Degenerated grassland soil function improving method based on microbial community regulation and control

Abstract

The invention relates to the technical field of grassland ecological restoration, in particular to a degraded grassland soil function improving method based on microbial community regulation and control, which comprises the steps of target plot preparation, improved matrix application, plant optimization configuration and the like. A multi-layer grassland ecosystem is constructed by combining microbial agents and plant functional characters, and the soil nutrient conversion efficiency and the vegetation stability are remarkably improved. The method can effectively solve the problems of insufficient attention of soil microflora and single vegetation in the prior art, is suitable for restoration engineering of degraded grassland in arid and semi-arid regions of Qinghai-Tibet Plateau in China, has wide popularization value, and can remarkably improve soil functions, restore vegetation coverage and biological diversity and assist construction of regional ecological safety barriers.

Description

Technical Field

[0001] The present invention belongs to the technical field of ecological environment restoration and soil improvement, and specifically is a method for improving the soil function of degraded grassland based on microbial community regulation. Background Art

[0002] Grassland ecosystems are an important component of terrestrial ecosystems and play a key role in regulating climate, conserving water and soil, and maintaining biodiversity. However, due to the multiple influences of natural and human factors, the soil function of degraded grasslands has gradually declined, becoming an important issue in global ecological governance. In recent years, driving factors such as climate change, overgrazing, and irrational land use have led to a significant decrease in grassland vegetation cover, a tendency towards a single plant community structure, and an imbalance in soil microbial communities, which in turn weakened the overall function of grassland ecosystems. For example, in the Qinghai-Tibet Plateau region of my country, the dominance of typical grass species such as Kentucky bluegrass, Chinese fescue, Elymus nutans, Elymus sibiricus, and Kentucky bluegrass has gradually declined, and has been replaced by more adaptable low-biomass plants. This has significantly reduced grassland productivity and reduced soil organic matter content, posing severe challenges to regional ecological security.

[0003] Grassland ecological restoration and reconstruction have gradually received attention. Since 2000, my country has successively introduced a series of grassland protection and restoration policies. The 2021 revision of the Grassland Law further clarified the goal of "maintaining grassland ecological functions and sustainable use", providing legal protection for grassland ecological protection. Despite this, current grassland restoration work is mostly focused on vegetation reconstruction and soil improvement, with relatively insufficient attention paid to the regulation of soil microbial communities, and the stability of the ecosystem still needs to be improved. On the other hand, during the natural restoration process, grassland vegetation succession is slow, the number of suitable plant species decreases, plant diversity and community stability are weak, and ecological functions are difficult to fully exert. At present, existing grassland restoration technologies are mainly aimed at improving single vegetation or soil physical and chemical properties. There is little research on the role of synergistic restoration of microbial communities and vegetation. Especially under complex environmental conditions, such as in arid and semi-arid areas, the grassland restoration effect is still not ideal. The needs for improving soil functions and restoring ecological balance still face great challenges. It is urgent to develop grassland soil function improvement technologies based on microbial community regulation to provide theoretical and technical support for the construction of national ecological security barriers. Summary of the Invention

[0004] In view of this, the present invention provides a method for improving the soil function of degraded grassland based on microbial community regulation, which solves the problems in existing grassland restoration technology of insufficient attention to soil microbial community regulation and the difficulty in fully restoring ecological functions due to the single vegetation.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A method for improving soil function of degraded grassland based on microbial community regulation, comprising the following steps: Step 1: Selection and arrangement of target plots Degraded grassland was selected as the target plot. Surface debris was removed and shallow tillage was performed to a depth of 15-20 cm. The topsoil was crushed to particles less than 2 cm in size to increase soil permeability and water retention. Subsequently, an improved matrix consisting of decomposed organic fertilizer and microbial agents was evenly applied to the surface of the target plot to a thickness of 3-5 cm. The mass ratio of decomposed organic fertilizer to microbial agents in the improved matrix was 10:1, and the microbial agents included arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and cellulolytic bacteria, with the ratio of each species being 4:3:2:1.

[0006] Step 2: Plant Optimization According to the ecological adaptability and functional characteristics of five plant species, namely, Kentucky bluegrass, Festuca australis, Elymus nutans, Elymus sibiricus and Kentucky bluegrass, the target sample site was divided into high slope area, middle slope area and low slope area according to the terrain slope and moisture conditions, and plants were arranged separately.

[0007] The high slope areas are equipped with Kentucky bluegrass and Chinese fescue; the mid-slope areas are equipped with Elymus nutans and Elymus sibiricus; the low slope areas are equipped with Poa frigida.

[0008] A combination of Kentucky bluegrass and Festuca sinensis was selected for high-slope areas, where soil moisture is low and susceptible to wind erosion. Kentucky bluegrass has a well-developed stolon structure, enabling rapid expansion of cover and reducing the time soil is exposed. Festuca sinensis, on the other hand, has a deep root system, with vertical taproots that penetrate deep into the soil, absorbing deep moisture and enhancing soil stability. The significant differences in root distribution between the two plants reduce competition for water and nutrients, while also forming a dense aboveground vegetation cover, effectively reducing wind erosion.

[0009] A combination of Elymus nutans and Elymus sibiricus was selected for the mid-slope site, where soil moisture is moderate but susceptible to short-term drought stress. Elymus nutans is highly tolerant to drought and salinity, with broad leaves and high photosynthetic efficiency, enabling it to maintain high productivity in drought conditions. Elymus sibiricus is known for its rapid establishment and high biomass accumulation, and its upright growth helps improve ventilation and light transmission in the grassland. The synergistic effect of these two plants improves vegetation stability and productivity in the mid-slope site.

[0010] Poa frigida was selected as the dominant species in low-slope areas, where soil moisture is high and short-term waterlogging is possible. Poa frigida has strong tolerance to moisture and low temperatures, and its dense root network effectively fixes soil particles, reducing soil erosion caused by waterlogging. Furthermore, its root secretions are rich in carbon, which can promote soil microbial activity, further increasing soil organic matter content and nutrient cycling efficiency.

[0011] Preferably, the soil surface after plowing in step 1 needs to be leveled to ensure that the slope is controlled between 3° and 5° to reduce the damage to the soil structure caused by water erosion.

[0012] Preferably, the improved substrate in step 1 is applied in a strip-type manner, with a strip width of 50 cm and a spacing of 30 cm to ensure sufficient contact between the improved substrate and the original soil and form a stable transition layer.

[0013] Preferably, meadow fescue is introduced by sowing, with a sowing amount of 15 g / m², and the soil covering thickness after sowing is 0.5-1 cm; Chinese fescue is planted by transplanting seedlings, with a transplanting density of 30 plants / m²; drooping dungleaf dunghill is introduced by sowing, with a sowing amount of 20 g / m²; old sibiricus is planted by transplanting rhizomes, with a transplanting density of 25 plants / m²; cold-weather bluegrass is planted by transplanting bulbous rhizomes, with a transplanting density of 40 plants / m².

[0014] Furthermore, Kentucky bluegrass, Elymus nutans, and Poa frigida require drip irrigation after transplanting or sowing. Drip irrigation is used to maintain a soil moisture content of 35%-40% in the 0-20 cm depth. Drip irrigation should be applied every two days during the seedling stage and every five days during the vegetative growth phase. The drip irrigation system should have nozzles spaced 50 cm apart and a flow rate of 2 L / h to ensure even water distribution.

[0015] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for improving the function of degraded grassland soil based on microbial community regulation, which has the following beneficial effects: By combining optimized plant configuration with microbial community regulation, the present invention fully utilizes the functional characteristics of different plants and the metabolic activities of microorganisms to construct a multi-level, multifunctional grassland ecosystem. The microbial agents in the improved matrix can significantly improve the efficiency of soil nutrient conversion. In particular, the symbiotic relationship formed between arbuscular mycorrhizal fungi and plant roots promotes the plant's absorption of mineral elements such as phosphorus and potassium, while nitrogen-fixing bacteria and phosphate-solubilizing bacteria further increase the availability of nitrogen and phosphorus in the soil. In addition, cellulolytic bacteria accelerate the decomposition of organic matter, increase the soil organic carbon content, and thus improve soil structure and fertility.

[0016] In terms of plant configuration, the present invention selects appropriate plant combinations based on the environmental conditions of different slopes, fully leveraging the complementary effects between plants. Kentucky bluegrass and Festuca australis on high slopes reduce resource competition through differential root distribution, while also enhancing soil resistance to wind erosion. Elymus nutans and Elymus sibiricus on mid-slopes enhance vegetation stability through the synergistic effects of drought tolerance and biomass accumulation. Kentucky bluegrass on low slopes promotes soil microbial activity and nutrient cycling efficiency through its moisture tolerance and root secretions.

[0017] The technical solution of this invention is highly operational and suitable for restoration of degraded grasslands in my country's Qinghai-Tibet Plateau, particularly in arid and semi-arid regions. Through its application, the soil functions of degraded grasslands have been significantly improved, vegetation coverage and biodiversity have been gradually restored, and the construction of regional ecological security barriers has been effectively supported. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a method for improving soil function of degraded grassland in an embodiment of the present invention, showing the main steps from target plot selection and arrangement to plant optimization configuration.

[0019] Figure 2 This is a schematic diagram of the plant configuration in different slope areas and its relationship with the microbial agent in the embodiment of the present invention, indicating the plant combination and the application method of the improved substrate in the high slope area, middle slope area and low slope area.

[0020] The accompanying drawings are numbered as follows: 1. Target plot; 2. Improved substrate; 3. High slope area; 4. Mid-slope area; 5. Low slope area; 6. Kentucky bluegrass; 7. Festuca australis; 8. Elymus nutans; 9. Elymus sibiricus; 10. Poa frutescens. DETAILED DESCRIPTION

[0021] The present invention provides a method for improving the function of degraded grassland soil based on microbial community regulation. Figure 1 and attached Figure 2The specific embodiments of the present invention are described in detail. During implementation, the selection and preparation of target plot 1 is the first step. Typical degraded grasslands located in arid or semi-arid regions are selected as target plots. Surface debris such as rocks and dead branches are removed, and shallow tillage is performed to improve soil structure. The tillage depth is strictly controlled between 15 and 20 cm, and a rotary tiller is used to break up the topsoil into particles less than 2 cm in size, thereby increasing soil permeability and water retention. After tillage, the soil surface must be leveled to ensure a slope between 3° and 5°. This slope range effectively reduces damage to soil structure caused by water erosion. Subsequently, the modified substrate 2 is applied in strips of 50 cm wide, 30 cm apart, and 3-5 cm thick. The modified substrate 2 is composed of a mixture of decomposed organic fertilizer and a microbial agent in a mass ratio of 10:1. The microbial agent includes arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and cellulolytic bacteria, with the ratio of each species being 4:3:2:1. The strip-type laying method can ensure that the improved substrate 2 is in full contact with the original soil and forms a stable transition layer, thereby promoting the uniform distribution of the microbial agent in the soil.

[0022] Plant optimization configuration is one of the core steps of the present invention. According to the terrain slope and moisture conditions of the target plot 1, it is divided into high slope area 3, medium slope area 4 and low slope area 5, and plants are configured separately. The soil moisture in high slope area 3 is low and it is easily affected by wind erosion, so meadow fescue 6 and Chinese fescue 7 are selected as the main plant combination. Meadow fescue 6 is introduced by sowing, with a sowing amount of 15 g / m² and a soil covering thickness of 0.5-1 cm after sowing; Chinese fescue 7 is planted by transplanting seedlings with a transplanting density of 30 plants / m². Meadow fescue 6 has a developed stolon structure, which can quickly expand the coverage area on the surface and reduce the soil exposure time, while Chinese fescue 7 is mainly based on a deep root system, and its main root can penetrate deep into the lower soil layer to absorb deep moisture and enhance soil stability. The root distribution of the two plants is significantly different, which reduces the competition for water and nutrients, while forming a dense ground vegetation cover, effectively reducing the intensity of wind erosion. In mid-slope site 4, soil moisture is moderate but susceptible to short-term drought stress. Therefore, Elymus nutans 8 and Elymus sibiricus 9 were selected as the primary plant combination. Elymus nutans 8 was introduced by seeding at a seeding rate of 20 g / m²; Elymus sibiricus 9 was transplanted via rhizomes at a density of 25 plants / m². Elymus nutans 8 has broad leaves and high photosynthetic efficiency, enabling it to maintain high productivity under drought conditions. Elymus sibiricus 9 is known for its rapid establishment and strong biomass accumulation, and its upright growth pattern helps improve ventilation and light transmission in the grassland. The synergistic effect of these two plants enhances vegetation stability and productivity in mid-slope site 4. In low-slope site 5, soil moisture is high and short-term waterlogging is possible. Therefore, Poa frigida 10 was selected as the dominant species. Poa frigida 10 was transplanted via bulbous rhizomes at a density of 40 plants / m². Poa frigida 10 has strong tolerance to moisture and low temperatures. Its dense root network effectively anchors soil particles, reducing soil erosion caused by waterlogging. Furthermore, its root secretions are rich in carbon, which promotes soil microbial activity, further increasing soil organic matter content and nutrient recycling efficiency.

[0023] Drip irrigation is required after transplanting or sowing plants. The nozzle spacing of the drip irrigation system is 50 cm, and the nozzle flow rate is 2 L / h to ensure even water distribution. Kentucky bluegrass 6, Elymus nutans 8, and Poa frigida 10 require drip irrigation after transplanting or sowing. Drip irrigation is required to maintain a soil moisture content of 35%-40% in the 0-20 cm depth. Drip irrigation is applied every two days during the seedling stage and every five days during the vegetative growth phase. Drip irrigation precisely controls soil moisture, preventing plant growth restriction or soil structure damage caused by insufficient or excessive water.

[0024] The microbial agents in Modified Substrate 2 begin to function after the plants are deployed. The symbiotic relationship between arbuscular mycorrhizal fungi and plant roots promotes plant absorption of mineral elements such as phosphorus and potassium, while nitrogen-fixing and phosphate-solubilizing bacteria further enhance the availability of nitrogen and phosphorus in the soil. Cellulolytic bacteria accelerate the decomposition of organic matter, increasing soil organic carbon content and thus improving soil structure and fertility. Arbuscular mycorrhizal fungi primarily colonize plant roots, their mycelium extending into the soil, expanding the root absorption range. Nitrogen-fixing bacteria convert atmospheric nitrogen into plant-usable nitrogen forms through biological nitrogen fixation. Phosphorus-solubilizing bacteria decompose insoluble phosphorus compounds in the soil, releasing soluble phosphorus for plant absorption. Cellulolytic bacteria, through the secretion of cellulase, decompose organic residues in the soil, releasing carbon and nutrients. The synergistic effect of these microbial agents significantly improves soil nutrient conversion efficiency, providing ample nutrient support for plant growth.

[0025] In practical application, the technical solution of the present invention operates as follows: First, the target plot 1 is cleaned and plowed. After plowing, the modified substrate 2 is applied and laid in strips. Then, appropriate plant combinations are selected and arranged according to the environmental conditions of different slope locations. Drip irrigation is implemented after plant transplanting or sowing to ensure that soil moisture remains within an appropriate range. As the plants grow, the microbial agents in the modified substrate 2 gradually take effect. Arbuscular mycorrhizal fungi form a symbiotic relationship with the plant roots, nitrogen-fixing and phosphate-solubilizing bacteria increase the availability of soil nutrients, and cellulolytic bacteria accelerate the decomposition of organic matter, ultimately achieving a comprehensive improvement in the soil functions of degraded grasslands. For example, in a degraded grassland on the Qinghai-Tibet Plateau, following implementation of the method of the present invention, Kentucky bluegrass 6 and Festuca sinensis 7 formed a dense vegetation cover in the high-slope area 3, significantly reducing wind erosion intensity. Elymus nutans 8 and Elymus sibiricus 9 exhibited good drought tolerance and biomass accumulation characteristics in the mid-slope area 4, improving vegetation stability. Kentucky bluegrass 10 promoted soil microbial activity and nutrient recycling efficiency in the low-slope area 5 through its dense root network and root secretions. After one growing season, the soil organic matter content of the target plot 1 increased significantly, vegetation coverage and biodiversity gradually recovered, and the construction of a regional ecological security barrier was effectively supported.

[0026] In order to enable those skilled in the art to fully understand and implement the present invention, the implementation principle of the present invention is supplementarily explained below with reference to a specific application scenario.

[0027] First, during the selection and preparation phase of target plot 1, a typical degraded grassland in an arid or semi-arid region was selected as the experimental plot. After removing surface debris such as rocks and dead branches, the soil was shallowly plowed using a rotary tiller, with the plowing depth strictly controlled between 15 and 20 cm. By breaking the topsoil down to particles less than 2 cm in size, the soil's air permeability and water retention capacity were significantly improved. Subsequently, the plowed soil surface was leveled, maintaining a slope within a range of 3°-5° to minimize damage to the soil structure caused by water erosion. Modified substrate 2 was then applied in strips of 50 cm wide, 30 cm apart, and 3-5 cm thick. Modified substrate 2 consisted of a mixture of decomposed organic fertilizer and microbial inoculants in a mass ratio of 10:1. The ratio of arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and cellulolytic bacteria was 4:3:2:1. The strip-laying method ensures full contact between the modified substrate 2 and the original soil, forming a stable transition layer and promoting uniform distribution of the microbial inoculant in the soil. Arbuscular mycorrhizal fungi extend their mycelium into the soil, expanding the absorption range of plant roots. Nitrogen-fixing bacteria convert atmospheric nitrogen into a form that plants can use through biological nitrogen fixation. Phosphate-solubilizing bacteria break down insoluble phosphorus compounds, releasing soluble phosphorus for plant absorption. Cellulolytic bacteria secrete cellulase enzymes to break down organic residues, releasing carbon sources and nutrients. The synergistic effect of these microbial inoculants significantly improves soil nutrient conversion efficiency.

[0028] Secondly, during the plant optimization phase, the target plot 1 was divided into high-slope area 3, mid-slope area 4, and low-slope area 5 based on its topographic slope and moisture conditions, and plant configurations were performed accordingly. In high-slope area 3, due to low soil moisture and susceptibility to wind erosion, Kentucky bluegrass 6 and Chinese fescue 7 were selected as the primary plant combinations. Kentucky bluegrass 6 was introduced by seeding at a rate of 15 g / m² and covered with a soil thickness of 0.5-1 cm after sowing; Chinese fescue 7 was transplanted from seedlings at a density of 30 plants / m². Kentucky bluegrass 6 has a well-developed stolon structure, enabling it to rapidly expand its surface coverage and reduce the time the soil is exposed. Chinese fescue 7, on the other hand, relies on its deep root system, with taproots penetrating deep into the soil to absorb deep moisture and enhance soil stability. The two plants exhibit significant vertical differences in their root distribution, reducing competition for water and nutrients while forming a dense aboveground vegetation cover, effectively reducing wind erosion intensity. In mid-slope site 4, soil moisture is moderate but susceptible to short-term drought stress. Therefore, Elymus nutans 8 and Elymus sibiricus 9 were selected as the primary plant combination. Elymus nutans 8 was introduced by seeding at a seeding rate of 20 g / m²; Elymus sibiricus 9 was transplanted via rhizomes at a density of 25 plants / m². Elymus nutans 8 has broad leaves and high photosynthetic efficiency, enabling it to maintain high productivity under drought conditions. Elymus sibiricus 9 is known for its rapid establishment and strong biomass accumulation, and its upright growth helps improve ventilation and light transmission in the grassland. The synergistic effect of these two plants enhances vegetation stability and productivity in mid-slope site 4. In low-slope site 5, soil moisture is high and short-term waterlogging is possible. Therefore, Poa frigida 10 was selected as the dominant species. Poa frigida 10 was transplanted via bulbous rhizomes at a density of 40 plants / m². Poa frigida 10 has strong tolerance to moisture and low temperatures. Its dense root network effectively anchors soil particles, reducing soil erosion caused by waterlogging. Furthermore, its root secretions are rich in carbon, which promotes soil microbial activity, further increasing soil organic matter content and nutrient recycling efficiency.

[0029] After transplanting or sowing, drip irrigation is required to maintain soil moisture within a suitable range. The drip irrigation system uses nozzles spaced 50 cm apart and a flow rate of 2 L / h to ensure even water distribution. Kentucky bluegrass 6, Elymus nutans 8, and Kentucky bluegrass 10 require drip irrigation after transplanting or sowing, supplying water to maintain a soil moisture content between 35% and 40% in the 0-20 cm depth. Drip irrigation is applied every two days during the seedling stage and every five days during the vegetative growth phase. Drip irrigation allows for precise control of soil moisture, preventing plant growth restriction or soil structure damage caused by insufficient or excessive water. In this way, the microbial agents in the modified substrate 2 gradually take effect. Arbuscular mycorrhizal fungi form a symbiotic relationship with plant roots, nitrogen-fixing and phosphate-solubilizing bacteria increase soil nutrient availability, and cellulolytic bacteria accelerate organic matter decomposition, ultimately achieving a comprehensive improvement in soil functions in degraded grasslands.

[0030] For example, in a degraded grassland in the Qinghai-Tibet Plateau, after implementing the above method, Kentucky bluegrass 6 and Chinese fescue 7 formed a dense vegetation cover in the high-slope area 3, significantly reducing the intensity of wind erosion. Elymus nutans 8 and Elymus sibiricus 9 showed good drought resistance and biomass accumulation characteristics in the mid-slope area 4, improving vegetation stability. Kentucky bluegrass 10 promoted soil microbial activity and nutrient recycling efficiency in the low-slope area 5 through its dense root network and root secretions. After one growing season, the soil organic matter content of the target plot 1 increased significantly, the vegetation coverage and biodiversity gradually recovered, and the construction of the regional ecological security barrier was effectively supported.

[0031] Any details not described in the specification are prior art known to those skilled in the art, and the model parameters of each device are not specifically limited; conventional devices can be used. Electrical control components not mentioned in this technical solution are prior art and are not shown in the figures, so they will not be described here.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving soil function of degraded grassland based on microbial community regulation, characterized in that: The following steps are involved: Step 1: Selection and arrangement of target plots Degraded grasslands were selected as target plots. Surface debris was removed and shallow tillage was performed to a depth of 15 to 20 cm, breaking the topsoil down to particles less than 2 cm in size. Subsequently, an improved matrix consisting of decomposed organic fertilizer and microbial agents was evenly applied to the surface of the target plots to a thickness of 3 to 5 cm. The mass ratio of decomposed organic fertilizer to microbial agents in the improved matrix was 10:1, and the microbial agents included arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and cellulolytic bacteria, with the respective species ratios being 4:3:2:

1. Step 2: Plant Optimization Based on the ecological adaptability and functional characteristics of five plant species, namely Kentucky bluegrass, Festuca sinensis, Elymus nutans, Elymus sibiricus and Kentucky bluegrass, the target plot was divided into high slope, mid slope and low slope areas according to the terrain slope and water conditions, and plant configuration was carried out accordingly. The high slope areas are equipped with Kentucky bluegrass and Chinese fescue; the mid-slope areas are equipped with Elymus nutans and Elymus sibiricus; the low slope areas are equipped with Poa frigida.

2. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: The soil surface after plowing in step 1 needs to be leveled to ensure that the slope is controlled between 3 degrees and 5 degrees.

3. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: In step 1, the improved substrate is applied in strips with a width of 50 cm and a spacing of 30 cm.

4. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: Meadow Kentucky was introduced by sowing with a sowing rate of 15 grams per square meter, and the thickness of the soil after sowing was 0.5 cm to 1 cm; Chinese fescue was planted by transplanting seedlings with a transplanting density of 30 plants per square meter; drooping dungleaf dunghill was introduced by sowing with a sowing rate of 20 grams per square meter; old sorghum was planted by transplanting rhizomes with a transplanting density of 25 plants per square meter; cold-weather bluegrass was planted by transplanting bulbous rhizomes with a transplanting density of 40 plants per square meter.

5. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: Meadow Kentucky bluegrass, Elymus nutans and Poa frigida need to be managed with drip irrigation after transplanting or sowing. Drip irrigation should be used to supply water to the soil layer from 0 cm to 20 cm to maintain the moisture content between 35% and 40%.

6. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 5, characterized in that: The nozzle spacing of the drip irrigation equipment is 50 cm, and the nozzle flow rate is 2 liters per hour.

7. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 5, characterized in that: Drip irrigation is carried out every 2 days during the seedling stage and every 5 days during the vegetative growth period.

8. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: The microbial agents in the improved substrate include arbuscular mycorrhizal fungi, nitrogen-fixing bacteria, phosphate-solubilizing bacteria and cellulolytic bacteria, with the ratio of each species being 4:3:2:

1.

9. The method for improving soil function of degraded grassland based on microbial community regulation according to claim 1, characterized in that: The high slope areas are equipped with Kentucky bluegrass and Chinese fescue, the middle slope areas are equipped with Elymus nutans and Elymus sibiricus, and the low slope areas are equipped with Poa frigida.

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