Method for reseeding and repairing alpine degraded grassland

Abstract

The invention discloses a method for reseeding and repairing alpine degraded grassland, which comprises the following steps: step 1, cutting: cutting native vegetation of a sample plot with the stubble height of 3-5cm; 2, sowing is conducted, before the rainy season comes, drilling is conducted on target grass seeds in a manual ditching mode, the target grass seeds are 2-3 grass seeds selected from each type of gramineae grass, leguminous grass and miscellaneous grass and mixed according to a certain proportion, and earthing is conducted after sowing is completed; 3, after-sowing management is conducted, agricultural measures such as impurity removal, fertilization and watering do not need to be conducted after sowing is completed, and grazing is forbidden for two years. According to the method, different functional types of plants and combinations suitable for the alpine region are screened out, the method suitable for reseeding restoration of the alpine degenerated grassland is formulated, the reseeding cost is controlled, meanwhile, plant communities high in yield, high in stability and diverse in function are built, and the problem of restoration of the degenerated grassland in the alpine region is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological restoration, and in particular relates to a method for reseeding and restoring alpine degraded grassland. Background Art

[0002] Alpine grassland is one of the main ecosystems on the Qinghai-Tibet Plateau. While playing ecological functions such as climate regulation, soil and water conservation, and soil improvement, it also supports the development of local animal husbandry. Due to the unique topographical features and harsh climatic conditions of the Qinghai-Tibet Plateau, global warming and humidification, intensified nitrogen deposition, and strong interference from human activities, key species in the alpine grassland ecosystem continue to be lost, biodiversity has sharply decreased, and vegetation productivity has declined. This has not only led to large-scale degradation of alpine grasslands, but also exacerbated the contradiction between grass and livestock supply and demand. The restoration of degraded alpine grasslands has become a major ecological problem that needs to be solved urgently.

[0003] Grassland reseeding is widely used in alpine degraded grassland restoration due to its remarkable results and quick effects. However, due to the influence of multiple factors such as the geochemical properties of degraded alpine grassland, microorganisms, harsh environmental conditions and the scarcity of available native grass species, the species that can be used for reseeding and restoration of alpine degraded grassland in the Qinghai-Tibet Plateau are very limited, especially legumes. At present, the most common reseeding and restoration method is to reseed a single grass grass such as Elymus nutans, Festucasinensis, Elymus sibiricus, Festuca rubra, etc. Although it can quickly restore the vegetation coverage and productivity of alpine degraded grassland in a short period of time, the stability and sustainability of the restored alpine grassland ecosystem are poor. This is because the natural ecosystem is a mixed system composed of multiple functional groups such as grass, legumes, and forbs. There is complementarity between the aboveground and underground ecological niches and nutrient resources between plants of different groups, which can help them use local resources more effectively, improve the colonization rate, yield and community stability, and thus achieve the purpose of increasing production.

[0004] Fully considering the redundancy and complementarity between reseeding species, selecting suitable grass species and combinations, and formulating highly operational, low-cost sowing and maintenance management plans based on local water, heat, climate and artificial conditions are crucial to improving and maintaining the productivity, multifunctionality, service diversity and post-restoration stability of high-altitude degraded grasslands. This is also the hot spot and difficulty of current research. Summary of the invention

[0005] In response to at least one defect or improvement need in the prior art, the present invention provides a method for reseeding and restoring alpine degraded grassland. The method of the present invention screens out plants and combinations of different functional types that are adapted to alpine areas, and develops a method suitable for reseeding and restoring alpine degraded grassland. While controlling the reseeding cost, a plant community with high yield, strong stability and diverse functions is established, thereby solving the problem of degraded grassland restoration in alpine areas.

[0006] To achieve the above object, according to one aspect of the present invention, a method for reseeding and restoring alpine degraded grassland is provided, comprising the following steps:

[0007] Step 1: mowing: mowing the native vegetation of the sample plot, leaving a stubble height of 3 to 5 cm;

[0008] Step 2: sowing. Before the rainy season comes, the target grass species are sown in artificial furrows. The target grass species are 2 to 3 grass species from each of the grass family, leguminous family and miscellaneous grasses, mixed in a certain proportion, and covered with soil after sowing.

[0009] Step three: Post-sowing management: after completion, there is no need for agronomic measures such as weeding, fertilization, and watering, and grazing is prohibited for 2 years.

[0010] Preferably, the grass species of the Poaceae family are Elymus nutans and Poa paniculata; the grass species of the Leguminosae family are Medicago truncatula and Astragalus membranaceus; and the weed grass species are Taraxacum officinale and Scopolamine.

[0011] Preferably, the sowing amount of cold-land bluegrass is 1 / 6kg / mu, the sowing amount of dung spike daffodil is 1 / 2kg / mu, the sowing amount of yellow alfalfa is 1 / 2kg / mu, the sowing amount of yellow astragalus is 5 / 6kg / mu, the sowing amount of dandelion is 5 / 6kg / mu, and the sowing amount of scopolamine is 7 / 6 plants / m 2 .

[0012] Preferably, the artificial trenching depth is 2 to 3 cm, and the row spacing is 40 cm.

[0013] Preferably, the target grass species are grass species that have been raised in advance, and the height of the grass species is 8 to 15 cm.

[0014] Preferably, the reseeding season is before the rain, and the period is from June to August.

[0015] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0016] (1) The present invention provides a method for reseeding and restoring alpine degraded grassland. Six grass species that can successfully germinate, establish and overwinter in alpine degraded grassland are selected from Gramineae, Leguminosae and miscellaneous grasses, and further single seeding and mixed seeding experiments are carried out on the six grass species. It is found that the mixed seeding of the six grass species greatly improves the vegetation coverage and biomass of grassland in alpine areas. Within two years after reseeding, the vegetation coverage of the mixed seeding of the six grass species is increased by an average of 59.50% compared with the control without reseeding, the biomass is increased by an average of 328.31% compared with the control without reseeding, and the plant diversity is increased by an average of 40.93% compared with the control without reseeding, achieving a better grassland restoration effect. Compared with the traditional reseeding of a single Gramineae plant, the method has higher productivity, community stability and functional diversity, and is more conducive to the reseeding and restoration of degraded grassland in alpine areas.

[0017] (2) The present invention provides a method for reseeding and restoring alpine degraded grassland. The two selected legume plants, Medicago falcata and Astragalus luteolus, have well-developed rhizomes and excellent growth performance in cold regions. They can fix nitrogen through rhizobia, and the excess nitrogen can be supplied to other plants. Therefore, there is no need to fertilize the grassland after reseeding, which can improve the survival rate of other plants and effectively reduce the application amount of fertilizer, especially nitrogen fertilizer. The two selected grass plants, Elymus nutans, Poa crymophila, and the weeds Taraxacum mongolicum and Anisodus tanguticus), which has strong adaptability and fertility. In particular, deep-rooted weeds can also transfer deep soil water to the surface soil through hydraulic lifting, improving the water supply of shallow-rooted grasses. This mutually beneficial effect on water utilization can help plant communities resist drought stress in high-altitude areas.

[0018] (3) The present invention provides a method for reseeding and restoration of alpine degraded grassland. First, the native vegetation of the sample plot is mowed before reseeding, and part of the stubble is left to reduce the degree of damage to the native grassland; secondly, the degraded grassland is sown by artificial ditching to simulate no-till reseeding, thereby avoiding agronomic measures such as deep plowing and pesticide weeding in existing reseeding research that are more destructive to the native grassland, thereby helping the reseeded grassland to be successfully established; after the reseeding is completed, there is no need to carry out agronomic measures such as weeding, fertilization, and watering, and the synergistic effect between the mixed sowing of grass seeds is fully utilized to utilize water and fertilizer, thereby enhancing the drought and stress resistance of grass plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a comparison diagram of soil organic carbon in the second year under different reseeding treatments provided by an embodiment of the present invention;

[0020] Figure 2 This is a growth diagram of six grass seeds provided by an embodiment of the present invention after single sowing for one year;

[0021] Figure 3 This is a growth chart of six grass seeds mixed one year after sowing according to an embodiment of the present invention; DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] Example 1 Preliminary verification of germination and winter survival of seeds of different grass species

[0028] In order to evaluate the germination and overwintering survival of different grass seeds in degraded grasslands in high-cold areas, the present invention selected more than a dozen grass seeds from the Leguminosae, Gramineae and weeds for sowing overwintering, so as to discover grass seeds with strong adaptability in high-cold areas. Specifically, several grass species were selected from the Leguminosae family, including wild yellow alfalfa, yellow astragalus, miscellaneous alfalfa, flat alfalfa, and red bean grass; several grass species were selected from the Gramineae family, including drooping spike dung grass, cold-land bluegrass, red fescue, awnless bromegrass, and Qinghai flat-stem bluegrass; and two grass species, dandelion and scopolamine, were selected as target grass species in the weed category. The above target grass seeds were respectively subjected to small-scale germination and overwintering growth tests in high-cold areas to observe the germination and overwintering growth effects of the grass seeds.

[0029] Target grass species seeds: yellow lucerne, yellow astragalus, miscellaneous lucerne, flat lucerne, sainfoin, drooping spike dung, cold-land bluegrass, red fescue, smooth brome, Qinghai flat-stem bluegrass, dandelion and scopolamine;

[0030] Sowing time: Sow the seeds of the above target grass species in June 2022 at a planting depth of 1.5 cm and perform conventional germination water and fertilizer management. Observe the germination of the target grass species and the winter growth of the plants after germination.

[0031] Statistical situation: The statistical results are shown in the table below, where a germination rate of more than 50% is counted as “+”, and a germination rate of less than 50% is counted as “-”; the grass seed survival rate after wintering is counted as “+” if it is above 40%, and “-” if it is less than 40%.

[0032] Table 1 Germination and winter survival of seeds of different grass species

[0033] Grass seeds Germination Overwintering survival Yellow clover + + Alfalfa + - Astragalus membranaceus + + Aloe vera + - Sainfoin - - Elymus nutans + + Bromus inermis - - Poa frostii + + Red Fescue - - Poa chinensis + - Dandelion + + Sconia + +

[0034] Result 1: From the results in Table 1, it can be seen that the seeds of the six grass species, namely, Elymus nutans, Poa annua, Medicago truncatula, Astragalus membranaceus, Taraxacum officinale, and Scopolamine, have good germination and overwintering survival, and have good adaptability to high-altitude cold areas. The seeds of other grass species are not well adaptable to high-altitude cold areas, have low germination rates, or cannot successfully overwinter after germination.

[0035] Example 2 Verification of the effect of grassland restoration by sowing six grass species alone and mixed

[0036] Using the six grass species with the best adaptability to high-cold areas screened in Example 1, this example further expanded the area of ​​single sowing and mixed sowing experiments, including the following steps:

[0037] Reseeding varieties: Elymus nutans, Poa frigida, Medicago truncatula, Astragalus truncatula, Dandelion, and Scopoloma scopolina. Elymus nutans, Poa frigida, Astragalus truncatula, and Dandelion were purchased from Beijing Teranpu Ecological Company, and the germination rate of seeds was higher than 95%. Wild Medicago truncatula was provided by China Agricultural University, and the germination rate of seeds was 92%. One-year-old Scopoloma scopolina seedlings were purchased from the Hongyuan Base of Sichuan Grassland Science Research Institute.

[0038] Sowing location: The test site is located in Tangri Yak Cooperative, Hongyuan County, Sichuan Province (33°12′N, 102°62′E), with an average altitude of 3480m. It has a plateau monsoon climate, which is characterized by short spring and autumn, low heat, distinct dry and rainy seasons, and rain and heat in the same season; long sunshine and strong solar radiation. The average temperature over the years is 1.4℃, the lowest extreme temperature is -36℃; the highest extreme temperature is 25℃; the annual rainfall is between 300mm and 600mm, and the precipitation is mainly concentrated in May to September; the soil of the test site is sandy loam.

[0039] Planting time: May 15, 2023

[0040] Preparation before sowing:

[0041] (1) Mowing: Mowing the native vegetation before sowing, leaving a stubble height of 3-5 cm.

[0042] (2) Seedling cultivation: As a wild species, the seeds of Hyacinthus annuus are very hard. To ensure the effect of reseeding, seedling cultivation is required in advance. The seedling cultivation cycle is about 1 year. After one year, the plant is 8-15 cm long and the whole plant is transplanted.

[0043] (3) Sowing: The rainy season for the reseeding area is from June to August. Before the rainy season comes, the reseeding grass seeds are mixed and then sown in rows. There are 8 treatments in total, including no reseeding control, single sowing of Elymus danglingii, single sowing of Poa annua, single sowing of Medicago truncatula, single sowing of Astragalus membranaceus, single sowing of Taraxacum officinale, single sowing of Anisodendron scoparia, and mixed sowing of 6 grass seeds. Each treatment is set with 5 blocks, i.e. 5 replicates, and the area of ​​a single plot is 4 m × 6 m = 24 m 2, 1m protection rows were set outside the plot, and the spacing between plots was 1m. Due to the small area of ​​reseeding, artificial furrowing was used to simulate the sowing of no-till reseeders, with a furrow depth of 2-3cm and a row spacing of 40cm. The six reseeding plants were sown at a single rate of 1kg / mu of cold-land bluegrass, 3kg / mu of drooping spiked dung grass, 2kg / mu of yellow alfalfa, 5kg / mu of yellow astragalus, 5kg / mu of dandelion, and 7 plants / m 2 Supplementary sowing was carried out in each experimental plot, and at the same time, 6 grass seeds were mixed at 1 / 6 of the single sowing amount of each grass seed. After the supplementary sowing was completed, the soil was covered.

[0044] (4) Post-sowing management: After re-sowing, no agronomic measures such as weeding, fertilization, and watering are required, but grazing is prohibited for 2 years. Reasonable grazing can be carried out in the third year.

[0045] Effect of reseeding: The coverage, biomass, and plant diversity of the reseeding treatment were counted on September 2, 2023 and August 11, 2024, with the unreseeded grassland as the control. The changes in soil organic carbon content after reseeding were detected on August 11, 2024, with the unreseeded grassland as the control. The number of reseeded species was counted on September 2, 2023 and May 17, 2024 to calculate the greening rate.

[0046] (1) The method for determining the number of plants and the rate of greening is as follows: a 50×50 cm sample box is randomly placed in each plot and marked. The number of plants of each reseeded species in the community is recorded in September of the reseeding year, and the number of plants of each reseeded species is surveyed again in May 2024 to determine the rate of greening. For the convenience of statistics, all plant numbers are converted to plants / m 2 .

[0047] (2) The coverage determination method is as follows: The coverage is determined by visual inspection. In 2023 and 2024, a 50×50 cm sample square frame is randomly placed in each plot, and the total coverage of the sample square and the coverage of each grass species are counted in percentage (%).

[0048] (3) The method for determining grassland productivity is as follows: Each treatment includes 5 reseeding plots. A 50×50 cm sample plot is randomly set up in each reseeding plot to monitor biomass. All vegetation in the sample plot is mowed evenly after planting, packed in cowhide seed bags and brought back to the laboratory. After drying in an oven at 65°C for 72 hours until constant weight is reached, the aboveground biomass of each species is weighed and recorded. The total aboveground productivity is the sum of the aboveground biomass of each species harvested after mowing. The average value of the total biomass of the five sample plots represents the total aboveground productivity of the treatment. For statistical purposes, all productivity units are converted to g / m 2 .

[0049] (4) The method for determining the content of soil organic carbon is as follows: using the potassium dichromate volumetric method (dilution heat method), weigh 0.2500 g of soil sample, add 10 ml of 1 mol / L potassium dichromate solution (1 / 6K2Cr2O7) and 20 ml of concentrated sulfuric acid (H2SO4), let it stand and then dilute it with water to 250 ml, add 3 drops of o-phenanthroline indicator, and then titrate with 0.5 mol / L FeSO4 standard solution until the solution color changes from green to brick red at the titration end point.

[0050] Result 2: As shown in Table 2, all six grass species were successfully established and overwintered smoothly after reseeding. Except for Astragalus membranaceus, the greening rates of the other reseeded grass species were all greater than 60.00%, and there was no significant difference in the greening rates, indicating that these grass species have good adaptability to high-altitude degraded grasslands and can be applied to large-scale promotion. Among them, dandelion had the highest greening rate when sown alone, followed by Scopolamine.

[0051] Table 2 Comparison of regreening rate of grass seeds under different reseeding treatments

[0052]

[0053] Results 3: As shown in Table 3, compared with the non-reseeding area, both the mixed sowing of 6 grass species and the single sowing of each species significantly increased the grassland vegetation coverage. In the first and second years after reseeding, the coverage of all reseeding treatments increased by an average of 45.09% and 46.54% compared with the control. The mixed sowing of 6 grass species and the single sowing of yellow alfalfa had the highest improvement in the vegetation coverage of reseeded grassland. From 2023 to 2024, the mixed sowing of 6 grass species increased by an average of 59.50% compared with the control, and the single sowing of yellow alfalfa increased by an average of 65.60% compared with the control. Due to its long growth cycle, Scots scoparia could not improve the vegetation coverage well in the early stage of reseeding. From 2023 to 2024, it increased by an average of 8.20% compared with the control.

[0054] Table 3 Comparison of grassland coverage in two years under different reseeding treatments

[0055]

[0056] Result 4: As shown in Table 4, the productivity improvement effect of all reseeding treatments was more significant in the second year. In the first and second years after reseeding, the productivity of all reseeding treatments increased by an average of 67.81% and 340.33% compared with the control. Among them, the mixed sowing of six grass species and the single sowing of alfalfa had the highest improvement in productivity, which increased by an average of 328.31% and 384.65% compared with the control in 2023-2024, respectively.

[0057] Table 4 Comparison of grassland productivity in two years under different reseeding treatments

[0058]

[0059] Results 5: As shown in Table 5, compared with the control, the mixed sowing of the six grass species significantly increased the grassland plant diversity in the first and second years after reseeding, increasing by 45.59% and 36.27% respectively. Some grass species, such as Elymus nutans, Medicago truncatula and Astragalus membranaceus, would suppress native weeds when sown alone, resulting in a decrease in grassland plant diversity.

[0060] Table 5 Comparison of grassland plant diversity under different reseeding treatments in two years

[0061]

[0062] Result 6: Figure 1 is a comparison diagram of soil organic carbon in the second year under different reseeding treatments of the present invention, Figure 1 It can be seen that all reseeding treatments significantly increased the soil organic carbon content, with an average increase of 259.31%. Among them, the mixed sowing of six grass species had the highest increase in soil organic carbon content, which increased by 378.23% in the second year of reseeding compared with the control.

[0063] In summary, the present invention has excavated 6 grass species and combinations that can be successfully established and overwintered in high-cold degraded grasslands, and has developed a method suitable for reseeding and repairing high-cold degraded grasslands. These 6 grass species belong to different functional groups of Gramineae, Leguminosae and miscellaneous grasses (edible and medicinal). When the 6 grass species are mixed, the ecological niches of plants of different functional groups complement each other to construct a more diverse and stable plant community. Compared with the control, the mixed sowing of 6 grass species significantly increased vegetation coverage, biomass and soil organic carbon content, and greatly increased forage yield and plant diversity while restoring high-cold degraded grasslands. Moreover, because the forage contains Leguminosae, the palatability and quality of the forage are improved, which helps to alleviate the contradiction between grass and livestock. In addition, we also found that yellow flower alfalfa has a high adaptability to high-cold grasslands. Whether it is sown alone or mixed with other grass species, the grassland coverage and biomass are greatly improved.

[0064] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for reseeding and restoration of alpine degraded grassland, characterized in that: The steps include: Step 1: mowing: mowing the native vegetation of the sample plot, leaving a stubble height of 3 to 5 cm; Step 2: sowing. Before the rainy season comes, the target grass species are sown in artificial furrows. The target grass species are 2 to 3 grass species from each of the grass family, leguminous family and miscellaneous grasses, mixed in a certain proportion, and covered with soil after sowing. Step 3: Post-sowing management: After sowing, there is no need for agronomic measures such as weeding, fertilization, and watering, and grazing is prohibited for 2 years.

2. The method for reseeding and restoration of alpine degraded grassland according to claim 1, characterized in that: The grass species of the Poaceae family are Elymus nutans and Poa paniculata; the grass species of the Leguminosae family are Medicago truncatula and Astragalus membranaceus; and the grass species of the weed family are Taraxacum officinale and Scopolamine.

3. The method for reseeding and restoration of alpine degraded grassland according to claim 2, characterized in that: The sowing amount of cold-land bluegrass is 1 / 6kg / mu, the sowing amount of dung spike daffodil is 1 / 2kg / mu, the sowing amount of yellow alfalfa is 1 / 2kg / mu, the sowing amount of yellow astragalus is 5 / 6kg / mu, the sowing amount of dandelion is 5 / 6kg / mu, and the sowing amount of scopolamine is 7 / 6 plants / m 2 .

4. The method for reseeding and restoration of alpine degraded grassland according to claim 1, characterized in that: The artificial trenching depth is 2 to 3 cm, and the row spacing is 40 cm.

5. The method for reseeding and restoration of alpine degraded grassland according to claim 1, characterized in that: The target grass seeds are grass seeds that have been raised in advance, and the height of the grass seeds is 8 to 15 cm.

6. The method for reseeding and restoration of alpine degraded grassland according to claim 1, characterized in that: The reseeding season is the reseeding season before the rain, and the period is from June to August.

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