Soil remediation agent for ecological remediation of loess slope and preparation method of soil remediation agent

Abstract

The invention discloses a soil remediation agent for ecological remediation of a loess slope and a preparation method of the soil remediation agent, and belongs to the technical field of soil remediation, the soil remediation agent comprises the following components in parts by mass: 5-15 parts of bacillus mucilaginosus, 5-10 parts of mushroom residues and 10-20 parts of sodium humate. Aiming at the special ecological defects of the loess slope, the invention provides the soil remediation agent with simple components, the required raw materials are wide in source, and the nutritional components of the loess slope soil are enriched through the interaction of the bacillus mucilaginosus, the mushroom residues and the humate. When ecological restoration is carried out on the loess slope, an amino acid and polypeptide mixed solution obtained through hydrothermal treatment of waste animal hair is added, formation of aggregates is promoted, the stability of soil is improved, dispersion and loss of soil particles are prevented, and by improving the arrangement and connection mode of the soil particles, the soil stability is improved. A tighter and more stable soil structure is formed, and the compressive strength of the soil is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of soil restoration, and in particular relates to a soil restoration agent for ecological restoration of loess slopes and a preparation method thereof. Background Art

[0002] Loess is a regional soil widely distributed in arid and semi-arid areas, mainly formed by wind blowing, transportation and accumulation since the Quaternary period. Loess has loose soil texture, loose structure, poor erosion resistance, low organic matter content, obvious vertical joint development characteristics, and is easy to be eroded. The Northwest region is the area with the strongest loess collapsibility. The region has serious soil erosion, low plant survival rate, and fragile ecological environment. The loess slope soil is poor and alkaline, has strong collapsibility, and low strength. The ecological restoration of loess slopes has always been one of the main problems of ecological construction in the Northwest region. With people's increasing attention to the concept of natural ecosystem restoration, more and more technologies are being applied to the ecological restoration of loess slopes. The ecological restoration of loess slopes is carried out through vegetation restoration, soil and water conservation projects, agricultural management, and ecological slope protection technology. Even if the existing restoration methods have achieved certain results, there are still many problems. For example, artificial grass slope protection is greatly affected by terrain, climate and soil conditions, which may lead to low vegetation survival rate and difficult to achieve the expected restoration effect. Some high-level ecological slope protection technologies, such as geocell grass slope protection and vegetation matrix plant slope protection, are relatively expensive and may exceed the budget. Some repair methods, such as paving turf slope protection, require regular replacement of turf and maintenance, which have high maintenance costs and difficult operations. In addition, the aging of some materials, such as geogrids, may lead to soil pollution and cause secondary damage to the environment.

[0003] Soil remediation agents are materials added to soil to improve the physical and chemical properties of soil and its biological activity. They usually contain a variety of beneficial microorganisms, organic matter, and trace elements. They are designed to promote the recovery and diversity of soil microbial communities, enhance soil fertility, improve crop resistance, and help reduce soil pollution. Soil remediation agents have a wide range of applications. For soil degradation problems caused by heavy metals, pesticides, fertilizers, etc., the microorganisms and organic matter in soil remediation agents can help degrade harmful substances and reduce the content of pollutants in the soil. They can also improve the self-repair ability of the soil by increasing the content of soil organic matter and improving soil structure. The salt and alkaline substances in saline-alkali soil are too high, which is not conducive to crop growth. Soil remediation agents can improve the soil environment of saline-alkali land by adjusting soil pH and increasing soil organic matter, making it more suitable for crop growth. However, the properties of loess slope soil are significantly different from the above soils. The existing soil remediation agents are not suitable for its ecological restoration, and there are few reports on soil remediation agents for the fragile ecological environment of loess slopes. Summary of the invention

[0004] The purpose of the present invention is to provide a soil remediation agent for loess slope ecological restoration and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art.

[0005] One of the technical solutions provided by the present invention:

[0006] A soil repair agent comprises the following components, measured by weight: 5-15 parts of bacillus subtilis, 5-10 parts of mushroom residues and 10-20 parts of sodium humate.

[0007] Preferably, the soil remediation agent comprises the following components in parts by mass: 5-10 parts of Bacillus subtilis, 5-8 parts of mushroom residues and 15-20 parts of sodium humate.

[0008] More preferably, the soil remediation agent comprises the following components, measured by weight: 10 parts of Bacillus subtilis, 5 parts of mushroom residues and 20 parts of sodium humate.

[0009] Loess is mainly composed of silt, containing a certain amount of fine sand and clay, and its mineral composition is quite rich. Specifically, the mineral composition of loess can be divided into detrital minerals, clay minerals and authigenic minerals. The main mineral components in loess include detrital minerals, clay minerals and authigenic minerals, among which detrital minerals are mainly quartz, feldspar and mica; clay minerals mainly include illite, montmorillonite, kaolinite, goethite, hydrous hematite, etc. Loess contains a large amount of carbonate minerals, mainly calcite, which often exists in a microparticle state, and occasionally recrystallized fine-grained calcite can be seen. According to the above-mentioned unique properties of loess, when preparing the soil remediation agent, the added colloidal Bacillus can decompose minerals such as feldspar and mica in the loess, releasing elements such as potassium and silicon therein, which play an important role in the stability and improvement of soil structure. Bacillus subtilis has the functions of solubilizing phosphorus, releasing potassium and fixing nitrogen. It can convert ineffective phosphorus and potassium in the soil into effective phosphorus and potassium. At the same time, it can also fix nitrogen in the air, provide nitrogen nutrition for plants, and significantly improve the soil fertility level.

[0010] Mushroom residue, as an organic waste, is rich in organic matter and nutrients. It can be used as an organic additive in soil remediation agents to increase the organic matter content of the soil. The organic matter it provides can intensify the activity of microorganisms in the soil, promote the degradation of organic matter in the soil by microorganisms and the release of nutrients.

[0011] Sodium humate can combine with cations in the soil to form a buffer system for the mutual conversion of humic acid and sodium humate, which plays a good role in regulating the pH value of the soil.

[0012] The second technical solution provided by the present invention is:

[0013] A method for preparing a soil repair agent comprises weighing raw materials according to their mass fractions, mixing them evenly, and preparing the soil repair agent.

[0014] The third technical solution provided by the present invention is:

[0015] An application of the soil repair agent in the ecological restoration of loess slopes is to add pre-treated discarded animal hair into water for hydrothermal reaction and keep it for later use after cooling; a pit is dug out on the surface of the loess to be treated, the dug loess is kept for later use, and the pit foundation is compacted. After the compaction is completed, the reserved loess, the cooled hydrothermal reaction solution and the soil repair agent are mixed to obtain a premixed slurry, which is then re-injected into the pit and naturally left to solidify.

[0016] Preferably, the mass ratio of the waste animal hair to water is 1:(5-7).

[0017] Preferably, the temperature of the hydrothermal reaction is 200-260° C., and the time of the hydrothermal reaction is 10 h.

[0018] Preferably, the mass ratio of the loess, the cooled hydrothermal reaction solution and the soil remediation agent is 1:(0.8-1):(0.1-0.2).

[0019] Preferably, the curing time is 5-7 days.

[0020] The present invention achieves efficient hydrolysis of discarded animal hair through hydrothermal reaction, and the hydrolysis product is a mixture of polypeptides and amino acids, which can change the physical and chemical properties of the soil, such as adjusting the pH of the soil, wherein the functional groups in the amino acids are adsorbed on the surface of soil mineral particles or organic matter to form a protective film, which can reduce the friction and collision between soil particles and prevent soil dispersion. In addition, the functional groups on the polypeptides can interact with multiple soil particles to form a bridging structure, which can increase the connection between soil particles and promote the formation of aggregates. The formation of aggregates can improve the internal pore space of the soil, increase the stability of the soil, prevent the dispersion and loss of soil particles, help reduce soil erosion and maintain soil fertility, and aggregates make the soil fine and uniform, making the soil easier to cultivate and manage.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] The present invention aims at the ecological defects unique to loess slopes, provides a soil repair agent with simple components, requires a wide range of raw materials, and enriches the nutritional components of loess slope soil through the interaction of Bacillus colloids, mushroom residues and sodium humate. When the present invention is used for ecological restoration of loess slopes, by adding a mixed solution of amino acids and polypeptides obtained by hydrothermal treatment of discarded animal hair, the formation of aggregates is promoted, the stability of the soil is increased, the dispersion and loss of soil particles are prevented, and a more compact and stable soil structure is formed by improving the arrangement and connection between soil particles, which helps to improve the compressive strength of the soil. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] In the embodiments of the present invention, “parts” refer to “parts by mass” unless otherwise specified.

[0029] Bacillus mucilaginosus (effective viable count ≥ 5 billion / g) was purchased from Hubei Xingdongcheng Chemical Co., Ltd.;

[0030] Sodium humate was purchased from Guangzhou Zelong Chemical Technology Co., Ltd.;

[0031] The mushroom residue was purchased from Dezhou Fubon Agricultural Development Co., Ltd.

[0032] Examples 1-3

[0033] Weigh the raw materials according to Table 1:

[0034] Table 1

[0035]

[0036]

[0037] The components are mixed evenly to prepare a soil remediation agent.

[0038] Comparative Example 1

[0039] The same as Example 1, except that no mushroom residue is added.

[0040] Comparative Example 2

[0041] Same as Example 1, except that no sodium humate is added.

[0042] Application Example 1

[0043] The washed waste animal hair is dried to constant weight, water is added to the high-pressure digestion tank, the mass of the added water is 500% of the mass of the waste animal hair, the sealed high-pressure digestion tank is heated to 200°C, hydrothermally reacted for 10 hours, cooled to room temperature, a pit is dug in the surface layer of the loess to be treated, the dug loess is reserved, the pit foundation is compacted, and after compaction, the reserved loess, the cooled hydrothermal reaction solution and the soil remediation agent prepared in Example 1 are mixed in a mass ratio of 1:0.8:0.2 to obtain a premixed slurry, the premixed slurry is re-injected into the pit, and naturally left to solidify for 5 days.

[0044] Application Example 2

[0045] The washed waste animal hair is dried to constant weight, water is added to the high-pressure digestion tank, the mass of the added water is 700% of the mass of the waste animal hair, the sealed high-pressure digestion tank is heated to 250°C, hydrothermally reacted for 10 hours, cooled to room temperature, a pit is dug in the surface layer of the loess to be treated, the dug loess is reserved, the pit foundation is compacted, and after compaction, the reserved loess, the cooled hydrothermal reaction solution and the soil remediation agent prepared in Example 2 are mixed in a mass ratio of 1:1:0.1 to obtain a premixed slurry, the premixed slurry is re-injected into the pit, and naturally left to solidify for 6 days.

[0046] Application Example 3

[0047] The washed waste animal hair is dried to constant weight, water is added to the high-pressure digestion tank, the mass of the added water is 600% of the mass of the waste animal hair, the sealed high-pressure digestion tank is heated to 260°C, hydrothermally reacted for 10 hours, cooled to room temperature, a pit is dug in the surface layer of the loess to be treated, the dug loess is reserved, the pit foundation is compacted, and after compaction, the reserved loess, the cooled hydrothermal reaction solution and the soil remediation agent prepared in Example 3 are mixed in a mass ratio of 1:0.8:0.2 to obtain a premixed slurry, the premixed slurry is re-injected into the pit, and naturally left to solidify for 7 days.

[0048] Application Example 4

[0049] The same as Application Example 1, except that the soil remediation agent prepared in Example 1 is replaced by the soil remediation agent prepared in Comparative Example 1.

[0050] Application Example 5

[0051] The same as Application Example 1, except that the soil remediation agent prepared in Example 1 is replaced by the soil remediation agent prepared in Comparative Example 2.

[0052] Application Example 6

[0053] A pit is dug out on the surface of the loess to be treated, and the dug loess is reserved. The pit foundation is compacted. After compaction, the reserved loess, water and the soil remediation agent prepared in Example 1 are mixed in a mass ratio of 1:0.8:0.2 to obtain a premixed slurry. The premixed slurry is re-injected into the pit and naturally left to solidify for 5 days.

[0054] Application Example 7

[0055] The washed discarded animal hair is dried to constant weight, water is added to the high-pressure digestion tank, the mass of the added water is 500% of the mass of the discarded animal hair, the sealed high-pressure digestion tank is heated to 200°C, hydrothermally reacts for 10 hours, and then cooled to room temperature, a pit is dug on the surface of the loess to be treated, the dug loess is reserved, the pit foundation is compacted, and after compaction, the reserved loess and the cooled hydrothermal reaction solution are mixed in a mass ratio of 1:0.8 to obtain a premixed slurry, the premixed slurry is re-injected into the pit, and naturally left to solidify for 5 days.

[0056] Performance Testing

[0057] The collapsible initial pressure of loess is the minimum pressure value when collapsible loess collapses. It is the basis for determining whether loess collapses by its own weight and the depth of its own weight collapse, as well as whether non-self-weight collapse occurs under external load. The present invention determines it through a double-line static load test. The compressive strength of loess is an important indicator for measuring its mechanical properties. The present invention places the loess sample in an unconfined compression instrument and applies vertical pressure until the sample is destroyed. The maximum pressure value when the sample is destroyed is recorded, which is the unconfined compressive strength of the loess. The present invention uses the potassium dichromate volumetric method to determine the content of organic matter in the soil. The results of the determination of the collapsible initial pressure, compressive strength and organic matter content of the soil after natural static curing in Example 1-7 are shown in Table 2.

[0058] Table 2

[0059]

[0060] It can be seen from Table 2 that when the present invention is used to carry out ecological restoration of loess slope soil, the addition of the amino acid and polypeptide mixed solution obtained by hydrothermal treatment of discarded animal hair significantly increases the stability of the soil, reduces the collapsibility of the soil, and improves the compressive strength; in addition, the added Bacillus colloidus, mushroom residue and sodium humate in the soil repair agent increase the organic matter content by mutual coordination. Application Examples 6 and 7 show that the soil repair agent prepared by the present invention also has the effect of improving soil structure to a certain extent, because the increase of appropriate organic matter helps to reduce the variation range of the soil between dry and wet states, thereby reducing the collapsibility of the soil. Organic matter can increase the viscosity of the soil, produce cementation, promote the combination of minerals, and form a consolidated structure, thereby increasing the stability of the soil.

[0061] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A soil remediation agent, characterized in that: The invention comprises the following components in parts by weight: 5-15 parts of bacillus subtilis, 5-10 parts of mushroom residues and 10-20 parts of sodium humate.

2. The soil remediation agent according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 5-10 parts of bacillus subtilis, 5-8 parts of mushroom residues and 15-20 parts of sodium humate.

3. The soil remediation agent according to claim 2, characterized in that: The invention comprises the following components in parts by weight: 10 parts of bacillus subtilis, 5 parts of mushroom residues and 20 parts of sodium humate.

4. A method for preparing the soil remediation agent according to any one of claims 1 to 3, characterized in that: The raw materials are weighed according to their mass fractions, mixed evenly, and the soil remediation agent is prepared.

5. Use of the soil remediation agent according to any one of claims 1 to 3 in ecological restoration of loess slopes, characterized in that: The pretreated waste animal hair is added into water for hydrothermal reaction and cooled for use; a pit is dug out on the surface of the loess to be treated, the dug loess is used for use, and the pit foundation is compacted. After compaction, the reserved loess, the cooled hydrothermal reaction solution and the soil remediation agent according to any one of claims 1 to 3 are mixed to obtain a premixed slurry, and the premixed slurry is re-injected into the pit and naturally left to solidify.

6. The use of the soil remediation agent according to claim 5 in the ecological restoration of loess slopes, characterized in that: The mass ratio of the waste animal hair to water is 1:(5-7).

7. The use of the soil remediation agent according to claim 5 in the ecological restoration of loess slopes, characterized in that: The temperature of the hydrothermal reaction is 200-260° C., and the time of the hydrothermal reaction is 10 hours.

8. The use of the soil remediation agent according to claim 5 in the ecological restoration of loess slopes, characterized in that: The mass ratio of the loess, the cooled hydrothermal reaction solution and the soil repair agent is 1:(0.8-1):(0.1-0.2).

9. The use of the soil remediation agent according to claim 5 in the ecological restoration of loess slopes, characterized in that: The curing time is 5-7 days.

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