A seed complex, its preparation method and application

Abstract

This invention relates to the field of ecological protection technology, specifically to a seed composite, its preparation method, and its application. The invention provides a seed composite comprising, from the inside out, a core layer, a middle framework layer, and an outer water-retaining layer; the core layer is a stress-resistant seed; the middle framework layer is an organic-inorganic porous sludge material coating the core layer; and the outer water-retaining layer is a water-supplying sludge-based hydrogel coating the middle framework layer. The seed composite provided by this invention can not only effectively enhance the environmental stress resistance of plant seeds and ensure the survival rate of plants under harsh environmental conditions such as rocky desertification, but also compensate for problems such as insufficient water and nutrient supply, inadequate water and fertilizer retention capacity, and poor stability in rocky desertification soils, achieving the goals of windbreak and sand fixation, and soil improvement.

Description

Technical Field

[0001] This invention relates to the field of ecological protection technology, specifically to a seed complex, its preparation method, and its application. Background Technology

[0002] The continued development of rocky desertification will lead to the comprehensive degradation and loss of land ecosystem functions: large areas of exposed bedrock result in soil layers that are generally less than 10 cm thick and discontinuously distributed, failing to provide a stable growth substrate for vegetation and thus leading to low vegetation cover in the region; surface seepage is exacerbated, the soil's water retention capacity is significantly reduced, soil erosion is prominent, and geological disasters such as flash floods and debris flows are easily induced. At the same time, key nutrients such as nitrogen and phosphorus in the soil are easily lost in large quantities through rainwater leaching and surface erosion, which not only further exacerbates soil impoverishment but also causes groundwater pollution, forming a vicious cycle of "intensified rocky desertification—soil degradation—intensified pollution," which seriously restricts the improvement of the ecological environment and sustainable development in rocky desertification areas.

[0003] Currently, existing technologies for the remediation of rocky desertification soils and vegetation restoration have many shortcomings: While conventional physical and chemical soil amendment methods can improve some soil physicochemical properties in the short term, they suffer from poor water retention, rapid loss of exogenous nutrients, and poor biodegradability of amendment materials, making it difficult to maintain long-term improvement effects. Although hydrogels have been applied in the field of rocky desertification soil remediation, pure natural polymer hydrogels have technical bottlenecks such as low mechanical strength, excessively rapid degradation rates in the soil environment, and insufficient nutrient supply, making it impossible to maintain a durable three-dimensional network structure for soil amendment. Regarding seed survival, existing technologies generally lack the ability to effectively regulate seed dormancy. They cannot induce seed dormancy to avoid loss under adverse conditions such as drought and barrenness, nor can they accurately break dormancy and promote synchronous germination under suitable conditions, resulting in low seed germination rates and field survival rates. In addition, the protective materials have simple structures, poor functional integration, and are incompatible with existing sand and soil fixation processes. These shortcomings collectively lead to low efficiency and unstable effects in ecological restoration of rocky desertification areas, failing to meet the needs of large-scale restoration.

[0004] Therefore, there is an urgent need for a comprehensive technology that combines long-term soil improvement, nutrient supply, and reversible regulation of seed dormancy to solve the technical problems of soil degradation, nutrient loss, and difficulty in seed survival in rocky desertification areas. Summary of the Invention

[0005] This invention provides a seed complex, its preparation method, and its application to solve the above-mentioned problems.

[0006] In a first aspect, the present invention provides a seed composite comprising, from the inside out, a core layer, an intermediate skeleton layer and an outer water-retaining layer; The core layer consists of stress-resistant seeds; The intermediate framework layer is an organic-inorganic porous sludge material that covers the core layer; The outer water-retaining layer is a water supply sludge-based hydrogel that covers the middle skeleton layer.

[0007] In one optional embodiment, the stress-resistant seed comprises the following raw materials: plant seeds, polymeric initiator solution, phenolic acid and its derivative solution, biodegradable polymer solution, and clay material; Optionally, the mass concentration of the polymeric initiator solution is 10wt%~20wt%; Optionally, the polymeric modulating initiator comprises a polymer. Further optionally, the polymeric initiator includes at least one of polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone; Optionally, the concentration of the phenolic acid and its derivative solution is 0.2~2.5 mmol / L; Optionally, the phenolic acids and their derivatives include at least one of salicylic acid and p-hydroxybenzoic acid; Optionally, the mass concentration of the biodegradable polymer solution is 1wt%~2wt%; Optionally, the biodegradable polymer material includes at least one of chitosan, cellulose derivatives, plant gums, and starch; Optionally, the clay material accounts for 0.5% to 1% of the mass of the chitosan solution; Further optionally, the clay material includes at least one of bentonite and kaolin. Further, optionally, the clay material includes clay that has been ground through a 300-mesh sieve; Optionally, the plant seeds include seeds of common drought-resistant plants; Further optionally, the common drought-resistant plants include at least one of Haloxylon ammodendron, Artemisia argyi, and Hippophae rhamnoides; Optionally, the amount of the polymeric initiator solution, phenolic acid and its derivative solution, and biodegradable polymeric material solution used is sufficient to completely immerse the plant seeds.

[0008] In one optional embodiment, the organic-inorganic porous sludge material comprises the following raw materials: composted sludge, inorganic porous material, organic binder, and humic acid compound fertilizer; Optionally, the mass ratio of the composted sludge, inorganic porous material, organic binder, and humic acid compound fertilizer is 1:(0.2~0.4):(0.05~0.2):(0.1~0.3). Optionally, the composted sludge comprises water supply sludge dewatered to a moisture content of less than 80%, mixed with crushed agricultural and forestry waste at a volume ratio of 1:(0.8~1.5), composted for 5~15 days, and then passed through a 2mm sieve to remove impurities. Further optionally, the agricultural and forestry waste includes at least one of branches, leaves, and straw; Optionally, the inorganic porous material includes at least one of vermiculite, perlite, and volcanic rock; Optionally, the organic binder includes at least one of starch and sodium carboxymethyl cellulose; Optionally, the humic acid compound fertilizer, by mass fraction, has a humic acid content of not less than 4.0% and a total nutrient (N+P2O5+K2O) content of not less than 30%.

[0009] In one optional embodiment, the water supply sludge-based hydrogel comprises the following raw materials: anionic natural polymer gel material, pore-forming agent, water supply sludge, water, and crosslinking agent; Optionally, the mass ratio of the anionic natural polymer gel material, the pore-forming agent, and the water supply sludge is 1:(0.5~1):(0.1~0.3). Further optionally, the water supply sludge includes sludge dried to a moisture content of <60% and ground through a 200-mesh sieve; Optionally, the mass ratio of the water to the total mass of the anionic natural polymer gel material, the pore-forming agent, and the water supply sludge is (2~4):1; Optionally, the crosslinking agent accounts for 3-10% of the total mass of the anionic natural polymer gel material, pore-forming agent, water supply sludge, and water. Optionally, the anionic natural polymer gel material includes at least one of sodium alginate, pectin, and sodium carboxymethyl cellulose; Optionally, the pore-forming agent includes at least one of polyethylene glycol, polypropylene glycol, and sodium bicarbonate; Optionally, the crosslinking agent comprises a calcium chloride solution; Further optionally, the concentration of the calcium chloride solution is 0.04~0.06 mol / L.

[0010] Secondly, the present invention also provides a method for preparing the above-mentioned seed complex, comprising the following steps: S1, the plant seeds are sequentially immersed in a polymeric initiator solution and a phenolic acid and its derivative solution for initiation, washed, immersed in a mixture of clay material and biodegradable polymer material solution, removed, and gradient dried to obtain stress-resistant seeds; S2, mix well-rotted sludge, inorganic porous material, organic binder, humic acid compound fertilizer and water to obtain mixture A, disperse stress-resistant seeds in mixture A, pour into a mold and compact, then freeze and dry in a gradient manner to obtain an intermediate; S3, mix anionic natural polymer gel material, pore-forming agent, water supply sludge, water and crosslinking agent to obtain mixture B, immerse intermediate in mixture B, let stand, dry and remove impurities to obtain the seed composite.

[0011] In one optional implementation, in S1, gradient drying includes sequentially performing a first drying, a second drying, and a third drying. Optionally, the temperature of the primary drying is 20~25℃, the humidity is 60~70%, and the time is 0.5~1.5h; Optionally, the secondary drying temperature is 25~30℃, the humidity is 45~55%, and the time is 0.5~1.5h; Optionally, the temperature of the three drying processes is 30~40℃, the humidity is 30~40%, and the time is 0.5~1.5h.

[0012] In one optional implementation, in step S2, gradient freezing includes performing a first freezing and a second freezing sequentially; Optionally, the temperature of the first freezing is -12 to -8°C, the time is 1.5 to 2 hours, and the cooling rate is 0.5 to 2°C / min; Optionally, the secondary freezing temperature is -27 to -23°C, the time is 5 to 10 hours, and the cooling rate is 0.5 to 2°C / min.

[0013] In one alternative implementation, in S2, drying includes vacuum freeze drying; Optionally, the vacuum freeze-drying includes vacuum freezing and low-temperature drying; Further optionally, the vacuum degree of the vacuum freezing is 0.05~0.1mbar, the freezing temperature is -22~-18℃, and the freezing time is 3~10h; Alternatively, the low-temperature drying temperature is 30~40℃, and the drying time is 4~8h.

[0014] In one optional embodiment, the mixture B includes slow stirring for 4 to 6 minutes, during which the mixture changes from a liquid state to a uniform and viscous sol state, and when picked up with a glass rod, it falls in a continuous thread without breaking immediately; In one optional implementation, the settling time in step S3 is 5 to 15 minutes.

[0015] In one optional embodiment, in step S3, the drying temperature is 25~40℃, the humidity is 20~40%, and the time is 1.5~3h.

[0016] In one optional implementation, step S1 specifically includes the following steps: (1) Seed screening: Select drought-resistant plant seeds with seed plumpness exceeding the average level to ensure the basic activity of the seeds. After screening, rinse with clean water 2-4 times and then drain the surface moisture.

[0017] (2) Initiation treatment: The selected seeds were soaked in a 10-20% polyethylene glycol solution at 15-35℃ for 4-12 h to adjust the osmotic pressure of the seeds, promote the synthesis of osmotic regulating substances in the seeds, and enhance the water retention capacity under drought conditions. Then the seeds were taken out and drained, and soaked again in a 0.2-2.5 mmol / L salicylic acid solution at 15-35℃ for 3-12 h to induce the increase of antioxidant enzyme activity in the seeds, reduce oxidative damage to the seeds, and inhibit premature germination of the seeds, thus adapting to the storage cycle of the material.

[0018] (3) Construction of surface protective layer: Rinse the seeds after initiation treatment with clean water 2-3 times, then immerse them in a 1-2% chitosan solution at 35-45℃, and add 0.5-1% clay material (including but not limited to one or more of bentonite, kaolin, etc., which can be ground and passed through a 300-mesh sieve to enhance the mechanical strength of the film layer and improve water retention capacity). Stir and mix for 10-35 minutes, then take them out. A thin film can be formed on the seed surface, which further strengthens the mechanical strength of the seeds.

[0019] (4) Gradient drying: The treated seeds are subjected to gradient drying treatment—drying at 20~25℃ and 60~70% humidity for 0.5~1.5h, followed by drying at 25~30℃ and 45~55% humidity for 0.5~1.5h, and then drying at 30~40℃ and 30~40% humidity for 0.5~1.5h. This avoids cracking of the seeds due to rapid dehydration, while strengthening the hardness of the seed coat and improving its resistance to mechanical extrusion during subsequent material preparation.

[0020] In one optional implementation, step S2 specifically includes the following steps: (1) Preparation of decomposed sludge substrate: The water supply sludge dehydrated to a moisture content of <80% is mixed with crushed agricultural and forestry waste (including but not limited to one or more of branches, leaves, straw, etc.) at a volume ratio of 1:0.8~1.5, composted for 5~15 days, and then passed through a 2mm sieve to remove impurities to obtain the decomposed sludge substrate.

[0021] (2) Preparation of organic-inorganic sludge protective layer precursor: The decomposed sludge substrate is mixed with inorganic porous filler (such as vermiculite, perlite, volcanic rock, etc.), organic binder (such as starch, sodium carboxymethyl cellulose, etc.), and humic acid compound fertilizer at a mass ratio of 1:0.2~0.4:0.05~0.2:0.1~0.3, and the moisture content is adjusted to 60~80% with deionized water to obtain the organic-inorganic sludge protective layer precursor.

[0022] (3) Seed complex preparation: The stress-resistant seeds obtained by S1 were pre-cooled at -15~-5℃ for 30 min to adapt to the low temperature environment in the subsequent material preparation process. Then, they were added to the organic-inorganic sludge protective layer precursor and mixed for 10~25 min to ensure that the seeds were evenly dispersed in the material (2~3 seeds per cubic centimeter). Then, they were poured into a cylindrical mold (1.5~3 cm in diameter and 2~4 cm in height), compacted, and covered with non-woven fabric. Then, gradient freezing was carried out: freezing at -12~-8℃ for 1.5~2 h, and deep freezing at -27~-23℃ for 5~10 h (cooling rate controlled at 0.5~2℃ / min).

[0023] (4) Preparation of organic-inorganic porous sludge-based stress-resistant seed composite material: The frozen seed composite material was freeze-dried under vacuum at -22 to -18°C for 3 to 10 hours in a vacuum environment (~0.05~0.1mbar), and then heated to 30 to 40°C for 4 to 8 hours to dry. The porous structure was formed by the sublimation of ice crystals, while avoiding thermal damage to the seeds, thus obtaining a stress-resistant seed composite material coated with organic-inorganic porous sludge material.

[0024] In one optional implementation, step S3 specifically includes the following steps: (1) Preparation of hydrogel prepolymer: The water supply sludge was dried in an oven to a moisture content of <60% and ground through a 200-mesh sieve. Then, sodium alginate, polyethylene glycol and the sieved water supply sludge powder were mixed in a ratio of 1:0.5~1:0.1~0.3. The mixture was dissolved in deionized water in a ratio of 1:2~4, heated to 35~40℃ and stirred for 20~40 min. After cooling to room temperature, 3~10% of 0.04-0.06mol / L calcium chloride solution was slowly added and stirred slowly for 4-6 min to crosslink and synthesize the hydrogel prepolymer.

[0025] (2) Outer hydrogel coating: The seed composite prepared by S2 is immersed in the hydrogel prepolymer solution (the solution covers the top of the material by 2~5cm), left to stand for 5~15min, and then dried at low temperature for 1.5~3h in an environment of 25~40℃ and 20~40% humidity to avoid excessive water absorption by the hydrogel leading to seed hypoxia.

[0026] (3) Preparation of water supply sludge-based seed dormancy chamber: After drying, remove surface impurities from the finished product, screen complete cylindrical materials, and prepare water supply sludge-based seed dormancy chamber. The product needs to be stored in a cool and dry environment (temperature ≤20℃, humidity ≤40%).

[0027] Thirdly, the present invention also provides an application of the above-mentioned seed complex or the seed complex prepared by the above-mentioned method in extreme arid environments such as rocky desertification.

[0028] In one alternative implementation, the application specifically includes the following steps: (1) Basic grass grid construction: Plant fiber materials such as wheat straw, rice straw or coconut coir are used for laying. The grass grid is 15~20cm high and buried 5~8cm deep. The specifications are 1m×1m or 1.5m×1.5m to ensure sand fixation stability.

[0029] (2) Seed dormancy chamber arrangement: Arrange seed dormancy chambers evenly in the grass square at a spacing of 20~35cm. Dig shallow pits (5~8cm deep, 3~5cm in diameter) in the grass squares. Place the seed composite vertically in the pits, with the top 1~3cm from the ground surface. Cover with a small amount of mixed soil (composted sludge: local soil = 1:3, 1~2cm thick) to avoid direct exposure of the material to strong light, which may cause hydrogel aging.

[0030] (3) If there is no natural rainfall within 72 hours after the materials are laid out, artificial watering is required (50-300mL of water per material). Drip irrigation should be used (to avoid water flow impact causing soil loss) to ensure that the hydrogel fully absorbs water (to reach the maximum water retention capacity).

[0031] The technical solution of this invention has the following advantages: 1. This invention provides a seed composite comprising, from the inside out, a core layer, an intermediate framework layer, and an outer water-retaining layer. The core layer is a stress-resistant seed, which can enhance the basic stress resistance of the seed and ensure the survival rate of the seed during the material preparation process. The intermediate framework layer is an organic-inorganic porous sludge material covering the core layer, which can provide a supporting framework and nutrients for the seed material. The outer water-retaining layer is a water-supplying sludge-based hydrogel covering the intermediate framework layer. Utilizing the multi-layered structure of the hydrogel and sludge-based nutrients, the material's nutrient and water retention capacity is enhanced, effectively strengthening the survival rate of seeds under rocky desertification conditions. The seed composite provided by this invention can not only effectively enhance the environmental stress resistance of plant seeds and ensure the survival rate of plants under harsh environmental conditions such as rocky desertification, but also compensate for the problems of insufficient water and nutrient supply, inadequate water and fertilizer retention capacity, and poor stability in rocky desertification soils, achieving the goals of windbreak and sand fixation and soil improvement.

[0032] 2. The present invention provides a seed complex in which the polymeric regulatory initiator solution is used to simulate a drought environment using high osmotic pressure substances, induce the expression of osmotic regulatory genes in seeds, accumulate soluble sugars, proline and other compatible solutes, and enhance the water-holding capacity of cells; the phenolic acid and its derivative solution can be used as signaling molecules to activate systemic acquired resistance in plants, enhance peroxidase activity, and scavenge reactive oxygen species; the biodegradable polymer material solution can utilize the adhesiveness, film-forming properties and semi-permeability of natural or synthetic polymer materials to form a physical barrier on the seed surface, and, together with inorganic fillers, enhance mechanical strength and slow down water loss.

[0033] 3. The present invention provides a seed composite, wherein the anionic natural polymer gel material can undergo ionic cross-linking with cations to form a three-dimensional network hydrogel; the pore-forming agent can occupy physical space in the hydrogel network, and after subsequent drying or dissolution, it can adjust the internal porosity of the gel, prevent the gel from being too dense and causing seed suffocation, and at the same time improve the flexibility of the gel film; the cross-linking agent is used to provide free high-valence metal ions to promote polymer cross-linking, so that the liquid sol is transformed into a solid hydrogel.

[0034] 2. The method for preparing the seed complex provided by the present invention, wherein in S1, gradient drying includes sequentially performing primary drying, secondary drying, and tertiary drying, which can prevent seeds from cracking due to rapid dehydration, while strengthening the hardness of the seed coat and improving its resistance to mechanical extrusion during subsequent material preparation; in S2, gradient freezing includes sequentially performing primary freezing and secondary freezing, which can control the freezing rate, reduce damage to seeds from sharp ice crystals, and improve seed survival rate; in S2, drying includes vacuum freeze-drying, which can realize the formation of a porous structure by sublimation of ice crystals, while avoiding thermal damage to seeds; in S3, standing and drying can prevent excessive water absorption by the hydrogel, which can lead to seed hypoxia. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of the seed complex obtained in Example 1 of the present invention.

[0037] Explanation of reference numerals in the attached figures: 1. Core layer; 2. Intermediate skeleton layer; 3. Outer water-retaining layer. Detailed Implementation

[0038] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0039] 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 limit the application; the terms “comprising” and “having” and any variations thereof in the text of this application are intended to cover non-exclusive inclusion.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed herein, and "0~5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to disclosing that the parameter can be, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0041] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0042] In the description of the embodiments of this application, the term "at least one" refers to one or more (including two).

[0043] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0044] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0045] The sludge used for water supply came from a waterworks in Anhui Province. On a dry basis, the organic matter content was 7.35%, and the inorganic components were SiO2 57.36%, Fe2O3 22.56%, Al2O3 10.41%, and CaO 6.67%. The preparation method and specific parameters of the composted sludge used are as follows: the water supply sludge dehydrated to 80% moisture content is mixed with crushed corn stalks and leaves at a volume ratio of 1:1 and composted for 10 days. Then, impurities are removed by passing through a 2mm sieve to obtain composted sludge. The humic acid compound fertilizer used was purchased from Yunnan Yuntianhua Co., Ltd., with a humic acid content of no less than 4%, and N, P2O5, and K2O contents of 15%, 15%, and 10%, respectively. The clay material used was bentonite that had been ground and passed through a 300-mesh sieve.

[0046] Example 1 This embodiment provides a seed complex, the structural schematic diagram of which is shown below. Figure 1 As shown, it includes a core layer, an intermediate skeleton layer, and an outer water-retaining layer; the specific preparation steps and parameter settings are as follows: S1. After screening the Haloxylon ammodendron seeds, soak them in a polyethylene glycol solution (15 wt%) at 25°C for 8 hours. Then, remove the seeds, drain them, and soak them again in a salicylic acid solution (1.0 mmol / L) at 25°C for 6 hours. Rinse them with water and then soak them in a chitosan solution (containing 0.8% bentonite by weight of chitosan solution) at 40°C with a chitosan concentration of 1.5 wt% for 20 minutes. Remove them and then perform gradient drying: dry at 22°C and 65% humidity for 1 hour, at 28°C and 50% humidity for 1 hour, and at 35°C and 35% humidity for 1 hour to obtain stress-resistant seeds. S2, well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer are mixed in a mass ratio of 1:0.3:0.1:0.2, and the moisture content is adjusted to 70% with deionized water to obtain mixture A; the stress-resistant seeds are pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter are added to mixture A, mixed and stirred for 20 min, poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm and compacted, and the surface of the mold is covered with non-woven fabric for gradient freezing: freezing at -10℃ for 1.5 h, deep freezing at -25℃ for 8 h (cooling rate of 1℃ / min), and then vacuum-freezing at -20℃ for 5 h using a vacuum freeze dryer at a vacuum degree of 0.08 mbar and a vacuum degree of 0.20 mbar, and then drying at 35℃ for 5 h to obtain an intermediate; S3. Sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:0.8:0.2 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 3:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, a 0.05 mol / L calcium chloride solution (the mass of the calcium chloride solution is 5% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. The intermediate is then immersed in mixture B (the solution covers the top of the material by 3 cm) and allowed to stand for 10 minutes. Subsequently, it is dried at 32°C and 30% humidity for 2 hours to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite, as shown in the schematic diagram. Figure 1 As shown.

[0047] Example 2 This embodiment provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. After screening the Haloxylon ammodendron seeds, they were soaked in a polyethylene glycol solution (18 wt%) at 25°C for 8 hours. The seeds were then drained and soaked again in a salicylic acid solution (1.8 mmol / L) at 25°C for 6 hours. After rinsing with water, they were soaked in a chitosan solution (containing 0.6% bentonite by mass of chitosan solution) at 40°C with a chitosan concentration of 1.8 wt% and stirred for 20 minutes. The mixture was then subjected to gradient drying: drying at 23°C and 66% humidity for 0.8 hours, drying at 26°C and 48% humidity for 0.8 hours, and drying at 36°C and 33% humidity for 0.8 hours to obtain stress-resistant seeds. S2, well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer were mixed in a mass ratio of 1:0.25:0.15:0.15, and the moisture content was adjusted to 70% with deionized water to obtain mixture A; the stress-resistant seeds were pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter were added to mixture A, mixed and stirred for 20 min, poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm and compacted, and the surface of the mold was covered with non-woven fabric for gradient freezing: freezing at -11℃ for 1.8 h, deep freezing at -26℃ for 7 h (cooling rate of 1.5℃ / min), and then vacuum-freezing at -20℃ for 5 h using a vacuum freeze dryer at a vacuum degree of 0.08 mbar and a low temperature of 35℃ for 5 h to obtain an intermediate; S3. Sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:0.6:0.15 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 2.5:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, a 0.055 mol / L calcium chloride solution (the mass of the calcium chloride solution accounts for 8% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. The intermediate is then immersed in mixture B (the solution covers the top of the material by 3 cm) and allowed to stand for 12 minutes. Subsequently, it is dried at 35°C and 35% humidity for 2.5 hours to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite.

[0048] Example 3 This embodiment provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. After screening Artemisia argyi seeds, they were soaked in a polyethylene glycol solution (10 wt%) at 25°C for 8 hours. The seeds were then drained and soaked again in a salicylic acid solution (2.5 mmol / L) at 25°C for 6 hours. After rinsing with water, they were soaked in a chitosan solution (containing 1% bentonite by weight of chitosan) at 40°C for 20 minutes. The mixture was then removed and subjected to gradient drying: drying at 20°C and 70% humidity for 0.5 hours, drying at 30°C and 45% humidity for 1.5 hours, and drying at 30°C and 40% humidity for 0.5 hours to obtain stress-resistant seeds. S2, well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer are mixed in a mass ratio of 1:0.2:0.2:0.1, and the moisture content is adjusted to 70% with deionized water to obtain mixture A; the stress-resistant seeds are pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter are added to mixture A, mixed and stirred for 20 min, poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm and compacted, and the surface of the mold is covered with non-woven fabric for gradient freezing: freezing at -8℃ for 1.5 h, deep freezing at -23℃ for 5 h (cooling rate of 2℃ / min), and then vacuum-freezing at -20℃ for 5 h using a vacuum freeze dryer at a vacuum degree of 0.08 mbar, and then drying at 35℃ for 5 h to obtain an intermediate; S3. Sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:0.5:0.3 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 2:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, a 0.06 mol / L calcium chloride solution (the mass of the calcium chloride solution accounts for 3% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. The intermediate is then immersed in mixture B (the solution covers the top of the material by 3 cm) and allowed to stand for 15 minutes. Then, it is dried at 25°C and 40% humidity for 1.5 hours to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite.

[0049] Example 4 This embodiment provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. After screening sea buckthorn seeds, they were soaked in a polyethylene glycol solution (20 wt%) at 25°C for 8 hours. The seeds were then drained and soaked again in a salicylic acid solution (0.2 mmol / L) at 25°C for 6 hours. After rinsing with water, they were soaked in a chitosan solution (containing 0.5% bentonite by weight of chitosan) at 40°C for 20 minutes. The mixture was then removed and subjected to gradient drying: drying at 25°C and 60% humidity for 1.5 hours, drying at 25°C and 55% humidity for 0.5 hours, and drying at 40°C and 30% humidity for 1.5 hours to obtain stress-resistant seeds. S2, well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer are mixed in a mass ratio of 1:0.4:0.05:0.3, and the moisture content is adjusted to 70% with deionized water to obtain mixture A; the stress-resistant seeds are pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter are added to mixture A, mixed and stirred for 20 min, poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm and compacted, and the surface of the mold is covered with non-woven fabric for gradient freezing: freezing at -12℃ for 2 h, deep freezing at -27℃ for 10 h (cooling rate of 0.5℃ / min), and then vacuum-freezing at -20℃ for 5 h using a vacuum freeze dryer at a vacuum degree of 0.08 mbar, and then drying at 35℃ for 5 h to obtain an intermediate; S3. Sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:1:0.1 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 4:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, a 0.04 mol / L calcium chloride solution (the mass of the calcium chloride solution is 10% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. The intermediate is then immersed in mixture B (the solution covers the top of the material by 3 cm) and allowed to stand for 5 minutes. Then, it is dried at 40°C and 20% humidity for 3 hours to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite.

[0050] Comparative Example 1 This comparative example provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. Well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer are mixed in a mass ratio of 1:0.4:0.05:0.3, and the moisture content is adjusted to 70% with deionized water to obtain mixture A. Screened Haloxylon ammodendron seeds are pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter are added to mixture A. The mixture is stirred for 20 min, poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm, compacted, and covered with non-woven fabric for gradient freezing: freezing at -12℃ for 2 h, deep freezing at -27℃ for 10 h (cooling rate of 0.5℃ / min). Then, a vacuum freeze dryer is used to first freeze at a vacuum degree of 0.08 mbar and a temperature of -20℃ for 5 h, and then dry at a low temperature of 35℃ for 5 h to obtain an intermediate. S2, sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:1:0.1 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 4:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, a 0.04 mol / L calcium chloride solution (the mass of the calcium chloride solution accounts for 10% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. The intermediate is then immersed in mixture B (the solution covers the top of the material by 3 cm) and allowed to stand for 5 minutes. Then, it is dried at 40°C and 20% humidity for 3 hours to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite.

[0051] Comparative Example 2 This comparative example provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. After screening the Haloxylon ammodendron seeds, soak them in a polyethylene glycol solution (20 wt%) at 25°C for 8 hours. Then, remove the seeds, drain them, and soak them again in a salicylic acid solution (0.2 mmol / L) at 25°C for 6 hours. Rinse them with water and then soak them in a chitosan solution (containing 0.5% bentonite by weight of chitosan solution) at 40°C for 20 minutes. Remove them and then perform gradient drying: dry at 25°C and 60% humidity for 1.5 hours, dry at 25°C and 55% humidity for 0.5 hours, and dry at 40°C and 30% humidity for 1.5 hours to obtain stress-resistant seeds. S2, sodium alginate, polyethylene glycol, and water supply sludge (60% moisture content and passed through a 200-mesh sieve) are mixed in a ratio of 1:1:0.1 and dissolved in deionized water (the mass ratio of water to the total mass of sodium alginate, polyethylene glycol, and water supply sludge is 4:1). The mixture is heated to 35°C and stirred for 30 minutes. After cooling to room temperature, the mixture is poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm. A 0.04 mol / L calcium chloride solution (the mass of the calcium chloride solution accounts for 10% of the total mass of sodium alginate, polyethylene glycol, water supply sludge, and water) is slowly added and stirred slowly for 5 minutes to obtain mixture B. Subsequently, stress-resistant seeds are immersed in mixture B at a rate of 3 seeds per cubic centimeter and allowed to stand for 5 minutes. Then, the mixture is dried for 3 hours at a temperature of 40°C and a humidity of 20% to remove surface impurities. Complete cylindrical materials are then screened to obtain the seed composite.

[0052] Comparative Example 3 This embodiment provides a seed complex, and the specific preparation steps and parameter settings are as follows: S1. After screening the Haloxylon ammodendron seeds, soak them in a polyethylene glycol solution (20 wt%) at 25°C for 8 hours. Then, remove the seeds, drain them, and soak them again in a salicylic acid solution (0.2 mmol / L) at 25°C for 6 hours. Rinse them with water and then soak them in a chitosan solution (containing 0.5% bentonite by weight of chitosan solution) at 40°C for 20 minutes. Remove them and then perform gradient drying: dry at 25°C and 60% humidity for 1.5 hours, dry at 25°C and 55% humidity for 0.5 hours, and dry at 40°C and 30% humidity for 1.5 hours to obtain stress-resistant seeds. S2, well-rotted sludge, volcanic rock, starch, and humic acid compound fertilizer are mixed in a mass ratio of 1:0.4:0.05:0.3, and the moisture content is adjusted to 70% with deionized water to obtain mixture A. The stress-resistant seeds are pre-cooled at -5℃ for 30 min, and then 3 seeds per cubic centimeter are added to mixture A and mixed for 20 min. The mixture is poured into a cylindrical mold with a diameter of 2 cm and a height of 3 cm and compacted. The mold surface is covered with non-woven fabric and subjected to gradient freezing: freezing at -12℃ for 2 h, deep freezing at -27℃ for 10 h (cooling rate of 0.5℃ / min). Then, a vacuum freeze dryer is used to first freeze at a vacuum degree of 0.08 mbar and a temperature of -20℃ for 5 h, and then dry at a low temperature of 35℃ for 5 h to remove surface impurities. Complete cylindrical profiles are screened to obtain the seed composite.

[0053] Experimental Example 1 The seed complexes prepared in each embodiment and comparative example were subjected to dormancy resistance tests. The specific test methods are as follows: The seed complexes prepared in each embodiment and comparative example were buried vertically in dry sand (10% moisture content, 1.2% organic matter content), with the material surface 2 cm below the sand surface. After 30 days, the seed complexes were removed and the germination rate of the seeds in the material was determined in accordance with GB / T 3543.4-2025 "Specifications for the Inspection of Crop Seeds Part 4: Germination Test for Sowing Quality".

[0054] The specific test results are shown in Table 1: Table 1 Seed germination rate

[0055] The data above shows that the seed germination rate of the example was significantly higher than that of the control group. This is because it constructed a three-layer structure: a core layer (stress-resistant seeds), an intermediate framework layer (organic-inorganic porous sludge material), and an outer water-retaining layer (water supply sludge-based hydrogel). This structure ensured seed survival during material preparation from three dimensions: seed pretreatment, material preparation process adaptation, and synergistic protection of the structural layers, significantly improving the environmental stress resistance of the seeds. Compared to Example 4, Comparative Example 1, due to insufficient basic stress resistance, experienced seed inactivation during material preparation due to drying, mechanical compression, and chemical stimulation, resulting in the most severe impact on its germination rate, which decreased to 31.8%. Comparative Example 2, lacking an intermediate framework layer (organic-inorganic porous sludge material), experienced partial seed inactivation due to mechanical compression and chemical stimulation during material preparation, ultimately resulting in a germination rate of 45.3%. Comparative Example 3, lacking an outer water-retaining layer (water supply sludge-based hydrogel), saw a decrease in seed survival rate after prolonged placement in arid sandy soil, ultimately achieving a germination rate close to that of Comparative Example 2, at 42.3%.

[0056] Experiment Example 2 The seed complexes prepared in each embodiment and comparative example were tested for application in soil improvement. The specific test methods are as follows: In the Kubuqi Desert environment of Inner Mongolia, seed complexes prepared in each embodiment and comparative example were vertically buried at 30 cm intervals in straw checkerboards with a height of 18 cm, a burial depth of 5 cm, and a depth of 1 m x 1 m. The top of the seed complexes was 2 cm below the ground surface, and the surface was covered with a mixed soil (composted sludge substrate: local soil = 1:3). After the arrangement was completed, 200 mL of water was added artificially. Six months later, the total biomass of all plants in the straw checkerboards, the moisture content of the sand, and the organic matter content of the sand were measured.

[0057] The total biomass is obtained by collecting all plants in the grass grid, drying them to constant weight in an oven at 105°C, and testing the total dry weight of the plants. The total dry weight of the plants per unit area is the total biomass. The moisture content of the sandy soil was tested by taking sandy soil samples at a depth of 10 cm and measuring the moisture content according to HJ 613-2011 "Determination of Dry Matter and Moisture in Soil - Gravimetric Method". The organic matter content of the sandy soil was tested by taking sandy soil from a depth of 10cm and measuring its organic matter content according to NY / T 1121.6-2006 "Soil Testing Part 6: Determination of Soil Organic Matter".

[0058] The specific test results are shown in Table 2: Table 2. Test data on soil amendment application

[0059] The data above show that the total biomass, sandy soil moisture content, and organic matter content of Examples 1-4 were significantly higher than those of the blank group and the control group, indicating that the seed complex prepared by the present invention significantly improved the seed germination rate in sandy soil environment, and its synergistic effect with grass checkerboard can significantly enhance its efficacy.

[0060] As shown in Experiment 1, the seed survival rates of the control group and comparative examples 1-3 under arid sandy soil conditions were lower than those of the example. Under the conditions of this experiment, the seed germination rates of the control group and comparative examples 1-3 were lower than those of the example. Obviously, their performance in soil improvement was weaker than that of the example.

[0061] Comparative Example 1, lacking stress resistance pretreatment, experienced a significantly lower seed germination rate, resulting in a relatively lower total biomass compared to Comparative Examples 2-3. Its intermediate and outer hydrogel layers were not significantly affected, and the soil moisture content and organic matter content were minimally impacted. Seed survival under extreme conditions remained superior to the control group, thus all indicators were better than the control group. Comparative Example 2, lacking an intermediate framework layer (organic-inorganic porous sludge material), suffered from insufficient seed nutrient supply, leading to a lower total biomass and a lower total organic matter content in the sand compared to Comparative Examples 1 and 3. However, its outer hydrogel layer was not significantly affected, minimizing the impact on soil moisture content. Comparative Example 3, lacking an outer water-retaining layer (water supply sludge-based hydrogel), exhibited reduced water retention. However, due to its intermediate organic-inorganic porous framework material, it still possessed certain water retention and nutrient slow-release capabilities. Its soil moisture content was slightly higher than the blank group and the control group, but lower than the examples and Comparative Examples 1 and 2, with minimal impact on soil organic matter.

[0062] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A seed complex, characterized in that, From the inside out, it includes a core layer, an intermediate skeleton layer, and an outer water-retaining layer; The core layer consists of stress-resistant seeds; The intermediate framework layer is an organic-inorganic porous sludge material that covers the core layer; The outer water-retaining layer is a water supply sludge-based hydrogel that covers the middle skeleton layer.

2. The seed complex according to claim 1, characterized in that, The stress-resistant seeds include the following raw materials: Plant seeds, polymeric initiator solutions, phenolic acids and their derivatives solutions, biodegradable polymer solutions, and clay materials; Optionally, the mass concentration of the polymeric initiator solution is 10wt%~20wt%; Optionally, the concentration of the phenolic acid and its derivative solution is 0.2~2.5 mmol / L; Optionally, the mass concentration of the biodegradable polymer solution is 1wt%~2wt%; Optionally, the mass of the clay material accounts for 0.5% to 1% of the mass of the biodegradable polymer solution.

3. The seed complex according to claim 1 or 2, characterized in that, The organic-inorganic porous sludge material comprises the following raw materials: Well-rotted sludge, inorganic porous materials, organic binders, and humic acid compound fertilizer; Optionally, the mass ratio of the composted sludge, inorganic porous material, organic binder and humic acid compound fertilizer is 1:(0.2~0.4):(0.05~0.2):(0.1~0.3).

4. The seed complex according to any one of claims 1 to 3, characterized in that, The water supply sludge-based hydrogel comprises the following raw materials: anionic natural polymer gel material, pore-forming agent, water supply sludge, water, and crosslinking agent; Optionally, the mass ratio of the anionic natural polymer gel material, the pore-forming agent, and the water supply sludge is 1:(0.5~1):(0.1~0.3). Optionally, the mass ratio of the water to the total mass of the anionic natural polymer gel material, the pore-forming agent, and the water supply sludge is (2~4):1; Optionally, the crosslinking agent accounts for 3 to 10% of the total mass of the anionic natural polymer gel material, pore-forming agent, water supply sludge, and water.

5. A method for preparing the seed complex according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1, the plant seeds are sequentially immersed in a polymeric initiator solution and a phenolic acid and its derivative solution for initiation, washed, immersed in a mixture of clay material and biodegradable polymer material solution, removed, and gradient dried to obtain stress-resistant seeds; S2, mix well-rotted sludge, inorganic porous material, organic binder, humic acid compound fertilizer and water to obtain mixture A, disperse stress-resistant seeds in mixture A, pour into a mold and compact, then freeze and dry in a gradient manner to obtain an intermediate; S3, mix anionic natural polymer gel material, pore-forming agent, water supply sludge, water and crosslinking agent to obtain mixture B, immerse intermediate in mixture B, let stand, dry and remove impurities to obtain the seed composite.

6. The preparation method according to claim 5, characterized in that, In S1, gradient drying includes sequentially performing a first drying, a second drying, and a third drying. Optionally, the temperature of the primary drying is 20~25℃, the humidity is 60~70%, and the time is 0.5~1.5h; Optionally, the secondary drying temperature is 25~30℃, the humidity is 45~55%, and the time is 0.5~1.5h; Optionally, the temperature of the three drying processes is 30~40℃, the humidity is 30~40%, and the time is 0.5~1.5h.

7. The preparation method according to claim 5 or 6, characterized in that, In S2, gradient freezing includes performing a first freezing and a second freezing sequentially. Optionally, the temperature of the first freezing is -12 to -8°C, the time is 1.5 to 2 hours, and the cooling rate is 0.5 to 2°C / min; Optionally, the secondary freezing temperature is -27 to -23°C, the time is 5 to 10 hours, and the cooling rate is 0.5 to 2°C / min.

8. The preparation method according to any one of claims 5-7, characterized in that, In step S2, drying includes vacuum freeze drying; Optionally, the vacuum freeze-drying includes vacuum freezing and low-temperature drying; And / or, in S3, the settling time is 5~15 minutes.

9. The preparation method according to any one of claims 5-8, characterized in that, In step S3, the drying temperature is 25~40℃, the humidity is 20~40%, and the time is 1.5~3h.

10. The application of a seed complex according to any one of claims 1-4 or a seed complex prepared by any one of claims 5-9 in a rocky desertification arid environment.

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