In-situ soil remediation reagent and preparation method thereof

Abstract

The present invention discloses an in-situ soil remediation reagent and a preparation method thereof, belonging to the technical field of soil remediation. The raw materials for preparing the in-situ soil remediation reagent include: in-situ soil microaggregates, in-situ soil powder-viscous aggregates, soil stock solution, yeast extract, tryptone, sodium chloride, Pseudomonas aeruginosa, sapodilla waste branch crude emulsion, and ethylenediaminetetraacetic acid solution. The preparation method of the in-situ soil remediation reagent includes: preparing an adaptive Pseudomonas aeruginosa culture medium, culturing adaptive Pseudomonas aeruginosa, reducing aggregate viscosity, and preparing the in-situ soil remediation reagent. The in-situ soil remediation reagent solves the problem of an excessively high proportion of small-particle soil aggregates in the soil by promoting soil particle aggregation, thereby improving soil structure, and increasing soil nutrient content and water retention capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to an in-situ soil remediation reagent and a preparation method thereof. Background Art

[0002] Soil aggregates are important structural units in soil. The composition and stability of soil particles of varying particle sizes directly influence the soil's physical and chemical properties, and also significantly impact its drought resistance, moisture retention, water conservation, and nutritional functions. In hot and humid climates, soils formed through weathering and micro-agglomeration often form wastelands with sparse vegetation, severe soil erosion, and poor water retention, due to their small aggregate size. This makes them susceptible to water erosion.

[0003] For this type of soil, the soil structure is usually improved by deep plowing, planting drought-tolerant plants, adding organic fertilizers or phosphate fertilizers, etc., in order to increase the water storage capacity of the soil, improve the physical and chemical properties of the soil, and then repair the soil. The method of deep plowing and planting drought-tolerant plants takes a long time, and the change of soil structure requires long-term management and maintenance, requires a lot of manpower, and is not suitable for large-scale soil repair. By applying organic fertilizers, phosphate fertilizers, etc. to increase soil nutrients, promote plant growth, and then modify the soil structure, but excessive application will accelerate the rate of soil erosion and lead to soil boarding. In addition, there are also high molecular organic substances such as polyacrylamide, polyvinyl alcohol resin, polyvinyl alcohol and polyethylene glycol as soil conditioners to increase soil viscosity and increase the particle size of soil aggregates to change the soil structure, and then improve soil quality. However, the stability of the aggregates formed by applying high molecular organic substances is poor, and can only promote soil agglomeration for a short time. Therefore, it is urgent to find a soil repair method that can promote soil particle agglomeration, reduce the proportion of small-particle soil, and improve soil structure to improve soil fertility and prevent soil nutrient loss. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an in-situ soil remediation reagent and a preparation method thereof, which can solve the problem of excessively high proportion of small-particle soil aggregates in the soil by promoting soil particle agglomeration, thereby improving soil structure, increasing soil nutrient content and water retention capacity, and preventing soil compaction after remediation.

[0005] The following technical means solve the above technical problems:

[0006] The present invention solves the above technical problems by providing an in-situ soil remediation reagent. The raw materials for preparing the in-situ soil remediation reagent include: in-situ soil microaggregates, in-situ soil powder-sticky aggregates, soil stock solution, yeast extract, tryptone, sodium chloride, Pseudomonas aeruginosa, sapodilla tree waste branch crude emulsion and 5.0g / L ethylenediaminetetraacetic acid solution.

[0007] Furthermore, the in-situ soil microaggregates, in-situ soil powder-clay aggregates and soil stock solution are prepared by wet screening after air-drying the pre-remediation soil.

[0008] Furthermore, the wet sieving method is used to prepare in-situ soil microaggregates, in-situ soil powder and sticky aggregates, and soil stock solution in the following specific operations:

[0009] The pre-remediation soil was air-dried and placed on the top layer of a 0.053 mm pore size sieve. The water level of the bucket under the sieve was adjusted to the state where the soil sample in the top sieve was just submerged. Then, it was soaked in distilled water at room temperature for 5 minutes. The sieve was moved up and down 5 cm. This process was repeated 100 times within 5 minutes. The in-situ soil powder and sticky aggregates were collected. Subsequently, the sieve was replaced with a 0.25 mm sieve. The sieve was moved up and down 3 cm. This process was repeated 50 times within 2 minutes. The in-situ soil microaggregates were collected. The soil was allowed to stand for stratification to remove the precipitate and obtain the soil stock solution.

[0010] The present invention also provides a method for preparing an in-situ soil remediation reagent, and the preparation method of the in-situ soil remediation reagent is as follows:

[0011] (1) Preparation of adaptive Pseudomonas aeruginosa culture medium: Yeast extract, tryptone, and sodium chloride were added to the soil stock solution and mixed evenly, and then sterilized at 121°C for 30 min to obtain an adaptive Pseudomonas aeruginosa culture medium;

[0012] (2) Adaptive Pseudomonas aeruginosa culture: Pseudomonas aeruginosa is inoculated into an adaptive Pseudomonas aeruginosa culture medium and cultured for 8-12 days at a temperature of 35-37°C and a humidity of 65-75% to obtain an in situ soil-adapted Pseudomonas aeruginosa bacterial solution;

[0013] (3) Aggregate viscosity reduction: After the in-situ soil microaggregates and in-situ soil powder-sticky aggregates are evenly mixed, 5.0 g / L ethylenediaminetetraacetic acid solution is added and allowed to stand for 1-3 h to obtain the de-sticky mixed in-situ soil;

[0014] (4) Preparation of in situ soil remediation reagent: The crude emulsion of sapodilla waste branches is added to the de-sticky mixed in situ soil while stirring, mixed evenly, and then subjected to high-temperature reaction. The mixture is then cooled to room temperature, and the in situ soil-adaptable Pseudomonas aeruginosa liquid is added and stirred evenly. The in situ soil remediation reagent is obtained by continuing to cultivate at 35-37°C for 6-8 days.

[0015] Furthermore, in step (1), the mass volume ratio of yeast extract, tryptone, sodium chloride and soil stock solution is (2-4) kg: (1-2) kg: (2-4) kg: (8-12) L.

[0016] Furthermore, in step (3), the mass volume ratio of the in-situ soil microaggregates, the in-situ soil powder and clay aggregates and the 5.0 g / L EDTA solution is (1-2) kg: (3-5) kg: (0.8-1.2) L.

[0017] Furthermore, the high temperature reaction in step (4) is carried out at a temperature of 120-140° C. and for a time of 20-30 minutes.

[0018] Furthermore, in the step (4), the mass volume ratio of the de-viscous mixed in-situ soil, the crude emulsion of sapodilla waste branches and the in-situ soil-adapted Pseudomonas aeruginosa bacterial solution is (3-5) kg: (1-2) L: (0.4-0.6) L.

[0019] Furthermore, the preparation method of the sapodilla waste branch crude emulsion is as follows:

[0020] The waste branches of the sapodilla tree are crushed and poured into clean water of equal mass ratio and stirred to mix evenly, then heated to 70-80°C, stirred at constant temperature until the solution turns orange-yellow, then cooled to room temperature, allowed to stand and stratified to remove the precipitate to obtain a crude emulsion of waste branches of the sapodilla tree.

[0021] The present invention combines a soil stock solution obtained by wet sieving with raw materials such as yeast extract, tryptone, and sodium chloride to form an adaptive Pseudomonas aeruginosa culture medium. Because the soil stock solution contains nutrients similar to those of the in-situ soil to be repaired, when Pseudomonas aeruginosa is inoculated and cultured in the adaptive Pseudomonas aeruginosa culture medium, it develops adaptability, allowing it to more quickly adapt to the soil environment to be repaired. When preparing the in-situ soil remediation reagent, ethylenediaminetetraacetic acid is added to reduce its viscosity to prevent electrostatic aggregation of in-situ soil microaggregates and in-situ soil powder and sticky aggregates to form loose large particles, which reduces the remediation effect of the soil remediation agent. This allows the prepared de-viscous mixed in-situ soil to disperse. A crude emulsion of sapodilla waste branches is then added. Under high temperature conditions, the sticky substances in the crude emulsion cause the de-viscous mixed in-situ soil to re-adhere to form new soil particles and produce a large amount of humic acid. Subsequently, the culture is continued by adding an adaptive Pseudomonas aeruginosa bacterial solution and stirring to produce acidic mucus, which can further bind new soil particles to produce an in-situ soil remediation reagent. At the same time, the acidic mucus produced by the adaptive Pseudomonas aeruginosa can improve the stability of the sticky substances in the soil particles, making the prepared in-situ soil remediation reagent highly stable.

[0022] The prepared in-situ soil remediation reagent is a new aggregate containing a large amount of adaptive Pseudomonas aeruginosa. When applied to the in-situ soil to be remediated, the adaptive Pseudomonas aeruginosa has strong adaptability to the in-situ soil to be remediated and needs to absorb and utilize nutrients, so it tends to move to the in-situ soil to be remediated and produces mucus. The acidic mucus produced by the adaptive Pseudomonas aeruginosa binds the soil together to form large-particle aggregates, thereby gradually reducing the proportion of small-particle soil in the soil, improving the soil structure, and improving the soil's resistance to soil erosion and water retention capacity.

[0023] Beneficial effects:

[0024] 1. The present invention successfully produces an in-situ soil remediation reagent. After using the in-situ soil remediation reagent to repair the in-situ soil, the proportion of small-particle soil aggregates in the soil is reduced, the soil structure is improved, and the nutrient content and water retention capacity of the soil are increased.

[0025] 2. The present invention cultured Pseudomonas aeruginosa in an adaptive Pseudomonas aeruginosa culture medium prepared from a soil stock solution, which enabled the bacteria to adapt to the in-situ soil, absorb nutrients from the in-situ soil, and exhibit tropism.

[0026] 3. After the in-situ soil microaggregates and in-situ soil powder-sticky aggregates of the present invention are de-sticked by the action of ethylenediaminetetraacetic acid solution, they react with the crude emulsion of sapodilla waste branches under high temperature conditions, and are added to the in-situ soil-adapted Pseudomonas aeruginosa bacterial liquid. The in-situ soil-adapted Pseudomonas aeruginosa is further cultured, effectively preventing the soil from becoming compacted when the in-situ soil remediation reagent is used to remediate the soil.

[0027] Figures in the specification

[0028] Figure 1 : Water evaporation rate curve of the in-situ soil remediation reagent prepared in Example 1 after in-situ remediation of soil and blank control soil DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the embodiments and accompanying drawings:

[0030] The pre-remediation soil used in the present invention is taken from a test site in the Laohushan small watershed of Taihe County in the central part of the Jitai Basin in central Jiangxi Province. The soil is red clay, and the ratio of macroaggregates, medium aggregates, microaggregates and powdery clay aggregates in the soil is approximately 1:2:6:10.

[0031] The in-situ soil microaggregates, in-situ soil powder-clay aggregates, and soil stock solution used in the examples and comparative examples of the present invention were prepared according to the following steps:

[0032] 10 kg of pre-remediation soil was air-dried and placed on the top layer of a 0.053 mm pore size sieve. The water level of the bucket under the sieve was adjusted to the state where the soil sample in the top sieve was just submerged. Then, 11 L of distilled water was used to soak the soil at room temperature for 5 minutes. The sieve was moved up and down 5 cm. This was repeated 100 times within 5 minutes. 5.19 kg of in-situ soil powder and sticky aggregates were collected. Subsequently, the sieve was replaced with a 0.25 mm sieve. The sieve was moved up and down 3 cm. This was repeated 50 times within 2 minutes. 2.29 kg of in-situ soil microaggregates were collected. The soil was allowed to stand for stratification to remove the precipitate and obtain 10 L of soil stock solution.

[0033] The sapodilla waste branch crude emulsion used in the examples of the present invention and the comparative examples was prepared according to the following steps:

[0034] 10 kg of sapodilla waste branches were crushed and poured into 10 kg of clean water, stirred and mixed evenly, then heated to 75° C. and stirred at constant temperature until the solution turned orange-yellow. The solution was then cooled to room temperature, allowed to stand and separated to remove the precipitate, thereby obtaining a crude emulsion of sapodilla waste branches.

[0035] Example 1: Preparation of in-situ soil remediation reagents

[0036] (1) Preparation of adaptive Pseudomonas aeruginosa culture medium: 3 kg of yeast extract, 1.5 kg of tryptone, and 3 kg of sodium chloride were added to 10 L of soil stock solution, stirred and mixed evenly, and then sterilized at 121°C for 30 min to obtain an adaptive Pseudomonas aeruginosa culture medium;

[0037] (2) Adaptive Pseudomonas aeruginosa culture: Pseudomonas aeruginosa was inoculated into an adaptive Pseudomonas aeruginosa culture medium and cultured for 10 days at a temperature of 36°C and a humidity of 70% to obtain an in situ soil-adapted Pseudomonas aeruginosa bacterial solution with a bacterial solution concentration of 10 8 cfu / mL;

[0038] (3) Aggregate viscosity reduction: 1.5 kg of in-situ soil microaggregates and 4.5 kg of in-situ soil sticky aggregates were mixed evenly, and then 1.0 L of 5.0 g / L ethylenediaminetetraacetic acid solution was added. After standing for 2 h, the de-sticky mixed in-situ soil was obtained;

[0039] (4) Preparation of in situ soil remediation reagent: 1.5 L of the crude emulsion of waste sapodilla branches was added to 4 kg of de-adhesive mixed in situ soil while stirring. The mixture was reacted at a temperature of 130 °C for 25 min and then cooled to room temperature. Subsequently, 0.5 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36 °C for 7 days.

[0040] Example 2: Preparation of in-situ soil remediation reagent II

[0041] (1) Preparation of adaptive Pseudomonas aeruginosa culture medium: 4 kg of yeast extract, 2 kg of tryptone, and 4 kg of sodium chloride were added to 12 L of soil stock solution, stirred and mixed evenly, and then sterilized at 121°C for 30 min to obtain an adaptive Pseudomonas aeruginosa culture medium;

[0042] (2) Adaptive Pseudomonas aeruginosa culture: Pseudomonas aeruginosa was inoculated into an adaptive Pseudomonas aeruginosa culture medium and cultured for 12 days at a temperature of 35°C and a humidity of 75% to obtain an in situ soil-adapted Pseudomonas aeruginosa bacterial solution with a bacterial solution concentration of 10 8 cfu / mL;

[0043] (3) Aggregate viscosity reduction: 2.0 kg of in-situ soil microaggregates and 5.0 kg of in-situ soil powdery aggregates were mixed evenly, and then 1.2 L of 5.0 g / L ethylenediaminetetraacetic acid solution was added. After standing for 1 h, the de-viscous mixed in-situ soil was obtained;

[0044] (4) Preparation of in situ soil remediation reagent: 2.0 L of the crude emulsion of waste sapodilla branches was added to 5 kg of de-adhesive mixed in situ soil while stirring. The mixture was reacted at a temperature of 140 °C for 20 min and then cooled to room temperature. Subsequently, 0.6 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 35 °C for 8 days.

[0045] Example 3: Preparation of in situ soil remediation reagents

[0046] (1) Preparation of adaptive Pseudomonas aeruginosa culture medium: 2 kg yeast extract, 1 kg tryptone, and 2 kg sodium chloride were added to 8 L of soil stock solution and stirred to mix evenly. The culture medium was then sterilized at 121°C for 30 min to obtain the adaptive Pseudomonas aeruginosa culture medium.

[0047] (2) Adaptive Pseudomonas aeruginosa culture: Pseudomonas aeruginosa was inoculated into an adaptive Pseudomonas aeruginosa culture medium and cultured for 8 days at a temperature of 37°C and a humidity of 65% to obtain an in situ soil-adapted Pseudomonas aeruginosa bacterial solution with a bacterial solution concentration of 10 8 cfu / mL;

[0048] (3) Aggregate viscosity reduction: 1.0 kg of in-situ soil microaggregates and 3.0 kg of in-situ soil sticky aggregates were mixed evenly, and then 0.8 L of 5.0 g / L ethylenediaminetetraacetic acid solution was added. After standing for 3 h, the de-sticky mixed in-situ soil was obtained.

[0049] (4) Preparation of in situ soil remediation reagent: 1.0 L of the crude emulsion of waste sapodilla branches was added to 3 kg of de-adhesive mixed in situ soil while stirring. The mixture was reacted at high temperature for 30 min at 120 °C and then cooled to room temperature. 0.4 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was then added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 37 °C for 6 days.

[0050] Comparative Example 1:

[0051] This comparative example is in contrast to Example 1, and the only difference is that the soil stock solution in step (1) is replaced with deionized water to prepare a common Pseudomonas aeruginosa culture medium, Pseudomonas aeruginosa is cultured in step (2) to obtain a Pseudomonas aeruginosa bacterial solution, Pseudomonas aeruginosa bacterial solution is used in step (4), and step (3) is the same as Example 1. Steps (1), (2), and (4) are specifically as follows:

[0052] (1) Preparation of common Pseudomonas aeruginosa culture medium: Add 3 kg of yeast extract, 1.5 kg of tryptone, and 3 kg of sodium chloride to 10 L of deionized water, stir and mix well, and sterilize at 121°C for 30 min to obtain common Pseudomonas aeruginosa culture medium;

[0053] (2) Pseudomonas aeruginosa culture: Pseudomonas aeruginosa was inoculated into a common Pseudomonas aeruginosa culture medium and cultured for 10 days at a temperature of 36°C and a humidity of 70% to obtain a Pseudomonas aeruginosa bacterial solution with a bacterial solution concentration of 10 8 cfu / mL;

[0054] (4) Preparation of in situ soil remediation reagent: 1.5 L of the crude emulsion of waste sapodilla branches was added to 4 kg of de-adhesive mixed in situ soil while stirring. The mixture was reacted at a temperature of 130 °C for 25 min and then cooled to room temperature. Subsequently, 0.6 L of Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36 °C for 7 days.

[0055] Comparative Example 2:

[0056] The only difference between this comparative example and Example 1 is that the 5.0 g / L EDTA solution in step (3) is replaced with deionized water to prepare the mixed in-situ soil, and the mixed in-situ soil is used in step (4). The remaining steps are the same. Steps (3) and (4) are specifically as follows:

[0057] (3) Aggregate viscosity reduction: 1.5 kg of in-situ soil microaggregates and 4.5 kg of in-situ soil powdery aggregates were mixed evenly, and then 1.0 L of deionized water was added. The mixture was allowed to stand for 2 h to obtain the mixed in-situ soil.

[0058] (4) Preparation of in situ soil remediation reagent: 1.5 L of the crude emulsion of sapodilla waste branches was added to 4 kg of mixed in situ soil while stirring. The mixture was reacted at a high temperature of 130 °C for 25 min and then cooled to room temperature. Subsequently, 0.6 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36 °C for 7 days.

[0059] Comparative Example 3:

[0060] This comparative example is a comparative example with Example 1, and the only difference is that the in-situ soil microaggregates and in-situ soil powdery aggregates in step (3) are replaced with in-situ soil to prepare debonded in-situ soil, and the debonded in-situ soil is used in step (4). The remaining steps are the same, and steps (3) and (4) are specifically as follows:

[0061] (3) Aggregate viscosity reduction: 1.0 L of 5.0 g / L ethylenediaminetetraacetic acid solution was added to 6 kg of in-situ soil and allowed to stand for 2 h to obtain de-sticky in-situ soil.

[0062] (4) Preparation of in situ soil remediation reagent: 1.5 L of the crude emulsion of waste sapodilla branches was added to 4 kg of de-adhesive in situ soil while stirring. The mixture was reacted at a temperature of 130 °C for 25 min and then cooled to room temperature. Subsequently, 0.6 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36 °C for 7 days.

[0063] Comparative Example 4:

[0064] This comparative example is a comparative example with Example 1, and the only difference is that in step (3), no in-situ soil powder and sticky aggregates are added. The remaining steps are the same. Step (3) is specifically as follows:

[0065] (3) Aggregate viscosity reduction: 1.0 L of ethylenediaminetetraacetic acid solution was added to 6 kg of in situ soil microaggregates and allowed to stand for 2 h to obtain a de-viscous mixed in situ soil.

[0066] Comparative Example 5:

[0067] This comparative example is in contrast to Example 1, the only difference being that in-situ soil microaggregates are not added in step (3). The remaining steps are the same. Step (3) is specifically as follows:

[0068] (3) Aggregate viscosity reduction: 1.0 L of ethylenediaminetetraacetic acid solution was added to 6 kg of in-situ soil powder and sticky aggregates, and the mixture was left for 2 h to obtain a de-sticky mixed in-situ soil.

[0069] Comparative Example 6:

[0070] This comparative example is in contrast to Example 1, and the only difference is that the crude emulsion of sapodilla waste branches in step (4) is replaced with deionized water. The remaining steps are the same. Step (4) is specifically as follows:

[0071] (4) Preparation of in situ soil remediation reagent: 1.5 L of deionized water was added to 4 kg of de-sticky mixed in situ soil while stirring. The mixture was reacted at a temperature of 130 °C for 25 min and then cooled to room temperature. Subsequently, 0.6 L of in situ soil-adaptable Pseudomonas aeruginosa liquid was added and stirred to mix evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36 °C for 7 days.

[0072] Comparative Example 7:

[0073] This comparative example is in contrast to Example 1, the only difference being that no high temperature reaction is performed in step (4). The remaining steps are the same. Step (4) is specifically as follows:

[0074] (4) Preparation of in situ soil remediation reagent: 1.5 L of the crude emulsion of sapodilla waste branches was added to 4 kg of de-sticky mixed in situ soil while stirring and mixed evenly, and then 0.6 L of in situ soil-adaptable Pseudomonas aeruginosa bacterial liquid was added and mixed evenly. The in situ soil remediation reagent was obtained by continuing to incubate at 36°C for 7 days.

[0075] 1. Soil in situ remediation experiment

[0076] The experimental area is located in the Laohushan small watershed in Taihe County in the middle of the Jitai Basin in central Jiangxi Province. The soil in the experimental area is red clay, and the ratio of macroaggregates, medium aggregates, microaggregates and silty clay aggregates in the soil is approximately 1:2:6:10.

[0077] The test site was divided into nine 5m 2 The in-situ soil remediation reagents prepared in Example 1 and Comparative Examples 1-7 were sprayed on the small plots at a spraying rate of 5 kg, and then the soil was turned over and normally maintained for 3 months.

[0078] Blank control: No in situ soil remediation reagent spraying was performed, only normal management and maintenance for 3 months.

[0079] 1. Soil aggregate composition analysis experiment

[0080] In Comparative Examples 6 and 7, due to large areas of soil compaction, it was not possible to conduct soil aggregate composition analysis experiments. 10 kg of soil remediation reagents prepared in Example 1 and Comparative Examples 1-5, as well as 10 kg of blank control soil after normal maintenance, were taken and sieved using the wet sieving method to analyze the soil aggregate composition. The specific procedures were as follows:

[0081] 10 kg of soil was air-dried and placed on the top layer of a 0.053 mm pore size sieve. The water level of the bucket under the sieve was adjusted to the state where the soil sample in the top sieve was just submerged. Then, the soil was soaked in distilled water at room temperature for 5 minutes. The sieve was moved up and down 5 cm, and the process was repeated 100 times within 5 minutes to collect the sticky aggregates. The sieve was replaced with a 0.25 mm sieve, and the sieve was moved up and down 3 cm, and the process was repeated 50 times within 2 minutes to collect the microaggregates. The sieve was replaced with a 2 mm sieve, and the sieve was moved up and down 2 cm, and the process was repeated 30 times within 2 minutes to collect the medium aggregates. The remaining part was the macroaggregates.

[0082] The masses of large aggregates, medium aggregates, microaggregates and powder-sticky aggregates were weighed respectively. The results are shown in Table 1:

[0083] Table 1

[0084] Large aggregates Medium aggregates microaggregates powder sticky aggregates Blank control 0.52kg 1.04kg 3.14kg 5.11kg Example 1 2.14kg 6.14kg 1.02kg 0.61kg Comparative Example 1 0.71kg 3.15kg 4.35kg 1.64kg Comparative Example 2 1.23kg 2.39kg 4.12kg 1.94kg Comparative Example 3 1.94kg 4.19kg 2.18kg 1.45kg Comparative Example 4 1.06kg 5.27kg 2.94kg 0.72kg Comparative Example 5 0.85kg 4.27kg 1.64kg 3.18kg Comparative Example 6 1.13kg 2.46kg 2.27kg 3.94kg Comparative Example 7 1.02kg 3.67kg 1.94kg 3.18kg

[0085] Result analysis:

[0086] Comparing the data of Example 1 and the blank control in Table 1, it can be seen that the macroaggregates and medium aggregates in the soil of Example 1 were 2.14 kg and 6.14 kg, respectively, which were increased by 1.62 kg and 5.10 kg, respectively, compared with the blank control; the microaggregates and powdery sticky aggregates were 1.02 kg and 0.61 kg, respectively, which were reduced by 2.12 kg and 4.50 kg, respectively, compared with the blank control. This shows that the soil structure has changed after repair, the proportion of small-particle soil aggregates has decreased, and the proportion of large-particle soil aggregates has increased, effectively solving the problem of excessively high proportion of small-particle soil aggregates in the soil, thereby improving the soil structure.

[0087] Comparing the data of Example 1 and Comparative Examples 1-2 in Table 1, it can be seen that in Comparative Example 1, the soil stock solution in step (1) is replaced with deionized water to prepare a common Pseudomonas aeruginosa culture medium; in Comparative Example 2, the ethylenediaminetetraacetic acid solution in step (3) is replaced with deionized water to prepare a mixed in-situ soil; when the in-situ soil remediation reagents prepared by the subsequent steps are used to repair the soil, the proportion of small-particle soil aggregates increases and the proportion of large-particle soil aggregates decreases. Comparative Example 1 is mainly due to the poor adaptation of Pseudomonas aeruginosa obtained by culturing in the common Pseudomonas aeruginosa culture medium, which slows down its movement speed in the soil. Comparative Example 2 lacks ethylenediaminetetraacetic acid solution, resulting in the electrostatic agglomeration of in-situ soil microaggregates and in-situ soil powder and sticky aggregates to form loose large particles, causing the subsequent reaction to fail, the stability of the prepared in-situ soil remediation reagent is reduced, and the soil remediation effect is unsatisfactory.

[0088] Comparing the data of Example 1 and Comparative Examples 3-5 in Table 1, it can be seen that in Comparative Example 3, in step (4), the in-situ soil microaggregates and in-situ soil powder and sticky aggregates are replaced with in-situ soil; in step (3) of Comparative Example 4, no in-situ soil powder and sticky aggregates are added; in step (3) of Comparative Example 5, no in-situ soil microaggregates are added; when the in-situ soil remediation reagents prepared are used to remediate soil, the proportion of small-sized soil aggregates increases and the proportion of large-sized soil aggregates decreases. This is mainly because after incubating the applicable Pseudomonas aeruginosa with the in-situ soil microaggregates and in-situ soil powder and sticky aggregates, the mucus produced by the applicable Pseudomonas aeruginosa can better bond the in-situ soil microaggregates and in-situ soil powder and sticky aggregates to obtain large-sized aggregates.

[0089] 2. Soil nutrient content test after restoration

[0090] The soil nutrient composition of the soil remediated by the in-situ soil remediation reagent prepared in Example 1 and the blank control (soil after normal management) were tested. The results are shown in Table 2:

[0091] Table 2

[0092]

[0093] 3. Test of soil water retention performance after restoration

[0094] The soil remediated by the in-situ soil remediation reagent prepared in Example 1 and the blank control (soil after normal management) were taken, and the same amount of tap water was sprayed on the soil surface to adjust the soil water content to the saturated moisture content. Then, the soil was placed under the same environmental conditions (40°C for 6 hours, 20°C for 18 hours, and 20% air humidity). The mass was weighed every 24 hours, the daily water evaporation was calculated, and the soil water evaporation rate curve was drawn, as shown in FIG. Figure 1 shown.

[0095] 4. Soil fertility test after restoration

[0096] The soil remediated by the in-situ soil remediation reagent prepared in Example 1 and the blank control (soil after normal management) were taken, and the soil bulk density was measured using the ring knife method, the organic matter content in the soil was measured by the burning method, the microbial biomass carbon in the soil was measured by the chloroform fumigation method, and the pH value of the soil was measured using the potentiometric method. The results are shown in Table 3 below:

[0097] Table 3

[0098] <![CDATA[Soil bulk density (g / cm 3 )]]> Organic matter (g / kg) Biochar content (g / kg) pH Blank control 1.61 9.68 217.26 5.12 Example 1 1.32 17.35 301.43 6.09

[0099] Result analysis:

[0100] Comparing the data of Example 1 and the blank control in Table 2, it can be seen that the overall nutrient content of the soil in Example 1 after being remediated with the in-situ soil remediation reagent is significantly improved compared to the blank control, with available nitrogen, available phosphorus, and available potassium increasing to 71.09 mg / kg, 51.29 mg / kg, and 51.29 mg / kg, respectively, and the moisture content increasing by 9.9%. Figure 1 It can be seen that the water retention of the soil after repair by the in-situ soil remediation reagent prepared in Example 1 is significantly improved compared with the blank control. Comparing the data in Table 3, it can be seen that the bulk density of the soil after repair by the in-situ soil remediation reagent is reduced, the organic matter is increased, the biocarbon content is increased, and the pH value is increased from 5.12 to 6.09. This shows that the in-situ soil remediation reagent prepared by the present invention effectively increases the content of available nitrogen, available phosphorus and available potassium in the soil, making the soil more fertile. At the same time, the repaired soil has good water retention, the soil pH value is significantly improved, and the soil environment is effectively improved to be more suitable for plant growth.

[0101] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents shall be encompassed by the claims of the present invention. Any techniques, shapes, and structures not described in detail herein are well known.

Claims

1. An in-situ soil remediation reagent, characterized in that: The raw materials for preparing the in-situ soil remediation reagent include: in-situ soil microaggregates, in-situ soil powder-sticky aggregates, soil stock solution, yeast extract, tryptone, sodium chloride, Pseudomonas aeruginosa, sapodilla waste branch crude emulsion and 5.0g / L ethylenediaminetetraacetic acid solution; The preparation method of the in-situ soil remediation reagent is as follows: (1) Preparation of adaptive Pseudomonas aeruginosa culture medium: Yeast extract, tryptone, and sodium chloride were added to the soil stock solution, stirred and mixed evenly, and then sterilized at high temperature to obtain the adaptive Pseudomonas aeruginosa culture medium; (2) Adaptive Pseudomonas aeruginosa culture: Pseudomonas aeruginosa is inoculated into an adaptive Pseudomonas aeruginosa culture medium and cultured for 8-12 days to obtain an in situ soil-adapted Pseudomonas aeruginosa bacterial solution; (3) Aggregate viscosity reduction: After the in-situ soil microaggregates and in-situ soil powder-sticky aggregates are evenly mixed, 5.0 g / L ethylenediaminetetraacetic acid solution is added and the mixture is left for 1-3 h to obtain the de-sticky mixed in-situ soil; (4) Preparation of in situ soil remediation reagent: Add the crude emulsion of sapodilla waste branches to the de-sticky mixed in situ soil while stirring, mix well and perform high-temperature reaction, then cool to room temperature, add the in situ soil-adaptable Pseudomonas aeruginosa liquid and stir to mix well, and continue to cultivate at 35-37°C for 6-8 days to obtain the in situ soil remediation reagent.

2. An in-situ soil remediation reagent according to claim 1, characterized in that: The in-situ soil microaggregates, in-situ soil powder-clay aggregates and soil stock solution are prepared by wet-sieving the pre-remediation soil after air-drying.

3. An in-situ soil remediation reagent according to claim 2, characterized in that: In step (1), the mass volume ratio of yeast extract, tryptone, sodium chloride and soil stock solution is (2-4) kg: (1-2) kg: (2-4) kg: (8-12) L.

4. An in-situ soil remediation reagent according to claim 3, characterized in that: In the step (3), the mass volume ratio of the in-situ soil microaggregates, the in-situ soil silt-clay aggregates and the 5.0 g / L ethylenediaminetetraacetic acid solution is (1-2) kg: (3-5) kg: (0.8-1.2) L.

5. An in-situ soil remediation reagent according to claim 4, characterized in that: The high temperature reaction in step (4) is carried out at a temperature of 120-140° C. and for a time of 20-30 minutes.

6. An in-situ soil remediation reagent according to claim 5, characterized in that: In the step (4), the mass volume ratio of the de-viscous mixed in-situ soil, the sapodilla tree waste branch crude emulsion and the in-situ soil-adapted Pseudomonas aeruginosa bacterial solution is (3-5) kg: (1-2) L: (0.4-0.6) L.

7. An in-situ soil remediation reagent according to claim 6, characterized in that: The preparation method of the sapodilla waste branch crude emulsion is as follows: The waste branches of the sapodilla tree are crushed and poured into clean water of equal mass ratio and stirred to mix evenly, then heated to 70-80°C, stirred at constant temperature until the solution turns orange-yellow, then cooled to room temperature, allowed to stand and stratified to remove the precipitate to obtain a crude emulsion of waste branches of the sapodilla tree.

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