A comprehensive evaluation method for ecological restoration grasses on grasslands

Abstract

The application discloses a kind of prairie ecological restoration grass comprehensive evaluation method, it is related to ecological restoration assessment technical field, the present application includes the following steps: obtaining the flora characteristics and distribution characteristics of grassland plant, selecting ecological restoration grass;Set the basic conditions of ecological restoration grass: first, no public nuisance, no pollution, no security risk species, then avoid selecting invasive species, finally, strong self-reproduction ability and strong soil and water conservation ability species;Set the optimization condition and specific index of ecological restoration grass, the optimization condition includes: environmental adaptability, soil and water conservation capacity, reproductive capacity;Specific index includes: cold resistance, drought resistance, salt tolerance, wide distribution, green period, green period, root biomass, aboveground biomass, crown width, growth rate, branch growth type, tillering / branching number, seed thousand-grain weight, seed germination force;Build comprehensive evaluation model;Calculate the total score of target layer, and comprehensively evaluate ecological restoration grass.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ecological restoration evaluation, in particular to a comprehensive evaluation method for ecological restoration grass on grassland. BACKGROUND

[0002] Grassland is an important national strategic resource, improving grassland vegetation coverage and enhancing the carbon sink function of grassland vegetation is an important measure for the country, and is also an important measure for the country to protect biodiversity, prevent desertification and respond to climate warming.

[0003] Since the establishment of the State Forestry and Grassland Administration, the promotion of grassland ecological services has been highly valued by the state, and grassland ecological restoration has become one of the important tasks of governments and forestry and grassland departments at all levels, therefore, high-quality grass variety breeding, local grass excavation and application, and grassland ecological protection have entered a rapid development stage.

[0004] Due to the particularity of climate, soil and terrain, introduced grasses from other places have poor adaptability, and it is difficult to form a stable community, therefore, Liaoning Province needs grasses with local characteristics and suitable for regional planting. SUMMARY

[0005] The present application provides a comprehensive evaluation method for ecological restoration grass on grassland according to the climate conditions, the particularity of the terrain, and the problems in the background art, comprising the following steps:

[0006] Obtain the flora characteristics and distribution characteristics of the grassland plants, and select ecological restoration grass according to the flora characteristics and distribution characteristics.

[0007] Set the basic conditions for ecological restoration grass, and select ecological restoration grass according to the basic conditions, the basic conditions including: first, a species without public hazards, pollution and safety hazards, then avoiding the use of invasive species, and finally a species with strong self-reproduction ability and strong soil and water conservation ability.

[0008] Set the preferred conditions and specific indicators for ecological restoration grass, the preferred conditions including: environmental adaptability, soil and water conservation ability, and reproduction ability, the specific indicators including: cold resistance, drought resistance, salt and alkali tolerance, wide distribution, green period, green period, root biomass, aboveground biomass, crown width, growth rate, branch growth type, tillering / branching number, seed thousand-grain weight, and seed germination force.

[0009] Establish a comprehensive evaluation model using the analytic hierarchy process, and the hierarchical structure of the comprehensive evaluation model includes: a target layer, a constraint layer, and an index layer, wherein the target layer is a comprehensive evaluation of ecological restoration grass, the constraint layer is the preferred conditions, and the index layer is the specific indicators.

[0010] Determine the weight and score of each indicator in the indicator layer. Calculate the total score of the target layer based on the weight and score of each indicator in the indicator layer.

[0011] The selected ecological restoration grasses are comprehensively evaluated based on the total score of the target layer.

[0012] Furthermore, the acquisition of the floristic and distribution characteristics of grassland plants specifically includes:

[0013] By conducting field plot surveys, we can understand the basic characteristics, family and genus composition, main dominant species and distribution characteristics of grassland plants, and screen out widely distributed species.

[0014] To obtain the seed characteristics, propagation ability, and growth patterns of different grass species, and to collect seeds of native plants to analyze their germination characteristics and propagation ability.

[0015] Furthermore, obtaining the weight values ​​of each indicator in the indicator layer specifically includes:

[0016] The indicators at the indicator layer were scored using a questionnaire survey method.

[0017] Based on the questionnaire results, the weight values ​​of each indicator in the indicator layer were obtained.

[0018] Furthermore, before obtaining the weight values ​​and scores of each indicator in the indicator layer, it is necessary to set the measurement standards for each indicator in the indicator layer, specifically including:

[0019] The standard for measuring cold resistance is the greening rate of grassland plants, which is obtained by measuring the overwintering rate of grassland plants.

[0020] The standard for determining drought resistance is the number of drought days that grassland plant species can tolerate, and this number is obtained through pot experiments.

[0021] The standard for determining salt tolerance is the growth status of grassland plants in saline-alkali land. The growth status of grassland plants in saline-alkali land is obtained by setting up three salt-alkali gradient experiments with low, medium and high levels, and the relative biomass between the control treatments is used as the standard.

[0022] The criteria for determining the distribution of grassland plants are the habitat species and frequency of occurrence. The habitat species and frequency of occurrence of grassland plants are obtained through field surveys and experiments. The relative frequency of other species is calculated based on the maximum frequency.

[0023] The standard for determining the greening period is the time when the number of new shoots and leaves with a height of 2 cm or more reaches 50% of the total number of grassland plants after overwintering.

[0024] The standard for determining the green period is the number of days from the greening stage to the yellowing stage of grassland plants.

[0025] The standard for measuring root biomass is the weight of the entire root system after the grassland plant has matured and been completely dug up.

[0026] The standard for measuring aboveground biomass is the weight of the aboveground branches after the entire grassland plant has matured and been dug up.

[0027] The standard for measuring crown width is the crown area calculated after measuring the length and width of the crown of grassland plants.

[0028] The standard for measuring growth rate is the rate at which grassland plants grow after the grass seeds are planted.

[0029] The standard for determining branch growth type is to classify grassland plants into rhizomatous, stolon, and clump-forming types.

[0030] The standard for determining the number of tillers / branches is the number of primary tillers that sprout directly from the basal tillering nodes of the main stem of a grassland plant, or the number of branches that sprout from the main stem.

[0031] The standard for determining the weight of a thousand seeds is to thoroughly mix the seeds of grassland plants, randomly select 1000 seeds, weigh them, repeat this process three times, and record their weight.

[0032] The standard for determining seed germination capacity is the germination rate of grass seeds of grassland plants.

[0033] Furthermore, before obtaining the weight values ​​and scores of each indicator in the indicator layer, it is necessary to set the scoring criteria for each indicator in the indicator layer, specifically including:

[0034] The cold resistance rating is based on the greening rate of grassland plants, with three levels: 5, 3, and 1, from high to low.

[0035] The drought resistance scoring standard is based on the number of drought days that grassland plant species can tolerate, with scores ranging from 5 to 1.

[0036] The scoring standard for salt and alkali tolerance is based on the growth status of grassland plants in saline-alkali land, with three levels of scoring from best to worst: 5, 3, and 1.

[0037] The scoring criteria for widespread distribution are based on the frequency of grassland plants, with three levels: 5, 3, and 1, from high to low.

[0038] The scoring standard for the greening period is based on the length of the greening period of grassland plants, with three levels: 5, 3, and 1.

[0039] The scoring standard for green period is based on the green period of grassland plants, divided into three levels: 5, 3, and 1, from longest to shortest.

[0040] The scoring standard for root biomass is based on the root weight of grassland plants, with three levels: 5, 3, and 1, from largest to smallest.

[0041] The scoring standard for aboveground biomass is based on the weight of the branches of grassland plants, with three levels: 5, 3, and 1, from largest to smallest.

[0042] The scoring standard for crown width is based on the crown area of ​​grassland plants, divided into three levels: 5, 3, and 1, from largest to smallest.

[0043] The growth rate is scored according to the growth rate of grassland plants, from fastest to slowest, with three levels: 5, 3, and 1.

[0044] The scoring criteria for branch-growing types are as follows: rhizomatous plants are scored 5 points, creeping plants are scored 3 points, and clump-forming plants are scored 1 point.

[0045] The scoring criteria for the number of tillers / branches are based on the number of tillers / branches of grassland plants, with three levels of scoring: 5, 3, and 1, from most to least.

[0046] The scoring standard for the thousand-seed weight of grassland plants is based on the thousand-seed weight of grassland plants, and is divided into three levels: 5, 3, and 1, from largest to smallest.

[0047] The scoring standard for seed germination ability is based on the germination rate of grassland plants, divided into three levels: 5, 3, and 1, from high to low.

[0048] Furthermore, obtaining the weight values ​​and scores of each indicator in the indicator layer specifically includes:

[0049] The indicators of the indicator layer are measured and scored according to the measurement standard and the scoring standard.

[0050] Furthermore, the comprehensive evaluation of the selected ecological restoration grasses specifically includes:

[0051] The weights and scores of each indicator in the indicator layer are multiplied and then summed to obtain a comprehensive evaluation of the ecological restoration grass. The comprehensive evaluation of the ecological restoration grass is divided into four levels from high to low:

[0052] Grade I, superior material, with outstanding adaptability and ecological restoration value, can be widely developed and utilized.

[0053] Grade II, good quality, has slightly lower adaptability and ecological restoration value than Grade I plants, and should be promoted for planting appropriately according to specific environments.

[0054] Grade III, general materials, have no obvious ecological restoration effect, but can be selectively planted in suitable environments.

[0055] Grade IV, inferior material, has low adaptability and is not suitable for development and utilization.

[0056] Compared with existing technologies, this invention provides a comprehensive evaluation method for ecological restoration grasses on grasslands, the beneficial effects of which are:

[0057] (I) This technical solution sets three basic conditions: first, the species must be pollution-free, harmless, and pose no safety hazards, with a focus on native species; second, invasive alien species should be avoided as much as possible; and third, the species should have strong self-reproduction capabilities, green up early, be able to cover the ground during the early spring windy season, and have strong soil and water conservation capabilities, avoiding annual plants that are repeatedly planted every year. Under the premise of meeting the basic conditions, three selection criteria—environmental adaptability, soil and water conservation capability, and self-reproduction capability—are established, which include 14 specific indicators. This invention provides a comprehensive method for screening and evaluating ecological restoration grasses in Liaoning Province from multiple perspectives.

[0058] (II) The evaluation indicators selected in this technical solution are derived by the research team members based on long-term field investigations and have adopted the opinions of the expert group. They are highly targeted and feasible, and can reflect the ecological applicability of the selected grass species. They provide a scientific method for the introduction and breeding of ecological restoration grasses in Liaoning Province and the improvement of the effect of ecological restoration projects. Attached Figure Description

[0059] Figure 1 The flowchart illustrates a comprehensive evaluation method for ecological restoration grasses on grasslands, as provided by this invention. Detailed Implementation

[0060] The following is in conjunction with the appendix Figure 1 The following description further illustrates specific embodiments of the present invention. These embodiments are merely for illustrating the technical solutions of the present invention more clearly and should not be construed as limiting the scope of protection of the present invention.

[0061] Example 1: This invention is designed for grassland ecological restoration in Liaoning Province, primarily for grassland vegetation restoration in western Liaoning. Therefore, the invention is chosen based on Liaoning Province's climate conditions, unique topography, and existing major problems. This invention provides a comprehensive evaluation method for ecological restoration grasses on grasslands, including the following steps:

[0062] 1. Thoroughly understand the floristic and distribution characteristics of grassland plants in Liaoning Province.

[0063] This study focuses on grassland resources in Liaoning Province. Through field surveys, the basic characteristics, family and genus composition, main dominant species, and distribution characteristics of grassland plants in Liaoning were determined, and widely distributed species were selected. The study also investigated the seed characteristics, propagation ability, greening-up, and yellowing-out patterns of different grass species, collected seeds of native plants, and analyzed their germination characteristics and propagation ability.

[0064] 2. Basic conditions that ecological restoration grass must meet.

[0065] Essential conditions are the basic requirements that ecological restoration grasses must meet. This invention sets three basic conditions: First, the species must be pollution-free, harmless, and pose no safety hazards, with a focus on native species; second, invasive alien species should be avoided as much as possible, because the adaptability and ecological safety risks of alien species are still uncertain and require long-term observation; third, the species should have strong self-reproduction capabilities, green up early, be able to cover the ground during the early spring windy season, and have strong soil and water conservation capabilities, avoiding annual plants that are repeatedly planted every year. All selected species must meet these basic conditions.

[0066] 3. Selection criteria and specific indicators for ecological restoration grasses

[0067] Because of my country's vast territory, ecological factors affecting plant growth, such as precipitation, average temperature, extreme temperatures, and aridity, vary greatly between regions. For example, in Yunnan, vegetation restoration on grassy slopes does not require consideration of cold and drought resistance; instead, heat tolerance should be a key indicator. However, in the cold Northeast and arid Northwest, cold and drought resistance are more important. Furthermore, ecological restoration must have a clear objective, addressing the primary ecological problems of the restored area. Therefore, the selection of optimal conditions should highlight regional characteristics.

[0068] The selection criteria are the standards for further screening. This standard sets three conditions: strong environmental adaptability, strong soil and water conservation capacity, and strong reproductive capacity.

[0069] 4. Establish the hierarchical structure and indicator weights of the comprehensive evaluation model.

[0070] 4.1 Determining the Hierarchical Structure

[0071] In this technical solution, a comprehensive evaluation model is constructed using the Analytic Hierarchy Process (AHP). The hierarchical structure consists of three levels: the target layer (O), the constraint layer (A), and the indicator layer (B). The target layer represents the ultimate overall objective, i.e., the comprehensive evaluation. The constraint layer refers to the adaptability and ecological value of the selected grass species. In this specification, the selection criteria are considered as the constraint layer. Therefore, the constraint layer includes three levels: environmental adaptability (A1), soil and water conservation capacity (A2), and reproductive capacity (A3).

[0072] 4.2 Determination of the Indicator Layer of the Constraint Layer

[0073] Environmental adaptability (A1) is the most important constraint layer, evaluated by four indicators: cold resistance, drought resistance, salt tolerance, and distribution of the selected grass species; soil and water conservation capacity is determined based on the actual situation of severe soil erosion in the western Liaoning mountainous area, and evaluated by five indicators: greening period, greening period, root biomass, aboveground biomass, and canopy width; reproductive capacity refers to the growth capacity and seed collection capacity of grass species, and evaluated by five indicators: growth rate, branch growth type, number of tillers / branches, thousand-seed weight, and seed germination rate.

[0074] 4.3 Hierarchical Single Sorting of Indicator Layers

[0075] Hierarchical single ranking refers to the ranking of the importance of each factor in the indicator layer relative to the previous constraint layer. The importance values ​​were determined based on scores from experts (professional and technical personnel with associate senior titles or above engaged in grassland-related work in Liaoning Province). The three indicators in the constraint layer and the fourteen indicators in the indicator layer were provided by the expert group. Questionnaires were distributed.

[0076] 4.4 Overall Hierarchical Ranking of Indicator Layers

[0077] The process of determining the ranking weights of all factors at a certain level in relation to the overall goal is as follows. This process proceeds sequentially from the highest level to the lowest. For the highest level, the result of its hierarchical ranking is also the result of the overall ranking. Based on the questionnaire survey results, the relative weight values ​​of each indicator to the previous constraint level are statistically calculated, and finally, the total weight value of each indicator to the target level is calculated, as shown in Table 1. Among them, environmental adaptability (A1) is 0.4881, soil and water conservation capacity (A2) is 0.3990, reproductive capacity (A3) is 0.1729, cold resistance (B1) is 0.1526, drought resistance (B2) is 0.1894, salt and alkali tolerance (B3) is 0.0711, and widespread distribution (B4) is 0.0750. The greening period (B5) was 0.0793, the greening period (B6) was 0.0638, the root biomass (B7) was 0.0793, the aboveground biomass (B8) was 0.0793, the crown width (B9) was 0.0374, the growth rate (B10) was 0.0514, the branch growth type (B11) was 0.0321, the number of tillers / branches (B12) was 0.0321, the thousand-seed weight (B13) was 0.0203, and the seed germination rate (B14) was 0.0369.

[0078] Table 1 - Comprehensive Evaluation Hierarchical Structure Model of Ecological Restoration Grass in Liaoning Province

[0079]

[0080] 5. Measurement and scoring standards for each indicator

[0081] 5.1 Methods for determining and scoring environmental adaptability (A1) indicators

[0082] B1 Cold Resistance: Green-up rate (%) of each grass species after overwintering. The green-up rate was calculated based on the overwintering rate in the Northwest Liaoning Resource Nursery. Based on the green-up rate of all species, a three-level rating of 5, 3, and 1 was assigned.

[0083] B2 Drought Resistance: Number of days (d) of drought tolerance of grass species. Pot experiments with varying numbers of drought days and different rainfall gradients were conducted to verify the drought resistance of different native grasses, with the number of drought-tolerant days used as the screening criterion. Based on the number of drought-tolerant days for all species, they were scored into three levels: 5, 3, and 1.

[0084] B3 Salt and Alkali Tolerance: Observation of plant growth in saline-alkali land. Three salt and alkali gradient experiments (low, medium, and high) were conducted to determine salt and alkali tolerance, with the relative biomass between control treatments used as the standard for calculation. A three-level scoring system (5, 3, and 1) was applied.

[0085] B4 Distributivity: Habitat diversity and frequency of occurrence for the species. Frequency data are obtained from field surveys and experiments. The relative frequencies of other species are calculated based on the highest frequency. Based on the frequencies of all species, a rating of 5, 3, or 1 is assigned.

[0086] 5.2 Methods for determining and scoring the indicators of soil and water conservation capacity (A2)

[0087] B5 Green-up Period: The time when 50% of the plants have new shoots and leaves that are 2cm or taller after overwintering. Based on the green-up period of all species, three levels of scoring are assigned: 5, 3, and 1.

[0088] B6 Green Period: The number of days (d) from the greening-up stage to the yellowing-out stage of the grass species. The number of days from greening-up to yellowing-out is scored into three levels: 5, 3, and 1, based on the number of days for all tested species.

[0089] B7 Root Biomass: The weight of the entire root system after the plant has matured and has been completely excavated. The maximum root biomass is used as the baseline, and the relative root biomass of other species is calculated to obtain a score.

[0090] B8 Aboveground biomass: The weight of the aboveground branches after the entire plant has been dug up when it has matured.

[0091] B9 Crown Width: The crown area calculated after measuring the length and width of the crown. Based on the crown width of all tested species, it is scored into three levels: 5, 3, and 1.

[0092] 5.3 Methods for determining and scoring reproductive capacity (A3)

[0093] B10 Growth Rate: The rate at which the grass seed grows after planting, in cm / 7 days. Based on the growth rate of all tested species, it is scored on a scale of 5, 3, or 1.

[0094] B11 Branching Growth Type: Classified according to the growth type of grass species: rhizomatous, stolon, and tufted. Assigned 5, 3, and 1 points respectively.

[0095] B12 Tillers / Branches: This measures the number of primary tillers that originate directly from the basal tillering nodes of the main stem, or the number of branches that branch off from the main stem. Based on the tiller / branch counts of all tested species, a score of 5, 3, or 1 is assigned.

[0096] B13 Seed 1000-seed weight: Thoroughly mix all grass seeds, randomly select 1000 seeds and weigh them, repeating this process 3 times. Based on the 1000-seed weight of all tested varieties, assign a score of 5, 3, or 1.

[0097] B14 Seed germination rate: The germination rate of grass seeds was determined. Based on the germination rate of all tested species, a three-level score of 5, 3, and 1 was assigned.

[0098] 6. Scoring principles for each indicator

[0099] In this method, 14 evaluation indicators are evaluated using a 5-point scale, as shown in Table 2. After obtaining the scores, the contribution to the constraint layer is finally calculated based on their weight values.

[0100] Table 2 - 5-point scoring rules for evaluation indicators

[0101]

[0102] The above indicators are used to comprehensively evaluate the grass species to be introduced and applied to ecological restoration.

[0103] Scoring formula:

[0104] V=B1×0.1526+B2×0.1894+B3×0.0711+B4×0.0750+B5×0.0793

[0105] +B6×0.0638+B7×0.0793+B8×0.0793+B9×0.0374+B10×0.0514

[0106] +B11×0.0321+B12×0.0321+B13×0.0203+B14×0.0369

[0107] In the formula:

[0108] V is the total score of the evaluated ecological restoration grass; B1 is cold resistance; B2 is drought resistance; B3 is salt and alkali tolerance; B4 is widespread distribution; B5 is the greening period; B6 is the greening period; B7 is root biomass; B8 is aboveground biomass; B9 is crown width; B10 is growth rate; B11 is branch growth type; B12 is tillering / branching number; B13 is seed weight per thousand seeds; B14 is seed germination ability.

[0109] The selected grass species were ultimately classified into four grades: Grade I, Grade II, Grade III, and Grade IV, as shown in Table 3. Grade I represents superior materials, which have outstanding adaptability and ecological restoration value and can be widely developed and utilized. Grade II represents good materials, whose adaptability and ecological restoration value are slightly lower than those of Grade I plants, and can be promoted and planted appropriately according to specific environments. Grade III represents general materials, whose ecological restoration effect is not obvious, and can be planted selectively in suitable environments. Grade IV represents inferior materials, whose adaptability is not high and is not suitable for development and utilization.

[0110] Table 3 - Comprehensive Evaluation and Grading Standards for Ecological Restoration Grass

[0111]

[0112] Through practice, this invention has demonstrated that by establishing scientific standards and regulating the scientific and rational aspects of grass seed introduction, it provides better protection for the grassland ecology of Liaoning Province, resulting in significant economic benefits.

[0113] (1) Significantly enhanced ecological benefits. Planting grass is an indispensable basic measure in the process of grassland ecological restoration and soil erosion prevention. However, effective ecological restoration can only be achieved by selecting the right grass species, scientifically proportioning them, adapting to local conditions, and adopting appropriate construction methods. The various evaluation indicators used in this invention are established based on native grasses of Liaoning Province. They can effectively reflect ecological adaptability and ecological value. Furthermore, in this invention, the greening period is used as a selection evaluation indicator; the selected grass species can green up early and have significant soil and water conservation effects.

[0114] (2) Increased economic benefits. With the restoration of ecological vegetation, urbanization and the development of modern grassland animal husbandry, the demand for grass seeds is increasing. From the perspective of ecological industry alone, my country invests more than 150 billion yuan annually in ecological restoration, more than 200 billion yuan in municipal landscaping and greening, and when real estate landscaping investment is added, the annual investment in ecological environment construction exceeds 450 billion yuan.

[0115] (3) It has a significant demonstration effect and remarkable social benefits. Grassland ecological restoration and vegetation recovery require a large amount of grass seeds. After selecting suitable grass species, the production of ecological restoration grass can be promoted through contact with farmers, thereby improving the localization process of grass species.

[0116] This invention has established the basic characteristics, family and genus composition, main dominant species, and distribution characteristics of grassland plants in Liaoning Province through field plot surveys, and screened out widely distributed species. The survey found that *Lespedeza bicolor*, *Potentilla chinensis*, *Cryptocoryne tuftedii*, *Cryptocoryne multifoliatus*, *Gnaphalium affine*, *Gnaphalium affine*, *Gnaphalium affine*, and *Hemiberlesia argyi* were widely found in 213 plots, with frequencies of 74.18%, 66.67%, 67.14%, 65.73%, 46.95%, 46.48%, 46.01%, and 45.07%, respectively. Furthermore, wild native grass seeds were collected during the field plot surveys and propagated at the western Liaoning propagation base. The seed characteristics, propagation ability, greening, and yellowing patterns of different grass species were understood, and the germination characteristics and propagation ability of native plant seeds were analyzed. Measurements of the growth of wild native grasses at the Liaoxi propagation base revealed that *Eriocaulon buergerianum*, *Eriocaulon buergerianum*, *Eriocaulon buergerianum*, and *Leymus chinensis* had significantly higher tiller numbers than other species, indicating their greater adaptability and nutrient acquisition ability in new environments. Measurements of the photosynthetic response of wild native grasses showed that *Potentilla chinensis* and *Sanguisorba officinalis* had significantly higher net photosynthetic rates than other species, indicating their better light acquisition ability.

[0117] By understanding the floristic and distribution characteristics of grassland plants in Liaoning Province and studying the wild native grasses in the western Liaoning propagation base, this technical solution can be improved, increasing its accuracy, comprehensiveness, and practicality.

[0118] The above-described embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any simple changes or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A comprehensive evaluation method for ecological restoration grasses on grasslands, characterized in that, The method comprises the following steps: Obtaining the flora characteristics and distribution characteristics of the grassland plants, and selecting the ecological restoration grass according to the flora characteristics and distribution characteristics; Setting the basic conditions of the ecological restoration grass, and screening the ecological restoration grass according to the basic conditions, wherein the basic conditions comprise the following aspects: firstly, the species without public hazards, pollution and safety hazards, secondly, avoiding the selection of invasive alien species, and finally, the species with strong self-reproduction ability and strong water and soil conservation ability; Setting the optimal conditions and specific indexes of the ecological restoration grass, wherein the optimal conditions comprise environmental adaptability, water and soil conservation ability and reproduction ability, and the specific indexes comprise cold resistance, drought resistance, salt and alkali resistance, wide distribution, green-up period, green period, root biomass, above-ground biomass, crown width, growth speed, branch growth type, tillering / branching number, seed thousand-grain weight and seed germination force; Establishing a comprehensive evaluation model by using the analytic hierarchy process, and the hierarchical structure of the comprehensive evaluation model comprises a target layer, a constraint layer and an index layer, wherein the target layer is the comprehensive evaluation of the ecological restoration grass, the constraint layer is the optimal conditions, and the index layer is the specific indexes; Determining the weight values and scores of the indexes of the index layer, and calculating the total score of the target layer according to the weight values and scores of the indexes of the index layer; Before the weight values and scores of the indexes of the index layer are obtained, the determination standards of the indexes of the index layer are set, and the determination standards comprise the following aspects: The determination standard of the cold resistance is the green-up rate of the grassland plants, and the green-up rate of the grassland plants is obtained by determining the overwintering rate of the grassland plants; The determination standard of the drought resistance is the drought endurance days of the grassland plants, and the drought endurance days of the grassland plants are obtained by potting test; The determination standard of the salt and alkali resistance is the growth status of the grassland plants in the saline-alkali land, and the growth status of the grassland plants in the saline-alkali land is obtained by setting low, medium and high salt and alkali gradient tests; The determination standard of the wide distribution is the habitat types and occurrence frequencies of the grassland plants, and the habitat types and occurrence frequencies of the grassland plants are obtained by field investigation test; The determination standard of the green-up period is the time when the number of the new branches and leaves with a height of more than 2 cm reaches 50% of the total number of the grassland plants after the grassland plants overwinter; The determination standard of the green period is the days from the green-up period to the yellowing period of the grass of the grassland plants; The determination standard of the root biomass is the total root weight of the whole plant after the grassland plants mature; The determination standard of the above-ground biomass is the total above-ground branch weight of the whole plant after the grassland plants mature; The determination standard of the crown width is the crown area calculated by measuring the length and width of the crown layer of the grassland plants; The determination standard of the growth speed is the growth speed of the grass of the grassland plants after planting; The determination standard of the branch growth type is the division of the grassland plants into rootstock type, creeping stem, clump type; The determination standard of the tillering / branching number is the number of the first tillers directly issuing from the main stem base or the number of the branches issuing from the main stem of the grass of the grassland plants; The determination standard of the seed thousand-grain weight is that the seeds of the grassland plants are mixed uniformly, 1000 seeds are randomly taken and weighed, and the weighing is repeated for 3 times; The determination standard of the seed germination force is the germination rate of the seeds of the grassland plants; According to the total score of the target layer, the selected ecological restoration grass is comprehensively evaluated.

2. The method of claim 1, wherein the method is characterized by, The acquisition of the flora characteristics and distribution characteristics of the grassland plants specifically includes: Through field sample plot investigation, the basic characteristics, family and genus composition, main dominant species and distribution characteristics of the grassland plants are mastered, and the species with wide distribution are screened out; The seed characteristics, propagation capacity and growth rule of different grass seeds are acquired, the seeds of native plants are collected, and the germination characteristics and propagation capacity are analyzed.

3. The method of claim 1, wherein the method is a comprehensive evaluation method for ecological restoration grasses in grasslands. The acquisition of the weight values of the indexes of the index layer specifically includes: Through questionnaire survey method, the indexes of the index layer are scored; According to the questionnaire survey result, the weight values of the indexes of the index layer are acquired.

4. The method of claim 1, wherein the method is a comprehensive evaluation method for ecological restoration grasses in grasslands. Before the weight values and scores of the indexes of the index layer are determined, the scoring standards of the indexes of the index layer are set, which specifically include: The scoring standard of cold resistance is that the grassland plants are scored in 5, 3 and 1 grades from high to low according to the regreening rate; The scoring standard of drought resistance is that the grassland plants are scored in 5, 3 and 1 grades from high to low according to the drought endurance days of the seeds of the grassland plants; The scoring standard of salt and alkali resistance is that the grassland plants are scored in 5, 3 and 1 grades from good to poor according to the growth conditions of the grassland plants in the saline-alkali land; The scoring standard of wide distribution is that the grassland plants are scored in 5, 3 and 1 grades from high to low according to the frequency; The scoring standard of regreening period is that the grassland plants are scored in 5, 3 and 1 grades from short to long according to the regreening period; The scoring standard of green period is that the grassland plants are scored in 5, 3 and 1 grades from long to short according to the green period; The scoring standard of root biomass is that the grassland plants are scored in 5, 3 and 1 grades from large to small according to the root weight; The scoring standard of above-ground biomass is that the grassland plants are scored in 5, 3 and 1 grades from large to small according to the branch weight; The scoring standard of crown width is that the grassland plants are scored in 5, 3 and 1 grades from large to small according to the crown width area; The scoring standard of growth speed is that the grassland plants are scored in 5, 3 and 1 grades from fast to slow according to the growth speed; The scoring standard of branch growth type is that the rhizome type plants in the grassland plants are scored as 5 points, the creeping stem plants are scored as 3 points, and the clump type plants are scored as 1 point; The scoring standard of tillering / branching number is that the grassland plants are scored in 5, 3 and 1 grades from more to less according to the tillering / branching number; The scoring standard of seed thousand-grain weight is that the grassland plants are scored in 5, 3 and 1 grades from large to small according to the seed thousand-grain weight; The scoring standard of seed germination force is that the grassland plants are scored in 5, 3 and 1 grades from high to low according to the seed germination rate.

5. The method of claim 4, wherein the method is characterized by, The acquisition of the weight values and scores of the indexes of the index layer specifically includes: According to the determination standard and the scoring standard, the indexes of the index layer are determined and scored.

6. The method of claim 1, wherein the method is a comprehensive evaluation method for ecological restoration grasses in grasslands. The comprehensive evaluation of the selected ecological restoration grass specifically includes: The weight value and score of each index of the index layer are multiplied and then added to obtain the comprehensive evaluation of the ecological restoration grass, and the comprehensive evaluation of the ecological restoration grass is divided into four levels from high to low: I level, excellent material, its adaptability and ecological restoration value are more outstanding, which can be widely developed and utilized; II level, good material, its adaptability and ecological restoration value are slightly lower than those of the I level plant, which can be moderately planted according to specific environment; III level, general material, its ecological restoration effect is not obvious, which can be planted in suitable environment; IV level, poor material, its adaptability is not high, which is not suitable for development and utilization.

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