Ecological restoration method for degraded grassland

Abstract

The invention discloses a degraded grassland ecological restoration method. The method comprises the following steps: S1, degradation evaluation; s2, carrying out primary division on a repair area; s3, preliminary repairing is carried out; s4, carrying out secondary division on the restoration area; s5, performing deep repair; s6, sowing at regular intervals. According to the method, the selection and division of the contour lines serve as reference conditions, a scientific and reasonable comprehensive restoration scheme is formed, the ecological fences are arranged along the contour lines to serve as restoration boundaries, the utilization of water resources can be improved, meanwhile, the maintenance of internal healthy grassland can be enhanced, and finally a dynamic restoration ecological system is formed; the method greatly reduces the use amount of chemical fertilizers and other additives, realizes a good ecological restoration effect on degraded grassland, and is especially suitable for areas with large altitude fluctuation.

Description

Technical Field

[0001] The present invention relates to the technical field of grassland ecological restoration, and specifically relates to a method for restoring degraded grassland ecology. Background Art

[0002] Grasslands are the largest terrestrial ecosystems in terms of area, with important production, living, and ecological functions, and are of great significance to global food security and ecological security. However, due to global change and human activities, grassland ecosystems have degraded to varying degrees. The restoration of degraded grasslands and the stability of the structure and function of grasslands after restoration have become hot issues of common concern globally.

[0003] There are many factors causing grassland degradation, such as long-term grazing, plant invasion, mineral development, oilfield exploitation, urban expansion, extreme precipitation, frequent droughts, etc. Grassland restoration is not a simple reverse process of grassland degradation, but a process of restoring the ecological functions and productivity of degraded grassland ecosystems to their original healthy levels through a series of grassland restoration measures based on basic ecological concepts and principles. Grassland restoration technologies can generally be classified into restoration technologies relying on natural forces, artificial-assisted restoration technologies, and artificial grassland establishment technologies.

[0004] Currently, most restoration methods for degraded grasslands adopt a comprehensive restoration with multiple methods coexisting. For example, the invention patent with the publication number CN118716131A discloses a method for restoring degraded grasslands by regulating oxygen and nutrients in the field of degraded grassland governance, including the following steps: Step 1, sample collection: According to the relevant grading standards for grassland degradation, randomly select 3 sampling areas from each degraded area, set 5 quadrats in each sampling area, with a quadrat spacing of 50 m and a quadrat size of 1 m × 1 m; Step 2, data measurement: Measure the aboveground vegetation biomass AGB, coverage Coverage, and height indicators of 4 degraded plots respectively, and calculate the community diversity characteristics; Step 3, index analysis: Analyze and compare the plant diversity, soil nutrients, and microbial biomass of grasslands with different degradation degrees through the above indicators; Step 4, regulation implementation: Take different measures for grasslands with different degradation degrees. This invention analyzes and compares the plant diversity, soil nutrients, and microbial biomass of grasslands with different degradation degrees, and takes different measures for different degradation situations, thereby achieving good governance effects.

[0005] However, in this method and other existing methods, little consideration is given to the factor of grassland elevation. However, the accumulation of rainwater is greatly affected by elevation. Under this background, the restoration effects of such restoration methods also fluctuate greatly. Summary of the Invention

[0006] In view of the above existing problems, the present invention provides a method for restoring degraded grassland ecology.

[0007] The technical solution of the present invention is as follows:

[0008] A method for ecological restoration of degraded grasslands, comprising the following steps:

[0009] S1. Degradation assessment: Assess the degradation degree of the grassland to be restored, and divide it into mild, moderate and severe;

[0010] S2. First division of the restoration area: Measure the altitude of the grassland to be restored, draw a contour map of the grassland to be restored, the area enclosed by the contour lines is the contour area, and count the above-ground biomass of the grassland to be restored. Plots with above-ground biomass > 1800 kg / ha are divided into healthy grasslands, and according to the degradation degree, determine the first inner restoration boundary. The first inner restoration boundary is a contour line where the area of the healthy grassland accounts for 75 - 85% of the total area of the contour area. Find the midpoints of the connections between the points on the first inner restoration boundary and the edges of the corresponding grassland to be restored, and connect the midpoints as the first outer restoration boundary;

[0011] S3. Preliminary restoration: Excavate drainage ditches on the first inner restoration boundary, install ecological fences inside the drainage ditches, apply nutrient solutions through the ecological fences, plant water-proof plants between the first outer restoration boundary and the first inner restoration boundary, and apply restoration agents between the first outer restoration boundary and the edge of the grassland to be restored;

[0012] S4. Second division of the restoration area: 3 - 6 months after the end of the preliminary restoration, divide plots with above-ground biomass > 2000 kg / ha into healthy grasslands, and according to the degradation degree, determine the second inner restoration boundary. The second inner restoration boundary is a contour line where the area of the healthy grassland accounts for 80 - 90% of the total area of the contour area. Find the midpoints of the connections between the points on the second inner restoration boundary and the edges of the corresponding grassland to be restored, and connect the midpoints as the second outer restoration boundary;

[0013] S5. Deep restoration: Excavate drainage ditches on the second inner restoration boundary, install ecological fences inside the drainage ditches, apply nutrient solutions through the ecological fences, plant water-proof plants between the second outer restoration boundary and the second inner restoration boundary, and apply compound fertilizers between the first outer restoration boundary and the edge of the grassland to be restored;

[0014] S6. Regular seeding: Sow seeds into the grassland to be restored 3 - 6 months after the end of the deep restoration.

[0015] Further, in S1, the degradation degree of the grassland to be restored is divided according to the coverage. When the coverage > 60%, the degradation degree of the grassland to be restored is mild. When 30% ≤ coverage ≤ 60%, the degradation degree of the grassland to be restored is moderate. When the coverage < 30%, the degradation degree of the grassland to be restored is severe.

[0016] Note: By introducing the coverage as a criterion for evaluating the degree of grassland degradation, it has a certain theoretical basis and provides guidance for subsequent specific restoration measures.

[0017] Furthermore, in S2, when the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 75 - 80% of the total area of the contour line region is used as the first inner restoration boundary; when the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 77 - 83% of the total area of the contour line region is used as the first inner restoration boundary; when the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 80 - 85% of the total area of the contour line region is used as the first inner restoration boundary.

[0018] Note: By selecting different methods for dividing the first inner restoration boundary according to different degradation degrees, the method for dividing the first inner restoration boundary becomes more scientific and reasonable.

[0019] Furthermore, in S4, when the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 80 - 85% of the total area of the contour line region is used as the second inner restoration boundary; when the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 83 - 86% of the total area of the contour line region is used as the second inner restoration boundary; when the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 85 - 90% of the total area of the contour line region is used as the second inner restoration boundary.

[0020] Note: By selecting different methods for dividing the second inner restoration boundary according to different degradation degrees, the method for dividing the second inner restoration boundary becomes more scientific and reasonable.

[0021] Furthermore, in S3 and S5, the components and mass fractions of the nutrient solution are: humic acid 3 - 4%, slow - release urea 0.5 - 1%, superphosphate 0.4 - 0.8%, and the balance is water. The water - isolating plants are one or more of vetiver, bahiagrass, and bermudagrass. The components and mass fractions of the repair agent in S3 are: quicklime 50 - 55%, straw biochar 15 - 20%, magnesium sulfate 3 - 5%, and the balance is slaked lime. Adjust the amount of the repair agent applied to ensure that the pH of the soil after restoration is 6.5 - 7. The components and mass fractions of the compound fertilizer in S5 are: microbial inoculant 3 - 5%, decomposed livestock manure 40 - 50%, straw biochar 15 - 20%, and the balance is urea. Among them, the microbial inoculant is one or more of rhizobia, azospirillum, bacillus megaterium, pseudomonas, and bacillus subtilis. The application amount of the compound fertilizer is 300 - 500 kg / ha, and the mixing depth during application is 10 - 15 cm.

[0022] Description: By means of the application method of the nutrient solution and the additive of the repair agent, the healthy-growing grassland can be maintained, and at the same time, the improved repair agent and compound fertilizer applied successively can promote the accelerated restoration of the severely degraded grassland.

[0023] Preferably, when the degradation degree of the grassland to be repaired is mild, the planting density of the water-blocking plants in S3 is 3 - 5 plants / m 3 , and the planting density of the water-blocking plants in S5 is 2 - 4 plants / m 3 , when the degradation degree of the grassland to be repaired is moderate, the planting density of the water-blocking plants in S3 is 3 - 8 plants / m 3 , and the planting density of the water-blocking plants in S5 is 3 - 5 plants / m 3 , when the degradation degree of the grassland to be repaired is severe, the planting density of the water-blocking plants in S3 is 5 - 10 plants / m 3 , and the planting density of the water-blocking plants in S5 is 4 - 8 plants / m 3 .

[0024] Description: Optimally adjust the planting density of the water-blocking plants according to different degradation degrees to ensure the water-blocking effect.

[0025] Furthermore, the width of the drainage ditch is 10 - 30 cm. The ecological fence includes hollow columns on both sides and several connecting rods between the two hollow columns. One connecting rod at the bottom is internally connected to the two hollow columns at both ends, and several openings are provided at the bottom of this connecting rod. The bottom of the hollow column is conical and provided with openings. Each ecological fence is connected by several steel wires. The length of the ecological fence is 80 - 120 cm, and the interval between adjacent ecological fences is 3 - 5 m.

[0026] Description: The specially made ecological fence can promote the application and discharge of the nutrient solution.

[0027] Even further, in S6, when sowing, the grassland to be repaired is equally spaced into several block units. Each block unit is separated by the ecological fence and the steel wire. One of the block units is selected as the grazing area for grazing in turn, and the grazing time is 1 - 2 months. Sowing starts in the block unit after grazing ends. The grazing and sowing directions are carried out sequentially from one side to the other side of the grassland to be repaired.

[0028] Description: By further optimizing the timing of sowing and grazing, the cyclic dynamic restoration of the grassland can be ensured, and at the same time, the ecological fence can be reused multiple times in different scenarios.

[0029] Furthermore, in S6, the sowing method is drone sowing, and the sowing density is 10 - 20 g / m 3, the crop species is one or more of Kobresia, Festucaovina, Hordeum brevisubulatum, Iris bulleyana, Bergenia purpurascens, Trikeraia hookeri, Imperata cylindrica, Zoysia japonica, Carex cinerascens, Lolium perenne, Artemisia annua.

[0030] Note: When specifically selecting the crops to be sown, they can be reasonably selected according to the local climate conditions and suitable crops.

[0031] The beneficial effects of the present invention are:

[0032] A method for ecological restoration of degraded grasslands according to the present invention takes the selection and division of contour lines as reference conditions, forming a set of scientific and reasonable comprehensive restoration plans. An ecological fence is arranged along the contour line as the restoration boundary, which can not only improve the utilization of water resources, but also strengthen the maintenance of the healthy grasslands inside. By intercepting precipitation runoff in space and prolonging water infiltration in time, the grassland restoration efficiency is significantly improved, the internal and external connection and transition of the degraded zone are strengthened, and the degradation is prevented. At the same time, as the restoration progresses, the restoration boundary is adjusted. After adjustment, targeted in-depth restoration is carried out on the basis of preliminary restoration. The two restoration processes promote each other, and finally a dynamically restored ecosystem is formed, greatly reducing the dosage of fertilizers and other additives, achieving a good ecological restoration effect for degraded grasslands, and is especially suitable for areas with large altitude fluctuations. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the healthy grassland after the first division of the S2 restoration area in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0034] Figure 2 It is a schematic diagram of the contour line position after the first division of the S2 restoration area in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0035] Figure 3 It is a schematic diagram of the restoration boundary after the first division of the S2 restoration area in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0036] Figure 4 It is a schematic diagram of the healthy grassland after the preliminary restoration of S3 in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0037] Figure 5 It is a schematic diagram of the contour line position after the second division of the S4 restoration area in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0038] Figure 6 It is a schematic diagram of the restoration boundary after the second division of the S4 restoration area in the experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0039] Figure 7It is a schematic diagram of the block unit and the grazing area during the regular seeding in S6 of an experimental example of a method for ecological restoration of degraded grasslands according to the present invention;

[0040] Figure 8 It is a schematic diagram of the ecological fence structure in a method for ecological restoration of degraded grasslands according to the present invention. Detailed implementation manners

[0041] Example 1

[0042] A method for ecological restoration of degraded grasslands includes the following steps:

[0043] S1. Degradation assessment: Assess the degradation degree of the grassland to be restored, and classify it into mild, moderate and severe;

[0044] The degradation degree of the grassland to be restored is classified according to the coverage. When the coverage > 60%, the degradation degree of the grassland to be restored is mild. When 30% ≤ coverage ≤ 60%, the degradation degree of the grassland to be restored is moderate. When the coverage < 30%, the degradation degree of the grassland to be restored is severe;

[0045] S2. First division of the restoration area: Measure the altitude of the grassland to be restored, draw a contour map of the grassland to be restored. The area enclosed by the contour lines is the contour area, and count the above-ground biomass of the grassland to be restored. Divide the plots with above-ground biomass > 1800 kg / ha into healthy grasslands, and determine the first internal restoration boundary according to the degradation degree. The first internal restoration boundary is a contour line where the area of the healthy grassland accounts for 77 - 83% of the total area of the contour area. Find the midpoints of the connections between the points on the first internal restoration boundary and the edges of the corresponding grassland to be restored, and use the connection of each midpoint as the first external restoration boundary;

[0046] When the degradation degree of the grassland to be restored is mild, a contour line where the area of the healthy grassland accounts for 77% of the total area of the contour area is used as the first internal restoration boundary. When the degradation degree of the grassland to be restored is moderate, a contour line where the area of the healthy grassland accounts for 80% of the total area of the contour area is used as the first internal restoration boundary. When the degradation degree of the grassland to be restored is severe, a contour line where the area of the healthy grassland accounts for 83% of the total area of the contour area is used as the first internal restoration boundary;

[0047] S3. Preliminary restoration: Dig drainage ditches on the first internal restoration boundary, and install ecological fences inside the drainage ditches. Apply nutrient solution through the ecological fences, plant water-blocking plants between the first external restoration boundary and the first internal restoration boundary, and apply a repair agent between the first external restoration boundary and the edge of the grassland to be restored;

[0048] The components and mass fractions of the nutrient solution are as follows: humic acid 3.5%, slow-release urea 0.7%, superphosphate 0.65%, and the balance is water. The water-insulating plants are bahiagrass and bermudagrass. The components and mass fractions of the repair agent are as follows: quicklime 52%, straw biochar 18%, magnesium sulfate 4%, and the balance is slaked lime. Adjust the amount of the repair agent applied to ensure that the pH of the soil after repair is 6.8;

[0049] When the degradation degree of the grassland to be repaired is mild, the planting density of the water-insulating plants is 4 plants / m 3 , when the degradation degree of the grassland to be repaired is moderate, the planting density of the water-insulating plants is 5 plants / m 3 , when the degradation degree of the grassland to be repaired is severe, the planting density of the water-insulating plants is 8 plants / m 3 ;

[0050] The width of the drainage ditch is 20 cm. The ecological fence includes hollow columns on both sides and several connecting rods between the two hollow columns. One connecting rod at the bottom is internally connected to the two hollow columns at both ends. There are several openings at the bottom of this connecting rod. The bottom of the hollow column is tapered and provided with openings. Each ecological fence is connected by several steel wires. The length of the ecological fence is 100 cm, and the interval between two adjacent ecological fences is 4 m;

[0051] S4. Secondary division of the repair area: Four months after the initial repair is completed, divide the plots with above-ground biomass > 2000 kg / ha into healthy grasslands, and determine the secondary internal repair boundary according to the degradation degree. The secondary internal repair boundary is a contour line where the area of the healthy grassland accounts for 83 - 88% of the total area of the contour line area. Find the midpoints of the connections between the points on the secondary internal repair boundary and the edges of the corresponding grassland to be repaired, and use the connections of each midpoint as the secondary external repair boundary;

[0052] When the degradation degree of the grassland to be repaired is mild, a contour line where the area of the healthy grassland accounts for 83% of the total area of the contour line area is used as the secondary internal repair boundary. When the degradation degree of the grassland to be repaired is moderate, a contour line where the area of the healthy grassland accounts for 85% of the total area of the contour line area is used as the secondary internal repair boundary. When the degradation degree of the grassland to be repaired is severe, a contour line where the area of the healthy grassland accounts for 88% of the total area of the contour line area is used as the secondary internal repair boundary;

[0053] S5. Deep repair: Excavate a drainage ditch on the secondary internal repair boundary, erect an ecological fence inside the drainage ditch, apply the nutrient solution through the ecological fence, plant water-insulating plants between the secondary external repair boundary and the secondary internal repair boundary, and apply compound fertilizer between the primary external repair boundary and the edge of the grassland to be repaired;

[0054] The components and mass fractions of the nutrient solution are as follows: humic acid 3.3%, slow-release urea 0.76%, superphosphate 0.66%, and the balance is water. The water-insulating plants are bahiagrass and bermudagrass. The components and mass fractions of the compound fertilizer are as follows: microbial inoculant 4%, decomposed livestock manure 46%, straw biochar 17%, and the balance is urea. Among them, the microbial inoculant is a mixture of Azospirillum, Bacillus megaterium, and Pseudomonas in equal mass. The application rate of the compound fertilizer is 400 kg / ha, and the mixing depth during application is 12 cm;

[0055] When the degradation degree of the grassland to be restored is mild, the planting density of the water-insulating plants is 3 plants / m 3 , when the degradation degree of the grassland to be restored is moderate, the planting density of the water-insulating plants is 4 plants / m 3 , when the degradation degree of the grassland to be restored is severe, the planting density of the water-insulating plants is 6 plants / m 3 ;

[0056] S6. Regular sowing: Four months after the end of the in-depth restoration, sow into the grassland to be restored. When sowing, divide the grassland to be restored into 7 block units at equal intervals. Each block unit is separated by an ecological fence and a steel wire rope. Select one of each block unit as a grazing area and graze in turn. The grazing time is 1.5 months. Sowing starts in the block unit after grazing ends. The grazing and sowing directions are carried out sequentially from one side to the other side of the grassland to be restored. The sowing method is drone sowing, and the sowing density is 15 g / m 3 , and the crop varieties are Bergenia purpurascens, Trikeraia hookeri, Imperata cylindrica, and Zoysia japonica.

[0057] Example 2

[0058] The difference between this example and Example 1 is as follows:

[0059] S2. First division of the restoration area: According to the degradation degree, determine the first internal restoration boundary, which is a contour line where the healthy grassland area accounts for 80 - 85% of the total area of the contour line area;

[0060] When the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 80% of the total area of the contour line area is used as the first internal restoration boundary. When the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 83% of the total area of the contour line area is used as the first internal restoration boundary. When the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 85% of the total area of the contour line area is used as the first internal restoration boundary.

[0061] Example 3

[0062] The difference between this example and Example 1 is as follows:

[0063] S2. Primary division of the restoration area: Determine the primary restoration boundary according to the degradation degree. The primary restoration boundary is a contour line where the healthy grassland area accounts for 75-80% of the total area of the contour line area.

[0064] When the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 75% of the total area of the contour line area is used as the primary restoration boundary. When the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 77% of the total area of the contour line area is used as the primary restoration boundary. When the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 80% of the total area of the contour line area is used as the primary restoration boundary.

[0065] Example 4

[0066] The difference between this example and Example 1 is as follows:

[0067] S3. Preliminary restoration: The composition and mass fraction of the nutrient solution are as follows: humic acid 3%, slow-release urea 0.5%, superphosphate 0.4%, and the balance is water. The water-insulating plant is vetiver. The composition and mass fraction of the repair agent are as follows: quicklime 50%, straw biochar 15%, magnesium sulfate 3%, and the balance is slaked lime. Adjust the amount of the repair agent applied to ensure that the pH of the soil after restoration is 6.5.

[0068] Example 5

[0069] The difference between this example and Example 1 is as follows:

[0070] S3. Preliminary restoration: The composition and mass fraction of the nutrient solution are as follows: humic acid 4%, slow-release urea 1%, superphosphate 0.8%, and the balance is water. The water-insulating plant is bermudagrass. The composition and mass fraction of the repair agent are as follows: quicklime 55%, straw biochar 20%, magnesium sulfate 5%, and the balance is slaked lime. Adjust the amount of the repair agent applied to ensure that the pH of the soil after restoration is 7.

[0071] Example 6

[0072] The difference between this example and Example 1 is as follows:

[0073] S3. Preliminary restoration: When the degradation degree of the grassland to be restored is mild, the planting density of the water-insulating plant is 3 plants / m 3 , when the degradation degree of the grassland to be restored is moderate, the planting density of the water-insulating plant is 3 plants / m 3 , when the degradation degree of the grassland to be restored is severe, the planting density of the water-insulating plant is 5 plants / m 3 .

[0074] Example 7

[0075] The difference between this example and Example 1 is as follows:

[0076] S3. Preliminary repair: When the degradation degree of the grassland to be repaired is mild, the planting density of the water-blocking plants is 5 plants / m 3 , when the degradation degree of the grassland to be repaired is moderate, the planting density of the water-blocking plants is 8 plants / m 3 , when the degradation degree of the grassland to be repaired is severe, the planting density of the water-blocking plants is 10 plants / m 3 .

[0077] Note: The planting density of the water-blocking plants is reasonably adjusted according to the degradation degree of the degraded grassland and the local precipitation. When the degradation is severe, the density is appropriately increased, and when the precipitation is less, the density is appropriately decreased.

[0078] Example 8

[0079] The difference between this example and Example 1 is that:

[0080] The width of the drainage ditch is 10 cm. The ecological fence includes hollow columns on both sides and several connecting rods between the two hollow columns. One connecting rod at the bottom is internally connected to the two hollow columns at both ends. There are several openings at the bottom of this connecting rod. The bottom of the hollow column is conical and provided with openings. Each ecological fence is connected by several steel wires. The length of the ecological fence is 80 cm, and the interval between two adjacent ecological fences is 3 m.

[0081] Example 9

[0082] The difference between this example and Example 1 is that:

[0083] The width of the drainage ditch is 30 cm. The ecological fence includes hollow columns on both sides and several connecting rods between the two hollow columns. One connecting rod at the bottom is internally connected to the two hollow columns at both ends. There are several openings at the bottom of this connecting rod. The bottom of the hollow column is conical and provided with openings. Each ecological fence is connected by several steel wires. The length of the ecological fence is 120 cm, and the interval between two adjacent ecological fences is 5 m.

[0084] Note: When the area of the grassland to be repaired is large, longer ecological fences and larger intervals between ecological fences can be selected.

[0085] Example 10

[0086] The difference between this example and Example 1 is that:

[0087] S4. Secondary division of the repair area: Three months after the preliminary repair is completed, according to the degradation degree, determine the secondary internal repair boundary, which is a contour line where the healthy grassland area accounts for 80-95% of the total area of the contour line area;

[0088] When the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 80% of the total area of the contour line region is used as the secondary inner restoration boundary. When the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 83% of the total area of the contour line region is used as the secondary inner restoration boundary. When the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 85% of the total area of the contour line region is used as the secondary inner restoration boundary.

[0089] Example 11

[0090] The difference between this example and Example 1 is as follows:

[0091] S4. Secondary division of the restoration area: Six months after the preliminary restoration is completed, according to the degradation degree, the secondary inner restoration boundary is determined. The secondary inner restoration boundary is a contour line where the healthy grassland area accounts for 85 - 90% of the total area of the contour line region.

[0092] When the degradation degree of the grassland to be restored is mild, a contour line where the healthy grassland area accounts for 85% of the total area of the contour line region is used as the secondary inner restoration boundary. When the degradation degree of the grassland to be restored is moderate, a contour line where the healthy grassland area accounts for 86% of the total area of the contour line region is used as the secondary inner restoration boundary. When the degradation degree of the grassland to be restored is severe, a contour line where the healthy grassland area accounts for 90% of the total area of the contour line region is used as the secondary inner restoration boundary.

[0093] Example 12

[0094] The difference between this example and Example 1 is as follows:

[0095] S5. Deep restoration: The components and mass fractions of the nutrient solution are as follows: humic acid 3%, slow-release urea 0.5%, superphosphate 0.4%, and the balance is water. The water-insoluble plants are one or more of vetiver grass, bahiagrass, and bermudagrass. The components and mass fractions of the compound fertilizer are as follows: microbial inoculant 3%, well-rotted livestock manure 40%, straw biochar 15%, and the balance is urea. Among them, the microbial inoculant is rhizobium. The application rate of the compound fertilizer is 300 kg / ha, and the mixing depth during application is 10 cm.

[0096] Example 13

[0097] The difference between this example and Example 1 is as follows:

[0098] S5. Deep restoration: The components and mass fractions of the nutrient solution are as follows: humic acid 4%, slow-release urea 1%, superphosphate 0.8%, and the balance is water. The water-blocking plants are one or more of vetiver, bahiagrass, and bermudagrass. The components and mass fractions of the compound fertilizer are as follows: microbial inoculant 5%, decomposed livestock manure 50%, straw biochar 20%, and the balance is urea. Among them, the microbial inoculant is Bacillus subtilis. The application rate of the compound fertilizer is 500 kg / ha, and the mixing depth during application is 15 cm.

[0099] Note: The application rate of the compound fertilizer is reasonably adjusted according to the degradation degree of the degraded grassland. When the degradation is severe, the application rate is increased, and at the same time, the mixing depth is appropriately increased.

[0100] Example 14

[0101] The difference between this example and Example 1 is as follows:

[0102] S5. Deep restoration: When the degradation degree of the grassland to be restored is mild, the planting density of the water-blocking plants is 2 plants / m 3 , when the degradation degree of the grassland to be restored is moderate, the planting density of the water-blocking plants is 3 plants / m 3 , when the degradation degree of the grassland to be restored is severe, the planting density of the water-blocking plants is 4 plants / m 3 .

[0103] Example 15

[0104] The difference between this example and Example 1 is as follows:

[0105] S5. Deep restoration: When the degradation degree of the grassland to be restored is mild, the planting density of the water-blocking plants is 4 plants / m 3 , when the degradation degree of the grassland to be restored is moderate, the planting density of the water-blocking plants is 5 plants / m 3 , when the degradation degree of the grassland to be restored is severe, the planting density of the water-blocking plants is 8 plants / m 3 .

[0106] Example 16

[0107] The difference between this example and Example 1 is as follows:

[0108] S6. Regular seeding: Three months after the end of the deep restoration, seeds are sown into the grassland to be restored. When sowing, the grassland to be restored is equally divided into 4 block units at equal intervals. Each block unit is separated by an ecological fence and a steel wire rope. One of the block units is selected as the grazing area for grazing in turn. The grazing time is 2 months. Sowing starts in the block unit after grazing ends. The grazing and sowing directions are carried out sequentially from one side to the other side of the grassland to be restored. The sowing method is drone seeding, and the sowing density is 10 g / m 3, the crop species are Kobresia, Festucaovina, Hordeum bogdanii, and Iris bulleyana.

[0109] Example 17

[0110] The difference between this example and Example 1 is as follows:

[0111] S6. Regular seeding: Six months after the end of in-depth restoration, seeds are sown in the grassland to be restored. When sowing, the grassland to be restored is evenly divided into 12 block units at equal intervals. Each block unit is separated by an ecological fence and a steel wire rope. One of the block units is selected as the grazing area for grazing in turn. The grazing time is 1 month. Sowing starts in the block unit after grazing. The grazing and sowing directions are carried out sequentially from one side to the other side of the grassland to be restored. The sowing method is drone seeding, and the seeding density is 20 g / m 3 , and the crop species are Carex cinerascens, Lolium perenne, and Artemisia annua.

[0112] Note: When the area of the grassland to be restored is large, more block units can be divided.

[0113] Experimental example

[0114] According to the method in Example 1, we carried out on-site restoration of a degraded grassland in a certain mountainous area in the southwest. As Figures 1 to 7 shown, the altitude of this area is 500 - 600 m, the mountain is relatively low, the terrain is gradually gentle, it belongs to the subtropical region, and the complex geographical conditions have formed various types of grassland vegetation and forage resources.

[0115] First, the degradation assessment is carried out according to the method in S1. The coverage of the grassland to be restored is 46%, and the degradation degree is moderate. Therefore, in the subsequent restoration process, the restoration parameters for the severe degradation degree given in Example 1 are used for restoration;

[0116] Subsequently, the schematic diagram after the first division of the restoration area according to S2 is as Figure 2 and Figure 3 shown. According to the indication of the contour line, the inner restoration boundary and the outer restoration boundary for the first time are obtained. After restoration according to the parameters of S3 for preliminary restoration, the grassland condition obtained is as Figure 4 shown. It can be seen that the healthy grassland has increased significantly at this time. Moreover, the evaluation standard for the healthy grassland at this time (aboveground biomass > 2000 kg / ha) has increased compared with that in S2 (aboveground biomass > 1800 kg / ha). That is to say, the grassland degradation has been controlled and begins to recover, and the coverage rate has reached 59%;

[0117] Subsequently, restoration is carried out again according to the method of S5 for in-depth restoration, as Figure 5 and Figure 6As shown, at this time, we will add compound fertilizer outside the corrected outer restoration boundary to replace the restoration agent. Because in the preliminary restoration, the restoration agent mainly plays the role of adjusting the soil pH and eliminating pests and diseases at the same time. While in the deep restoration, preparations for vegetation restoration are started. Therefore, by applying the two additives before and after, a more scientific and reasonable soil regulation effect can be achieved, and the regulation position is allocated according to the restored situation, which can greatly reduce the dosage of the two regulators. Cooperating with storing water in the drainage ditches and adding nutrient solution can ensure the maintenance of healthy grassland. The addition amount of the nutrient solution is 0.2 - 0.3 L / m for the inner restoration boundary, and the addition frequency is once a week;

[0118] Finally, at the beginning of the regular sowing in S6, that is, 4 months after the end of the deep restoration, the grassland coverage rate in this area has reached 86%. According to the evaluation criteria of healthy grassland in S4, the healthy grassland area has reached 81%, and moderate grazing can be carried out. Therefore, we carry out intermittent grazing according to the steps in S6, as Figure 7 shown. By this way, it can not only ensure the continuous restoration of the grassland, but also generate certain economic value, and finally realize the dynamic ecological restoration of the degraded grassland.

Claims

1. A method for ecological restoration of degraded grassland, characterized in that: The following steps are involved: S1. Degradation assessment: assess the degree of degradation of the grassland to be restored, which is divided into mild, moderate and severe; S2. Primary division of the restoration area: measure the altitude of the grassland to be restored, draw a contour diagram of the grassland to be restored, and the area surrounded by the contour lines is the contour area. Count the aboveground biomass of the grassland to be restored, and divide the plots with aboveground biomass>1800kg / ha into healthy grasslands. According to the degree of degradation, determine the primary internal restoration boundary, which is a contour line where the area of ​​healthy grassland accounts for 75-85% of the total area of ​​the contour area. Find the midpoint of the line connecting the point on the primary internal restoration boundary and the edge of the corresponding grassland to be restored, and use the line connecting each midpoint as the primary external restoration boundary; S3, preliminary restoration: digging a water diversion ditch on the first inner restoration boundary, erecting an ecological fence inside the water diversion ditch, applying nutrient solution through the ecological fence, planting water-isolating plants between the first outer restoration boundary and the first inner restoration boundary, and applying a restoration agent between the first outer restoration boundary and the edge of the grassland to be restored; S4. Secondary division of the restoration area: 3 to 6 months after the completion of the initial restoration, the plots with aboveground biomass > 2000 kg / ha are divided into healthy grasslands, and the secondary internal restoration boundary is determined according to the degree of degradation. The secondary internal restoration boundary is a contour line where the area of ​​healthy grassland accounts for 80 to 90% of the total area of ​​the contour line area. The midpoints of the lines connecting the points on the secondary internal restoration boundary and the edges of the corresponding grassland to be restored are found, and the line connecting the midpoints is used as the secondary external restoration boundary; S5, deep restoration: digging a water diversion ditch on the secondary inner restoration boundary, and setting up an ecological fence inside the water diversion ditch, applying nutrient solution through the ecological fence, planting water-isolating plants between the secondary outer restoration boundary and the secondary inner restoration boundary, and applying compound fertilizer between the primary outer restoration boundary and the edge of the grassland to be restored; S6. Regular sowing: Sow seeds in the grassland to be repaired 3 to 6 months after the deep restoration is completed.

2. A method for ecological restoration of degraded grassland according to claim 1, characterized in that: In S1, the degree of degradation of the grassland to be restored is divided according to the coverage. When the coverage is greater than 60%, the degree of degradation of the grassland to be restored is mild. When 30%≤coverage≤60%, the degree of degradation of the grassland to be restored is moderate. When the coverage is less than 30%, the degree of degradation of the grassland to be restored is severe.

3. A method for ecological restoration of degraded grassland according to claim 2, characterized in that: In S2, when the degree of degradation of the grassland to be restored is light, a contour line in which the area of ​​healthy grassland accounts for 75% to 80% of the total area of ​​the contour line area is used as an internal restoration boundary. When the degree of degradation of the grassland to be restored is moderate, a contour line in which the area of ​​healthy grassland accounts for 77% to 83% of the total area of ​​the contour line area is used as an internal restoration boundary. When the degree of degradation of the grassland to be restored is severe, a contour line in which the area of ​​healthy grassland accounts for 80% to 85% of the total area of ​​the contour line area is used as an internal restoration boundary.

4. A method for ecological restoration of degraded grassland according to claim 2, characterized in that: In S4, when the degree of degradation of the grassland to be restored is mild, a contour line in which the area of ​​healthy grassland accounts for 80% to 85% of the total area of ​​the contour line area is used as the secondary internal restoration boundary. When the degree of degradation of the grassland to be restored is moderate, a contour line in which the area of ​​healthy grassland accounts for 83% to 86% of the total area of ​​the contour line area is used as the secondary internal restoration boundary. When the degree of degradation of the grassland to be restored is severe, a contour line in which the area of ​​healthy grassland accounts for 85% to 90% of the total area of ​​the contour line area is used as the secondary internal restoration boundary.

5. A method for ecological restoration of degraded grassland according to claim 2, characterized in that: In S3 and S5, the composition and mass fraction of the nutrient solution are: 3-4% humic acid, 0.5-1% slow-release urea, 0.4-0.8% superphosphate, and the balance is water. The water-proof plants are one or more of vetiver, bahia grass, and bermudagrass. The composition and mass fraction of the repair agent in S3 are: 50-55% quicklime, 15-20% straw biochar, 3-5% magnesium sulfate, and the balance is slaked lime. The amount of the repair agent applied is adjusted to ensure that the soil after repair The pH value is 6.5-7. The components and mass fractions of the compound fertilizer in S5 are: 3-5% microbial agent, 40-50% decomposed livestock manure, 15-20% straw biochar, and the balance is urea. The microbial agent is one or more of Rhizobium, Azospirillum, Bacillus megaterium, Pseudomonas, and Bacillus subtilis. The application amount of the compound fertilizer is 300-500 kg / ha, and the stirring depth during application is 10-15 cm.

6. A method for ecological restoration of degraded grassland according to claim 5, characterized in that: When the degradation degree of the grassland to be restored is mild, the planting density of water-retaining plants in S3 is 3 to 5 plants / m 3 The planting density of water-insulating plants in S5 is 2 to 4 plants / m 3 When the degradation degree of the grassland to be restored is moderate, the planting density of water-isolating plants in S3 is 3 to 8 plants / m 3 The planting density of water-insulating plants in S5 is 3 to 5 plants / m 3 When the degradation degree of the grassland to be restored is severe, the planting density of water-retaining plants in S3 is 5 to 10 plants / m 3 The planting density of water-insulating plants in S5 is 4 to 8 plants / m 3 .

7. The method for ecological restoration of degraded grassland according to claim 1, characterized in that: The width of the water diversion ditch is 10 to 30 cm. The ecological fence includes hollow columns on both sides and a plurality of connecting rods between the two hollow columns. The two ends of the connecting rod at the bottom are connected to the interior of the two hollow columns. A plurality of openings are provided at the bottom of the connecting rod. The bottom of the hollow column is conical and has openings. The ecological fences are connected by a plurality of steel ropes. The length of the ecological fence is 80 to 120 cm, and the interval between two adjacent ecological fences is 3 to 5 m.

8. A method for ecological restoration of degraded grassland according to claim 7, characterized in that: In S6, the grassland to be restored is divided into a number of block units at equal intervals during sowing. Each block unit is separated by the ecological fence and the wire rope. One block unit is selected as a grazing area for grazing in turn. The grazing time is 1 to 2 months. After the grazing is completed, sowing begins in the block unit. The grazing and sowing direction is from one side of the grassland to be restored to the other side in sequence.

9. The method for ecological restoration of degraded grassland according to claim 1, characterized in that: In the above S6, the sowing method is drone sowing, and the sowing density is 10-20g / m 3 The crop types are one or more of Kobresia sinensis, Fescue, Barley grass, Iris suspensa, Bergenia rapa, Triptera officinalis, Imperata cylindrica, Zoysia japonica, Carex ash, Ryegrass, and Artemisia annua.

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