) on the sandy ground of the photovoltaic power station is a rectangle with a length of d4 and a width of d3.

[0066] In some embodiments, 200cm≤d4≤250cm, 10cm≤d3≤30cm.

[0067] In some embodiments, d4 can be selected from any value between 200cm and 250cm, such as 200cm, 210cm, 220cm, 230cm, 240cm, 250cm, etc., and d3 can be selected from any value between 10cm and 30cm, such as 10cm, 15cm, 20cm, 25cm, 30cm, etc.

[0068] refer to Figure 1 and Figure 2 There is a certain distance between any two photovoltaic panels in the photovoltaic array, which is d6 on the horizontal axis (x-axis) and d7 on the vertical axis (y-axis).

[0069] In some embodiments, 400cm≤d6≤600cm, 150cm≤d7≤250cm.

[0070] In some embodiments, d6 is selected from any value between 400cm and 600cm, such as 400cm, 450cm, 500cm, 550cm, 600cm, etc., and d7 is selected from any value between 150cm and 250cm, such as 150cm, 200cm, 250cm, etc.

[0071] In some embodiments, the step of performing a first water-retaining treatment on the planting strip includes: mixing a first water-retaining agent into the sandy soil of the planting strip, with a mixing thickness of 3cm-8cm, wherein the mixed sandy soil contains 0.5%-1.5% of the first water-retaining agent by weight percentage.

[0072] In some embodiments, the step of performing a second water retention treatment on the water catchment area includes: mixing the sandy land of the water catchment area with a second water retention agent and a first saline-alkali soil, with a mixing thickness of 5cm-10cm, wherein the mixed sandy land includes 2.5%-3.5% of the second water retention agent and 10%-20% of the first saline-alkali soil by weight percentage.

[0073] In some embodiments, the step of performing a third water retention treatment on the sand-fixing belt includes: mixing the sandy land of the sand-fixing belt with a third water retention agent and second saline-alkali soil, with a mixing thickness of 8cm-12cm, and the mixed sandy land including 1.5%-2.5% of the third water retention agent and 5%-15% of the second saline-alkali soil by weight percentage.

[0074] In this application, the mixing thickness refers to the thickness of the sand dug down from the surface of the sand dune used for photovoltaic power stations in the corresponding area.

[0075] In some embodiments, the mixing method involves excavating sand from the corresponding area to form a sand pit, adding an appropriate amount of water-retaining agent and / or saline-alkali soil to the excavated sand, mixing it evenly, and then backfilling it into the sand pit.

[0076] In some embodiments, the first water-retaining agent, the second water-retaining agent, and the third water-retaining agent are each independently polymer particles.

[0077] In some embodiments, the polymer particles have a particle size of 0.2 mm to 0.5 mm, an absorption rate of 300 to 500 times for pure water, and an absorption rate of 50 to 80 times for an aqueous solution of sodium chloride; the mass concentration of the aqueous solution of sodium chloride is 0.5% to 1%.

[0078] In some embodiments, the polymer particles are made of one or more of the following: polyacrylamide-potassium acrylate crosslinked copolymer, cellulose-grafted acrylamide copolymer, and poly(acrylic acid-co-acrylamide) potassium salt.

[0079] In some embodiments, the first saline-alkali soil and the second saline-alkali soil each independently comprise mineral elements.

[0080] In some embodiments, the mineral elements include one or more of calcium, magnesium, potassium, and iron.

[0081] In some embodiments, the first and second saline-alkali soils are taken from the saline-alkali soils in the area where the photovoltaic power station is located.

[0082] In some embodiments, the first and second saline-alkali soils can provide the nutrients required for algal and / or lichen seed sources.

[0083] In some embodiments, the first and second saline-alkali soils can adjust the pH of the sandy land in the photovoltaic power station.

[0084] In some embodiments, the algal source includes one or more of cyanobacteria, green algae, and diatoms.

[0085] In some embodiments, cyanobacteria include one or more of Microsheathella, Nostoc, Anabaena, and Cephalotaxus.

[0086] In some embodiments, the inoculation amount of algal germplasm into the sand-fixing zone is 1.5 × 10⁻⁶ based on the cell density of the algal germplasm. 8 -2.5×10 9 pcs / m 2 .

[0087] In some embodiments, algal seed sources are inoculated into the sand-fixing zone after the spring snowmelt or during the autumn rainy season.

[0088] In some embodiments, the lichen source is selected from crustacean lichens.

[0089] In some embodiments, crustacean lichens include one or more of the genera *Cryptotympany* and *Microsporum*.

[0090] In some embodiments, the inoculation amount of lichen seed source into the planting strip is 40 g / m². 2 -60g / m 2 .

[0091] In some embodiments, the lichen germplasm is lichen propagule particles with a particle size of 0.1cm-0.5cm. Using lichen propagule particles changes the lichen inoculation method from the traditional "plant-by-plant" approach to "particle-by-particle," increasing the coverage efficiency per unit mass of germplasm by more than two orders of magnitude, enabling large-scale engineered inoculation of lichens. This method requires only a very small amount of field collection to meet the needs of large-scale inoculation, effectively avoiding damage to native lichen resources and achieving sustainable germplasm acquisition.

[0092] In some embodiments, the step of inoculating algal seed sources into sand-fixing zones includes:

[0093] The algal seed source was diluted with water to prepare an algal solution; the cell density of the algal solution was 1×10⁻⁶. 6 -1×10 7 cells / mL;

[0094] The algal solution was prepared at a rate of 150 mL / m 2 -250mL / m 2 The standard spraying method is applied to the sand-fixing belt.

[0095] In some embodiments, the step of inoculating lichen seed sources into the planting strip includes:

[0096] The lichen seed source was crushed, and the resulting particles were granulated at a ratio of 40 g / m³. 2 -60g / m2 The standard is to sow the seeds in the planting strip.

[0097] In some embodiments, after the algae seed source is inoculated into the sand-fixing zone, the damaged areas are re-inoculated every year.

[0098] In some embodiments, the duration of continuous drought is monitored after the lichen seed source is inoculated into the planting zone;

[0099] When the continuous drought lasts for 60 days, the photovoltaic panels are cleaned, and the water used for cleaning is diverted from the lower side of the photovoltaic panels to the water collection belt.

[0100] The following are some specific examples.

[0101] In the following specific embodiments, the raw materials and reagents whose sources are not explicitly stated are all commercially available, or can be prepared by those skilled in the art using known methods.

[0102] The salt-resistant polyacrylamide-potassium acrylate crosslinked copolymer (SAP) used in the following examples was prepared by solution polymerization or reverse suspension polymerization. The mass ratio of acrylic acid to acrylamide in the monomers ranged from 1:0.3 to 1:0.8, the degree of neutralization was 70% to 90%, and the amount of crosslinking agent was 0.05% to 0.2% of the total monomer mass. The resulting polymer had a saturation absorption ratio of 300 to 500 times in deionized water and 50 to 80 times in 0.9% NaCl aqueous solution. This polymer can be a commercially available product (e.g., but not limited to NSI-415 water-retaining agent or Wote SAP003 water-retaining agent), and the composition and properties of the commercially available product are the same as those of the salt-resistant polyacrylamide-potassium acrylate crosslinked copolymer used in this example.

[0103] Example 1

[0104] 1. Implementation location environment

[0105] The project site is located in a large-scale photovoltaic power station already built and put into operation in the Qaidam Basin. The photovoltaic panels are installed at a fixed tilt angle facing due south, with a spacing of approximately 2 meters between the panels. The area beneath the panels receives no direct sunlight year-round, and the evaporation intensity is approximately 35% of that of bare ground; the area between the panels receives direct sunlight, resulting in significant wind erosion. The soil is aeolian sand with a pH of 8.0-9.0, a salt content of 0.5%-1.2%, and extremely low organic matter content.

[0106] 2. Preparation of biomaterials

[0107] Cyanobacterial seed source: Microcoleus vaginatus, isolated and propagated from saline-alkali sandy soil surrounding the power station, was cultured indoors under controlled temperature (23℃-27℃) and light (40 μmol·m⁻¹). -2 ·s -1The algal culture yielded a cell density of 1.2 × 10⁻⁶ cells / mL. 7 Cells / mL, viable cell rate 88%.

[0108] Lichen germplasm: Crustacean lichens (approximately 70% Placidium and approximately 30% Acarospora) were collected from naturally distributed areas around the power station. After removing impurities, the lichens were air-dried for 48 hours, crushed, and sieved. Particles with a diameter of 0.1 cm to 0.5 cm were used as lichen propagules. The germination rate of the live lichens was tested to be 65%.

[0109] 3. Matrix Modification Materials

[0110] The water-retaining agent is a salt-resistant polyacrylamide-potassium acrylate cross-linked copolymer (SAP) with a particle size of 0.2mm-0.5mm. It has a pure water absorption rate of 380 times and a 0.6% NaCl salt water absorption rate of 55 times.

[0111] The substrate formulations for each zone are as follows:

[0112] High moisture retention colonization zone under the board: SAP content 1.0% (i.e., 1.0 kg SAP + 100 kg in-situ sand), improvement thickness 5 cm.

[0113] Water collection and diversion strip at the edge of the board: SAP content 3.0%, plus 15% local saline-alkali soil (i.e. 3.0 kg SAP + 15 kg saline-alkali soil + 82 kg in-situ sand), with a modified thickness of 8 cm.

[0114] Inter-slab light-based sand-fixing zone: SAP content 2.0%, plus 10% local saline-alkali soil (i.e., 2.0 kg SAP + 10 kg saline-alkali soil + 88 kg in-situ sand), with a modified thickness of 10 cm.

[0115] 4. Build Process

[0116] Step 1: Site functional zoning and differentiated substrate laying

[0117] The photovoltaic array was measured in a grid pattern to precisely divide it into three functional zones: a high-moisture-retaining colonization zone under the panels, a water collection and diversion zone at the edges of the panels, and a light-irradiated sand-fixing zone between the panels. Each zone was independently mixed according to the above formula. After ensuring that the SAP particles and sand were fully and evenly mixed, the substrate was laid in sections and lightly compacted to form a continuous substrate layer.

[0118] Step 2: Inoculation of interplate cyanobacteria

[0119] In mid-April (after local snowmelt and before strong evaporation), the propagated cyanobacteria solution was evenly sprayed onto the substrate surface in the inter-board and edge areas using a low-pressure sprayer, with an inoculum size of 200 mL / m². 2After inoculation, thanks to the residual soil moisture after snowmelt and the diversion effect of photovoltaic panels on the trace amounts of precipitation in late spring, no additional artificial watering is required.

[0120] Step 3: Sowing of lichen propagules under the board

[0121] On day 25 after cyanobacterial inoculation, the algal crust between the substrate layers was basically formed, and the surface appeared as a continuous dark green. Green traces of cyanobacteria naturally spreading downwards from the substrate edges were visible. At this point, the prepared lichen propagule particles were evenly sown onto the substrate surface in the area beneath the substrate at a rate of 50 g / m². 2 After sowing, lightly press down with a flat plate to ensure close contact between the lichen propagules and the substrate.

[0122] Step 4: Maintenance-free management

[0123] No manual water replenishment is required throughout the entire construction process. Routine operations consist only of the following monitoring and emergency procedures:

[0124] Inspect the substrate once a month and record the moisture level of the substrate under the board and the germination of lichens.

[0125] The third month saw a prolonged drought (62 days without effective rainfall). Using the cleaning water from the power station's quarterly cleaning operations, the surface flushing water was diverted to the edge and underside areas of the panels for a one-time replenishment of moisture, with a replenishment volume of approximately 1.5 L / m². 2 ;

[0126] The following spring, an inspection revealed three localized wind erosion damages between the panels (totaling approximately 0.5 m). 2 After the snow melts, add 100 mL / m² of cyanobacteria solution.

[0127] 5. Effectiveness Evaluation

[0128] Using the method described in this embodiment, the coverage rate of cyanobacterial crust between the algae reached 92% by week 6, and the surface wind erosion decreased by 76% compared to the untreated control area. By month 6, the lichen germination rate under the algae reached 82%, and the lichen hyphae had penetrated the algal crust layer between the algae, forming a continuous composite structure. Throughout the entire construction process, apart from one instance of replenishment with water from the power station cleaning system, no special artificial irrigation was carried out, which is significantly less than traditional artificial methods for constructing cyanobacterial crusts (requiring approximately 45-60 L / m² of water). 2 This application achieves a water saving rate of over 95%.

[0129] Example 2

[0130] This embodiment is basically the same as Embodiment 1, except that the cyanobacteria inoculation time was chosen to be mid-September (early autumn rainy season in the local area) to take advantage of the relatively concentrated natural rainfall in autumn to promote cyanobacteria colonization. Lichen propagules were sown 30 days after cyanobacteria inoculation. Due to the low temperatures in autumn and winter, the lichen germination rate was slow, reaching 75% by May of the following year, still meeting the expected results.

[0131] This embodiment shows that the inoculation time window of the method of this application is flexible and can be implemented in spring and autumn to meet the needs of different operation and maintenance schedules of photovoltaic power plants.

[0132] Example 3

[0133] This embodiment is basically the same as Embodiment 1, except that: all lichen seed sources are crustacean lichens of the genus Acarospora, and the lichen propagule particle sowing rate is 60 g / m². 2 Because the rhizoids of the *Microcystis* lichen are more developed, the compressive strength of the resulting composite crust is about 15% higher than that in Example 1.

[0134] This embodiment demonstrates that different lichen types or an appropriate increase in the seeding amount can be selected based on the engineering requirements for the final compressive strength of the crust.

[0135] Comparative Example 1

[0136] Within the same photovoltaic power station as Example 1, a control area with the same area and similar site conditions as in Example 1 was selected. The traditional biocrust construction method was used, and the specific steps are as follows:

[0137] 1. Site preparation

[0138] No functional zones are created under, around, or between the photovoltaic panels. The entire control area is uniformly loosened with sand (15cm deep) without adding any water-retaining agents or saline-alkali soil.

[0139] 2. Algae inoculation

[0140] The same microsheathed algal solution as in Example 1 (cell density 1.2 × 10⁶) was used. 7 (number / mL), at 200 mL / mL throughout the control area. 2 Apply the standard even spray once.

[0141] 3. Lichen inoculation

[0142] On day 25 after algal inoculation, the same lichen propagule particles as in Example 1 (Trichoderma: Microsporum = 7:3, particle size 0.1-0.5 cm) were added at a concentration of 50 g / m³. 2 The standard was evenly spread throughout the control area.

[0143] 4. Artificial water replenishment management

[0144] Following the conventional practice of constructing biological crusts:

[0145] Immediately after inoculating the algae, water thoroughly once, with a water replenishment volume of 20 L / m². 2 ;

[0146] Then replenish fluids once on the 3rd, 7th, 15th, and 30th days, each time at 10 L / m². 2 ;

[0147] Afterwards, water twice a month depending on the dryness or wetness of the surface, at a rate of 5 L / m² each time. 2 This continues until the end of the 6th month.

[0148] Total water replenishment: 20 + 10×4 + 5×2×5 = 20 + 40 + 50 = 110 L / m 2 However, due to runoff loss and deep seepage in the control area, the actual effective utilization rate was only about 50% to 60%, and significant water was lost through evaporation. Actual measurements showed that the cumulative water consumption in the control area over the sixth month was 58.0 L / m³. 2 (Based on the actual amount of water consumed for replenishment).

[0149] 5. Effectiveness Evaluation

[0150] Measurements taken in the 6th month:

[0151] Sand loss rate: 4.5% ± 0.9% (no statistical difference from Example 1, p>0.05);

[0152] The algal crust coverage was approximately 88%, and the lichen germination rate was approximately 75% (slightly lower than in Example 1).

[0153] While traditional methods achieve similar sand-fixing effects, their water consumption is 38.7 times that of Example 1 of this application. In water-scarce regions, this high water consumption limits large-scale application.

[0154] 6. Comparison of Sand Fixation Effect and Water Consumption Indicators

[0155] The following indicators were measured 6 months after the implementation of Example 1 and Comparative Example 1:

[0156] Sand loss rate (%): determined using the wind erosion ring method. A wind erosion ring (30 cm in diameter and 5 cm in depth) was buried in the center of each test area. Five replicates were set up for each area. The wind erosion / deposition within the ring was weighed monthly, and the percentage of cumulative net wind erosion to the original dry mass of the soil surface was calculated as the sand loss rate.

[0157] Water consumption (L / m 2 ): Statistics on artificial water replenishment during the period from construction to the 6th month (excluding natural precipitation and water diversion for photovoltaic panel cleaning).

[0158] Biocrust coverage (%): The coverage of algal crusts and lichen crusts was counted using the quadrat method (50cm×50cm grid).

[0159] Table 1. Statistical results of sand loss rate, crust coverage rate and water consumption in Example 1 and Comparative Example 1

[0160]

[0161] Table 1 shows that, under similar sand fixation effects with a sand loss rate of less than 5%, the water consumption of Example 1 was only 1.5 L / m³. 2 Compared to 58.0 L / m in Comparative Example 1 2 The water-saving rate reached 97.4%. This indicates that the present application, through zoned water conservation, differentiated substrate improvement, and sequential inoculation, can achieve low water consumption and high efficiency in biological crusting sand fixation in extremely arid sandy areas.

[0162] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0163] The embodiments described above merely illustrate several implementation methods of this application and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Furthermore, it should be understood that after reading the above teachings, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the protection scope of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the protection scope of the appended claims. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A biological crusting sand fixation method for photovoltaic power station sandy land, characterized in that, The photovoltaic power station is equipped with a photovoltaic panel array on the sandy ground. Each photovoltaic panel in the array has a high side and a low side. The height of the high side relative to the ground is d1, and the height of the low side relative to the ground is d2, where d1 > d2. The aforementioned biological crust sand-fixing method includes the following steps: The sandy area of ​​the photovoltaic power station is divided into a planting zone, a water collection zone, and a sand-fixing zone. The planting zone includes the area of ​​the orthographic projection of the photovoltaic panels onto the sandy area of ​​the photovoltaic power station. The water collection zone includes the area extending outward from the orthographic projection line of the lower side of the photovoltaic panels onto the sandy area of ​​the photovoltaic power station by d3, where 10cm≤d3≤30cm. The sand-fixing zone includes the area between any two photovoltaic panels that is not part of the water collection zone. The planting strip was subjected to a first water retention treatment; The water collection belt is subjected to a second water retention treatment; The sand-fixing zone is subjected to a third water-retention treatment; Algae seed sources were inoculated into the sand-fixing zone, and after 4-6 weeks of growth, lichen seed sources were inoculated into the planting zone.

2. The biological crust sand fixation method according to claim 1, characterized in that, The first water-retaining treatment of the planting strip includes: mixing a first water-retaining agent into the sandy soil of the planting strip to a thickness of 3cm-8cm, wherein the mixed sandy soil contains 0.5%-1.5% of the first water-retaining agent by weight; and / or, The second water-retaining treatment of the catchment area includes: mixing a second water-retaining agent and a first saline-alkali soil into the sandy soil of the catchment area, with a mixing thickness of 5cm-10cm. The mixed sandy soil comprises, by weight percentage, 2.5%-3.5% of the second water-retaining agent and 10%-20% of the first saline-alkali soil; and / or, The steps for the third water retention treatment of the sand-fixing belt include: mixing the sandy land of the sand-fixing belt with a third water retention agent and second saline-alkali soil, with a mixing thickness of 8cm-12cm. The mixed sandy land includes 1.5%-2.5% of the third water retention agent and 5%-15% of the second saline-alkali soil by weight percentage.

3. The biological crust sand fixation method according to claim 2, characterized in that, The first water-retaining agent, the second water-retaining agent, and the third water-retaining agent are each independently polymer particles; Optionally, the polymer particles have a particle size of 0.2 mm to 0.5 mm, an absorption rate of 300 to 500 times for pure water, and an absorption rate of 50 to 80 times for an aqueous solution of sodium chloride; the mass concentration of the aqueous solution of sodium chloride is 0.5% to 1%. Optionally, the polymer particles include one or more of the following: polyacrylamide-potassium acrylate crosslinked copolymer, cellulose-grafted acrylamide copolymer, and poly(acrylic acid-co-acrylamide) potassium salt.

4. The biological crust sand fixation method according to claim 2, characterized in that, The first and second saline-alkali soils each independently comprise mineral elements; Optionally, the mineral element includes one or more of calcium, magnesium, potassium, and iron; Optionally, the first saline-alkali soil and the second saline-alkali soil are taken from the saline-alkali soil in the area where the photovoltaic power station is located; Optionally, the first and second saline-alkali soils can provide the nutrients required by the algal and / or lichen seed sources; Optionally, the first and second saline-alkali soils can adjust the pH of the sandy land in the photovoltaic power station.

5. The biological crusting sand fixation method according to any one of claims 1-4, characterized in that, The algal strains include one or more of cyanobacteria, green algae, and diatoms; Optionally, the cyanobacteria include one or more of the following: Micrococcus sheathingus, Nostoc, Anabaena, and Cephalotaxus. Optionally, the inoculation amount of the algal germplasm into the sand-fixing zone is 1.5 × 10⁻⁶ based on the cell density of the algal germplasm. 8 -2.5×10 9 pcs / m 2 ; Optionally, the algal seed source may be inoculated into the sand-fixing zone after the spring snowmelt or during the autumn rainy season.

6. The biological crusting sand-fixing method according to any one of claims 1-4, characterized in that, The lichen germplasm was selected from crustacean lichens; Optionally, the crust-like lichens include one or more of the genera *Cryptophyte* and *Microsporum*. Optionally, the inoculation amount of the lichen seed source into the planting strip is 40 g / m². 2 -60g / m 2 ; Optionally, the lichen germplasm is lichen propagule particles with a particle size of 0.1cm-0.5cm.

7. The biological crusting sand-fixing method according to any one of claims 1-4, characterized in that, The steps of inoculating algal seed sources into the sand-fixing zone include: The algal seed source was diluted with water to prepare an algal solution; the cell density of the algal solution was 1×10⁻⁶. 6 -1×10 7 cells / mL; The algal solution was prepared at a rate of 150 mL / m 2 -250mL / m 2 The standard spray is applied to the sand-fixing zone.

8. The biological crusting sand fixation method according to any one of claims 1-4, characterized in that, The steps of inoculating the planting strip with lichen seed sources include: The lichen seed source was crushed, and the resulting particles were granulated at a density of 40 g / m³. 2 -60g / m 2 The standard seeding was applied to the planting strip.

9. The biological crusting sand-fixing method according to any one of claims 1-4, characterized in that, After inoculating the sand-fixing zone with algae seed sources, the damaged areas are re-inoculated every year.

10. The biological crusting sand fixation method according to any one of claims 1-4, characterized in that, After inoculating the lichen seed source into the planting zone, the duration of continuous drought was monitored; When the continuous drought lasts for 60 days, the photovoltaic panels are cleaned, and the water used for cleaning is diverted from the lower side of the photovoltaic panels to the water collection belt.

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