A hydrophilic soil conditioner and its preparation method and application

Abstract

The application provides a hydrophilic soil conditioner and a preparation method and application thereof, and the preparation method comprises the following steps: (1) reacting fly ash and a hydrophilic modifier solution to obtain hydrophilic fly ash; (2) mixing organic fertilizer and the hydrophilic fly ash obtained in the step (1) and obtaining the hydrophilic soil conditioner after composting; the hydrophilic modifier solution in the step (1) comprises an acid solution. The hydrophilic soil conditioner is applied in a surface layer of saline-alkali soil, a hydrophobic soil conditioner is applied in a soil layer adjacent to the surface layer, and saline-alkali soil improvement is completed after irrigation; the hydrophobic soil conditioner is obtained by reacting fly ash and a hydrophobic modifier solution. The application can improve the hydrophilic water-retention capacity of the surface of the surface layer, inhibit water evaporation, reduce the migration of saline-alkali components to the surface layer, reduce the water transport capacity of capillary pores, and reduce the salt content of the surface layer, so that the purpose of improving saline-alkali soil is achieved.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement, and relates to a soil conditioner, its preparation method and application, and more particularly to a hydrophilic soil conditioner, its preparation method and application. Background Technology

[0002] Saline-alkali soil is a type of soil in which excessive salt and alkali components accumulate on the surface, affecting the normal growth of crops. The global area of ​​saline-alkali land is approximately 954.4 million hectares. Saline-alkali land causes extremely low farmland yields, mainly due to the following two aspects: (1) It affects plant growth and development. Under the influence of high salt concentration, the starch formation process in the guard cells of plant stomata is inhibited, and the stomata cannot close normally, resulting in drought or even wilting of plants. Excessive salt environment will also directly increase soil osmotic pressure, making it difficult for plant roots to absorb water, causing physiological drought in plants, and in severe cases, it can lead to wilting or even death of plants; (2) It changes the physical properties of the soil, causing soil compaction, poor aeration and water permeability, and reduced oxygen content, resulting in a decrease in soil nutrient utilization and a reduction in crop yield and quality.

[0003] CN109369298A discloses a method for improving saline-alkali soil. The method involves evenly spreading a soil conditioner on the soil surface, turning it over, digging several parallel channels, watering, covering with mulch, removing the mulch, watering repeatedly, and then dripping shrub vinegar solution onto the soil. This technical solution prevents soil compaction and ensures balanced soil fertility, making it suitable for crop growth. While conserving resources, it minimizes soil salinity and pH levels. However, the improvement process is cumbersome and requires significant water and labor resources.

[0004] CN114402730A discloses a method for improving saline-alkali land by mixed planting of various salt-tolerant plants, including *Canavalia gladiata*, *Vigna angularis*, *Peanuta spp.*, and *Vigna arvense*. The method involves deep tillage and soil refinement, soaking the field to drain salt, mixed planting of various salt-tolerant plants, routine field management, and the construction of drainage ditches. This method can effectively reduce the incidence of pests and diseases, increase the interaction of nitrogen-fixing root nodules, significantly improve soil nutrients, and remove salt through drainage ditches, thus achieving the purpose of soil improvement. However, this method is costly, has a long improvement cycle, and improper operation of the drainage ditches may potentially impact the surrounding environment, leading to secondary salinization.

[0005] Fly ash is the powdery residue left after coal combustion. Statistics show that the annual production of fly ash reaches 600 million tons, with a stockpile of nearly 200 million tons, occupying a large amount of land and posing environmental pollution risks. Fly ash generally has a fine particle size and possesses certain water retention and adsorption capabilities. When applied to soil, it can improve soil structure to some extent. Fly ash also contains abundant nutrients such as potassium (K), calcium (Ca), magnesium (Mg), and silicon (Si). After activation treatment, it can improve soil nutrient balance. Current technologies using fly ash as a raw material, after modification, have achieved good results in improving saline-alkali soils.

[0006] CN107663132A discloses a method for improving saline-alkali land using a soil amendment fertilizer produced from waste materials from thermal power plants. The amendment fertilizer comprises desulfurized gypsum, fly ash, expanded soil, zeolite, urea, ammonium phosphate, and calcium chloride. After mixing and granulating these components, the mixture is applied to the soil, effectively improving soil physical structure, enhancing soil aeration and permeability, increasing soil fertility, and reducing salinity. Soil pH decreases from 8.5 to 7.3, alkalinity decreases by 2.0%, soil porosity reaches 48.4%, and aeration porosity is approximately 19.2%, demonstrating significant improvement effects. However, chemical fertilizers need to be added to the raw materials to supplement nutrients, and their accumulation can easily cause soil compaction. Furthermore, desulfurized gypsum itself is a salt, which can increase soil salinity and easily lead to saline soil formation.

[0007] In view of the shortcomings of the existing technology, the present invention prepares a soil conditioner by modifying fly ash and provides a method for improving saline-alkali soil. Summary of the Invention

[0008] The purpose of this invention is to provide a hydrophilic soil conditioner, its preparation method and application, so that the hydrophilic soil conditioner can improve the hydrophilicity of the soil, reduce the accumulation of salt and alkali components in the soil surface, and achieve the improvement of saline-alkali soil.

[0009] To achieve this objective, the present invention employs the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a hydrophilic soil conditioner, the method comprising the following steps:

[0011] (1) After the fly ash reacts with the hydrophilic modifier solution, hydrophilic fly ash is obtained;

[0012] (2) Mix the organic fertilizer and the hydrophilic fly ash obtained in step (1), and after composting, obtain the hydrophilic soil conditioner;

[0013] The hydrophilic modifier solution in step (1) includes an acid solution.

[0014] This invention involves reacting a hydrophilic modifier solution with fly ash to increase the hydrophilic groups on the fly ash surface, thereby enhancing its hydrophilicity. The resulting hydrophilic soil conditioner improves soil water retention, reduces transpiration, inhibits salt accumulation on the soil surface due to capillary water rise, and increases the effective water content of the soil. The hydrogen ions in the acid-modified fly ash neutralize alkaline particles in the soil, further regulating the soil pH. Furthermore, the organic fertilizer in the hydrophilic soil conditioner is rich in nutrients, supplementing the nutrients needed for crop growth, improving the soil ecological environment, and increasing crop yield and quality.

[0015] Preferably, the acid used in the acid solution includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, acetic acid, citric acid, or oxalic acid. Typical but non-limiting combinations include combinations of sulfuric acid and hydrochloric acid, hydrochloric acid and acetic acid, acetic acid and citric acid, citric acid and oxalic acid, sulfuric acid, hydrochloric acid and acetic acid, hydrochloric acid, acetic acid, citric acid and oxalic acid, or sulfuric acid, hydrochloric acid, acetic acid, citric acid and oxalic acid.

[0016] Preferably, the concentration of the acid solution is 0.1-2 mol / L, for example, it can be 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.3 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0017] In this invention, the concentration of the acid solution is in the range of 0.1-2 mol / L, which is beneficial for improving the hydrophilicity of fly ash, thereby enhancing the water retention capacity of hydrophilic soil conditioners, inhibiting water transpiration, and reducing the accumulation of salts on the soil surface due to capillary water rise. When the concentration of the acid solution is below 0.1 mol / L, the effect of improving the hydrophilicity of fly ash decreases, surface water evaporation is intense, and salts in groundwater accumulate on the soil surface due to capillary water rise, which is detrimental to the improvement of saline-alkali soils. When the concentration of the acid solution is above 2 mol / L, it will damage the structure of the fly ash itself, causing fly ash dissolution and loss, weakening the improvement effect; at the same time, it will increase soil acidity, which is not conducive to crop growth.

[0018] Preferably, the solid-liquid ratio of the fly ash to the hydrophilic modifier solution in step (1) is 1:(3-10), for example, it can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited to the values ​​given. Other values ​​not given are also applicable within the range of values. The unit of the solid-liquid ratio is g / mL.

[0019] Preferably, the reaction temperature in step (1) is 20-90°C, for example, it can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0020] Preferably, the reaction time in step (1) is 0.5-7h, for example, it can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h or 7h, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0021] Preferably, the reaction in step (1) is accompanied by stirring at a speed of 10-700 rpm, such as 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 150 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm or 700 rpm, but not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0022] Preferably, the mass fraction of the hydrophilic fly ash in step (2) relative to the hydrophilic soil conditioner is 50-90%, for example, it can be 50%, 60%, 70%, 80% or 90%, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0023] Preferably, the organic fertilizer in step (2) includes any one or at least two of the following: slag, straw, or manure. Typical but non-limiting combinations include the combination of slag and straw, the combination of slag and manure, the combination of straw and manure, or the combination of slag, straw, and manure.

[0024] Preferably, the residue includes any one or a combination of at least two of vinegar residue, wine residue, or oil residue. Typical but non-limiting combinations include a combination of vinegar residue and wine residue, a combination of vinegar residue and oil residue, a combination of wine residue and oil residue, or a combination of vinegar residue, wine residue, and oil residue.

[0025] Preferably, the mass fraction of the vinegar residue relative to the hydrophilic soil conditioner is 0.5-30%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28% or 30%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0026] Preferably, the mass fraction of the lees relative to the hydrophilic soil conditioner is 0.5-20%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18% or 20%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0027] Preferably, the mass fraction of the oil residue relative to the hydrophilic soil conditioner is 0.5-20%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18% or 20%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0028] Preferably, the mass fraction of the straw relative to the hydrophilic soil conditioner is 0.5-10%, for example, it can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0029] Preferably, the mass fraction of the feces relative to the hydrophilic soil conditioner is 0.5-20%, for example, it can be 0.5%, 1%, 3%, 5%, 8%, 10%, 13%, 15%, 18% or 20%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0030] Preferably, the feces include cow dung and / or sheep dung.

[0031] Preferably, the composting temperature is 20-60℃, for example, it can be 20℃, 30℃, 40℃, 50℃ or 60℃, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0032] Preferably, the composting time is 5-60 days, for example, 5 days, 10 days, 20 days, 30 days, 40 days, 50 days or 60 days, but not limited to the values ​​given in the examples. Other values ​​within the range that are not given in the examples are also applicable.

[0033] As a preferred embodiment of the preparation method described in the first aspect of the present invention, the preparation method includes the following steps:

[0034] (1) At 20-90℃, fly ash with a solid-liquid ratio of 1:(3-10)g / mL and a hydrophilic modifier solution are reacted for 0.5-7h, with stirring during the reaction, to obtain hydrophilic fly ash; the hydrophilic modifier solution is an acid solution with a concentration of 0.1-2mol / L, and the acid used includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, acetic acid, citric acid or oxalic acid;

[0035] (2) Mix the organic fertilizer and the hydrophilic fly ash obtained in step (1) and allow it to decompose for 5-60 days at 20-60℃ to obtain the hydrophilic soil conditioner; the mass fraction of the hydrophilic fly ash is 50-90% and the organic fertilizer includes any one or at least two of vinegar residue, wine residue, oil residue, straw, cow manure or sheep manure.

[0036] In a second aspect, the present invention provides a hydrophilic soil conditioner, which is obtained by the preparation method described in the first aspect.

[0037] Thirdly, the present invention provides a method for improving saline-alkali soil, the method comprising the following steps:

[0038] Hydrophobic soil conditioner and the hydrophilic soil conditioner described in the second aspect are applied to the soil layer of saline-alkali land, and the soil improvement of saline-alkali land is completed after irrigation.

[0039] The hydrophilic soil conditioner is applied to the surface layer of the saline-alkali soil.

[0040] The hydrophobic soil conditioner is applied to the soil layer adjacent to the surface layer.

[0041] The hydrophobic soil conditioner is obtained by reacting fly ash with a hydrophobic modifier solution;

[0042] The hydrophobic modifier solution includes any one or a combination of at least two of the following: sodium dodecyl sulfate modifier solution, Triton modifier solution, or KH550 silane coupling agent modifier solution. Typical but non-limiting combinations include a combination of sodium dodecyl sulfate modifier solution and Triton modifier solution, a combination of Triton modifier solution and KH550 silane coupling agent modifier solution, a combination of sodium dodecyl sulfate modifier solution and KH550 silane coupling agent modifier solution, or a combination of sodium dodecyl sulfate modifier solution, Triton modifier solution, and KH550 silane coupling agent modifier solution.

[0043] This invention utilizes a hydrophobic soil conditioner obtained by reacting a hydrophobic modifier solution with fly ash. This causes long-chain groups of surfactants to adhere to the surface of the fly ash, enhancing its hydrophobicity and effectively inhibiting the upward migration of water through capillary action. Different functional soil conditioners are applied layer by layer to different soil layers for saline-alkali land improvement. Adding a hydrophilic soil conditioner to the surface soil enhances its hydrophilicity, improves soil aggregate structure, significantly increases its water retention capacity, inhibits transpiration, and reduces the migration of salt and alkali components to the surface soil, creating a favorable environment for crop growth and increasing crop yield and quality. Applying a hydrophobic soil conditioner to the adjacent soil layer increases its hydrophobicity, reducing the upward transport of water through capillary pores, weakening the migration of salt to the surface with evaporation, reducing surface salt accumulation, and simultaneously enhancing the downward transport of water, facilitating salt leaching from the soil, thereby achieving the goal of improving saline-alkali land. Meanwhile, fly ash contains trace elements for crop growth, providing abundant nutrients at a low cost. After modification, it can be prepared into a soil conditioner to improve saline-alkali soil. This not only enables high-value applications of fly ash but also effectively solves the problem of fly ash storage and reduces the harm of fly ash to the ecological environment and human health.

[0044] Preferably, the reaction temperature of the fly ash and the hydrophobic modifier solution is 20-90℃, for example, it can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃ or 90℃, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0045] Preferably, the reaction time is 0.5-7h, for example, it can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h or 7h, but is not limited to the values ​​given in the examples. Other values ​​within the range that are not given in the examples are also applicable.

[0046] Preferably, the reaction is accompanied by stirring at a speed of 10-700 rpm, such as 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 150 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, or 700 rpm, but not limited to the values ​​given. Other values ​​within the range not given are also applicable.

[0047] Preferably, the solid-liquid ratio of the fly ash to the sodium dodecyl sulfate modifier solution is 1:(3-15), for example, it can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:13, 1:14 or 1:15, but is not limited to the values ​​given. Other values ​​within the range that are not given are also applicable. The unit of the solid-liquid ratio is g / mL.

[0048] Preferably, the mass percentage of sodium dodecyl sulfate modifier in the hydrophobic conditioning agent is 0.1-3%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2% or 3%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0049] Preferably, the solid-liquid ratio of the fly ash to the Triton modifier solution is 1:(3-15), for example, it can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:13, 1:14 or 1:15, but is not limited to the values ​​given. Other values ​​within the range that are not given are also applicable. The unit of the solid-liquid ratio is g / mL.

[0050] Preferably, the mass percentage of the Triton modifier in the hydrophobic conditioning agent is 0.1-3%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2% or 3%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0051] Preferably, the pH is adjusted by adding any one or at least two of glacial acetic acid, citric acid, malic acid, tartaric acid, or oxalic acid to the KH550 silane coupling agent modifier solution. Typical but non-limiting combinations include combinations of glacial acetic acid and citric acid, combinations of citric acid and malic acid, combinations of malic acid and tartaric acid, combinations of tartaric acid and oxalic acid, combinations of glacial acetic acid, citric acid, and malic acid, combinations of citric acid, malic acid, tartaric acid, and oxalic acid, or combinations of glacial acetic acid, citric acid, malic acid, tartaric acid, and oxalic acid.

[0052] Preferably, the pH of the KH550 silane coupling agent modifier solution is 3-7, for example, it can be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0053] Preferably, the solid-liquid ratio of the fly ash to the KH550 silane coupling agent modifier solution is 1:(0.1-5), for example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:1, 1:2, 1:3, 1:4 or 1:5, but is not limited to the values ​​given. Other values ​​within the range that are not given are also applicable. The unit of the solid-liquid ratio is g / mL.

[0054] Preferably, the mass percentage of KH550 silane coupling agent modifier in the hydrophobic conditioning agent is 0.1-3%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2% or 3%, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0055] Preferably, the application rate of the hydrophilic soil conditioner is 1-10 t / mu, for example, it can be 1 t / mu, 2 t / mu, 3 t / mu, 4 t / mu, 5 t / mu, 6 t / mu, 7 t / mu, 8 t / mu, 9 t / mu or 10 t / mu, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0056] Preferably, the thickness of the hydrophilic soil conditioner applied to the soil layer is 1-40cm, for example, it can be 1cm, 5cm, 10cm, 15cm, 20cm, 25cm, 30cm, 35cm or 40cm, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0057] Preferably, the application rate of the hydrophobic soil conditioner is 1-10 t / mu, for example, it can be 1 t / mu, 2 t / mu, 3 t / mu, 4 t / mu, 5 t / mu, 6 t / mu, 7 t / mu, 8 t / mu, 9 t / mu or 10 t / mu, but is not limited to the values ​​given, and other values ​​not given are also applicable within the range.

[0058] Preferably, the thickness of the hydrophobic soil conditioner applied to the soil layer is 1-60cm, for example, it can be 1cm, 5cm, 10cm, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 45cm, 50cm or 60cm, but is not limited to the values ​​given, and other values ​​within the range not given are also applicable.

[0059] As a preferred embodiment of the improved method described in the third aspect of the present invention, the improved method includes the following steps:

[0060] Apply 1-10 t / mu of hydrophobic soil conditioner with a thickness of 1-60 cm and 1-10 t / mu of hydrophilic soil conditioner as described in the second aspect to the soil layer of saline-alkali land; the hydrophilic soil conditioner is applied to the surface layer of the saline-alkali land soil, and the hydrophobic soil conditioner is applied to the soil layer adjacent to the surface layer. After irrigation, the saline-alkali land soil improvement is completed.

[0061] The hydrophobic soil conditioner is obtained by reacting fly ash with a hydrophobic modifier solution at 20-90℃ for 0.5-5 hours, with stirring during the reaction. The hydrophobic modifier solution includes any one or a combination of at least two of sodium dodecyl sulfate modifier solution, Triton modifier solution, or KH550 silane coupling agent modifier solution.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] (1) The preparation method provided by the present invention involves reacting a hydrophilic modifier solution with fly ash to obtain a hydrophilic soil conditioner that can improve the soil's water retention capacity, inhibit water evaporation, reduce the accumulation of salt on the soil surface as it rises with capillary water, increase the effective water content of the soil, loosen the soil, and improve soil texture and structure. The hydrogen ions contained in the fly ash modified by the acid solution can neutralize the alkaline ions in the soil and further regulate the soil pH. Moreover, the organic fertilizer in the hydrophilic soil conditioner contains abundant nutrients, which can supplement the nutrients needed for crop growth, improve the soil ecological environment, and increase crop yield and quality.

[0064] (2) In the improved method provided by the present invention, soil conditioners with different functions are applied in layers to different soil layers of saline-alkali land. Adding hydrophilic soil conditioners to the surface soil improves the hydrophilicity of the surface soil, improves the soil aggregate structure, greatly improves the water retention capacity of the surface soil, inhibits water evaporation, reduces the migration of salt and alkali components to the surface soil, provides a good environment for crop growth, and increases crop yield and quality. Applying hydrophobic soil conditioners to the soil layer adjacent to the surface soil improves the hydrophobicity of the soil, reduces the ability of capillary pores to transport water upward, weakens the migration of salt to the surface with evaporation, reduces the amount of salt in the surface soil, and at the same time improves the ability of water to transport downward, which is conducive to the leaching of salt in the soil, thereby achieving the purpose of improving saline-alkali land.

[0065] (3) Fly ash contains trace elements for crop growth, which can provide rich nutrients and is low in cost. The present invention modifies fly ash to prepare soil conditioner, which can not only improve the problem of soil salinization and realize the high added value application of fly ash, but also effectively solve the problem of fly ash storage and reduce the harm of fly ash to the ecological environment and human health. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the structure of saline-alkali soil.

[0067] 1. Soil surface layer; 2. Soil subsoil layer; 3. Soil subsoil layer. Detailed Implementation

[0068] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0069] The fly ash, vinegar residue, distiller's grains, oil residue, crop straw, animal manure, and other materials required in this invention can all be obtained from or purchased from the corresponding production plants. For example, the fly ash mentioned in this invention is obtained from a power plant; the fly ash used in the following embodiments is obtained from a power plant in Ningxia. The vinegar residue, distiller's grains, oil residue, and straw are obtained from the corresponding production plants; the distiller's grains, vinegar residue, oil residue, and straw used in the following embodiments are obtained from wineries, vinegar plants, oil mills, and farms in Ningxia, respectively. The cow dung and sheep dung are obtained from livestock farms; the cow dung and sheep dung used in the following embodiments are obtained from livestock farms in Inner Mongolia.

[0070] Example 1

[0071] This embodiment provides a method for preparing a hydrophilic soil conditioner, the preparation method comprising the following steps:

[0072] (1) At 35℃, fly ash with a solid-liquid ratio of (1:5) g / mL was reacted with sulfuric acid solution for 5 h to obtain hydrophilic fly ash, wherein the concentration of the sulfuric acid solution was 1.5 mol / L, and stirring was carried out during the reaction.

[0073] (2) Mix the lees, oil residue, sheep manure and hydrophilic modified fly ash obtained in step (1) in proportions of 15%, 15%, 10% and 60% by mass, respectively, and let them decompose at 40℃ for 35 days to obtain a hydrophilic soil conditioner.

[0074] Example 2

[0075] This embodiment provides a method for preparing a hydrophilic soil conditioner, the preparation method comprising the following steps:

[0076] (1) At 20℃, fly ash with a solid-liquid ratio of (1:10) g / mL was reacted with citric acid solution for 7 h to obtain hydrophilic fly ash, wherein the concentration of the citric acid solution was 0.1 mol / L, and stirring was carried out during the reaction.

[0077] (2) Mix the wine lees, oil residue, vinegar residue, straw, cow manure and hydrophilic modified fly ash obtained in step (1) evenly in proportions of 0.5%, 0.5%, 5%, 2%, 2% and 90% by mass, respectively, and allow them to decompose at 20℃ for 60 days to obtain a hydrophilic soil conditioner.

[0078] Example 3

[0079] This embodiment provides a method for preparing a hydrophilic soil conditioner, the preparation method comprising the following steps:

[0080] (1) At 90℃, fly ash with a solid-liquid ratio of (1:3) g / mL was reacted with oxalic acid solution for 0.5 h to obtain hydrophilic fly ash, wherein the concentration of the oxalic acid solution was 2 mol / L, and stirring was carried out during the reaction.

[0081] (2) Mix the lees, oil residue and hydrophilic modified fly ash obtained in step (1) in proportions of 20%, 30% and 50% by mass, respectively, and let them decompose at 60°C for 5 days to obtain a hydrophilic soil conditioner.

[0082] Example 4

[0083] This embodiment provides a method for preparing a hydrophilic soil conditioner. Except for the concentration of the sulfuric acid solution in step (1) being 0.03 mol / L, the rest is the same as in Example 1.

[0084] Example 5

[0085] This embodiment provides a method for preparing a hydrophilic soil conditioner. Except for the concentration of the sulfuric acid solution in step (1) being 2.5 mol / L, the rest is the same as in Example 1.

[0086] Comparative Example 1

[0087] This comparative example provides a method for preparing a soil conditioner, except that the sulfuric acid solution in step (1) is replaced with an equal volume fraction of pure water, and all other steps are the same as in Example 1.

[0088] In this comparative example, the product of fly ash treated with pure water is named pretreated fly ash.

[0089] Comparative Example 2

[0090] This comparative example provides a method for preparing a soil conditioner. The raw materials of the soil conditioner include, by mass fraction: 30% vinegar residue, 20% distiller's grains, 20% oil residue, 10% straw, 5% cow dung, and 5% sheep dung. The raw materials are mixed evenly, meaning that the soil conditioner does not contain hydrophilic modified fly ash. The mixture is then composted at 40°C for 35 days to obtain the final product.

[0091] Performance testing

[0092] Contact angle tests were performed on the hydrophilic modified fly ash obtained in Examples 1-5 and the pretreated fly ash obtained in Comparative Example 1. The test method was as follows: using a contact angle meter, 20g of sample was placed in a mold and pressed under 15MPa pressure for 15min to form a sheet. The prepared sheet was placed on the test stage, and deionized water was drawn in through a micro-syringe and fixed on the instrument's automatic liquid injection device. 2μL of sample was automatically injected, and the results were recorded using a high-speed camera. The results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] As shown in Table 1, the hydrophilic modified fly ash provided by the present invention has a contact angle of less than 35° and exhibits good hydrophilicity.

[0097] A comparison of Examples 4 and 5 with Example 1 shows that when the acid solution concentration during the hydrophilic modification process is below 0.1 mol / L, the improvement in hydrophilicity of the modified fly ash is not significant. When the acid solution concentration is above 2 mol / L, although the hydrophilicity increases, it damages the fly ash structure, weakens the modification effect, and increases the fly ash dissolution loss. Therefore, controlling the acid solution concentration within the range of 0.1-2 mol / L during the hydrophilic modification process of fly ash is beneficial to improve its hydrophilicity without damaging the structural integrity of the fly ash.

[0098] As can be seen from the comparison between Comparative Example 1 and Example 1, the contact angle of fly ash without hydrophilic modification is 38.83°. The contact angle of fly ash after acid solution treatment is reduced, and the hydrophilicity is significantly improved.

[0099] The hydrophilic soil conditioners prepared in Examples 1-5 and the soil conditioners prepared in Comparative Examples 1 and 2 were applied to the improvement of saline-alkali soils. Along the direction penetrating the ground, the saline-alkali soils sequentially comprise a topsoil layer 1, a subsoil layer 2, and a subsoil layer 3 (see...). Figure 1 ).

[0100] Application Example 1

[0101] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0102] (1) At 35℃, fly ash with a solid-liquid ratio of (1:0.2) g / mL was reacted with a KH550 silane coupling agent modifier solution with glacial acetic acid added to adjust the pH value to 4 for 5 h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass ratio of KH550 silane coupling agent modifier in the hydrophobic soil conditioner was 2%.

[0103] (2) Apply 3 t / mu, 30 cm hydrophobic soil conditioner obtained in step (1) and 3 t / mu, 30 cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0104] Application Example 2-5

[0105] Application Examples 2-5 provide a method for improving saline-alkali soil. Except that the hydrophilic soil conditioner obtained in Example 1 in step (2) is replaced with the hydrophilic soil conditioner obtained in Example 2-5, everything else is the same as in Application Example 1.

[0106] Application Example 6

[0107] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0108] (1) At 20℃, fly ash with a solid-liquid ratio of (1:2) g / mL was reacted with a KH550 silane coupling agent modifier solution with citric acid added to adjust the pH value to 7 for 7 hours to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass ratio of KH550 silane coupling agent modifier in the hydrophobic soil conditioner was 1%.

[0109] (2) Apply 4 t / mu, 1 cm hydrophobic soil conditioner obtained in step (1) and 1 t / mu, 40 cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0110] Application Example 7

[0111] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0112] (1) At 90℃, fly ash with a solid-liquid ratio of (1:5) g / mL was reacted with a KH550 silane coupling agent modifier solution with malic acid added to adjust the pH value to 3 for 0.5 h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass ratio of KH550 silane coupling agent modifier in the hydrophobic soil conditioner was 3%.

[0113] (2) Apply 1 t / mu, 60cm hydrophobic soil conditioner obtained in step (1) and 4 t / mu, 1cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0114] Application Example 8

[0115] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0116] (1) At 30℃, fly ash with a solid-liquid ratio of (1:4) g / mL was reacted with sodium dodecyl sulfate modifier solution for 3h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass percentage of sodium dodecyl sulfate modifier in the hydrophobic soil conditioner was 1.5%.

[0117] (2) Apply 1 t / mu, 40cm hydrophobic soil conditioner obtained in step (1) and 2 t / mu, 20cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0118] Application Example 9

[0119] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0120] (1) At 20℃, fly ash with a solid-liquid ratio of (1:15) g / mL was reacted with sodium dodecyl sulfate modifier solution for 7h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass percentage of sodium dodecyl sulfate modifier in the hydrophobic soil conditioner was 1%.

[0121] (2) Apply 4 t / mu, 1 cm hydrophobic soil conditioner obtained in step (1) and 10 t / mu, 40 cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0122] Application Example 10

[0123] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0124] (1) At 90℃, fly ash with a solid-liquid ratio of (1:3) g / mL was reacted with sodium dodecyl sulfate modifier solution for 0.5 h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass percentage of sodium dodecyl sulfate modifier in the hydrophobic soil conditioner was 3%.

[0125] (2) Apply 10 t / mu, 60 cm hydrophobic soil conditioner obtained in step (1) and 4 t / mu, 1 cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0126] Application Example 11

[0127] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0128] (1) At 35℃, fly ash with a solid-liquid ratio of (1:15) g / mL was reacted with Triton modifier solution for 4h to obtain a hydrophobic soil conditioner. The reaction was accompanied by stirring. The mass percentage of Triton modifier in the hydrophobic soil conditioner was 2%.

[0129] (2) Apply 3 t / mu of hydrophobic soil conditioner with a thickness of 30 cm and 3 t / mu of hydrophilic soil conditioner obtained in Example 1 to the soil layer of saline-alkali land; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0130] Application Example 12

[0131] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0132] (1) At 20℃, fly ash with a solid-liquid ratio of (1:10) g / mL was reacted with Triton modifier solution for 7h to obtain hydrophobic soil conditioner. Stirring was carried out during the reaction. The mass ratio of Triton modifier in the hydrophobic soil conditioner was 1%.

[0133] (2) Apply 1 t / mu, 60cm hydrophobic soil conditioner obtained in step (1) and 4 t / mu, 1cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0134] Application Example 13

[0135] This application example provides a method for improving saline-alkali soil, the method comprising the following steps:

[0136] (1) At 90℃, fly ash with a solid-liquid ratio of (1:3) g / mL was reacted with Triton modifier solution for 0.5h to obtain hydrophobic soil conditioner. Stirring was carried out during the reaction. The mass ratio of Triton modifier in the hydrophobic soil conditioner was 3%.

[0137] (2) Apply 4 t / mu, 1 cm hydrophobic soil conditioner obtained in step (1) and 1 t / mu, 40 cm hydrophilic soil conditioner obtained in Example 1 to the saline-alkali soil layer; such as Figure 1 As shown, the hydrophilic soil conditioner is applied to the top layer 1 of the saline-alkali land, and the hydrophobic soil conditioner is applied to the lower layer 2 of the soil adjacent to the top layer. The soil improvement of the saline-alkali land is completed after irrigation.

[0138] Comparative Application Example 1

[0139] This comparative application example provides a method for improving saline-alkali soil. Except that the hydrophilic soil conditioner obtained in Example 1 in step (2) is replaced with the hydrophilic soil conditioner obtained in Comparative Example 1, everything else is the same as in Application Example 1.

[0140] Comparative Application Example 2

[0141] This comparative application example provides a method for improving saline-alkali soil. Except that the hydrophilic soil conditioner obtained in Example 1 in step (2) is replaced with the hydrophilic soil conditioner obtained in Comparative Example 2, everything else is the same as in Application Example 1.

[0142] Comparative Application Example 3

[0143] This comparative application example provides a method for improving saline-alkali soil. Except that the KH550 silane coupling agent modifier solution in step (1) is replaced with an equal volume fraction of pure water, i.e., the fly ash is not modified to be hydrophobic, the rest is the same as in application example 1.

[0144] In this comparative application example, the product of fly ash after being treated with pure water is named fly ash A.

[0145] Comparative Application Example 4

[0146] This comparative application example provides a method for improving saline-alkali soil. Except that the KH550 silane coupling agent modifier solution in step (1) is replaced with pure water of equal volume fraction, and the hydrophilic soil conditioner obtained in Example 1 in step (2) is replaced with the soil conditioner obtained in Comparative Example 1, the fly ash is not modified for hydrophilicity and hydrophobicity, and the rest is the same as in Application Example 1.

[0147] In this comparative application example, the product of fly ash after being treated with pure water is named fly ash B.

[0148] Performance testing

[0149] Test Example 1

[0150] Contact angle tests were conducted on the hydrophobic soil conditioner obtained from corresponding application examples 1-13 and comparative application examples 1-2, fly ash A obtained from comparative application example 3, and fly ash B obtained from comparative application example 4. The test method was as follows: using a contact angle meter, 20g of sample was placed in a mold and pressed under 15MPa pressure for 15min to form a sheet. The prepared sheet was placed on the test stage, and deionized water was drawn in through a micro-syringe and fixed on the instrument's automatic injection device. 2μL of sample was automatically injected, and a high-speed camera was used to take pictures and record the results. The results are shown in Table 2.

[0151] Table 2

[0152]

[0153]

[0154] In the hydrophobic soil conditioners prepared in Application Examples 1-13, Application Examples 1-7 used KH550 silane coupling agent modifier solution as hydrophobic modifier. The hydrophobic soil conditioner obtained in Application Example 1 had the best hydrophobic effect, with a contact angle of up to 108.36°. Application Examples 8-10 used sodium dodecyl sulfate modifier solution as hydrophobic modifier. The hydrophobic soil conditioner obtained in Application Example 8 had the best hydrophobic effect, with a contact angle of up to 76.95°. Application Examples 11-13 used Triton modifier solution as hydrophobic modifier. The hydrophobic soil conditioner obtained in Application Example 11 had the best hydrophobic effect, with a contact angle of up to 88.97°.

[0155] As can be seen from the comparison of application examples 3 and 4 with application example 1, the contact angle of unmodified fly ash is about 37°. After modification, the contact angle of fly ash increases and the hydrophobicity is significantly improved.

[0156] Test Example 2

[0157] Soil quality testing was conducted using the soil improvement methods for saline-alkali land provided in Case 1-13 and Comparative Application Example 1-4. The changes in soil bulk density and moisture content before and after improvement were measured. The specific test methods are as follows:

[0158] Soil bulk density: 100 cm³ 3 The ring cutter is cleaned, dried, and weighed. The weight of the empty aluminum box is recorded as m1. A standard profile is dug in the sample plot. The ring cutter is driven into the soil at a depth of 0-20cm from the surface layer to fill the ring cutter with soil sample. The ring cutter is removed, the box is covered, and the weight is recorded as m2. The calculation is performed according to formula (1).

[0159]

[0160] Moisture content: Take a covered aluminum box, wash, dry, and weigh it, and record it as m1; take a soil sample using a ring cutter according to the above soil bulk density test method, put it into the aluminum box, about 2 / 3 of the volume of the aluminum box, cover the box, weigh it, and record it as m2; open the box lid, put it in an oven, and dry it at 105℃ for about 6 hours; take it out, cover it, cool it, and weigh it; open the box lid, put it in the oven and dry it for another 2 hours, cool it, weigh it until constant weight, and record it as m3. Calculate according to formula (2).

[0161]

[0162] The results are shown in Table 3.

[0163] Table 3

[0164]

[0165]

[0166] Table 3 shows that the improved soil bulk density decreased by 0.3 g / cm³. 3 Around 5 wt% of water was added to the soil moisture content, significantly improving the hydrophilic and water-retention properties of saline-alkali soil. This helps to inhibit water evaporation and reduce the migration of salt and alkali components to the surface soil.

[0167] A comparison of Application Examples 4 and 5 with Application Example 1 shows that when the concentration of the acid solution during the hydrophilic modification process is below 0.1 mol / L, the modification effect is not significant, and the changes in soil bulk density and water content are not obvious. When the concentration of the acid solution is above 2 mol / L, it will damage the fly ash structure, weaken the improvement effect, and significantly reduce the improvement effect on soil bulk density and water content. Therefore, an acid solution concentration in the range of 0.1-2 mol / L during the hydrophilic modification process is beneficial for reducing soil bulk density, increasing soil water content, and improving the soil's hydrophilic and water-retention properties.

[0168] A comparison of Application Examples 1-4 with Application Example 1 shows that, without treatment with a hydrophilic modifier, the soil bulk density of fly ash decreased by only 0.224 g / cm³. 3 The moisture content increased by 1.43%; when only organic fertilizer was added to the soil conditioner without adding hydrophilic modified fly ash, the soil bulk density decreased by only 0.224 g / cm³. 3 The water content increased by 1.43%, therefore adding organic fertilizer alone cannot improve the soil's hydrophilicity; without hydrophobic modifier treatment, the soil bulk density only decreased by 0.118 g / cm³. 3 The water content increased by 1.04%; without hydrophilic and hydrophobic modification, the changes in soil bulk density and water content were minimal. Therefore, in the improvement of saline-alkali soil, hydrophilic and hydrophobic soil conditioners need to be applied simultaneously in layers to achieve synergistic effects, thereby maximizing the soil's hydrophilic and water-retention capacity and improving soil salinization.

[0169] Test Example 3

[0170] Soil quality testing was conducted using the soil improvement methods for saline-alkali land provided in Use Case 1-13 and Comparative Application Example 1-4. The pH value, EC value (soluble salt content), and salinity of the soil before and after improvement were measured. The specific test methods are as follows:

[0171] Mix the soil sample with deionized water at a solid-liquid ratio of 1:50 (unit: g / mL), stir for 5 minutes, let stand for 1 hour, and then use a pH meter to measure the pH value of the supernatant, which is the pH value of the soil.

[0172] Soil samples were mixed with deionized water at a solid-liquid ratio of 1:50 (unit: g / mL), stirred for 5 minutes, and allowed to stand for 1 hour. The EC value of the supernatant was then measured using a conductivity meter, which is the EC value of the soil.

[0173] Soil salinity was determined according to DB37 / T 1303-2009 (gravimetric method for determining total soil salinity).

[0174] The results are shown in Table 4.

[0175] Table 4

[0176]

[0177]

[0178] As shown in Table 4, the improved soil pH decreased by about 2, the EC value decreased by about 0.7 ms / cm, the soil salinity decreased by about 4 g / kg, and the content of salt and alkali components was significantly reduced, indicating a significant improvement effect.

[0179] A comparison of Application Examples 4 and 5 with Application Example 1 shows that when the acid solution concentration during the hydrophilic modification process is below 0.1 mol / L, the reduction in pH, EC value, and salinity of the improved soil is smaller. When the acid solution concentration is above 2 mol / L, the changes in pH, EC value, and salinity of the improved soil are also relatively small. Furthermore, a comparison of Application Examples 4 and 5 with Comparative Application Example 1 shows that when the acid solution concentration during the hydrophilic modification process is below 0.1 mol / L, the effect is similar to that of the untreated conditioner, indicating that the modification effect is not significant. When the concentration is above 2 mol / L, the effect is lower than that of the untreated conditioner, indicating that excessively high acid concentrations inhibit the improvement effect. Therefore, an acid solution concentration in the range of 0.1-2 mol / L during the hydrophilic modification process is beneficial for reducing soil pH, EC value, and salinity, reducing soil salinity and alkalinity, and improving salinization problems.

[0180] A comparison of Application Examples 1-4 with Application Example 1 shows that without treatment with the hydrophilic modifier, the soil pH decreased by only 0.91, the EC value decreased by 0.21 ms / cm, and the salinity decreased by 1.54 g / kg. When only organic fertilizer was added to the soil conditioner without hydrophilic modified fly ash, the decreases in soil pH, EC value, and salinity were also small. Without treatment with the hydrophobic modifier, the soil pH decreased by only 1.02, the EC value decreased by 0.26 ms / cm, and the salinity decreased by 1.72 g / kg. Without both hydrophilic and hydrophobic modifications, the changes in soil pH, EC value, and salinity were minimal, indicating an insignificant improvement effect on saline-alkali soil. Therefore, in the improvement of saline-alkali soil, it is necessary to apply both hydrophilic and hydrophobic soil conditioners in layers simultaneously to achieve a synergistic effect, thereby reducing soil pH, EC value, and salinity and improving salinization.

[0181] In summary, this invention provides a hydrophilic soil conditioner, its preparation method, and its application. The surface of fly ash modified with acid solution is rich in hydrophilic groups and hydrogen ions, which can improve water retention capacity, neutralize alkaline ions in the soil, and regulate soil pH. The resulting hydrophilic soil conditioner can enhance the soil's hydrophilic water retention capacity. Applying the hydrophilic soil conditioner to the surface layer of saline-alkali soil and the hydrophobic soil conditioner to the adjacent soil layer inhibits water evaporation, reduces the migration of salt and alkali components to the surface soil, decreases the ability of capillary pores to transport water upwards, weakens the migration of salt to the surface with evaporation, and reduces the surface salt content, thereby achieving the purpose of improving saline-alkali soil. Simultaneously, this invention, through the modification treatment of fly ash to prepare a soil conditioner, not only improves the problem of soil salinization and realizes the high-value application of fly ash, but also effectively solves the problem of fly ash storage and reduces the harm of fly ash to the ecological environment and human health.

[0182] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for improving saline-alkali soil, characterized in that, The improved method includes the following steps: Hydrophobic and hydrophilic soil conditioners are applied to the soil layer of saline-alkali land, and the soil improvement is completed after irrigation. The hydrophilic soil conditioner is applied to the surface layer of the saline-alkali soil. The hydrophobic soil conditioner is applied to the soil layer adjacent to the surface layer. The hydrophobic soil conditioner is obtained by reacting fly ash with a hydrophobic modifier solution; The hydrophobic modifier solution is a KH550 silane coupling agent modifier solution; The solid-liquid ratio of fly ash to the KH550 silane coupling agent modifier solution in the hydrophobic soil conditioner is 1:(0.1-5), and the unit of the solid-liquid ratio is g / mL; the pH of the KH550 silane coupling agent modifier solution is 3-7. The preparation method of the hydrophilic soil conditioner includes the following steps: (1) After the fly ash and the hydrophilic modifier solution react, hydrophilic fly ash is obtained; the solid-liquid ratio of the fly ash and the hydrophilic modifier solution is 1:(3-10), and the unit of the solid-liquid ratio is g / mL; (2) Mix the organic fertilizer and the hydrophilic fly ash obtained in step (1), and after composting, obtain the hydrophilic soil conditioner; The hydrophilic modifier solution in step (1) includes an acid solution; the concentration of the acid solution is 0.1-2 mol / L; the acid used in the acid solution includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, acetic acid, citric acid or oxalic acid.

2. The improved method according to claim 1, characterized in that, The reaction temperature in step (1) is 20-90℃.

3. The improved method according to claim 1, characterized in that, The reaction time in step (1) is 0.5-7 hours.

4. The improved method according to claim 1, characterized in that, The reaction described in step (1) is accompanied by stirring at a speed of 10-700 rpm.

5. The improved method according to claim 1, characterized in that, In step (2), the mass fraction of the hydrophilic fly ash relative to the hydrophilic soil conditioner is 50-90%.

6. The improved method according to claim 1, characterized in that, The organic fertilizer mentioned in step (2) includes any one or a combination of at least two of the following: slag, straw or manure.

7. The improved method according to claim 6, characterized in that, The residue includes any one or a combination of at least two of vinegar residue, wine residue, or oil residue.

8. The improved method according to claim 7, characterized in that, The mass fraction of the vinegar residue relative to the hydrophilic soil conditioner is 0.5-30%.

9. The improved method according to claim 7, characterized in that, The mass fraction of the lees relative to the hydrophilic soil conditioner is 0.5-20%.

10. The improved method according to claim 7, characterized in that, The mass fraction of the oil residue relative to the hydrophilic soil conditioner is 0.5-20%.

11. The improved method according to claim 6, characterized in that, The mass fraction of the straw relative to the hydrophilic soil conditioner is 0.5-10%.

12. The improved method according to claim 6, characterized in that, The mass fraction of the feces relative to the hydrophilic soil conditioner is 0.5-20%.

13. The improved method according to claim 6, characterized in that, The feces include cow dung and / or sheep dung.

14. The improved method according to claim 1, characterized in that, The fermentation temperature is 20-60℃.

15. The improved method according to claim 1, characterized in that, The composting time is 5-60 days.

16. The improved method according to claim 1, characterized in that, The preparation method of the hydrophilic soil conditioner includes the following steps: (1) At 20-90℃, fly ash with a solid-liquid ratio of 1:(3-10)g / mL and a hydrophilic modifier solution are reacted for 0.5-7h, with stirring during the reaction, to obtain hydrophilic fly ash; the hydrophilic modifier solution is an acid solution with a concentration of 0.1-2mol / L, and the acid used includes any one or a combination of at least two of sulfuric acid, hydrochloric acid, acetic acid, citric acid or oxalic acid; (2) Mix the organic fertilizer and the hydrophilic fly ash obtained in step (1) and decompose at 20-60℃ for 5-60 days to obtain the hydrophilic soil conditioner; the mass fraction of the hydrophilic fly ash is 50-90% and the organic fertilizer includes any one or at least two of vinegar residue, wine residue, oil residue, straw, cow manure or sheep manure.

17. The improved method according to claim 1, characterized in that, The reaction temperature between the fly ash and the hydrophobic modifier solution is 20-90℃.

18. The improved method according to claim 17, characterized in that, The reaction time is 0.5-7 hours.

19. The improved method according to claim 17, characterized in that, The reaction is accompanied by stirring at a speed of 10-700 rpm.

20. The improved method according to claim 1, characterized in that, The pH is adjusted by adding any one or a combination of at least two of glacial acetic acid, citric acid, malic acid, tartaric acid, or oxalic acid to the KH550 silane coupling agent modifier solution.

21. The improved method according to claim 1, characterized in that, The mass percentage of KH550 silane coupling agent modifier in the hydrophobic soil conditioner is 0.1-3%.

22. The improved method according to claim 1, characterized in that, The application rate of the hydrophilic soil conditioner is 1-10 t / mu.

23. The improved method according to claim 1, characterized in that, The hydrophilic soil conditioner is applied to a soil layer thickness of 1-40cm.

24. The improved method according to claim 1, characterized in that, The application rate of the hydrophobic soil conditioner is 1-10 t / mu.

25. The improved method according to claim 1, characterized in that, The hydrophobic soil conditioner is applied to a soil layer thickness of 1-60cm.

26. The improved method according to claim 1, characterized in that, The improved method includes the following steps: Apply 1-10 t / mu of hydrophobic soil conditioner with a thickness of 1-60 cm and 1-10 t / mu of hydrophilic soil conditioner with a thickness of 1-40 cm to the soil layer of saline-alkali land. The hydrophilic soil conditioner is applied to the surface layer of the saline-alkali land soil, and the hydrophobic soil conditioner is applied to the soil layer adjacent to the surface layer. The saline-alkali land soil improvement is completed after irrigation. The hydrophobic soil conditioner is obtained by reacting fly ash with a hydrophobic modifier solution at 20-90℃ for 0.5-7h, with stirring during the reaction. The hydrophobic modifier solution is a KH550 silane coupling agent modifier solution.

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