Method for recovering severely degraded Coilin grassland vegetation

Abstract

The invention discloses a method for recovering severely degraded Coilin grassland vegetation. The method comprises the following steps: S1, investigating; s2, investigating plant community characteristics and biomass; s3, determining the quality of the forage grass in the plant community; s4, collecting a soil sample; s5, reseeding the following raw materials according to a ratio of (1.5-2.5): (0.5-1.5): (1.5-2.5): (0.5-1.5): (0.5-1.5): (0.5-1.5): (1.5-2.5): (0.5-1.5), continuously reseeding for four years, and carrying out fence breeding; s6, fertilization: the ratio of nitrogen to phosphorus to potassium is 2: 1: 1; according to the actual condition of the severely-degraded Coilexin grassland, by reseeding the following raw materials: Astragalus mongolicus, Astragalus mongolicus and sweet clover in a ratio of (1.5-2.5): (0.5-1.5): (1.5-2.5): (0.5-1.5), and applying a fertilizer bag, the severely-degraded Coilexin grassland monoennial and biennial plants are finally reduced, perennial gramineae, hybrid grass and perennial leguminous plants all grow, the pH value of soil tends to be neutral, and the yield of the severely-degraded Coilexin grassland is increased. Moreover, nutrient substances are increased, and severely-degraded Colexin grassland vegetation is recovered.

Description

Technical Field

[0001] This invention belongs to the field of ecological governance and restoration technology of degraded grasslands, specifically relating to a method for restoring the vegetation of the severely degraded Horqin grassland. Background Technology

[0002] The original vegetation of the Horqin Grassland belongs to the transitional type between forest and grassland. For a long time, due to natural factors such as climate change and human factors, the Horqin Grassland has experienced severe degradation and desertification, manifested as reduced grass yield, decreased utilization rate, reduced carrying capacity, frequent biological disasters, and an increase in natural disasters. Therefore, as an important component of the northern ecological security barrier, the vegetation restoration and ecological restoration of the Horqin Grassland has become an urgent task to be addressed. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for restoring severely degraded vegetation in the Horqin grassland, comprising the following steps: S1. Survey: Investigate the geographical overview, climate characteristics, vegetation overview, and soil overview of the Horqin Grassland, and identify the severely degraded areas of the Horqin Grassland. S2. Plant community characteristics and biomass survey: During the peak growth period of pasture grass in July and August, a survey was conducted on severely degraded Horqin grassland plots to monitor the height, cover and density of the Horqin grassland plant community and collect data. S3. Determination of forage quality in plant communities: The quality of forage in the severely degraded Horqin grassland plant community was determined by measuring moisture content, plant protein, plant ash, plant fat, neutral detergent fiber, and acid detergent fiber. S4. Soil sample collection: Soil samples were collected in August to determine soil chemical properties, soil bacterial community species composition, and soil fungal community species composition. S5. Reseeding: Reseeding with grass seeds on the severely degraded Horqin grassland. The reseeded grass seeds are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Syzygium spp.*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Syzygium spp.* = 1.5-2.5: 0.5-1.5: 1.5-2.5: 0.5-1.5. The reseeding rate is 40-50 kg / hm². 2 Sow at a depth of 1-2 cm, re-sow for four consecutive years, and then fence off the area. S6. Fertilization: Fertilize in the 2nd-4th year after the first reseeding, before rainfall, by manually spreading fertilizer packets of 200-240 kg / hm. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:1.

[0004] Preferably, the reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, with a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 1.5:0.5:2.5:1.5, and the reseeding rate is 40 kg / hm². 2 Sow at a depth of 1cm.

[0005] Preferably, the reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, with a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 2.5:1.5:1.5:0.5, and the reseeding rate is 50 kg / hm². 2 Sowing depth 2 cm.

[0006] Preferably, the reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 2:1:2:1, and the reseeding rate is 45 kg / hm². 2 Seeding depth 1.5 cm.

[0007] Preferably, the nitrogen fertilizer is urea, the phosphate fertilizer is superphosphate, and the potassium fertilizer is potassium oxide fertilizer.

[0008] Preferably, the urea has a nitrogen content of ≥46%, the phosphate fertilizer has a phosphorus pentoxide content of ≥44%, and the potassium fertilizer has a potassium oxide content of ≥51%.

[0009] Preferably, in step S3, the moisture content is determined by drying method, the plant protein is determined by Kjeldahl method using fully automated nitrogen analyzer, the plant ash is determined by muffle furnace, the plant fat is determined by fat analyzer, the neutral detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system, and the acid detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system.

[0010] Preferably, in step S3, the soil chemical characteristics indicators include the content of total nitrogen, total phosphorus, available potassium, and organic matter in the soil.

[0011] Preferably, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil bacterial communities in soil samples from typical degraded grasslands in Horqin.

[0012] Preferably, the method for restoring severely degraded Horqin grassland vegetation as described in claim 1 is characterized in that, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil fungal communities in soil samples of typical degraded Horqin grassland.

[0013] In this invention, the following levels of degradation of the Hormi grassland constitute severe degradation: Vegetation and soil have deteriorated severely, and forage yields have decreased by more than 40%. The grassland is severely eroded, soil nutrients are being lost in large quantities, and soil structure is being damaged. The original plant communities and native dominant plants have basically disappeared, and degenerate indicator plants (such as Camel Hump and Oxheart Root) have begun to grow haphazardly and take the lead. Grassland productivity has declined significantly, livestock have not received enough nutrients for a long time, their growth and development have been hindered, and their productivity has declined. The productivity and ecological functions of the entire grassland ecosystem have been severely affected. If restoration measures are not taken in time, the entire system may collapse and the grassland will cease to exist.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, based on the geographical overview, climate characteristics, vegetation overview, and soil overview of the severely degraded Horqin Grassland, restores the vegetation of the severely degraded Horqin Grassland by reseeding *Isodon japonicus*: *Isodon japonicus*: *Isodon japonicus*: *Osmanthus fragrans* = 1.5-2.5:0.5-1.5:1.5-2.5:0.5-1.5, with a reseeding rate of 40-50 kg / hm2 and a sowing depth of 1-2 cm for four consecutive years, followed by fencing. Additionally, fertilizer packets of 200-240 kg / hm2 are applied manually. These fertilizer packets are a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, containing nitrogen, phosphorus, and potassium fertilizers in a nitrogen:phosphorus:potassium ratio of 2:1:1. Ultimately, this restores the vegetation of the severely degraded Horqin Grassland by reducing the number of annual and biennial plants, promoting the growth of perennial grasses, miscellaneous weeds, and perennial legumes, neutralizing the soil pH, increasing nutrient levels, and restoring the grassland's vegetation. Attached Figure Description

[0015] Figure 1 This shows the aboveground biomass of each experimental group in this invention in 2020. Detailed Implementation Example 1

[0016] A method for restoring severely degraded vegetation in the Horqin grassland includes the following steps: S1. Survey: Investigate the geographical overview, climate characteristics, vegetation overview, and soil overview of the Horqin Grassland, and identify the severely degraded areas of the Horqin Grassland. S2. Plant community characteristics and biomass survey: During the peak growth period of pasture grass in July and August, a survey was conducted on severely degraded Horqin grassland plots to monitor the height, cover and density of the Horqin grassland plant community and collect data. S3. Determination of forage quality in plant communities: The quality of forage in the severely degraded Horqin grassland plant community was determined by measuring moisture content, plant protein, plant ash, plant fat, neutral detergent fiber, and acid detergent fiber. S4. Soil sample collection: Soil samples were collected in August to determine soil chemical properties, soil bacterial community species composition, and soil fungal community species composition. S5. Reseeding: Reseeding with grass seeds on the severely degraded Horqin grassland. The reseeded grass seeds are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Syzygium spp.*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Syzygium spp.* = 2.5:1.5:1.5:0.5, with a reseeding rate of 40 kg / hm². 2 Sow at a depth of 2 cm, reseed continuously for four years, and then fence off the area for protection. S6. Fertilization: Fertilize in the 2nd-4th year after the first reseeding. Before rainfall, apply fertilizer packets of 200 kg / hm² manually. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:1.

[0017] Preferably, the nitrogen fertilizer is urea, the phosphate fertilizer is superphosphate, and the potassium fertilizer is potassium oxide fertilizer.

[0018] Preferably, the urea has a nitrogen content of ≥46%, the phosphate fertilizer has a phosphorus pentoxide content of ≥44%, and the potassium fertilizer has a potassium oxide content of ≥51%.

[0019] Preferably, in step S3, the moisture content is determined by drying method, the plant protein is determined by Kjeldahl method using fully automated nitrogen analyzer, the plant ash is determined by muffle furnace, the plant fat is determined by fat analyzer, the neutral detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system, and the acid detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system.

[0020] Preferably, in step S3, the soil chemical characteristics indicators include the content of total nitrogen, total phosphorus, available potassium, and organic matter in the soil.

[0021] Preferably, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil bacterial communities in soil samples from typical degraded grasslands in Horqin.

[0022] Preferably, the method for restoring severely degraded Horqin grassland vegetation as described in claim 1 is characterized in that, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil fungal communities in soil samples of typical degraded Horqin grassland. Example 2

[0023] A method for restoring severely degraded vegetation in the Horqin grassland includes the following steps: S1. Survey: Investigate the geographical overview, climate characteristics, vegetation overview, and soil overview of the Horqin Grassland, and identify the severely degraded areas of the Horqin Grassland. S2. Plant community characteristics and biomass survey: During the peak growth period of pasture grass in July and August, a survey was conducted on severely degraded Horqin grassland plots to monitor the height, cover and density of the Horqin grassland plant community and collect data. S3. Determination of forage quality in plant communities: The quality of forage in the severely degraded Horqin grassland plant community was determined by measuring moisture content, plant protein, plant ash, plant fat, neutral detergent fiber, and acid detergent fiber. S4. Soil sample collection: Soil samples were collected in August to determine soil chemical properties, soil bacterial community species composition, and soil fungal community species composition. S5. Reseeding: Reseeding with grass seeds on the severely degraded Horqin grassland. The reseeded grass seeds are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Syzygium spp.*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Syzygium spp.* = 1.5:0.5:2.5:1.5, and the reseeding rate is 50 kg / hm². 2 Sow at a depth of 1 cm, reseed continuously for four years, and then fence off the area. S6. Fertilization: Fertilize in the 2nd-4th year after the first reseeding. Before rainfall, apply fertilizer packets of 240 kg / hm² manually. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:1.

[0024] Preferably, the nitrogen fertilizer is urea, the phosphate fertilizer is superphosphate, and the potassium fertilizer is potassium oxide fertilizer.

[0025] Preferably, the urea has a nitrogen content of ≥46%, the phosphate fertilizer has a phosphorus pentoxide content of ≥44%, and the potassium fertilizer has a potassium oxide content of ≥51%.

[0026] Preferably, in step S3, the moisture content is determined by drying method, the plant protein is determined by Kjeldahl method using fully automated nitrogen analyzer, the plant ash is determined by muffle furnace, the plant fat is determined by fat analyzer, the neutral detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system, and the acid detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system.

[0027] Preferably, in step S3, the soil chemical characteristics indicators include the content of total nitrogen, total phosphorus, available potassium, and organic matter in the soil.

[0028] Preferably, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil bacterial communities in soil samples from typical degraded grasslands in Horqin.

[0029] Preferably, the method for restoring severely degraded Horqin grassland vegetation as described in claim 1 is characterized in that, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil fungal communities in soil samples of typical degraded Horqin grassland. Example 3

[0030] A method for restoring severely degraded vegetation in the Horqin grassland includes the following steps: S1. Survey: Investigate the geographical overview, climate characteristics, vegetation overview, and soil overview of the Horqin Grassland, and identify the severely degraded areas of the Horqin Grassland. S2. Plant community characteristics and biomass survey: During the peak growth period of pasture grass in July and August, a survey was conducted on severely degraded Horqin grassland plots to monitor the height, cover and density of the Horqin grassland plant community and collect data. S3. Determination of forage quality in plant communities: The quality of forage in the severely degraded Horqin grassland plant community was determined by measuring moisture content, plant protein, plant ash, plant fat, neutral detergent fiber, and acid detergent fiber. S4. Soil sample collection: Soil samples were collected in August to determine soil chemical properties, soil bacterial community species composition, and soil fungal community species composition. S5. Reseeding: Reseeding with grass seeds on the severely degraded Horqin grassland. The reseeded grass seeds are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongholicus*, and *Syzygium spp.*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongholicus*: *Syzygium spp.* = 2:1:2:1, with a reseeding rate of 45 kg / hm². 2 Sow at a depth of 1.5 cm, reseed continuously for four years, and then fence off the area for protection. S6. Fertilization: Fertilize in the 2nd-4th year after the first reseeding. Before rainfall, apply fertilizer packets of 220 kg / hm² manually. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:1.

[0031] Preferably, the nitrogen fertilizer is urea, the phosphate fertilizer is superphosphate, and the potassium fertilizer is potassium oxide fertilizer.

[0032] Preferably, the urea has a nitrogen content of ≥46%, the phosphate fertilizer has a phosphorus pentoxide content of ≥44%, and the potassium fertilizer has a potassium oxide content of ≥51%.

[0033] Preferably, in step S3, the moisture content is determined by drying method, the plant protein is determined by Kjeldahl method using fully automated nitrogen analyzer, the plant ash is determined by muffle furnace, the plant fat is determined by fat analyzer, the neutral detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system, and the acid detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system.

[0034] Preferably, in step S3, the soil chemical characteristics indicators include the content of total nitrogen, total phosphorus, available potassium, and organic matter in the soil.

[0035] Preferably, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil bacterial communities in soil samples from typical degraded grasslands in Horqin.

[0036] Preferably, the method for restoring severely degraded Horqin grassland vegetation as described in claim 1 is characterized in that, in step S4, high-throughput sequencing technology is used to analyze the species composition of soil fungal communities in soil samples of typical degraded Horqin grassland.

[0037] Experiment 1: Effects of reseeding on vegetation density in severely degraded grasslands

[0038] From 2015 to June 2018, reseeding was carried out on the severely degraded Hormi grassland. Treatments A, B, C, and a control group were reseeded for four consecutive years, as detailed in Table 1 below. Fertilization began in the second year and continued for three years. Before rainfall, fertilizer packets of 240 kg / hm² were applied manually. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:1. The nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, the urea contains ≥46% nitrogen, the phosphorus fertilizer contains ≥44% phosphorus pentoxide, and the potassium fertilizer contains ≥51% potassium oxide. The enclosure was not disturbed by human intervention. Surveys were conducted in 2019 and 2020, and the results are shown in Table 2.

[0039] Table 1. Re-broadcast Group Design

[0040] Plant density (D) refers to the number of plants (or clumps) of a particular species per unit area, expressed by the formula D = N / S (plants or clumps / m²). 2D represents species density, N represents the number of individuals (plants or clumps) of a particular species within the plot, and S represents the plot area. Plant density surveys were conducted in August of both 2019 and 2020, during the peak growth period of grassland vegetation. 1 m × 1 m quadrats were randomly selected in each plot within a fixed time period. The grassland was enclosed, and there were few external interferences except for sampling. Plant density was determined using a counting method (clump-forming grasses were recorded by the number of clumps, and other grasses by the number of individual plants). The results are shown in Table 2.

[0041] Table 2. Effects of reseeding on plant density of different functional groups

[0042] As can be seen from Table 2, in the severely degraded grassland plots (Group A) that were reseeded with the present invention, the density of annual and biennial plants decreased in 2019, while the density of perennial grasses, miscellaneous weeds, and perennial leguminous plants was higher than that of other groups, and the situation in 2020 was significantly better than that in 2019.

[0043] Experiment 2: Effects of reseeding on vegetation cover in severely degraded grasslands Plant cover refers to the percentage of the vertical projection area of ​​a plant population or community above ground to the sampled area. It reflects the area of ​​vegetation undergoing photosynthesis and its density. There are two types of cover: base cover and projection cover (total plant cover). This experiment used projection cover, which is the percentage of the vertical projection area of ​​plant stems and leaves to the area of ​​the sample plot. The average value was taken by visual estimation. The plant cover of the sample plot in Experiment 1 was measured in 2019 and 2020, and the results are shown in Table 3.

[0044] Table 3. Effects of reseeding on plant cover of different functional groups

[0045] As can be seen from Table 3, in the severely degraded grassland plots (Group A) that were reseeded with the present invention, the coverage of annual and biennial plants decreased in 2019, while the coverage of perennial grasses, miscellaneous grasses, and perennial leguminous plants was relatively high and higher than that of other groups. The situation in 2020 was significantly better than that in 2019.

[0046] Experiment 3: Effect of reseeding on soil pH For the sample plots in Experiment 1, the soil pH values ​​of the 0-20 cm soil layer, 20-30 cm soil layer, and 30-50 cm soil layer were measured respectively. The results are shown in Table 4.

[0047] Table 4. Effects of reseeding on soil pH in different soil layers

[0048] As can be seen from the table above, the pH values ​​of the severely degraded Hormi grassland plots (Group A) that were reseeded using this invention were lower and closer to neutral in 2019 and 2020 than those of other groups, while the other groups were all alkaline.

[0049] Experiment 4: Effects of reseeding on soil hydrolyzable nitrogen content In 2020, the hydrolyzable nitrogen content of the soil in the 0-20 cm, 20-30 cm, and 30-50 cm soil layers of the sample plot in Experiment 1 was measured, as shown in Table 5.

[0050] Table 5. Effects of reseeding on the hydrolyzable nitrogen content in different soil layers.

[0051] As can be seen from Table 5, under the same treatment, the hydrolyzable nitrogen content in the 0-20 cm soil layer of the present invention (Group A) was significantly higher than that in the 20-30 cm and 30-50 cm soil layers, and also higher than that in other groups.

[0052] Experiment 5: Effects of overseeding on aboveground biomass of different functional communities In August 2020, during the peak growth period of grassland vegetation, a community characteristic survey was conducted. At fixed time intervals, 1 m × 1 m quadrats were randomly set up in each plot. The grassland was enclosed, with minimal external interference except for sampling. Samples were cut at ground level, bagged, and dried in a laboratory oven at 105 ℃ for 30 min to kill the green, then dried at 65 ℃ to constant weight. Aboveground biomass was measured. The aboveground biomass was the sum of the aboveground biomass of all plants in a specific functional group within the quadrat. The results are shown in […]. Figure 1 .

[0053] pass Figure 1 It can be seen that the aboveground biomass of the present invention (Group A) was significantly higher than that of perennial plants in 2020 compared with other groups, while the biomass of annual plants decreased.

[0054] Experiment 6: Effects of fertilization on plant cover of different functional groups From 2015 to June 2018, reseeding was carried out on the severely degraded Hormi grassland: *Isodon japonicus* + *Isodon sambac* + *Isodon mongolicum* + *Osmanthus fragrans* (15+7.5+15+7.5=45). Fertilizer was applied in the 2nd to 4th year after the first reseeding, for three consecutive years. Before rainfall, fertilizer packets of 220 kg / hm2 were applied manually (Table 6). The nitrogen fertilizer was urea, the phosphate fertilizer was superphosphate, the urea had a nitrogen content ≥46%, the phosphate fertilizer had a phosphorus pentoxide content ≥44%, and the potassium fertilizer had a potassium oxide content ≥51%. Afterwards, the area was fenced off without human interference. Surveys were conducted in 2019 and 2020, and the results are shown in Table 7.

[0055] Table 6 Fertilizer group design

[0056] Table 7. Effects of fertilization on plant cover of different functional groups

[0057] As can be seen from the table above, the reasonable combination of nitrogen, phosphorus and potassium ratios using the technical solution of this invention can increase the vegetation cover of the severely degraded Hormi grassland, thereby reducing the cover of annual and biennial plants and increasing the cover of other plants.

[0058] Experiment 7: Effects of fertilization on soil pH For the land where Example 8 was implemented, the soil pH values ​​of the 0-20 cm, 20-30 cm, and 30-50 cm soil layers were measured in 2019 and 2020, respectively, as shown in Table 8.

[0059] Table 8 Effects of fertilization on soil pH in different soil layers

[0060] As can be seen from Table 8, the use of the technical solution of the present invention, with reasonable grass species and a reasonable ratio of nitrogen, phosphorus and potassium, can adjust the soil pH value and improve the soil alkaline conditions.

Claims

1. A method for restoring severely degraded vegetation in the Horqin grassland, characterized in that, Includes the following steps: S1. Survey: Investigate the geographical overview, climate characteristics, vegetation overview, and soil overview of the Horqin Grassland, and identify the severely degraded areas of the Horqin Grassland. S2. Plant community characteristics and biomass survey: During the peak growth period of pasture grass in July and August, a survey was conducted on severely degraded Horqin grassland plots to monitor the height, cover and density of the Horqin grassland plant community and collect data. S3. Determination of forage quality in plant communities: The quality of forage in the severely degraded Horqin grassland plant community was determined by measuring moisture content, plant protein, plant ash, plant fat, neutral detergent fiber, and acid detergent fiber. S4. Soil sample collection: Soil samples were collected in August to determine soil chemical properties, soil bacterial community species composition, and soil fungal community species composition. S5. Reseeding: Reseeding with grass seeds on the severely degraded Horqin grassland. The reseeded grass seeds are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Syzygium spp.*, in a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Syzygium spp.* = 1.5-2.5: 0.5-1.5: 1.5-2.5: 0.5-1.

5. The reseeding rate is 40-50 kg / hm². 2 Sow at a depth of 1-2 cm, re-sow for four consecutive years, and then fence off the area. S6. Fertilization: Fertilize in the 2nd-4th year after the first reseeding, before rainfall, by manually spreading fertilizer packets of 200-240 kg / hm. 2 The fertilizer package is a nitrogen-phosphorus-potassium (NPK) mixed fertilizer, which includes nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer. In the NPK mixed fertilizer, the ratio of nitrogen:phosphorus:potassium is 2:1:

1.

2. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, The reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, with a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 1.5:0.5:2.5:1.5, and the reseeding rate is 40 kg / hm². 2 Sow at a depth of 1cm.

3. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, The reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, with a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 2.5:1.5:1.5:0.5, and a reseeding rate of 50 kg / hm². 2 Sowing depth 2 cm.

4. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, The reseeding grass species are *Agrostis pilosa*, *Agrostis spp.*, *Agrostis mongolica*, and *Sweet clover*, with a mass ratio of *Agrostis pilosa*: *Agrostis spp.*: *Agrostis mongolica*: *Sweet clover* = 2:1:2:1, and the reseeding rate is 45 kg / hm². 2 Seeding depth 1.5 cm.

5. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, The nitrogen fertilizer is urea, the phosphate fertilizer is superphosphate, and the potassium fertilizer is potassium oxide fertilizer.

6. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 5, characterized in that, The urea has a nitrogen content of ≥46%, the phosphate fertilizer has a phosphorus pentoxide content of ≥44%, and the potassium fertilizer has a potassium oxide content of ≥51%.

7. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, In step S3, the moisture content is determined by drying method, the plant protein is determined by Kjeldahl method using fully automated nitrogen analyzer, the plant ash is determined by muffle furnace, the plant fat is determined by fat analyzer, the neutral detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system, and the acid detergent fiber is determined by FOSS Fibertec 2010 fully automated fiber analysis system.

8. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, In step S3, the soil chemical characteristics indicators include the content of total nitrogen, total phosphorus, available potassium, and organic matter.

9. A method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, In step S4, high-throughput sequencing technology is used to analyze the species composition of soil bacterial communities in soil samples from typical degraded grasslands in Horqin.

10. The method for restoring severely degraded vegetation in the Horqin grassland as described in claim 1, characterized in that, In step S4, high-throughput sequencing technology is used to analyze the species composition of soil fungal communities in soil samples from typical degraded grasslands in Horqin.

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