A composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, its preparation method and application

Abstract

This invention discloses a composite material based on "sponge soil" to enhance the water retention and slow evaporation performance of sandy soil, its preparation method, and its application, belonging to the field of sandy soil improvement technology in arid areas. The preparation method includes the following steps: preparing a plant-derived colloidal solution using natural gum powder and a crosslinking agent as raw materials; mixing the plant-derived colloidal solution with a porous matrix material to obtain the composite material based on "sponge soil" to enhance the water retention and slow evaporation performance of sandy soil. This invention constructs a multi-level porous structure of "porous channel water-retaining colloidal network," achieving rapid water absorption and efficient water retention while effectively inhibiting ineffective evaporation and deep seepage of water. This significantly improves the water retention capacity of sandy soil and extends the effective water supply time, providing an environmentally friendly and easy-to-apply improvement method for the ecological restoration of desertified soils. It solves the problems of poor water retention capacity, severe water evaporation and seepage in sandy soils, and the limited functionality and insufficient long-term effectiveness of single improvement materials in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of sandy soil improvement technology in arid areas, specifically to a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, its preparation method and application. Background Technology

[0002] According to data from the Sixth National Desertification and Sandification Survey, the area of ​​desertified land in my country has reached 257.3713 million hectares. 3 Sandy soils, accounting for 77.59% of the total surveyed area and 26.81% of the national land area, pose a persistent threat to food security and ecological restoration. Due to their coarse particles, large pores, and lack of organic matter, sandy soils generally suffer from poor water retention, rapid nutrient loss, and loose structure, severely hindering vegetation restoration and ecological reconstruction. Against this backdrop, the concept of "sponge soil," simulating the excellent water-holding function of natural soils, has emerged. Exploring new materials and methods for improving sandy soils with intelligent water regulation has become an urgent need for ecological governance in arid and semi-arid regions. Among these, developing a composite material system that can synergistically achieve efficient water storage and evaporation suppression is crucial for improving soil water resource utilization efficiency and promoting ecological restoration in sandy areas.

[0003] CN 118307373 A discloses a biomass-based soil conditioner and its preparation method. The method involves combining modified charcoal powder loaded with humic acid with sodium alginate hydrogel to form hydrogel beads, and introducing citric acid-modified cellulose nanocrystals to improve the slow-release effect of humic acid and soil water retention, thereby enhancing fertilizer efficacy and reducing water loss. While this invention helps improve soil structure and fertility, it presents challenges due to the complex modified charcoal process, potential chemical risks such as skin allergies, eye irritation, and water pollution from the modifying agents used (e.g., polyethyleneimine), and the generation of greenhouse gases during raw material production.

[0004] CN 120699282 A discloses a hydrothermal carbon-reinforced dual-network composite hydrogel and its preparation method. This invention constructs a hydrogel with a dual-network structure by mixing sodium alginate with biomass hydrothermal carbon and introducing monomers such as acrylamide for polymerization. This method significantly improves the hydrogel's water absorption, water retention, mechanical toughness, and thermal stability, making it better suited for long-term load-bearing and repeated expansion and contraction applications in soil. However, the hydrothermal carbon used in this technology is currently limited in commercial production and is expensive; furthermore, if the acrylamide and other chemical monomers used in the preparation process do not react completely and remain in the gel, there may be certain biotoxicity risks. In contrast, alternative raw materials such as expanded minerals or biomass porous materials have advantages such as wide availability, lower cost, and higher environmental compatibility.

[0005] Currently, common methods for improving water retention in sandy soils often rely on single materials, such as traditional water-retaining agents or locally sourced topsoil. These methods are often functionally limited, lacking synergy between materials, and struggle to consistently exert their "water absorption-storage-slow release" regulatory effects in the long term, especially in arid, high-evaporation sandy areas. Furthermore, while many laboratory experimental formulations perform well under ideal conditions, they face challenges such as poor adaptability to field environments, weak resilience, high costs, or complex construction, making them difficult to effectively replicate and promote in large-scale desertification control. Therefore, developing a porous material-hydrogel composite improvement technology that is highly environmentally responsive, has efficient material synergy, and is easy to apply in the field has become an important research direction in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a composite material based on "sponge soil" to enhance the water retention and slow evaporation performance of sandy soil, along with its preparation method and application. By constructing a multi-level porous structure of "multi-channel water storage - colloidal network water locking," it achieves rapid water absorption and storage, efficient water retention, and effectively inhibits ineffective water evaporation and deep seepage. This significantly enhances the water retention capacity of sandy soil, prolongs the ineffective evaporation and deep seepage of water, and extends the effective water supply time. It also provides an environmentally friendly and easy-to-apply improvement method for the ecological restoration of desertified soil, solving the problems of poor water retention capacity, severe water evaporation and seepage in sandy soil, and the limited function and insufficient long-term effectiveness of single improvement materials in existing technologies.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides a method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, comprising the following steps: S1. Preparation of plant-derived colloidal solutions using natural gum powder and crosslinking agents as raw materials; S2. The plant-derived colloidal solution obtained in S1 is mixed with a porous matrix material to prepare a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil.

[0008] The beneficial effects of this invention are as follows: This invention provides a method for preparing a composite material based on "sponge soil" to enhance the water storage and slow evaporation performance of sandy soil. The method uses plant-derived colloidal materials with water absorption and swelling properties and temperature-sensitive water release characteristics, and porous matrix materials with hydrophilicity, large specific surface area, and semi-closed pore structure as the main raw materials. The preparation method is simple, mild, and low-cost. By combining the characteristics of plant-derived colloidal materials with those of porous matrix materials, a multi-level pore structure of "porous channel water storage - alternating network water locking" is constructed. This achieves in-situ optimization of the sandy soil pore structure, enhancing rapid water absorption while effectively inhibiting gravity loss and evaporation, significantly enhancing the sandy soil's own water storage and retention capacity. Furthermore, the plant-derived colloidal materials form a dynamic hydration network on the surface and between particles of the porous matrix material. When wet, they absorb water and swell to fill large pores; when dry, they shrink to slow water evaporation, forming a stable slow-release microenvironment in the sandy soil and extending the continuous supply time of effective water.

[0009] Furthermore, S1 specifically includes the following steps: Natural rubber powder solution and crosslinking agent solution were prepared separately, and then the natural rubber powder solution and crosslinking agent solution were mixed to obtain plant-derived colloidal solution.

[0010] Furthermore, the mass concentration of the natural rubber powder solution is 0.1%-1%; the mass concentration of the crosslinking agent solution is 0.1%-1%; and the mass ratio of the natural rubber powder solution to the crosslinking agent solution is (5-15):1.

[0011] Preferably, the mass concentration of the natural rubber powder solution is 0.5%; the mass concentration of the crosslinking agent solution is 0.5%; and the mass ratio of the natural rubber powder solution to the crosslinking agent solution is 10:1.

[0012] Furthermore, the natural gum powder is a natural polysaccharide containing cis-ortho-hydroxyl groups (cis-ortho-hydroxyl groups such as...). Figure 1 (As shown in red); the crosslinking agent is a borate or its derivative.

[0013] Furthermore, the natural polysaccharide containing cis-ortho-hydroxyl groups is at least one of guar gum, guar gum, and locust bean gum.

[0014] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention uses plant-derived colloidal materials with water absorption and expansion and temperature-sensitive water release characteristics as one of the raw materials. After absorbing water, the volume of such materials increases, and when the temperature rises, the internal water can be slowly released and the volume shrinks slightly. Through the reversible "water absorption-water release" process, the water retention and regulation function similar to "sponge soil" is achieved, which is suitable for soil improvement in arid desert areas.

[0015] Furthermore, the porous matrix material in S2 includes at least one of expanded perlite (EP), expanded vermiculite (EV), rock wool (RW), porous ceramsite (CP), and coconut coir (YK).

[0016] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: This invention uses a variety of natural mineral / biomass porous matrix materials that exhibit superior performance in terms of water content and evaporation rate. These materials possess hydrophilicity, large specific surface area, and a semi-closed pore structure, enabling them to rapidly store water and release it slowly and controllably when the temperature rises, while maintaining the basic stability of the pore structure; its water storage... The water release process has the characteristics of efficient water buffering and continuous water supply, and can form a multi-level porous structure with soil particles, thereby improving the structure of sandy soil, enhancing water retention capacity, slowing down water migration, and forming a water-storing structure with the function of "sponge soil". Slow evaporation system.

[0017] Furthermore, in S2, the mixing method is either immersion or spraying.

[0018] Furthermore, the conditions for the impregnation method are to immerse the porous matrix material in a plant-derived colloidal solution for 30-120 minutes.

[0019] Furthermore, the conditions for the spraying method are as follows: the plant-derived colloidal solution is sprayed into the porous matrix material, and the solution is sprayed evenly 2-4 times, with an interval of 5-10 minutes between each spraying.

[0020] In a second aspect, the present invention provides a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, which is prepared by the above-described preparation method.

[0021] The beneficial effects of the present invention are as follows: The present invention prepares a composite material with a "sponge soil" structure by using plant-derived colloids and porous matrix materials as raw materials. This material can be applied to sandy soil by direct mixing or surface covering, which can significantly enhance the water storage and water retention capacity of the sandy soil itself, and form a water slow-release microenvironment to prolong the continuous supply time of effective water.

[0022] In a third aspect, the present invention provides the application of the above-mentioned composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil in the improvement of arid sandy soil.

[0023] The beneficial effects of this invention are as follows: The composite material obtained by this invention can be directly applied to the improvement of arid sandy soil. By utilizing its beneficial effects such as enhancing the water storage and holding capacity of sandy soil and extending the effective water supply time, it can improve water use efficiency while reducing irrigation frequency and water consumption, and provide an economical and effective technical approach for the improvement of sandy soil and vegetation restoration in arid and semi-arid regions.

[0024] In a fourth aspect, the present invention provides a method for improving arid sandy soil, comprising the following steps: incorporating the above-mentioned composite material based on "sponge soil" to improve the water storage and slow evaporation performance of sandy soil into the arid sandy soil to be improved, and after mixing, laying and curing, the arid sandy soil improvement is completed.

[0025] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: This invention provides a method for improving arid sandy soil by using a composite material based on "sponge soil" to enhance the water storage and slow evaporation performance of sandy soil. The method has a simple application process, and the raw materials of the composite material itself are widely available and biodegradable, and will not cause secondary pollution. It provides an economical and effective technical approach for sandy soil improvement and vegetation restoration, and has broad application prospects and economic benefits.

[0026] Furthermore, the amount of porous matrix material incorporated into the composite material is 10%-25% of the volume of the arid sandy soil to be improved, and the amount of plant-derived colloidal solution incorporated is 20%-25% of the mass of the arid sandy soil to be improved.

[0027] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The present invention has optimized the application amount of the composite material in the improvement of arid sandy soil, which further improves the effect of the composite material on the structure, water retention capacity and water transport of sandy soil.

[0028] Furthermore, plant selection and sowing were carried out on the arid sandy soil to be improved.

[0029] Furthermore, the aforementioned plants include Leymus chinensis, Suaeda salsa, Smilax china, and Camel thorn.

[0030] Furthermore, the sowing density for Leymus chinensis is 1.5-2.5 kg / mu, for Suaeda salsa var. ...

[0031] Preferably, the sowing density of Leymus chinensis is 2 kg / mu, the sowing density of Suaeda salsa is 1.5 kg / mu, the sowing density of Alternaria lobata is 1.5 kg / mu, and the sowing density of Saussurea costatum is 1.5 kg / mu.

[0032] In a fifth aspect, the present invention provides an improved soil based on a composite material for enhancing the water retention and slow evaporation performance of sandy soil using a "sponge soil" approach. The improved soil is prepared by the following method: the above-mentioned composite material for enhancing the water retention and slow evaporation performance of sandy soil using a "sponge soil" approach is compounded with soil to obtain the improved soil.

[0033] The beneficial effects of this invention are as follows: This invention prepares improved soil by compounding composite materials with soil, which can be directly applied to the improvement of sandy soil by surface covering. The soil to be improved can be selected from the sandy soil to be improved. The improvement process is simple and will not cause secondary pollution.

[0034] Furthermore, the amount of porous matrix material incorporated into the composite material is 10%-25% of the soil volume, and the amount of plant-derived colloidal solution incorporated is 20%-25% of the soil mass.

[0035] The present invention has the following beneficial effects: 1. In this invention, a composite of biomass-based porous materials and plant-derived colloids is used to achieve water storage through porous channels. A multi-level porous structure with a "colloidal network for water locking" creates a "sponge soil" structure. This structure achieves in-situ optimization of the sandy soil's pore structure, enhancing rapid water absorption while effectively inhibiting gravity loss and evaporation, significantly improving the sandy soil's water storage and retention capacity.

[0036] 2. In this invention, plant-derived colloids form a dynamic hydration network on the surface of porous materials and between particles. When wet, they absorb water and swell to fill large pores, and when dry, they shrink to slow down water evaporation. This structure not only retains water inside the porous material and in the colloidal network through capillary action and hydrogen bonding, but also enables reversible regulation of the water absorption and release process during wet-dry cycles, thereby forming a stable slow-release microenvironment in sandy soil and extending the continuous supply time of effective water.

[0037] 3. The composite material obtained in this invention has good environmental adaptability and ease of application. The material itself is widely available, biodegradable, and will not cause secondary pollution; its application process is simple, and it can be applied to sandy soil by direct mixing or surface covering. While reducing the frequency of irrigation and water consumption, it improves water use efficiency, providing an economical and effective technical approach for sandy soil improvement and vegetation restoration in arid and semi-arid regions. Attached Figure Description

[0038] Figure 1 This is a structural diagram of cis-ortho-hydroxyl compounds, where the red markings represent cis-ortho-hydroxyl groups; Figure 2 This is a schematic diagram illustrating the mechanism by which the composite material prepared according to the present invention improves soil. Figure 3 Figure 1 shows the experimental results of soil saturation volume water content improved by natural porous materials in Experiment Example 1. Figure 4 Figure 2 shows the experimental results of saturated volumetric water content of soil modified with composite materials in Experiment Example 2. Figure 5 Map showing annual precipitation and average annual temperature in Hotan Prefecture, Xinjiang; Figure 6 This is a diagram showing the results of field application experiments of composite materials. Detailed Implementation

[0039] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0040] Example 1: A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil includes the following steps: S1. Preparation of plant-derived colloidal solutions First, guar gum is stirred and dispersed evenly in water to prepare a natural gum powder aqueous solution with a mass fraction of 0.5%; then, organoboroester is stirred and dispersed in water to prepare a crosslinking agent solution with a mass fraction of 0.5%; finally, the natural gum powder aqueous solution and the crosslinking agent solution are mixed at a mass ratio of 10:1 to form a uniform slurry, thus obtaining a plant-derived colloidal solution.

[0041] S2, Preparation of composite materials Coconut coir (YK) was mixed with the plant-derived colloidal solution obtained in S1 and soaked for 30 min to obtain a composite material. The ratio of YK to plant-derived colloidal solution was determined by the amount of YK incorporated when improving the sand. In this embodiment, the amount of YK incorporated was 10%, 15%, 20%, and 25% of the volume of the sand to be improved, and the amount of plant-derived colloidal solution incorporated was 20%, 22.5%, and 25% of the mass of the sand to be improved.

[0042] A method for improving arid sandy soil (see schematic diagram) Figure 2 (As shown), including the following steps: The composite material was prepared according to the above-mentioned dosage, and then the obtained composite material was mixed into the sandy soil to be improved. After mixing, laying and curing, a coating with water retention and structural reinforcement functions was formed. Finally, plants were planted in the sandy soil area to be improved, including Leymus chinensis, Suaeda salsa, Smilax china and Camel thorn. The sowing density of Leymus chinensis was 2 kg / mu, Suaeda salsa was 1.5 kg / mu, Camel thorn was 1.5 kg / mu, and Smilax china was 1.5 kg / mu. Finally, the improvement of arid sandy soil was completed.

[0043] Example 2: A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil includes the following steps: S1. Preparation of plant-derived colloidal solutions First, guar gum is stirred and dispersed evenly in water to prepare a natural gum powder aqueous solution with a mass fraction of 0.5%; then, organoboroester is stirred and dispersed in water to prepare a crosslinking agent solution with a mass fraction of 0.5%; finally, the natural gum powder aqueous solution and the crosslinking agent solution are mixed at a mass ratio of 10:1 to form a uniform slurry, thus obtaining a plant-derived colloidal solution.

[0044] S2, Preparation of composite materials Expanded vermiculite (EV) was mixed with the plant-derived colloidal solution obtained in S1 and soaked for 30 min to obtain a composite material. The ratio of EV to plant-derived colloidal solution was determined by the amount of EV incorporated when improving the sand. In this embodiment, the amount of EV incorporated was 10%, 15%, 20%, and 25% of the volume of the sand to be improved, and the amount of plant-derived colloidal solution incorporated was 20%, 22.5%, and 25% of the mass of the sand to be improved.

[0045] A method for improving arid sandy soil includes the following steps: The composite material was prepared according to the above-mentioned dosage, and then the obtained composite material was mixed into the sandy soil to be improved. After mixing, laying and curing, a coating with water retention and structural reinforcement functions was formed. Finally, plants were planted in the sandy soil area to be improved, including Leymus chinensis, Suaeda salsa, Smilax china and Camel thorn. The sowing density of Leymus chinensis was 2 kg / mu, Suaeda salsa was 1.5 kg / mu, Camel thorn was 1.5 kg / mu, and Smilax china was 1.5 kg / mu. Finally, the improvement of arid sandy soil was completed.

[0046] Example 3: A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil includes the following steps: S1. Preparation of plant-derived colloidal solutions First, guar gum is stirred and dispersed evenly in water to prepare a natural gum powder aqueous solution with a mass fraction of 0.5%; then, organoboroester is stirred and dispersed in water to prepare a crosslinking agent solution with a mass fraction of 0.5%; finally, the natural gum powder aqueous solution and the crosslinking agent solution are mixed at a mass ratio of 10:1 to form a uniform slurry, thus obtaining a plant-derived colloidal solution.

[0047] S2, Preparation of composite materials Expanded perlite (EP) was mixed with the plant-derived colloidal solution obtained in S1 and soaked for 30 min to obtain a composite material. The ratio of EP to plant-derived colloidal solution was determined by the amount of EP incorporated when improving the sand. In this embodiment, the amount of EP incorporated was 10%, 15%, 20%, and 25% of the volume of the sand to be improved, and the amount of plant-derived colloidal solution incorporated was 20%, 22.5%, and 25% of the mass of the sand to be improved.

[0048] A method for improving arid sandy soil includes the following steps: The composite material was prepared according to the above-mentioned dosage, and then the obtained composite material was mixed into the sandy soil to be improved. After mixing, laying and curing, a coating with water retention and structural reinforcement functions was formed. Finally, plants were planted in the sandy soil area to be improved, including Leymus chinensis, Suaeda salsa, Smilax china and Camel thorn. The sowing density of Leymus chinensis was 2 kg / mu, Suaeda salsa was 1.5 kg / mu, Camel thorn was 1.5 kg / mu, and Smilax china was 1.5 kg / mu. Finally, the improvement of arid sandy soil was completed.

[0049] Example 4: A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil includes the following steps: S1. Preparation of plant-derived colloidal solutions First, guar gum is stirred and dispersed evenly in water to prepare a natural gum powder aqueous solution with a mass fraction of 0.5%; then, organoboroester is stirred and dispersed in water to prepare a crosslinking agent solution with a mass fraction of 0.5%; finally, the natural gum powder aqueous solution and the crosslinking agent solution are mixed at a mass ratio of 10:1 to form a uniform slurry, thus obtaining a plant-derived colloidal solution.

[0050] S2, Preparation of composite materials Rock wool (RW) was mixed with the plant-derived colloidal solution obtained in S1 and soaked for 30 min to obtain a composite material. The ratio of RW to plant-derived colloidal solution was determined by the amount of RW incorporated when improving the sand. In this embodiment, the amount of RW incorporated was 10%, 15%, 20%, and 25% of the volume of the sand to be improved, and the amount of plant-derived colloidal solution incorporated was 20%, 22.5%, and 25% of the mass of the sand to be improved.

[0051] A method for improving arid sandy soil includes the following steps: The composite material was prepared according to the above-mentioned dosage, and then the obtained composite material was mixed into the sandy soil to be improved. After mixing, laying and curing, a coating with water retention and structural reinforcement functions was formed. Finally, plants were planted in the sandy soil area to be improved, including Leymus chinensis, Suaeda salsa, Smilax china and Camel thorn. The sowing density of Leymus chinensis was 2 kg / mu, Suaeda salsa was 1.5 kg / mu, Camel thorn was 1.5 kg / mu, and Smilax china was 1.5 kg / mu. Finally, the improvement of arid sandy soil was completed.

[0052] Comparative Example 1: A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil includes the following steps: The preparation method of this comparative example is basically the same as that of Example 1, except that YK, which is a porous matrix material, is not added to the composite material in this comparative example, while the other steps remain unchanged.

[0053] Experiment Example 1: Experiment on Improving Soil Saturated Volume Moisture Content with Natural Porous Materials I. Experimental Methods RW, EP, YK, EV1 (expanded vermiculite with a particle size of 1-3 mm), and EV2 (expanded vermiculite with a particle size of 3-5 mm) were used individually as porous matrix materials to improve arid sandy soil (initial soil moisture content of 10%), with incorporation amounts of 10%, 15%, 20%, and 25%, respectively. A control group (CK) without incorporation was used. The saturated volumetric water content of the improved soil was calculated. Three parallel experimental groups were set up for each material ratio, as shown below: The required amount of soil and porous matrix material was calculated based on the ring sampler volume (V). The ring sampler dimensions were 2 cm in height and 6.18 cm in diameter. Before sample preparation, the mass of the ring sampler (w1) was weighed. After sample preparation, the total mass of the ring sampler and dry soil (w2) was weighed. After saturation treatment, w3 was obtained. The soil saturated moisture content w was calculated using the following formula:

[0054] The sample saturation process is as follows: place the sample in a vacuum saturation cylinder and evacuate it for 1 hour, then soak it for 6 hours to fully saturate it.

[0055] II. Results and Analysis Experimental results are as follows Figure 3 As shown in the figure. The results show that, compared with the blank control group, the present invention can effectively improve the saturated water content of the soil by incorporating porous matrix materials into the soil. The improvement effect generally increases with the amount of incorporation within the range of 10%-25%, and the improvement rate of YK and EV is relatively higher. The main reason is that the porous matrix material used in the present invention has hydrophilicity, large specific surface area and semi-closed pore structure, which can quickly store water and form a multi-level pore structure with soil particles, thereby improving the sandy soil structure and enhancing the soil's water retention capacity.

[0056] Experiment Example 2: Experiment on the saturated volumetric water content of soil improved by composite materials I. Experimental Methods The saturated moisture content of the improved soil was determined using the composite materials prepared in Examples 1-4 and Comparative Example 1, following the method described in Experimental Example 1.

[0057] II. Results and Analysis Experimental results are as follows Figure 4As shown in the figure. The results show that, compared with Comparative Example 1 which only incorporated plant-derived colloidal solution, the composite materials prepared by combining RW, EP, YK, and EV1 with plant-derived colloidal solution in Examples 1-4 of this invention can significantly improve the saturated volumetric water content of the improved soil. The results indicate that, by using a compounding process, when the composite material obtained by combining plant-derived colloids with porous matrix materials is compounded with soil a second time, the plant-derived colloids and porous matrix materials form a multi-level pore structure of "porous channels for water storage - colloidal network for water locking", constructing a "sponge soil structure". This achieves in-situ optimization of the pore structure of sandy soil, enhancing rapid water absorption while effectively inhibiting gravity loss and evaporation. Compared with a single porous matrix material, the present invention can significantly increase soil moisture content through compound application (from a maximum increase of 15.52% with a single porous matrix material to an increase of up to 30.63% after compound application), significantly enhancing the water storage and retention capacity of sandy soil itself.

[0058] Experiment Example 3: Field Application of Composite Materials I. Experimental Methods The composite materials obtained in Examples 1-3 were used for the improvement of desert soil in the field. The field application demonstration area was located in the oasis-desert transition zone of Moyu County, Hotan Prefecture, Xinjiang (79°76′35″-79°76′40″E, 37°49′68″-37°11′67″N). The average annual temperature in this area is 12.5℃, and the average annual precipitation is less than 50 mm. Figure 5 Plant configurations were carried out in demonstration areas in the transition zone between desert and oasis, including Leymus chinensis, Suaeda salsa, Salix babylonica, and Alternaria lobata. The sowing density of Leymus chinensis was 2 kg / mu, Suaeda salsa 1.5 kg / mu, Alternaria lobata 1.5 kg / mu, Salix babylonica 1.5 kg / mu, and Salix babylonica 1.5 kg / mu. The amount of plant-derived colloidal solution incorporated was 20% of the mass of sandy soil, and the amount of porous matrix material incorporated was 20% of the volume of sandy soil.

[0059] II. Results and Analysis Experimental results are as follows Figure 6As shown in the figure. The results show that, compared with the blank control group, the number of plant clumps in the improved area after incorporation of the composite material obtained in the embodiments of the present invention is significantly increased. Among them, the change trend of Suaeda salsa is the most obvious, while the changes of Camelthorn and Pigweed are relatively less obvious, mainly because they are relatively weak in competition with other plants; the composite material prepared by EV as a porous matrix material has the most significant increase in the number of plant clumps. The above results indicate that the composite material prepared by the present invention can effectively accelerate the remediation of sandy soil and improve the soil's water retention capacity and vegetation growth. The main reasons include, on the one hand, the combination of plant-derived colloids and porous matrix materials significantly enhances the water storage and water retention capacity of sandy soil itself, providing the necessary conditions for vegetation growth and soil remediation; on the other hand, the combination of plant-derived colloids and porous matrix materials forms a dynamic hydration network on the surface of porous materials and between particles. This structure not only retains water inside the porous material and in the colloidal network through capillary action and hydrogen bonding, but also enables reversible regulation of water absorption and release processes in the wet-dry cycle, forming a stable water-slow-release microenvironment in sandy soil, prolonging the continuous supply time of effective water, and further promoting vegetation growth.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, characterized in that, Includes the following steps: S1. Preparation of plant-derived colloidal solutions using natural gum powder and crosslinking agents as raw materials; S2. The plant-derived colloidal solution obtained in S1 is mixed with a porous matrix material to prepare a composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil.

2. The method for preparing the composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil according to claim 1, characterized in that, S1 specifically includes the following steps: Natural rubber powder solution and crosslinking agent solution were prepared separately, and then the natural rubber powder solution and crosslinking agent solution were mixed to obtain plant-derived colloidal solution.

3. The method for preparing the composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil according to claim 2, characterized in that, The mass concentration of the natural rubber powder solution is 0.1%-1%; the mass concentration of the crosslinking agent solution is 0.1%-1%; and the mass ratio of the natural rubber powder solution to the crosslinking agent solution is (5-15):

1.

4. The method for preparing the composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil according to any one of claims 1-3, characterized in that, The natural gum powder is a natural polysaccharide containing cis- or ortho-hydroxyl groups; the crosslinking agent is a borate or its derivative.

5. The method for preparing the composite material based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil according to claim 1, characterized in that, The porous matrix material in S2 includes at least one of expanded perlite, expanded vermiculite, rock wool, porous ceramsite, and coconut coir.

6. A composite material for improving the water retention and slow evaporation performance of sandy soil based on "sponge soil", characterized in that, It is prepared by the preparation method according to any one of claims 1-5.

7. The application of the composite material described in claim 7, which enhances the water retention and slow evaporation performance of sandy soil based on "sponge soil", in the improvement of arid sandy soil.

8. A method for improving arid sandy soil, characterized in that, The process includes the following steps: incorporating the composite material described in claim 6, which enhances the water retention and slow evaporation performance of sandy soil based on "sponge soil", into the arid sandy soil to be improved, and then completing the arid sandy soil improvement after mixing, laying and curing.

9. The method for improving arid sandy soil according to claim 8, characterized in that, The porous matrix material in the composite material is incorporated at a rate of 10%-25% of the volume of the arid sandy soil to be improved, and the plant-derived colloidal solution is incorporated at a rate of 20%-25% of the mass of the arid sandy soil to be improved.

10. A soil amendment based on a composite material that enhances the water retention and slow evaporation properties of sandy soil using a "sponge soil" approach, characterized in that... The improved soil is prepared by compounding the composite material of claim 6, which is based on "sponge soil" to improve the water retention and slow evaporation performance of sandy soil, with soil.

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