A method for rapidly restoring soil microbial diversity in damaged slopes

Abstract

The present invention discloses a method for rapidly repairing the microbial diversity of damaged slope soil, which belongs to the field of ecological restoration and environmental protection. The method provides a new solution for the ecological restoration of damaged slopes. The present invention includes the following steps: 1) cleaning up debris on the slope and removing dangerous rock masses; 2) carrying out normal spraying and greening construction operations; 3) carrying out watering and maintenance after normal spraying; 4) after determining that the target plant seeds have finished germinating, spraying the surface of the repaired slope with an extract of the surrounding natural soil for 3 to 5 consecutive days to inoculate natural microorganisms; 5) during the spraying of the extract, the surface soil of the slope should be kept moist. Compared with conventional spraying repair methods, this method solves the problem of soil microbial diversity loss in the original spraying technology. By spraying the extract of natural soil to inoculate natural microbial flora, the artificial soil formed has a microbial diversity similar to or better than that of the natural soil microbial community, thereby improving the overall effect of ecological restoration.

Description

Technical Field

[0001] The invention relates to a pellet spraying method capable of repairing soil microbial communities, and belongs to the field of ecological restoration and environmental protection. Background Art

[0002] Soil microbial communities can transform soil nutrients, improve soil structure, and play a huge role in plant nutrient acquisition in poor environments. Existing pelletized spraying technology will remove the original topsoil layer during implementation, thereby destroying the diversity of the original natural soil microorganisms, such as CN201910879371.4. Applying bacterial fertilizers or bacterial residues to increase the diversity of soil microorganisms does not repair the original natural microbial community, such as CN201911343851.5. Most technologies that increase soil microbial diversity through crop rotation or agricultural management are used in cultivated land environments and cannot be used to repair microbial communities in natural ecological environments, such as CN202111264213.1. Therefore, there is an urgent need to invent a restoration technology that can protect natural soil microbial communities in ecological restoration projects.

[0003] Restoring the microbial community in sprayed soil typically requires a lengthy process of dissemination and introduction of new microorganisms from surrounding natural areas, resulting in inconsistent results. Natural soil microorganisms contain not only symbiotic bacteria that benefit plants but also pathogens that can cause plant disease. Inoculating natural soil microbiota during the budding stage, when plants have low resistance, can easily lead to infection and disease in the restored plants, resulting in poor vegetation restoration. Therefore, the method and timing of inoculation are crucial for restoring the natural soil microbial community. Summary of the Invention

[0004] The present invention provides a method for rapidly repairing the microbial diversity of damaged slope soil, which solves the problem of loss of natural soil microbial diversity in the existing aggregate spraying technology.

[0005] The present invention provides a pelletized spraying method for restoring soil microbial diversity, which is specifically achieved through the following technical solutions: 1) cleaning up debris on the slope and removing dangerous rock masses; 2) carrying out normal spraying and greening construction operations, including preparing an artificial substrate layer and a spraying topsoil layer, wherein the sprayed topsoil layer contains germinated seeds; 3) carrying out watering and maintenance after normal spraying; 4) after determining that target plant seeds have completed germination, spraying the surface of the repaired slope with an extract of the surrounding natural soil for 3 to 5 consecutive days to inoculate natural microorganisms; 5) during the spraying of the extract, the surface soil of the slope should be kept moist.

[0006] In a preferred embodiment, the artificial substrate layer in step 2) comprises primarily 40-50% by volume of raw red soil, 30-40% by volume of plant fiber, and may also contain a binder, stabilizer, and fertilizer. The artificial substrate layer is 4-7 cm thick.

[0007] In a preferred embodiment, the topsoil layer in step 2) is primarily composed of: 35-40% by volume of raw red soil, 40-45% by volume of plant fiber, and may also contain a binder, stabilizer, and fertilizer. The topsoil layer is 1-2 cm thick.

[0008] As a preferred embodiment, the germination of the seeds in step 2) is carried out by soaking the seeds in water at 40-50° C. for 6-12 hours; and then treating the seeds with a 0.01-0.05% gibberellin solution for 12 hours.

[0009] As a preferred embodiment, the salinity of the irrigation water in step 3) is less than 0.1%, and the pH value is less than 8.

[0010] As a preferred embodiment, in step 4), the method for preparing the natural soil extract for spraying is as follows: 9-10 kg of surface soil at a depth of 0-10 cm from a fresh natural vegetation area is taken for each hectare of land to be sprayed, and the soil is thoroughly mixed with water at a soil:water volume ratio of 1:50-100, and then filtered.

[0011] As a preferred embodiment, in step 4), the natural soil extract is sprayed by spraying, sprinkler irrigation or other methods, and the application specification is 50-60 kg of extract per mu of land.

[0012] As a preferred embodiment, in step 4), the fresh water used to prepare the natural soil extract is purified seawater or lake water, and the water quality requirements are salt content <0.1% and pH <8.

[0013] As a preferred embodiment, in step 4), the natural soil extract should be sprayed when the weather is cloudy or drizzling, and no fungicide should be used within 30 days before and 45 days after spraying.

[0014] The beneficial effect of the present invention is that by inoculating natural soil extract into artificial soil, the diversity of soil microorganisms is restored while ensuring the vegetation restoration effect, thereby improving the overall effect of ecological restoration and solving the problem of soil microbial diversity loss in existing pellet spraying technology. DETAILED DESCRIPTION

[0015] The essential content of the present invention is further illustrated below with reference to examples, which are described in detail by comparing the examples with two groups of comparative examples, but the content of the present invention is not limited thereto.

[0016] Example 1:

[0017] Location: Slope A on a tropical island

[0018] The project area, located south of the Tropic of Cancer, has a tropical monsoon climate. The average annual temperature is above 20°C, with a minimum temperature above 5°C and annual rainfall exceeding 1,800 mm. Due to quarrying activities, the slope vegetation coverage is less than 20%, requiring urgent restoration.

[0019] Specific implementation steps:

[0020] (1) Slope cleaning

[0021] Clear away debris from the slopes and remove dangerous rock masses.

[0022] (2) Spray seeding construction

[0023] The artificial substrate layer and topsoil layer were sprayed sequentially. The artificial substrate layer was approximately 5 cm thick and mainly composed of 45% red soil and 40% rice husks. The topsoil layer was approximately 2 cm thick and mainly composed of 40% red soil, 45% rice husks, and germinated plant seeds. The plant seeds used included Leucaena leucophylla, Vitex nigra, Rhus chinensis, Morus altissima, and Cassia tora.

[0024] (3) Watering and maintenance

[0025] Desalinated seawater or lake fresh water is used for irrigation, and the maintenance period is 15 months after spraying.

[0026] (4) Inoculation of microorganisms

[0027] After the target plant seeds have finished germinating, spray the extract of the surrounding natural soil on the surface of the repaired slope for 3 to 5 consecutive days to inoculate natural microorganisms.

[0028] Comparative Example 1:

[0029] Location: Slope B on a tropical island

[0030] The project area, located south of the Tropic of Cancer, has a tropical monsoon climate. The average annual temperature is above 20°C, with a minimum temperature above 5°C and annual rainfall exceeding 1,800 mm. Due to quarrying activities, the slope vegetation coverage is less than 20%, requiring urgent restoration.

[0031] Specific implementation steps:

[0032] (1) Slope cleaning

[0033] Clearing surface debris and reinforcing dangerous rock masses

[0034] (2) Spray seeding construction

[0035] The artificial substrate layer and topsoil layer were sprayed sequentially. The artificial substrate layer was approximately 5 cm thick and mainly composed of 45% red soil and 40% rice husks. The topsoil layer was approximately 2 cm thick and mainly composed of 40% red soil, 45% rice husks, and germinated plant seeds. The plant seeds used included Leucaena leucophylla, Vitex nigra, Rhus chinensis, Morus altissima, and Cassia tora.

[0036] (3) Irrigation and maintenance

[0037] A sprinkler irrigation system is used for maintenance, using desalinated seawater. The maintenance period is 15 months after seeding.

[0038] Comparative Example 2:

[0039] Location: Slope C on a tropical island

[0040] The project area, located south of the Tropic of Cancer, has a tropical monsoon climate. The average annual temperature is above 20°C, with a minimum temperature above 5°C and annual rainfall exceeding 1,800 mm. Natural vegetation grows on the slopes, including palm trees, banyan trees, ferns, acanthus, alligator beak, honeysuckle, and casuarinas.

[0041] Comparative Example 2 was used as natural soil for comparison with Example 1 and Comparative Example 1 without any artificial intervention.

[0042] The experimental comparison record table of Example 1, Comparative Example 1 and Comparative Example 2 is shown in Table 1:

[0043] Table 1 Record of the effects of each case after one year of restoration

[0044]

[0045] Note: The bacterial and fungal diversity in Table 1 were obtained using 16s and ITS high-throughput sequencing methods, respectively.

[0046] As can be seen above, the repair effects vary significantly between cases:

[0047] 1. Example 1 is an artificial soil inoculated with natural soil microorganisms. After one year of restoration, the coverage of Example 1 is the same as that of Comparative Example 1 and significantly higher than that of Comparative Example 2. The diversity of soil microorganisms is better than that of Comparative Examples 1 and 2.

[0048] 2. Comparative Example 1 used conventional pellet seeding technology. Although the coverage after one year of restoration was the same as that of Example 1, the diversity of soil microorganisms was lower than that of Example 1 and Comparative Example 2.

[0049] 3. Comparative Example 2 is healthy natural vegetation soil, and its coverage is lower than that of Example 1 and Comparative Example 1; its microbial diversity is lower than that of Example 1 but higher than that of Comparative Example 1.

Claims

1. A method for rapidly restoring the microbial diversity of damaged slope soil, characterized by: The following steps are involved: 1) Clear away debris on the slope and remove dangerous rock masses; 2) Conduct normal spray-seeding greening operations, including preparing an artificial substrate layer and a spray-seeding topsoil layer, wherein the spray-seeded topsoil layer contains germinated seeds; the main raw materials of the artificial substrate layer are: 40-50% of the total volume of raw red soil, 30-40% of the total volume of plant fiber, and also contain adhesives, stabilizers, and fertilizers; the thickness of the artificial substrate layer is 4-7 cm; the main raw materials of the topsoil layer are: 35-40% of the total volume of raw red soil, 40-45% of the total volume of plant fiber, and also contain adhesives, stabilizers, and fertilizers; the thickness of the topsoil layer is 1-2 cm; the germination method of the germinated seeds is: soak the seeds in water at 40-50°C for 6-12 hours, and then treat them with a 0.01-0.05% concentration of gibberellin solution for 12 hours; 3) Carry out watering and maintenance after normal spraying; 4) After the target plant seeds have germinated, spray the surface of the repair slope with extracts from the surrounding natural soil for 3 to 5 consecutive days to inoculate natural microorganisms. The method for spraying the natural soil extract is as follows: take 9 to 10 kg of fresh natural vegetation area 0 to 10 cm deep surface soil, mix it with water at a soil: water volume ratio of 1:50 to 100, and filter it. The extract can be sprayed on 1 hm 2 For sites, the time to spray natural soil extract should be when the weather is cloudy or drizzling. No fungicide should be used within 30 days before and 45 days after spraying. 5) During the spraying of the extract, the surface soil of the slope should be kept moist.

2. A method for rapidly restoring the microbial diversity of damaged slope soil according to claim 1, characterized in that: In the step 4), the natural soil extract is sprayed by spraying or sprinkler irrigation, and the application specification is 50-60 kg of extract per mu of land.

3. The method for rapidly restoring the microbial diversity of damaged slope soil according to claim 1, characterized in that: In step 4), the fresh water used to prepare the natural soil extract is purified seawater or lake water, and the water quality requirements are salt content <0.1% and pH <8.

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