Ecological mulching film laying method based on MICP technology

Abstract

The invention provides an ecological mulching film laying method based on the MICP technology, and belongs to the technical field of agricultural production.The ecological mulching film laying method comprises the following steps that 1, a urease positive bacterium solution, a urea solution and a calcium source solution are prepared and mixed to obtain a mixed solution 1, and the mixed solution 1 is sprayed to the soil surface layer between field ridges; 2, a urea solution and a calcium source solution are prepared and mixed, a mixed solution 2 is obtained, after spraying in the step 1 is completed, the mixed solution 2 is periodically sprayed in a supplementary mode, and the ecological mulching film is formed 3-5 days after last time of supplementary spraying is completed. The ecological mulching film prepared through the MICP technology can reduce water evaporation, inhibit weed growth and enhance soil stability and corrosion resistance, can be gradually degraded in the crop growth cycle, does not need manual recovery, is environmentally friendly, has good ecological degradability, is low in cost and is suitable for large-area agricultural popularization.

Description

Technical Field

[0001] The invention belongs to the field of agricultural production, and in particular relates to a method for laying an ecological mulch film based on MICP technology. Background Art

[0002] Traditional agricultural mulch plays an important role in modern agriculture. It can reduce water evaporation, inhibit weed growth, and increase crop yields by covering the soil. However, commonly used plastic mulch is difficult to degrade, which will lead to the problem of "white pollution" and have a negative impact on the environment. Therefore, there is an urgent need for an environmentally friendly soil covering technology that can replace plastic mulch, which can maintain the functionality of agricultural mulch and achieve natural degradation, meeting the requirements of green agriculture.

[0003] Microbially Induced Calcite Precipitation (MICP) is a biomineralization technology that can generate calcium carbonate through microbial activity under specific conditions. The principle of MICP technology is to use urease-positive microorganisms to decompose urea to produce carbonate ions (CO3 2- ), carbonate and calcium ions (Ca 2+ ) combine to form insoluble calcium carbonate deposits. This deposit can fill the pores in the soil or form a surface layer, stabilizing the soil structure and preventing erosion. It is widely used in soil reinforcement, crack repair and other fields, showing its potential in environmentally friendly materials. Summary of the invention

[0004] The purpose of the present invention is to provide a new ecological mulch film which has the water-retaining and weed-preventing functions of traditional mulch films and is environmentally friendly and pollution-free.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for laying an ecological mulch film based on MICP technology, comprising the following steps:

[0007] 1) preparing a urease-positive bacteria solution, a urea solution and a calcium source solution respectively, and mixing them to obtain a mixed solution 1, and spraying the mixed solution 1 onto the soil surface between the ridges of the field;

[0008] 2) preparing a urea solution and a calcium source solution, mixing them to obtain a mixed solution 2; after the spraying in step (1) is completed, periodically spraying the mixed solution 2; and the ecological mulch film is formed 3 to 5 days after the last spraying.

[0009] Preferably, the urease-positive bacteria include Bacillus or Pseudomonas; the bacterial concentration is 10 6 ~10 9 CFU / mL.

[0010] Preferably, the urease-positive bacteria are urease-producing indigenous bacteria extracted from the soil where mulch film is to be laid.

[0011] Preferably, the concentration of the urea solution in step (1) and step (2) is 0.5 to 2.0 mol / L.

[0012] Preferably, the calcium source solution in step (1) and step (2) is a calcium chloride solution or a calcium nitrate solution with a concentration of 0.25 to 1.0 mol / L.

[0013] Preferably, the volume ratio of the urease-positive bacteria solution, urea solution and calcium source solution when mixed in step (1) is (1.5:1:1) to (3:1:1); the spraying amount of the mixed solution 1 is 5 to 15 L / m 2 .

[0014] Preferably, in step (2), the volume ratio of the urea solution and the calcium source solution when mixed is (1:2) to (2:1);

[0015] When spraying, the spraying amount of mixed solution 2 is 5-15L / m 2 .

[0016] Preferably, the periodic supplementary spraying in step (2) means that after the first spraying is completed, the mixed solution 2 is sprayed every 1 to 5 days, for a total of 3 to 5 times.

[0017] Beneficial Effects

[0018] The ecological mulch film based on MICP technology provided by the present invention has at least the following advantages:

[0019] 1. Environmentally friendly and degradable: Traditional plastic mulch is difficult to degrade, causing serious "white pollution" problems and increasing environmental burdens. The calcium carbonate deposition layer generated by the MICP technology in the present invention can be naturally degraded without generating residual pollutants, which meets the requirements of green agriculture and sustainable development.

[0020] 2. Improve the soil environment: After MICP treats the soil, although the number and diversity of beneficial microorganisms (and the overall indigenous microorganisms) are often affected or competed to a certain extent in the short term, most beneficial microorganisms will gradually recover and re-establish a new balance as exogenous bacteria disappear and soil conditions gradually stabilize. In acidic soils, a slight increase in alkalinity may even increase the activity of some beneficial microorganisms. Traditional plastic mulch has a negative impact on the soil environment and microbial communities. Its use may lead to decreased soil aeration and suppressed microbial activity. Over time, the content and diversity of beneficial microorganisms in the soil tend to gradually decrease. In summary, the present invention induces the formation of a thin layer of calcium carbonate through microorganisms, which has high air permeability and appropriate water retention capacity, while supporting the activity of beneficial microorganisms in the soil and improving the soil ecological environment.

[0021] 3. Enhance soil structure stability: The calcium carbonate deposit layer formed by MICP technology not only covers the soil surface, but also strengthens the soil structure, improves its anti-erosion ability, and prevents wind and water erosion. This feature is particularly suitable for arid and sandy soil areas and can significantly improve the stability of farmland.

[0022] 4. Good water retention and weed control effects: The mulch layer generated by MICP technology can effectively reduce water evaporation, maintain soil moisture, and help reduce the frequency and amount of water used in farmland irrigation. At the same time, the sediment layer can inhibit weed growth, meet the basic functional requirements of agricultural mulch, and reduce the need for weed control.

[0023] 5. Easy operation: The preparation process of the present invention does not require complicated processes such as high temperature and high pressure, and is easy to operate. It is suitable for direct application on farmland, especially in areas with frequent agricultural production activities.

[0024] The present invention prepares an ecological mulch film by using MICP technology, introduces harmless urease bacteria solution and urea and calcium source solution into the surface of farmland soil, and generates a calcium carbonate deposition layer 1 through microbial reaction. The calcium carbonate deposition layer 1 covers the soil surface, can reduce water evaporation, inhibit weed growth, enhance soil stability and corrosion resistance, and achieve soil protection. The calcium carbonate deposition layer 1 gradually degrades during the crop growth cycle, does not require manual recovery, and is environmentally friendly.

[0025] The present invention uniformly applies urease-positive bacteria, urea solution and calcium source solution to the soil surface between the ridges, and waits for calcium carbonate to be deposited layer by layer to form a breathable ground film deposition layer. Compared with traditional plastic ground films, the ecological ground film provided by the present invention not only has good ecological degradability, but also can improve soil structure, has low cost, is suitable for large-scale agricultural promotion, and meets the needs of green and sustainable development.

[0026] In summary, the present invention applies MICP technology to the development of agricultural mulch films. Through the microbial-induced deposition of calcium carbonate, a thin protective film is formed on the soil surface, which can effectively inhibit water evaporation and weed growth, while achieving ecological degradation and reducing environmental pollution caused by plastic mulch films. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The preparation flow chart of ecological mulch film;

[0028] Figure 2 The relationship diagram of the position of ecological mulch and soil (1 is ecological mulch, 2 is field ridge);

[0029] Figure 3 A comparison chart of the thickness of ecological mulch films in various embodiments;

[0030] Figure 4 A comparison diagram of soil temperature under ecological mulch films in various embodiments;

[0031] Figure 5 It is a comparison chart of soil moisture content under ecological mulch film in various embodiments. DETAILED DESCRIPTION

[0032] In terms of the bacterial source, urease-producing indigenous bacteria can be first extracted and screened from the local soil where the mulch needs to be laid, and then purified and cultured to serve as the bacterial source for MICP treatment (refer to the method in "Isolation and Identification of Urease-Producing Bacteria in Karst Soil in Guizhou"). Using the isolated and screened indigenous bacteria as the bacterial source of the present invention can significantly reduce the disturbance and competition of foreign bacteria on the microbial content in the local soil. Urease-positive bacteria can also be directly purchased for experiments.

[0033] The urease-positive bacteria used in the following examples of the present invention are Sporosarcina pasteurii, which were purchased from the Institute of Microbiology, Chinese Academy of Sciences, with the number: CGMCC.NO.1.3687.

[0034] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0035] Example 1

[0036] (1) The laboratory is equipped with urease-positive bacterial solution (Bacillus pasteurianus), urea solution and calcium chloride solution. The bacterial concentration in the urease-positive bacterial solution is 10 7 CFU / mL, urea solution concentration was 0.5 mol / L, calcium chloride solution concentration was 0.5 mol / L;

[0037] The urease-positive bacterial solution (Bacillus pasteurii), urea solution and calcium chloride solution were fully mixed in a volume ratio of 1.5:1:1 to obtain a mixed solution 1, and the mixture was heated at 5 L / m 2 Spray the soil surface between the ridges with a spraying amount of 1000 ml to wait for microorganisms to catalyze the formation of calcium carbonate deposition layer;

[0038] (2) The urea solution and the calcium chloride solution were fully mixed in a volume ratio of 1:1 to obtain a mixed solution 2. After the first spraying in step (1) was completed, during the calcium carbonate reaction, the mixed solution 2 was sprayed once every 3 days for a total of 3 times, and the spraying amount each time was 5 L / m 2 , ensure the density and stability of the sediment layer. After the last spraying, let it stand for 3 days to form the final ecological mulch.

[0039] The preparation process of ecological mulch film is as follows: Figure 1 As shown in Figure 2, the positional relationship between the ecological mulch and the soil is as follows: Figure 2 As shown, Figure 2 In the middle, 1 is the formed ecological mulch film, and 2 is the field ridge.

[0040] Example 2

[0041] In this embodiment, the bacterial concentration in the urease positive bacterial solution is 10 8 CFU / mL, and other aspects are exactly the same as in Example 1.

[0042] Example 3

[0043] In this embodiment, the bacterial concentration in the urease positive bacterial solution is 10 9 CFU / mL, and other aspects are exactly the same as in Example 1.

[0044] Example 4

[0045] In this embodiment, the concentration of urea solution is 1 mol / L, the concentration of calcium chloride solution is 1 mol / L, and other aspects are exactly the same as those in Example 1.

[0046] Example 5

[0047] In this embodiment, after the first spraying in step (2) is completed, during the calcium carbonate reaction, the mixed solution 2 is sprayed once every day, for a total of 5 times, for a total of 1 week, and other aspects are exactly the same as in Example 1.

[0048] Example 6

[0049] In this embodiment, the mixed solution 2 is sprayed once more on the 7th day after the first spraying in step (2). Other aspects are completely the same as those in embodiment 1.

[0050] Test example

[0051] Performance Evaluation

[0052] After the calcium carbonate deposition layer is formed on the soil surface, a complete sample with a circular cross-sectional area is cut out with a circular knife. The thickness of the deposition layer, the soil temperature under the deposition layer (the surface temperature is 15°C) and the moisture content (the initial soil moisture content is 20%) are measured. The results are as follows: Figures 3 to 5 As shown;

[0053] like Figure 3 As shown in the figure, the thickness of the deposition layer increases with the increase of bacterial concentration, urea and calcium chloride solution concentration, and increases with the increase of the number of periodic spraying of urea and calcium chloride solution. Spraying once may not penetrate into the depth corresponding to the desired film thickness. This shows that the thickness of the calcium carbonate deposition layer can be controlled by adjusting the bacterial concentration and the amount of urea and calcium source applied.

[0054] like Figure 4 As shown in the figure, the temperature of the soil under the ecological mulch increases with the increase of bacterial concentration, urea and calcium chloride solution concentration, and increases with the increase of the number of periodic spraying of urea and calcium chloride solution. It can be seen that the ecological mulch based on MICP technology can provide effective insulation function.

[0055] like Figure 5 As shown in the figure, the moisture content of the soil under the ecological mulch increases with the increase of bacterial concentration, urea and calcium chloride solution concentration, and increases with the increase of the number of periodic spraying of urea and calcium chloride solution. It can be seen that the ecological mulch based on MICP technology can provide effective water retention function.

[0056] It can be seen from the above embodiments that the ecological mulch film based on MICP technology provided by the present invention can control the thickness of the mulch film by the bacterial concentration and the application amount of urea and calcium source, and has good heat preservation and water retention effects.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for laying ecological mulch based on MICP technology, characterized in that: The following steps are involved: 1) preparing a urease-positive bacteria solution, a urea solution and a calcium source solution respectively, and mixing them to obtain a mixed solution 1, and spraying the mixed solution 1 onto the soil surface between the ridges of the field; 2) preparing a urea solution and a calcium source solution, mixing them to obtain a mixed solution 2; after the spraying in step (1) is completed, periodically spraying the mixed solution 2; and the ecological mulch film is formed 3 to 5 days after the last spraying.

2. The laying method according to claim 1, characterized in that: The urease-positive bacteria include Bacillus or Pseudomonas; The bacterial concentration was 10 6 ~10 9 CFU / mL.

3. The laying method according to claim 1, characterized in that: The urease-positive bacteria are urease-producing indigenous bacteria extracted from the soil where mulch film needs to be laid.

4. The laying method according to claim 2, characterized in that: The concentration of the urea solution in step (1) and step (2) is 0.5 to 2.0 mol / L.

5. The laying method according to claim 4, characterized in that: The calcium source solution in step (1) and step (2) is a calcium chloride solution or a calcium nitrate solution with a concentration of 0.25 to 1.0 mol / L.

6. The laying method according to claim 5, characterized in that: The volume ratio of the urease-positive bacteria solution, urea solution and calcium source solution when mixed in step (1) is (1.5:1:1) to (3:1:1); The spraying amount of the mixed solution 1 is 5 to 15 L / m 2 .

7. The laying method according to claim 6, characterized in that: In step (2), the volume ratio of the urea solution and the calcium source solution when mixed is (1:2) to (2:1); When spraying, the spraying amount of mixed solution 2 is 5-15L / m 2 .

8. The laying method according to claim 7, characterized in that: The periodic supplementary spraying in step (2) means that after the first spraying is completed, the mixed solution 2 is sprayed every 1 to 5 days, for a total of 3 to 5 times.

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