Preparation method and application of a soil remediation agent for salinized greenhouse vegetables

Abstract

This invention discloses a method for preparing and applying a soil remediation agent for salinized soil in greenhouse vegetable production. It belongs to the field of agricultural resources and environmental technology. This invention uses garlic stalks and corn stalks produced during garlic production and processing. These stalks are burned into biochar and then immobilized with microorganisms to obtain microbially immobilized biochar, which is the soil remediation agent for salinized soil in greenhouse vegetable production. This invention utilizes garlic stalks and corn stalks to prepare biochar, immobilizes it with microorganisms, and then applies it to the remediation of salinized soil in greenhouse vegetable production. This invention not only contributes to the resource utilization of garlic stalks and corn stalks but also provides technical support for the remediation of salinized soil in greenhouse vegetable production.

Description

Technical Field

[0001] This invention relates to the field of agricultural resources and environmental technology, and more specifically to a method for preparing and applying a soil remediation agent for salinized greenhouse vegetables. Background Technology

[0002] In recent years, greenhouse vegetables have played an increasingly important role in agricultural development, achieving significant economic and social benefits and making important contributions to the year-round supply of vegetables and increasing farmers' income. By the end of 2021, the area of ​​greenhouse vegetables in my country had reached over 60 million mu (approximately 4 million hectares). However, due to the characteristics of greenhouse vegetables, such as large amounts of fertilizer, sufficient sunlight, high transpiration, lack of rainwater leaching, and continuous planting, secondary soil salinization is easily caused. Currently, soil salinization or mild salinization has become a major obstacle in greenhouse vegetable fields.

[0003] Soil salinization in greenhouse vegetable production is a significant manifestation of soil degradation and a major obstacle to cultivating healthy soil. The theme of World Soil Day on December 5, 2021, was "Preventing Soil Salinization, Enhancing Soil Productivity," further illustrating the severity and urgency of this problem. Soil salinization is characterized by soluble salts (such as Na+). + Ca 2+ Cl - SO2 4- High levels of certain substances (such as alkali) and strong alkalinity often result in poor physical, chemical, and biological properties, leading to low primary soil productivity and ecological degradation. The improvement and utilization of saline soils are crucial for ensuring global food security and mitigating global climate change.

[0004] Garlic is a well-known plant used for both food and medicine, rich in nutrients and possessing excellent nutritional and medicinal value. my country has the world's largest garlic-growing area, reaching 10.13 million mu in 2021. However, garlic stalks produced during production and processing are difficult to store, highly susceptible to mold, and have low utilization rates.

[0005] In recent years, the use of biochar for soil remediation has become a research hotspot. Biochar is a solid residue produced by the thermal pyrolysis of biomass, possessing a porous structure, a large specific surface area, and strong adsorption capacity. Adding biochar to saline soil can increase soil porosity, thereby promoting the removal of sodium phosphate from the soil. + Leaching reduces conductivity and sodium adsorption ratio. Mg in soil 2+ and Ca 2+ Replace Na +Biochar reduces the sodium adsorption ratio in the soil, thereby mitigating the salt stress on crops. It can also increase soil organic carbon content and promote nutrient conversion, thus increasing crop yield. The application of biochar in saline soil remediation is highly effective, reducing soil salinity and sodium content. + While microbial immobilized biochar can mitigate damage to soil structure and improve soil nutrient status, the synergistic effect of biochar and microorganisms will produce better results in the remediation of saline-alkali soils.

[0006] In summary, how to provide a garlic straw biochar soil remediation agent is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a method for preparing and applying a soil remediation agent for salinized greenhouse vegetable soil. Addressing the problem of soil salinization in greenhouse vegetable production, the present invention provides microbial immobilized biochar. The raw materials used are widely available, the process equipment is simple, the cost is low, and the operation is convenient. Simultaneously, it solves the problems of soil salinization in greenhouse vegetable production and the resource utilization of garlic and corn stalks.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for preparing a soil remediation agent for salinized greenhouse vegetables includes the following steps:

[0010] (1) Air dry, crush, grind and sieve the garlic stalks and corn stalks separately, and set aside;

[0011] (2) Burn garlic stalks and corn stalks at a heating rate of 10℃·min. -1 The pyrolysis temperature is 400-600℃ and the pyrolysis time is 2h to obtain biochar;

[0012] (3) After sterilization, biochar was inoculated into Bacillus fermentum of soybean to obtain a mixed solution;

[0013] (4) The mixed solution was cultured, centrifuged, washed, and centrifuged again to obtain immobilized microbial precipitate;

[0014] (5) The soil remediation agent is obtained by freeze-drying the immobilized microbial precipitate.

[0015] Furthermore, the mass ratio of garlic stalks to corn stalks is 1 to 2:1.

[0016] Furthermore, in step (1), the garlic stalks and corn stalks are crushed to 3-5 cm, ground, and then passed through a 100-mesh sieve.

[0017] Furthermore, a tube furnace is used for firing in step (2).

[0018] Furthermore, the tube furnace is an OTF-1200X1200℃ open-type tube furnace.

[0019] Furthermore, the pyrolysis temperature is 500℃.

[0020] Furthermore, the Bacillus sacchariformis mentioned in step (3) is Bacillus sacchariformis ASD02, with accession number CGMCC No.17806, classified as Bacillus sacchariformis glycinifermentans, and deposited on May 15, 2019 at the China General Microbiological Culture Collection Center, located at No.3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0021] Furthermore, in step (3), the inoculation amount of Bacillus fermentum soybeani is 1-3%, and the viable count of Bacillus fermentum soybeani is 10. 8 cell·mL -1 .

[0022] Furthermore, the optimal inoculation amount of Bacillus fermentum in step (3) is 2%.

[0023] Furthermore, the specific operation of step (4) is as follows: the mixed solution is heated at 30°C and 180 rpm. -1 The microorganisms were cultured under the specified conditions for 24 hours, then centrifuged for 10 minutes. The supernatant was discarded, and the precipitate was washed with 1% physiological saline. The mixture was centrifuged and washed three times. The solid obtained by centrifugation was the immobilized microbial precipitate.

[0024] Further, the specific operation of step (5) is as follows: the immobilized microbial precipitate is dispensed into glass bottles, pre-frozen after dispensing, and then freeze-dried using a freeze dryer to obtain a solid, which is the soil remediation agent.

[0025] Furthermore, the pre-freezing process lasts for 3 hours, with the temperature reaching -20℃ to -35℃.

[0026] Furthermore, the dispensing time of the immobilized microbial precipitate should be as short as possible, controlled within 1 to 2 hours. Aseptic conditions should be maintained during dispensing.

[0027] Furthermore, the freeze dryer condenser operates at -84°C and a chamber pressure of 0.04 mbar, and the freeze drying process lasts for 48 hours.

[0028] The application of the soil remediation agent prepared by the above method in the remediation of salinized soil for greenhouse vegetables.

[0029] Furthermore, the dosage of the soil remediation agent is 100-300 kg / mu.

[0030] Furthermore, the prepared soil remediation agent is applied to the soil of the greenhouse vegetables, and after thorough tilling, the soil is watered to the maximum water holding capacity of the field. The soil is kept moist for 10-15 days before planting the greenhouse vegetables.

[0031] Furthermore, in greenhouses where vegetables have been grown continuously for more than 5 years, soil salinization has become a problem.

[0032] Furthermore, soils suitable for greenhouse vegetables with a salt content of 2.0–5.0 g / kg are preferred.

[0033] As can be seen from the above technical solution, compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0034] (1) The garlic stalk and corn stalk biochar of the present invention have a stable structure, a large surface area and porous properties, which make them highly stable and adsorbent.

[0035] (2) The microbial immobilized biochar of the present invention can immobilize microorganisms in biochar material to form a new microbial material;

[0036] (3) The microbial immobilized biochar of the present invention, i.e. soil remediation agent, can improve soil structure, increase soil water and fertilizer utilization efficiency and soil nutrient content, increase soil surface temperature and increase crop yield through the dual action of biochar and microorganisms when applied to saline-alkali soil.

[0037] (4) This invention is based on waste garlic stalks and corn stalks. The raw materials used are inexpensive, the process equipment is simple, and the operation is convenient. It can reduce the pollution caused by random dumping of straw and is in line with the national policy of developing a circular economy, saving energy, reducing emissions and making use of waste. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 The attached figure shows the morphology (5 μm) of the biochar before and after microbial loading of the present invention, where A is before loading and B is after loading;

[0040] Figure 2 The attached figure shows the morphology (2 μm) of the biochar before and after microbial loading of the present invention, where A is before loading and B is after loading. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The tube furnace used in this embodiment of the invention is an OTF-1200X1200℃ open-type tube furnace, purchased from Hefei Kejing Materials Technology Co., Ltd.

[0043] The freeze dryer used in this embodiment of the invention was purchased from Chongqing Myrus Experimental Equipment Co., Ltd.

[0044] Experimental methods not mentioned are standard experimental methods and will not be described in detail here.

[0045] Example 1

[0046] A method for preparing a soil remediation agent for salinized soil in greenhouse vegetable production mainly includes the following steps:

[0047] 1) Collect garlic stalks generated during garlic production or processing, and collect corn stalks. Dry both separately, chop them, crush and grind them using a pulverizer, and then sieve them.

[0048] The mass ratio of garlic stalks to corn stalks is 1 to 2:1;

[0049] Crush garlic stalks and corn stalks to 3-5 cm, grind them, and then pass them through a 100-mesh sieve.

[0050] 2) Weigh out a certain amount of garlic stalks and corn stalks respectively, place them in a tube furnace, and set the heating rate to 10℃·min. -1 Biochar was prepared by pyrolysis at 400℃ for 2 hours.

[0051] 3) Place the biochar in the culture medium, sterilize at 121℃ for 20 min, and inoculate with 10 at a 2% inoculum. 8 cell·mL -1 The soybean fermentation Bacillus ASD02 was cultured to the logarithmic growth phase to obtain a mixed solution.

[0052] 4) Incubate the mixed solution at 30℃ and 180 rpm. -1 The microorganisms were cultured under the specified conditions for 24 hours, then centrifuged for 10 minutes. The supernatant was discarded, and the lower precipitate was washed with 1% (mass fraction) physiological saline. The mixture was centrifuged and washed three times. The solid obtained by centrifugation was the immobilized microbial precipitate.

[0053] 5) The immobilized microbial precipitate is dispensed into glass bottles, pre-frozen after dispensing, and then freeze-dried using a freeze dryer to obtain a solid, which is the microbial immobilized biochar-remediation agent for salinized soil in facility vegetables.

[0054] Example 2

[0055] The difference from Example 1 is that the pyrolysis temperature is 400°C.

[0056] Example 3

[0057] The difference from Example 1 is that the pyrolysis temperature is 600°C.

[0058] Example 4

[0059] The specific surface area, pore size, and pore volume of the soil remediation agents prepared in Examples 1-3 were compared, and the results are shown in Table 1.

[0060] As can be seen from Table 1, the soil remediation agent of Example 1 has better specific surface area, pore size and pore volume than the remediation agents of Examples 2 and 3.

[0061] Table 1. Performance Comparison of Three Soil Remediation Agents

[0062]

[0063]

[0064] Example 5

[0065] An application of a remediation agent for salinized soil in greenhouse vegetable production involved applying microbial immobilized biochar prepared in Example 1 to the soil of greenhouse vegetable plants. The greenhouse vegetable plants had been continuously cropped for over 5 years, and the soil exhibited salinization, with a measured salt content of 4.25 g / kg. After thorough tilling, the soil was irrigated to maximum field capacity and kept moist for 12 days. Greenhouse vegetables were then grown for 2 years and 4 seasons. The application rate of microbial immobilized biochar was 100 kg / mu (approximately 667 square meters).

[0066] Example 6

[0067] The amount of microbial immobilized biochar used was 300 kg / mu, and the rest was the same as in Example 5.

[0068] Example 7

[0069] The amount of microbial immobilized biochar used was 360 kg / mu, and the rest was the same as in Example 5.

[0070] Example 8

[0071] The repair effects of Examples 5-7 were compared, and the results are shown in Table 2.

[0072] As can be seen from Table 2, the soil remediation agent of the present invention has the best effect when the dosage is 300 kg / mu.

[0073] Table 2 Comparison of the effects of three different dosages of soil remediation agents

[0074]

[0075] Example 9

[0076] The morphology of the biochar prepared in Example 1 of this invention before and after microbial loading was observed under a microscope, and the results are as follows: Figure 1 , Figure 2 As shown.

[0077] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0078] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a soil remediation agent for salinized greenhouse vegetables, characterized in that, Includes the following steps: (1) Air dry, crush, grind and sieve the garlic stalks and corn stalks separately, and set aside; (2) Burn garlic stalks and corn stalks at a heating rate of 10℃·min. -1 The pyrolysis temperature was 400℃ and the pyrolysis time was 2h to obtain biochar. (3) After sterilization, biochar was inoculated into Bacillus fermentum of soybean to obtain a mixed solution; The Bacillus fermentum of soybean is Bacillus fermentum ASD02, with accession number CGMCCNo.17806. It was deposited on May 15, 2019 at the China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, No.3, No.1 Beichen West Road, Chaoyang District, Beijing. (4) The mixed solution was cultured, centrifuged, washed, and centrifuged again to obtain immobilized microbial precipitate; (5) The soil remediation agent is obtained by freeze-drying the immobilized microbial precipitate.

2. The method for preparing the soil remediation agent as described in claim 1, characterized in that, The mass ratio of garlic stalks to corn stalks is 1 to 2:

1.

3. The method for preparing the soil remediation agent as described in claim 1, characterized in that, In step (1), garlic stalks and corn stalks are crushed to 3-5 cm, ground, and then passed through a 100-mesh sieve.

4. The method for preparing the soil remediation agent as described in claim 1, characterized in that, A tube furnace is used for firing in step (2).

5. The method for preparing the soil remediation agent as described in claim 1, characterized in that, In step (3), the inoculation amount of Bacillus fermentum in soybean is 1-3%, and the viable count of Bacillus fermentum in soybean is 10. 8 cell·mL -1 .

6. The method for preparing the soil remediation agent as described in claim 1, characterized in that, The specific operation of step (4) is as follows: the mixed solution is heated at 30°C and 180 rpm. -1 The microorganisms were cultured under the specified conditions for 24 hours, then centrifuged for 10 minutes. The supernatant was discarded, and the precipitate was washed with 1% physiological saline. The mixture was centrifuged and washed three times. The solid obtained by centrifugation was the immobilized microbial precipitate.

7. The application of the soil remediation agent prepared by any one of claims 1 to 6 in the remediation of salinized soil for greenhouse vegetables.

8. The application as described in claim 7, characterized in that, The dosage of the soil remediation agent is 100-300 kg / mu.

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