Preparation method for wetting reversible soil based on photoresponse

Abstract

The invention relates to the technical field of soil conditioning, and discloses a preparation method for wetting reversible soil based on photoresponse. The invention relates to a preparation method for wetting reversible soil based on photoresponse. According to the preparation method, soil and a photoresponse soil wetting agent are mixed according to the mass ratio of (80-100): 1. The reversible wetting soil based on photoresponse disclosed by the invention shows different wettability under different illumination conditions; free azobenzene does not exist in the wetted reversible soil based on photoresponse, so that the soil environment is not damaged; the preparation method of the reversible soil wetted based on photoresponse is simple and beneficial to popularization and application; after other fertilizers are added into the photoresponse-based wetted reversible soil disclosed by the invention, the fertilizer efficiency of the other fertilizers can be facilitated, and the absorptivity of plants to the fertilizers is improved.

Description

Technical Field

[0001] The invention relates to the technical field of soil conditioning, and in particular to a method for preparing reversible wetting soil based on light response. Background Art

[0002] Soil water is the main source of water absorbed by plants and plays a vital role in plant growth. Therefore, people often add soil conditioners such as water retaining agents and wetting agents to the soil to regulate the soil moisture content.

[0003] However, environmental conditions in nature change rapidly, such as the alternation of strong light and weak light, which leads to different demands for soil water by plants under different environmental conditions. This means that using a wetting agent that can only increase the wettability of the surface soil or reduce the wettability of the surface soil cannot meet the soil moisture requirements under different environmental conditions.

[0004] Therefore, preparing a light-responsive soil wetting agent that can regulate soil moisture content under different environmental conditions, and using the light-responsive soil wetting agent to prepare a reversible wetting soil, has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing reversible wettability soil based on light response, wherein the reversible wettability soil exhibits different wettability under different light conditions, which is beneficial to the growth of plants.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A method for preparing reversible soil that wets under light response comprises mixing soil and a light-responsive soil wetting agent in a mass ratio of (80-100):1.

[0009] Furthermore, the soil includes clay soil and loam.

[0010] The addition amount of the light-responsive soil wetting agent of the present invention is determined based on the wettability of the soil. Generally, if the soil is clay soil, since clay soil has poor wettability, the clay soil and the light-responsive soil wetting agent are mixed at a mass ratio of (80-90):1. If the soil is loam, since loam has relatively good wettability, the loam and the light-responsive soil wetting agent are mixed at a mass ratio of (90-100):1.

[0011] The present invention adds a light-responsive soil wetting agent to the soil, realizes the dynamic regulation of the wettability of the soil under different light conditions, and provides soil conditions that are more conducive to the growth of plants.

[0012] The method for preparing the reversibly wettable soil based on light response is simple, and only requires mixing the light-responsive soil wetting agent with the soil, which is conducive to promotion and application.

[0013] Furthermore, the light-responsive soil wetting agent comprises the following raw materials in parts by weight: 10 to 20 parts of modified polymethyl hydrogen siloxane, 40 to 60 parts of sodium polyacrylate, 1 to 3 parts of borax and 1 to 3 parts of polyacrylamide;

[0014] Preferably, the light-responsive soil wetting agent comprises the following raw materials in parts by weight: 15 parts of modified polymethyl hydrogen siloxane, 50 parts of sodium polyacrylate, 2 parts of borax and 2 parts of polyacrylamide.

[0015] Furthermore, the molecular formula of the modified polymethyl hydrogen siloxane is:

[0016]

[0017] Furthermore, the preparation method of the modified polymethyl hydrogen siloxane includes the following steps: using azobenzene as a raw material, under the action of N,N-dimethylaniline and dichloromethane, a five-membered heterocyclic molecule with a BNN bond is formed, then the CB bond is converted into a CO bond using alkali and hydrogen peroxide, and finally the modified polymethyl hydrogen siloxane is obtained under the catalysis of chloroaurate.

[0018] The preparation process of the modified polymethyl hydrogen siloxane of the present invention is as follows:

[0019]

[0020] Furthermore, the preparation method of the light-responsive soil wetting agent comprises the following steps: heating the modified polymethylhydrogensiloxane to 50-70° C., adding sodium polyacrylate, borax and polyacrylamide while stirring to obtain the soil wetting agent;

[0021] Preferably, the preparation method of the light-responsive soil wetting agent comprises the following steps: heating the modified polymethylhydrogensiloxane to 60° C., and adding sodium polyacrylate, borax and acrylamide while stirring.

[0022] The light-responsive soil wetting agent disclosed in the present invention can change the wettability of soil under different lighting conditions; specifically, under different lighting conditions, the raw material in the light-responsive soil wetting agent disclosed in the present invention, namely, modified polymethylhydrogensiloxane, can change its polarity, which enables the light-responsive soil wetting agent to achieve a transition between hydrophilicity and hydrophobicity under different lighting conditions, that is, a change in wettability. Therefore, applying the light-responsive soil wetting agent disclosed in the present invention to soil can achieve a reversible change in soil wettability.

[0023] The principle of polarity change of the modified polymethylhydrogensiloxane of the present invention under different lighting conditions:

[0024] The present invention introduces a photosensitive monomer, azobenzene, into polymethylhydrogensiloxane through a series of reactions. Azobenzene can achieve the flipping of the nitrogen-nitrogen double bond configuration under different lighting conditions, as shown below, resulting in the change of the polarity of azobenzene under different lighting conditions, thereby achieving the change of the polarity of the modified polymethylhydrogensiloxane under different lighting conditions.

[0025]

[0026] Azobenzene has certain soil hazard, but in order to meet the change of soil light-responsive wetting reversibility, the present invention needs to add a certain amount of azobenzene to the light-responsive soil wetting agent. In order to reduce the harm of azobenzene to the soil, the present invention introduces azobenzene into polymethylhydrogensiloxane, and strictly controls the addition amount of modified polymethylhydrogensiloxane, uses polymethylhydrogensiloxane to produce a "binding" effect on azobenzene, and reduces the amount of azobenzene used, reduces the content of free azobenzene and inhibits the diffusion of free azobenzene; experimentally determined, the light-responsive soil wetting agent disclosed in the present invention is compounded with soil according to the compounding ratio specified in the present invention, and no free azobenzene is detected in the soil, that is, under the compounding ratio specified in the present invention, the light-responsive soil wetting agent disclosed in the present invention does not cause harm to the soil; moreover, the soil wetting agent disclosed in the present invention is directly tested for azobenzene content, and no free azobenzene is detected, which shows that the light-responsive soil wetting agent disclosed in the present invention does not cause safety problems to users.

[0027] The present invention uses polymethylhydrogensiloxane as a carrier of the photosensitive monomer, which not only inhibits the harm of the photosensitive monomer to the soil, but also the Si-O-Si unit in the polymethylhydrogensiloxane enables the polymethylhydrogensiloxane to have a good adsorption effect on soil particles, and can "agglomerate" the soil, thereby effectively exerting the reversible change of the photoresponsive wettability of the photosensitive monomer, and the "agglomeration" of the soil can also effectively retain the moisture in the soil, playing a certain role in water retention; in addition, polymethylhydrogensiloxane can also adjust the acidity and alkalinity of the soil under certain conditions. Therefore, the light-responsive soil wetting agent disclosed in the present invention is applied to saline-alkali land with relatively mild conditions, which also has a certain effect on the improvement of the saline-alkali land.

[0028] The light-responsive soil wetting agent disclosed in the present invention uses sodium polyacrylate as a raw material, can cooperate with modified polymethylhydrogensiloxane, promote the change of polarity of photosensitive monomer under different light conditions, thereby facilitating the reversible change of soil wettability by the light-responsive soil wetting agent, and sodium polyacrylate can also cooperate with polymethylhydrogensiloxane to inhibit the harm of azobenzene to the soil and protect the ecological environment of the soil; in addition, sodium polyacrylate can also effectively increase the porosity of the soil, improve the air permeability and water retention performance of the soil, and provide soil conditions that are more conducive to the growth of plants;

[0029] When the light-responsive soil wetness regulator disclosed in the present invention is added in conjunction with fertilizer, sodium polyacrylate can promote the fertilizer effect of the fertilizer. Specifically, sodium polyacrylate can absorb the nutrient elements in the fertilizer to form a slow-release fertilizer, thereby effectively improving the fertilizer effect.

[0030] The present invention adds borax to a light-responsive soil wetting agent, which can effectively promote the change of the polarity of a photosensitive monomer, namely, azobenzene. According to analysis, borax has certain optical properties, can improve the transmittance of surface soil to ultraviolet rays, so that more ultraviolet rays can be absorbed by the photosensitive monomer, thereby promoting the change of the polarity of azobenzene. In addition, borax contains a large amount of boron element, which is one of the indispensable nutrients for plant growth. Therefore, the present invention adds borax to the light-responsive soil wetting agent, which can provide sufficient nutrients for plant growth. However, excessive addition of borax can cause soil salinization. In order to avoid soil salinization, the present invention adds polymethylhydrogensiloxane to the light-responsive soil wetting agent, and uses the polymethylhydrogensiloxane to adjust the acidity and alkalinity of the soil, thereby avoiding soil salinization caused by the addition of borax.

[0031] The present invention adds polyacrylamide to the light-responsive soil wetting agent, which can promote the change of polarity of photosensitive monomers under different light conditions. Specifically, polyacrylamide can enhance the stability of soil aggregates formed by Si-O-Si units, thereby effectively exerting the reversible change of photoresponsive wettability of photosensitive monomers. Moreover, the stabilizing effect of polyacrylamide on soil aggregates can also reduce soil particle loss and reduce water evaporation and leakage, prevent soil erosion, and improve soil water retention capacity. In addition, polyacrylamide can also adjust the porosity of the soil, improve the air permeability and water retention performance of the soil, and promote the growth and development of plant roots. When the light-responsive soil wetting regulator disclosed in the present invention is added in conjunction with fertilizers, polyacrylamide can enhance the adhesion and retention of fertilizer particles, reduce the loss and volatilization of fertilizers, make fertilizers more easily absorbed by crops, improve the utilization rate of fertilizers, and reduce the release and loss of nutrients in farmland.

[0032] When preparing the light-responsive soil wetting agent, the modified polymethyl hydrogen siloxane is first heated to 50-70° C. and then sodium polyacrylate, borax and acrylamide are added, which can promote the dissolution of sodium polyacrylate, borax and polyacrylamide and is beneficial to the preparation of the light-responsive soil wetting agent.

[0033] The second technical solution of the present invention:

[0034] The reversible wetting soil is prepared by the method for preparing reversible wetting soil under light response.

[0035] The third technical solution of the present invention:

[0036] The above-mentioned reversible wetting soil is used in plant cultivation.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1) The reversible wettability soil based on light response disclosed in the present invention exhibits different wettability under different light conditions, which is beneficial to the growth of plants;

[0039] 2) There is no free azobenzene in the reversible wetting soil based on light response disclosed by the present invention, and no harm is caused to the soil environment;

[0040] 3) The method for preparing reversible soil wettable under light response disclosed in the present invention is simple and is conducive to popularization and application;

[0041] 4) The reversible soil based on light response wetting disclosed in the present invention can be beneficial to the fertilizer efficiency of other fertilizers and improve the absorption rate of fertilizers by plants after adding other fertilizers. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In the following embodiments, a method for preparing reversible soil that wets under light response is provided, which comprises mixing soil and a light-responsive soil wetting agent in a mass ratio of (80-100):1.

[0044] Wherein, the soil includes clay soil and loam.

[0045] The light-responsive soil wetting agent comprises the following raw materials in parts by weight: 10 to 20 parts of modified polymethyl hydrogen siloxane, 40 to 60 parts of sodium polyacrylate, 1 to 3 parts of borax and 1 to 3 parts of polyacrylamide;

[0046] The preparation method of modified polymethyl hydrogen siloxane comprises the following steps:

[0047] 1) Azobenzene, boron tribromide and N,N-dimethylaniline were mixed in a molar ratio of 1:3:1.5, and dichloromethane was used as a reaction solvent. The mixture was reacted at room temperature for 24 hours to obtain a five-membered heterocyclic molecule with a BNN bond;

[0048] 2) mixing the five-membered heterocyclic molecule with a BNN bond obtained in step 1) with sodium hydroxide and hydrogen peroxide in a molar ratio of 1:10:10, using ether as a reaction solvent, reacting at 40° C. for 24 hours to convert the CB bond into a CO bond;

[0049] 3) The product converted into CO bonds in step 2) is mixed with polymethyl hydrogen siloxane at a molar ratio of 30:1, tetrahydrofuran is used as a solvent, sodium chloroaurate is used as a catalyst, and the mixture is reacted at 60° C. for 12 hours to obtain the modified polymethyl hydrogen siloxane.

[0050] The preparation method of the light-responsive soil wetting agent comprises the following steps: heating the modified polymethylhydrogensiloxane to 50-70° C., adding sodium polyacrylate, borax and polyacrylamide while stirring to obtain the soil wetting agent.

[0051] In the following examples, the polymethylhydrogensiloxane with an average molecular weight of 1700 to 3200 was purchased from Shanghai Koraman Reagent Co., Ltd.; the sodium polyacrylate was purchased from Jianghai JH-09 low molecular weight sodium polyacrylate of Hunan Jianghai Environmental Protection Industrial Co., Ltd.; the borax was purchased from Henan Yejiusheng Industrial Co., Ltd.; and the polyacrylamide was purchased from Jinan Shanhai Chemical Technology Co., Ltd.

[0052] In the following examples, the chemical reagents were commercially available and of analytical grade unless otherwise specified.

[0053] In the following examples, the soil is loam, which was collected from Experimental Field 3.

[0054] Example 1

[0055] A reversible soil wetting based on light response

[0056] 1) Azobenzene, boron tribromide and N,N-dimethylaniline were mixed in a molar ratio of 1:3:1.5, and dichloromethane was used as a reaction solvent. The mixture was reacted at room temperature for 24 hours to obtain a five-membered heterocyclic molecule with a BNN bond;

[0057] 2) mixing the five-membered heterocyclic molecule with a BNN bond obtained in step 1) with sodium hydroxide and hydrogen peroxide in a molar ratio of 1:10:10, using ether as a reaction solvent, reacting at 40° C. for 24 hours to convert the CB bond into a CO bond;

[0058] 3) mixing the product converted into CO bonds in step 2) with polymethyl hydrogen siloxane at a molar ratio of 30:1, using tetrahydrofuran as solvent and sodium chloroaurate as catalyst, reacting at 60° C. for 12 hours to obtain the modified polymethyl hydrogen siloxane;

[0059] 4) heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 15:50:2:2 of the modified polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent;

[0060] 5) The soil wetting agent obtained in step 4) is mixed with soil at a mass ratio of 1:90 to obtain the reversible wetting soil based on light response.

[0061] Example 2

[0062] A reversible soil wetting based on light response

[0063] 1) Azobenzene, boron tribromide and N,N-dimethylaniline were mixed in a molar ratio of 1:3:1.5, and dichloromethane was used as a reaction solvent. The mixture was reacted at room temperature for 24 hours to obtain a five-membered heterocyclic molecule with a BNN bond;

[0064] 2) mixing the five-membered heterocyclic molecule with a BNN bond obtained in step 1) with sodium hydroxide and hydrogen peroxide in a molar ratio of 1:10:10, using ether as a reaction solvent, reacting at 40° C. for 24 hours to convert the CB bond into a CO bond;

[0065] 3) mixing the product converted into CO bonds in step 2) with polymethyl hydrogen siloxane at a molar ratio of 30:1, using tetrahydrofuran as solvent and sodium chloroaurate as catalyst, reacting at 60° C. for 12 hours to obtain the modified polymethyl hydrogen siloxane;

[0066] 4) heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 10:40:1:1 to the modified polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent;

[0067] 5) The soil wetting agent obtained in step 4) is mixed with soil at a mass ratio of 1:90 to obtain the reversible wetting soil based on light response.

[0068] Example 3

[0069] A reversible soil wetting based on light response

[0070] 1) Azobenzene, boron tribromide and N,N-dimethylaniline were mixed in a molar ratio of 1:3:1.5, and dichloromethane was used as a reaction solvent. The mixture was reacted at room temperature for 24 hours to obtain a five-membered heterocyclic molecule with a BNN bond;

[0071] 2) mixing the five-membered heterocyclic molecule with a BNN bond obtained in step 1) with sodium hydroxide and hydrogen peroxide in a molar ratio of 1:10:10, using ether as a reaction solvent, reacting at 40° C. for 24 hours to convert the CB bond into a CO bond;

[0072] 3) mixing the product converted into CO bonds in step 2) with polymethyl hydrogen siloxane at a molar ratio of 30:1, using tetrahydrofuran as solvent and sodium chloroaurate as catalyst, reacting at 60° C. for 12 hours to obtain the modified polymethyl hydrogen siloxane;

[0073] 4) heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 20:60:3:3 of the modified polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent;

[0074] 5) The soil wetting agent obtained in step 4) is mixed with soil at a mass ratio of 1:90 to obtain the reversible wetting soil based on light response.

[0075] Comparative Example 1

[0076] A moist soil

[0077] 1) heating polymethyl hydrogen siloxane to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 15:50:2:2 of polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent;

[0078] 2) The soil wetting agent obtained in step 1) is mixed with soil at a mass ratio of 1:90 to obtain the wetted soil.

[0079] Comparative Example 2

[0080] A moist soil

[0081] The same as Example 1, except that: Step 3) is: the product converted into CO bonds in Step 2) is mixed with polymethyl hydrogen siloxane at a molar ratio of 40:1, tetrahydrofuran is used as a solvent, sodium chloroaurate is used as a catalyst, and the reaction is carried out at 60°C for 12 hours to obtain the modified polymethyl hydrogen siloxane.

[0082] Comparative Example 3

[0083] A moist soil

[0084] The same as Example 1, except that: Step 3) is: the product after conversion into CO bonds in Step 2) is mixed with polymethyl hydrogen siloxane at a molar ratio of 20:1, tetrahydrofuran is used as solvent, sodium chloroaurate is used as catalyst, and the reaction is carried out at 60° C. for 12 hours to obtain the modified polymethyl hydrogen siloxane.

[0085] Comparative Example 4

[0086] A moist soil

[0087] The same as Example 1, except that: Step 4) is: heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 25:50:2:2 of modified polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent.

[0088] Comparative Example 5

[0089] A moist soil

[0090] The same as Example 1, except that: Step 4) is: heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate, borax and polyacrylamide in a mass ratio of 5:50:2:2 of modified polymethyl hydrogen siloxane, sodium polyacrylate, borax and polyacrylamide while stirring to obtain a soil wetting agent.

[0091] Comparative Example 6

[0092] A moist soil

[0093] The same as Example 1, except that: Step 4) is: heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding borax and polyacrylamide in a mass ratio of modified polymethyl hydrogen siloxane, borax and polyacrylamide of 15:2:2 while stirring to obtain a soil wetting agent.

[0094] Comparative Example 7

[0095] A moist soil

[0096] The same as Example 1, except that: Step 4) is: heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate and polyacrylamide in a mass ratio of modified polymethyl hydrogen siloxane, sodium polyacrylate and polyacrylamide of 15:50:2 while stirring to obtain a soil wetting agent.

[0097] Comparative Example 8

[0098] A moist soil

[0099] The same as Example 1, except that: Step 4) is: heating the modified polymethyl hydrogen siloxane obtained in step 3) to 60° C., and then adding sodium polyacrylate and borax in a mass ratio of modified polymethyl hydrogen siloxane, sodium polyacrylate and borax of 15:50:2 while stirring to obtain a soil wetting agent.

[0100] Comparative Example 9

[0101] A moist soil

[0102] The same as Example 1, except that: Step 5) is: mixing the soil wetting agent obtained in step 4) with the soil at a mass ratio of 1:80.

[0103] Comparative Example 10

[0104] A moist soil

[0105] The same as Example 1, except that: Step 5) is: mixing the soil wetting agent obtained in step 4) with the soil at a mass ratio of 1:110.

[0106] Effect verification

[0107] 1. Light-responsive soil wettability test

[0108] The collected soil, the soil prepared in Examples 1 to 3, and the soil prepared in Comparative Examples 1 to 10 were subjected to a light-responsive soil wettability test, and the test was repeated three times in parallel. The test method includes the following steps:

[0109] 1) The soil was placed in two closed containers with a relative humidity of 80%. One portion of the soil was irradiated with a solar simulated light source for 30 minutes, and the other portion was placed in a dark environment for 30 minutes.

[0110] 2) Weigh 20 g (accurate to 0.01 g) of the irradiated or light-protected soil obtained in step 1) and place them in aluminum boxes of known mass, cover the boxes, and weigh the mass m1 of the aluminum box plus the soil;

[0111] 3) Open the lid of the box and put it in an oven to dry until the weight is constant, then cool the aluminum box in a desiccator to 25°C;

[0112] 4) Take out the aluminum box from the dryer, cover the box, and weigh the mass of the aluminum box plus the soil m2;

[0113] 5) Calculate the soil mass moisture content using the formula:

[0114] Soil mass moisture content (%) = [(m1-m2) / m2] × 100%

[0115] The results of the light-responsive soil wettability test are shown in Table 1:

[0116] Table 1 Photoresponsive soil wettability

[0117]

[0118] It can be seen from the data in Table 1 that the reversible wettability soil based on light response obtained in the present invention can improve the wettability of the soil under light conditions and reduce the wettability of the soil under light-proof conditions;

[0119] In addition, omitting the modification of polymethylhydrogensiloxane, omitting the addition of sodium polyacrylate, borax or polyacrylamide, changing the addition amount of modified polymethylhydrogensiloxane, and changing the mass ratio of soil wetting agent to soil will affect the wettability of the soil to varying degrees.

[0120] 2. Determination of azobenzene content in soil

[0121] Referring to the azobenzene detection method described in the document "Detection of dye precursors azobenzene and carbazole in soil by accelerated solvent extraction-gas chromatography-mass spectrometry", Zhang Li et al., the azobenzene content of the collected soil, the soil prepared in Examples 1 to 3, and the soil prepared in Comparative Examples 1 to 10 was measured, and the results are shown in Table 2;

[0122] Table 2 Azobenzene content

[0123]

[0124]

[0125] Note: Azobenzene content “-” means not detected.

[0126] It can be seen from the data in Table 2 that there is no free azobenzene in the reversible wetting soil based on light response obtained by the present invention, and it will not cause harm to the soil environment, but excessive addition of azobenzene or modified polymethylhydrogensiloxane will lead to an increase in the azobenzene content.

[0127] 3. Field trials

[0128] The soil wetting agent prepared in Example 1 was mixed with the surface soil in test fields 1 to 4, and the soil wettability test was performed according to effect verification 1, and the azobenzene content in the soil was determined according to effect verification 2, and the test was repeated 3 times. The test results are shown in Table 3;

[0129] Table 3 Field test

[0130]

[0131] Note: Azobenzene content “-” means not detected.

[0132] It can be seen from the data in Table 3 that the soil wetting agent obtained in the present invention can successfully prepare reversible soil wetting based on light response after being mixed with different soils.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing reversible soil based on light response wetting, characterized in that: The method for preparing reversible soil wettable under light response is to mix soil and a light-responsive soil wetting agent in a mass ratio of (80-100):

1.

2. A method for preparing reversible soil based on light response wetting according to claim 1, characterized in that: The soil includes clay soil and loam.

3. The method for preparing reversible soil based on light response wetting according to claim 1, characterized in that: The light-responsive soil wetting agent comprises the following raw materials in parts by weight: 10 to 20 parts of modified polymethyl hydrogen siloxane, 40 to 60 parts of sodium polyacrylate, 1 to 3 parts of borax and 1 to 3 parts of polyacrylamide.

4. A method for preparing reversible soil based on light response wetting according to claim 3, characterized in that: The molecular formula of the modified polymethyl hydrogen siloxane is:

5. The method for preparing reversible soil based on light response wetting according to claim 3, characterized in that: The preparation method of the modified polymethyl hydrogen siloxane comprises the following steps: using azobenzene as a raw material, under the action of N,N-dimethylaniline and dichloromethane, forming a five-membered heterocyclic molecule with a BNN bond, then using alkali and hydrogen peroxide to convert the CB bond into a CO bond, and finally obtaining the modified polymethyl hydrogen siloxane under the catalysis of chloroaurate.

6. The method for preparing reversible soil based on light response wetting according to claim 3, characterized in that: The preparation method of the light-responsive soil wetting agent comprises the following steps: heating the modified polymethylhydrogensiloxane to 50-70° C., adding sodium polyacrylate, borax and polyacrylamide while stirring, to obtain the soil wetting agent.

7. A reversible wetting soil prepared by the method for preparing reversible wetting soil under light response according to any one of claims 1 to 6.

8. Use of the reversible moistening soil according to claim 7 in plant cultivation.

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