Plant substrate with long water retention time and good mechanical property and preparation method thereof

Abstract

The invention discloses a plant substrate with long water retention time and good mechanical property and a preparation method thereof, and relates to the technical field of plant cultivation, the plant substrate is prepared by the preparation method of the plant substrate with long water retention time and good mechanical property, and the preparation method comprises the following steps: S1, adding a mixed solution and substrate raw materials into a mold, the matrix raw material is composed of peat, perlite and vermiculite, the volume of the mixed liquid is 0.7-1.22, and the mixed liquid is composed of a first curing material and a second curing material; s2, the mixed solution and the matrix raw materials in the mold are subjected to at least two times of freezing and thawing cycles, the plant matrix is obtained, the freezing temperature ranges from-30 DEG C to-4 DEG C, the duration time ranges from 14 h to 16 h, the thawing temperature ranges from 10 DEG C to 40 DEG C, and the duration time ranges from 7 h to 9 h.

Description

Technical Field

[0001] The invention relates to the technical field of plant cultivation, and in particular to a plant matrix with long water retention time and good mechanical properties and a preparation method thereof. Background Art

[0002] As urbanization increases, cultivated land decreases, and vertical greening continues to rise. Currently, horticultural substrates are mostly loose substrates, which are difficult to apply to vertical greening. On the other hand, loose substrates are easily washed away by rainwater, causing substrate loss, thus affecting plant growth and development.

[0003] The loose matrix is ​​solidified by certain technical means to prepare the matrix raw material. Compared with the traditional loose cultivation matrix, the matrix raw material has a certain resistance to rain erosion and is non-toxic and harmless. It can not only meet the growth needs of plants, but also meet the requirements of the matrix in the field of vertical greening.

[0004] At present, when preparing matrix raw materials with technology, three methods are usually used to solidify the matrix: heating solidification, compression solidification, and glue bonding solidification. The heating solidification technology generally adds a certain amount of hot-melt fiber to the matrix. The hot-melt fiber is a substance composed of semi-melting polyester fibers in a skin-core structure. During the melting process, it will form a three-dimensional network structure inside the matrix. During preparation, the matrix raw material needs to be heated to melt the hot-melt fiber inside it, and then the matrix is ​​pressed into shape using a pressing device. Compression solidification obtains a molded matrix block by physically compressing the matrix raw material. Glue bonding solidification is to evenly apply glue around the matrix block to achieve a shaping effect.

[0005] In summary, the matrix curing technology in the prior art mainly adopts three schemes: 1. Add hot-melt fiber to the matrix material, and then heat the material with hot-melt fiber added to obtain a solidified matrix block. Such as CN105367216B and CN105297178B. In this case, the equipment expenditure is high, and because it needs to be heated, the energy consumed is also high. 2. The matrix material is compressed to make the matrix material dense and achieve the curing effect. In this case, the compression equipment needs to be more precise and the expenditure is higher. In addition, the effect after compression will vary greatly due to the difference in matrix raw materials, and the overall curing effect is poor. 3. By evenly applying glue on all sides of the matrix block, the plasticizing effect is achieved by using the bonding properties of the glue, such as CN112335489A. However, glue usually has phytotoxicity, and can only be simply cured from the outer layer, making it difficult to achieve an overall uniform curing effect of the matrix block. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a plant matrix with long water retention time and good mechanical properties and a preparation method thereof, so as to solve the above-mentioned problems.

[0007] The objective of the present invention is achieved through the following technical solutions: A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1, adding a mixed liquid and a matrix raw material into a mold, wherein the matrix raw material consists of peat, perlite and vermiculite, the volume of the mixed liquid: the volume of the matrix raw material is 0.7-1.2, wherein the mixed liquid consists of a first solidifying material and a second solidifying material; S2. The mixed liquid and matrix raw materials in the mold are subjected to at least two freeze-thaw cycles to obtain a plant matrix, wherein the freezing temperature is -30°C to -4°C, the duration is 14 to 16 hours, and the melting temperature is 10°C to 40°C, the duration is 7 to 9 hours.

[0008] The concentration of the first solidifying material is 0.25% to 2%, and the concentration of the second solidifying material is 0.5% to 3%.

[0009] The first solidifying material is one or more of agarose, sodium alginate, carrageenan, chitosan, pectin and gelatin.

[0010] The second solidifying material is one or more of polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyvinyl pyrrolidone and sodium alginate.

[0011] The weight ratio of peat:perlite:vermiculite in the matrix raw material is 8:4:1.

[0012] The method further comprises step S0, wherein the step S0 is to add the first curing material and the second curing material into deionized water, and stir the mixture at 95° C. to obtain a mixed solution.

[0013] A plant matrix with long water retention time and good mechanical properties is prepared by a method for preparing a plant matrix with long water retention time and good mechanical properties.

[0014] The beneficial effects of the present invention are as follows: the present invention is a technology for solidifying ordinary loose matrix raw materials using a first solidifying material and a second solidifying material to obtain a solidified soilless cultivation matrix. The principle of the formation of the first solidifying material and the second solidifying material through freeze-thaw cycles mainly depends on the molecular structure and crystallization ability of the second solidifying material. During the freeze-thaw process, the second solidifying material solution freezes at low temperatures to form tiny ice crystals, which melt when thawed, causing the second solidifying material molecules to rearrange and form crystallization regions. As the number of freeze-thaw cycles increases, the hydrogen bonds and crystallization regions between the molecules of the second solidifying material gradually increase, and finally form a stable three-dimensional network structure, so that the matrix block has good mechanical strength and elasticity. The addition of the first solidifying material can further improve the physical properties and biocompatibility of the matrix block. Under this technical support, the matrix can be easily solidified into different forms, and it is also easy to regulate the mechanical properties of the matrix as a whole, while ensuring excellent mechanical properties, it can also ensure good water-holding and air-permeability, which is conducive to plant growth. And because the first solidifying material and the second solidifying material are biocompatible and environmentally friendly materials, the plant matrix obtained by the production is easy to recycle and degrade, and no secondary pollution will be generated. DETAILED DESCRIPTION

[0015] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0016] Example 1 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1.5%, and the concentration of agarose in the mixed solution is 1%; S2, filling the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm respectively, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 0.7; S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 1.

[0017] Example 2 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1.5%, and the concentration of agarose in the mixed solution is 0.5%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 0.9 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 2.

[0018] Example 3 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1%, and the concentration of agarose in the mixed solution is 1%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 1.1 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 3.

[0019] Example 4 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1%, and the concentration of agarose in the mixed solution is 0.5%; S2, filling the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm respectively, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 1.2; S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 4.

[0020] Example 5 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 3%, and the concentration of agarose in the mixed solution is 0.25%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 0.7 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 5.

[0021] Example 6 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix them at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 3%, and the concentration of agarose in the mixed solution is 2%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 0.9 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 6.

[0022] Example 7 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1%, and the concentration of agarose in the mixed solution is 0.25%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 1.1 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 7.

[0023] Example 8 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix them at 95° C. to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 0.5%, and the concentration of agarose in the mixed solution is 2%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 1.2 S3. The mixed solution and matrix raw materials in the mold are subjected to three freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 8.

[0024] Example 9 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1%, and the concentration of agarose in the mixed solution is 1%; S2, fill the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 1.1 S3. The mixed solution and matrix raw materials in the mold are subjected to two freeze-thaw cycles, each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain plant matrix 9.

[0025] Example 10 A method for preparing a plant matrix with long water retention time and good mechanical properties comprises the following steps: S1. Add polyvinyl alcohol and agarose to deionized water, and stir and mix at 95°C to obtain a mixed solution, wherein the concentration of polyvinyl alcohol in the mixed solution is 1.5%, and the concentration of agarose in the mixed solution is 0.5%; S2, filling the mixed liquid and matrix raw materials into a mold container with a length, width and height of 10cm*10cm*6cm respectively, and a cylinder with a diameter of 4cm and a height of 2.5cm at the bottom, wherein the matrix raw materials are composed of peat, perlite and vermiculite in a weight ratio of 8:4:1, and the volume of the mixed liquid: the volume of the matrix raw materials is 0.9; S3. The mixed solution and matrix raw materials in the mold are subjected to four freeze-thaw cycles, with each cycle being frozen at -20°C for 16 hours and thawed at room temperature 25°C for 8 hours, to obtain a plant matrix 10.

[0026] Test Results 1. Determination of mechanical properties of plant matrix The impact resistance of the plant matrix was tested using a pendulum impact tester, and the surface hardness of the matrix raw materials in dry and wet states was tested using a Shore hardness tester. The results are shown in Table 1.

[0027] Table 1 2. Determination of the pore structure of plant matrices The pore structure of the matrix is ​​the space between the solid particles of the matrix material that can accommodate water and air. It is also the space for the activities of plant roots and animal microorganisms between the matrix. A reasonable pore structure is very important for plant growth.

[0028] The matrix porosity refers to the percentage of the pore volume per unit volume to the total volume of the matrix. The matrix porosity is defined as: matrix porosity (%) = (1-matrix raw material volume / matrix volume) * 100%. The results are shown in Table 2.

[0029] Table 2 3. Determination of water holding capacity of plant substrates The moisture content of plant substrate refers to the number of grams of water retained in every 100 grams of substrate. We calculate water holding capacity according to the following formula: Water holding capacity measurement = (W 湿 -W 干 ) / W 干 *100%. Take a 10cm*10cm*6cm square fiber culture soil and soak it for 10 minutes to fully absorb water, spread it dry, weigh it, and then bake it in an oven at 65℃ to constant weight, move it into a desiccator to cool it to room temperature, and weigh it. The results are shown in Table 3.

[0030] Table 3 4. Observation of plant matrix stability After the lettuce was planted and harvested, the substrate blocks were observed for changes in appearance such as collapse, volume shrinkage, and cracking. If there was collapse, volume shrinkage to less than 95% of the volume before cultivation, or cracking, 1 point was recorded; if there were two of the above three situations, 2 points were recorded; if there were three of the above three situations, 3 points were recorded; if there were none of the above three situations, 0 points were recorded; if the substrate block could not be solidified, 3* was recorded. The results are shown in Table 4.

[0031] Table 4 5. Observation of plant growth In each implementation, lettuce was sown and the growth of lettuce was observed for 4 weeks (28 days in total). The lettuce plants were strong, with thick leaves, normal leaf color, well-formed root balls, strong root systems, and well-developed capillary roots, which were considered good, and other growth conditions were considered poor. In addition, after the lettuce was grown for four weeks, the fresh weight and dry weight of the individual lettuce plants were recorded. The heavier the fresh weight and dry weight of the lettuce plants that grew well, the better the cultivation effect of the lettuce in the substrate.

[0032] Table 5 From the comparison in Tables 1-5 above, it is found that the content of polyvinyl alcohol and agarose has a significant effect on the mechanical properties, pore structure, water holding capacity, stability and plant growth of the matrix raw materials. In addition, the number of freeze-thaw cycles will also affect the effect of the final matrix raw materials.

[0033] In Examples 1-4, in terms of impact resistance, Example 1 is 1.780 kJ / m2, the highest. This shows that the matrix has the strongest resistance when subjected to external force impact and is suitable for use in environments that require high-intensity protection. Example 2 is 1.395 kJ / m2, the second highest. The impact resistance is strong, but slightly lower than Example 1. Example 3: 1.195 kJ / m2, medium. The impact resistance is moderate and suitable for use in general environments. Example 4 is 1.002 kJ / m2, the lowest. It is also suitable for use in general environments. The trend of the surface hardness of the wet and dry substrates is consistent with the impact resistance, with Example 1 being the highest, Example 2 being the second highest, Example 3 being medium, and Example 4 being the lowest. Combined with the growth of the plants, Example 1 is too hard, which affects the growth and expansion of the plant roots, and also limits the respiration and water absorption of the roots. Examples 2-4, which have a more appropriate hardness, are conducive to the growth of the plant roots, and are conducive to the respiration and water absorption of the roots. Therefore, compared with Examples 2-4, the growth of plants in Example 1 was significantly worse.

[0034] In Examples 1-4, the porosity of the matrix plays a vital role in the growth of plants because it directly affects the air permeability and water holding capacity of the matrix, thereby affecting the respiration and water absorption of the plant roots. The lower porosity of Example 1 means that the air permeability of the matrix is ​​poor, which may limit the oxygen supply to the roots and affect the respiration of the roots. In addition, the water holding capacity of Example 1 is relatively low (376%), and coupled with the low porosity, the fluidity of water in the matrix may be poor, making it difficult for the roots to obtain sufficient water.

[0035] Therefore, the growth of lettuce was poor, with the lowest fresh weight and dry weight, indicating that low porosity and water holding capacity were not conducive to the growth of lettuce.

[0036] In comparison, the porosity and water holding capacity of Examples 2-4 are higher, and the air permeability is better, which is beneficial to the oxygen supply of the root system and promotes root respiration. It can also provide sufficient water, which is beneficial for plants to retain water under drought conditions.

[0037] By comparing the matrix porosity of the four examples and their effects on the growth of lettuce, it can be seen that the matrix porosity of Example 4 is the highest, the water holding capacity and air permeability are the best, and it is most conducive to the growth of lettuce. The porosity of Example 1 is the lowest, and the water holding capacity and air permeability are poor, resulting in the worst growth of lettuce. The porosity and water holding capacity of Examples 2 and 3 are moderate, both of which are conducive to the growth of lettuce, but are still slightly inferior to that of Example 4.

[0038] By comparing the matrix stability, impact resistance and surface hardness of Examples 1-4, it can be seen that Example 4 performs the worst in terms of matrix stability, because its impact resistance and surface hardness are low, resulting in the collapse of the matrix block after cultivation. However, these characteristics do not have a negative impact on the growth of lettuce. On the contrary, due to the higher water holding capacity and porosity, it provides a more suitable growth environment. However, due to the poor matrix stability, structural changes may occur during use, affecting its long-term use effect. In comparison, Examples 2 and 3 perform well in terms of matrix stability. There are no obvious changes or damage to the external structure during the plant growth cycle, and the lettuce also grows well. If used for long-growth cycle plant cultivation, Examples 2 and 3 may be better than Example 4.

[0039] By comparing the four embodiments 1-4 horizontally, if the plants are cultivated in a short-term non-vertical manner, embodiment 4 performs best in multiple key performance indicators and can provide the best growth environment for lettuce. However, considering its low impact resistance and surface hardness, the substrate stability is poor, so it can only be used for short-term and general scene cultivation.

[0040] However, it can be found from Example 5, Example 6 and Example 8 that it is not only to achieve a simple solidification effect that a soilless cultivation matrix block that can be used for plant cultivation can be produced. Excessive concentrations of polyvinyl alcohol and agarose will cause the matrix block to be too hard, and the plant is difficult to grow normally. The overall mechanical properties of Example 5, Example 6 and Example 8 are all very excellent, and the solidification of the matrix material can be fully achieved, but because the overall matrix is ​​too hard, it cannot be used normally for plant cultivation. In addition, during the cultivation process of Example 6 and Example 8, the surface hardness was too high, and the plant could not take root into the matrix block after transplanting, and the planting of lettuce could not be achieved. Although the lettuce can take root and grow during the cultivation process of Example 5, the root system has difficulty in growing, resulting in insufficient water, nutrients and air, so that the growth of lettuce is extremely poor. In contrast, in Example 7, because the polyvinyl alcohol and agarose in the mixed solution are too low, the fixing effect of the matrix block is not achieved after three freeze-thaw cycles. Therefore, the appropriate polyvinyl alcohol and agarose ratio will significantly affect the mechanical properties, pore structure, water holding capacity and stability of the matrix block, thereby affecting the growth of the plant.

[0041] Comparing Example 3 and Example 9, it can be found that Example 2 and Example 10 show that as the number of freeze-thaw cycles increases, the matrix raw material effect is better. For example, in Example 9, the matrix block cannot be well shaped after two freeze-thaw cycles, and the curing effect cannot be achieved. However, Example 3 with the same ratio has excellent mechanical properties after three freeze-thaw cycles, and the lettuce cultivation effect is also good. However, by comparing Example 2 and Example 10, it can be found that there is no obvious difference in performance between the two, which can be explained as the hydrogel can achieve excellent cross-linking effect after three freeze-thaw cycles, so it changes less after the fourth freeze-thaw cycle. Considering the time cost and the energy consumption cost of the freeze-thaw cycle, 3 freeze-thaw cycles are sufficient.

[0042] In general, Example 2 and Example 3 have relatively balanced performance in various performance indicators, are both beneficial to the growth of lettuce, and also have excellent stability, and can be applied to long-term cultivation in multiple scenarios.

[0043] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a plant matrix with long water retention time and good mechanical properties, characterized in that: The following steps are included: S1, adding a mixed liquid and a matrix raw material into a mold, wherein the matrix raw material consists of peat, perlite and vermiculite, the volume of the mixed liquid: the volume of the matrix raw material is 0.7-1.2, wherein the mixed liquid consists of a first solidifying material and a second solidifying material; S2. The mixed liquid and matrix raw materials in the mold are subjected to at least two freeze-thaw cycles to obtain a plant matrix, wherein the freezing temperature is -30°C to -4°C, the duration is 14 to 16 hours, and the melting temperature is 10°C to 40°C, the duration is 7 to 9 hours.

2. The method for preparing a plant matrix with long water retention time and good mechanical properties according to claim 1, characterized in that: The concentration of the first solidifying material is 0.25% to 2%, and the concentration of the second solidifying material is 0.5% to 3%.

3. The method for preparing a plant matrix with long water retention time and good mechanical properties according to claim 2, characterized in that: The first solidifying material is one or more of agarose, sodium alginate, carrageenan, chitosan, pectin and gelatin.

4. The method for preparing a plant matrix with long water retention time and good mechanical properties according to claim 2, characterized in that: The second solidifying material is one or more of polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyvinyl pyrrolidone and sodium alginate.

5. The method for preparing a plant matrix with long water retention time and good mechanical properties according to claim 1, characterized in that: The weight ratio of peat:perlite:vermiculite in the matrix raw material is 8:4:

1.

6. The method for preparing a plant matrix with long water retention time and good mechanical properties according to claim 1, characterized in that: The method further comprises step S0, wherein the step S0 is to add the first curing material and the second curing material into deionized water, and stir the mixture at 95° C. to obtain a mixed solution.

7. A plant matrix with long water retention time and good mechanical properties, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 5.

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