A method for ecological restoration of degraded grasslands in black soil areas

Abstract

This invention belongs to the field of ecological restoration technology, specifically disclosing a method for ecological restoration of degraded grasslands in black soil areas. The method includes: disinfecting with sodium hypochlorite and soaking seeds in gibberellin; raising seedlings using a mixed substrate of peat moss, perlite, well-rotted organic fertilizer, and vermiculite; after the seedlings have 4-6 true leaves, they are hardened off in situ and transplanted to the degraded black soil grasslands from late June to early July; weeding is carried out within 30 days after transplanting. The method provided by this invention, through transplanting *Heliotropium indicum*, increases the aboveground biomass, vegetation cover, species richness, and soil moisture content after restoration, effectively promoting the formation of multi-species symbiotic communities and significantly improving the ecological restoration effect of degraded black soil grasslands.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological restoration, and specifically relates to a method for ecological restoration of degraded meadows on black soil beaches. Background Art

[0002] As an extremely important type of grassland in China, alpine grassland is an important strategic resource reserve and ecological security barrier in China. However, due to its unique geographical location and climate type, serious degradation has occurred in recent years.

[0003] Overseeding is the main restoration measure for degraded meadows on black soil beaches at present. The grass seeds for overseeding usually choose gramineous and leguminous plants with relatively high nutritional value, such as Elymus nutans ( Elymus nutans ), Medicago sativa ( Medicago sativa ), etc. This type of scheme aims directly at quickly forming vegetation cover and obtaining a relatively high aboveground biomass, but it causes irreversible structural defects at the community construction level. The highly competitive cultivated gramineous and leguminous species form a single dominant stratum, squeezing ecological niches, resulting in the inability of native indigenous plants with important ecological functions to colonize, and the community species richness being at a relatively low level, which is not conducive to the sustainable development of the restoration of degraded meadows on black soil beaches. Summary of the Invention

[0004] The present invention provides a method for ecological restoration of degraded meadows on black soil beaches. The method provided by the present invention conducts ecological restoration of degraded meadows on black soil beaches by transplanting Lamiophlomis rotata. After restoration, the average aboveground biomass is increased to <27.69 g / m²>, the vegetation coverage is increased to <67.34%>, the species richness is increased from <2> species to <6> species, and the soil water content from <0> cm to <10> cm is increased from <23.1%> to <51.2%>, effectively promoting the formation of a multi-species symbiotic community and significantly improving the ecological restoration effect of degraded meadows on black soil beaches; at the same time, after harvesting the aboveground medicinal parts of Lamiophlomis rotata, it can also increase the economic income of herdsmen, achieving the coordinated improvement of ecological restoration and economic benefits.

[0005] The present invention provides a method for ecological restoration of degraded meadows on black soil beaches. The method promotes the colonization of Elsholtzia densa, Potentilla bifurca, Potentilla anserina var. gerardiana, Potentilla anserina or Morina chinensis by transplanting Lamiophlomis rotata, and improves the aboveground biomass, vegetation coverage, species richness or soil water content of degraded meadows on black soil beaches; Specifically, it includes the following steps: After disinfecting the seeds of Lamiophlomis rotata, soak them in a gibberellin solution of <100 mg / L> to <150 mg / L for <15> h to <30> h for germination; Sow the germinated seeds of Lamiophlomis rotata in a seedling tray filled with a seedling substrate for cultivation, and transplant them after thinning and hardening off.

[0006] This invention achieves a germination rate of 78.56% for *Ligusticum striatum* seeds by disinfecting them with 1% sodium hypochlorite for 10 minutes combined with soaking them in 150 mg / L gibberellin for 24 hours. After transplanting, the flat, spreading leaves of *Ligusticum striatum* form a biological cover, increasing soil moisture content from 23.1% to 51.2% and species richness from 2 to 6 species, successfully driving positive succession of degraded grasslands in black soil areas. Simultaneously, since the medicinal part of *Ligusticum striatum* is the above-ground portion, the complete underground root system is preserved during harvesting, ensuring continued germination and growth through the root system the following year, promoting population establishment and density increase. This guarantees sustainable harvesting of the medicinal herb, increases the economic income of herders, and achieves a synergistic improvement in ecological restoration and economic benefits.

[0007] Furthermore, the disinfection process involves soaking the seeds of *Erigeron breviscapus* in a 1%–1.5% sodium hypochlorite solution for 8–12 minutes.

[0008] Furthermore, the seedling substrate, by parts, consists of 35-45 parts peat moss, 25-35 parts perlite, 15-25 parts well-rotted organic fertilizer, and 5-15 parts vermiculite.

[0009] Furthermore, the seeding amount per hole in the seedling tray is 3 to 5 seeds, and the soil covering thickness is 0.3 cm to 0.7 cm.

[0010] Furthermore, the thinning is carried out when the seedlings have grown 1-2 true leaves, with one seedling retained in each hole.

[0011] Furthermore, the hardening-off process involves: when the seedlings have 4-6 true leaves, a crown width of 5-10 cm, and a root ball formed, the seedling trays are transferred to degraded grasslands in black soil areas, and shade nets are erected for in-situ hardening-off for 8-12 days, while gradually reducing the shaded area.

[0012] Furthermore, the transplanting is as follows: in the bare patch area of ​​degraded grassland, use a soil drill with a diameter of 4 cm to 6 cm to make planting holes with a depth of 8 cm to 12 cm, and transplant the seedlings together with the root ball substrate, with 1 to 3 seedlings transplanted per hole and a plant spacing of 15 cm to 25 cm.

[0013] Furthermore, irrigation is supplemented according to rainfall after transplanting, thinning is carried out after 13 to 17 days, and weeds around the plants are removed within 28 to 32 days.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention relates to the transplantation of *Duyiwei* (a type of herb). Lamiophlomis rotataAfter restoration, its broad leaves spread flat along the ground, forming a natural biological cover on the bare soil surface, significantly increasing soil moisture content (from 23.1% to 51.2% at a depth of 0 cm to 10 cm), creating a cool and moist environment for the germination and colonization of other plant seeds. Following restoration, species richness increased from an average of 2 species to an average of 6 species, forming a stable community with multiple species coexisting, including *Potentilla discolor*, *Elsholtzia ciliata*, *Potentilla biloba*, *Potentilla chinensis*, *Potentilla spp.*, and *Stichopus japonicus*, significantly improving ecological benefits and achieving positive succession of degraded grasslands in the black soil area.

[0015] *Lysimachia christinae*, a perennial alpine herb belonging to the genus *Lysimachia* in the family Lamiaceae, is a valuable wild medicinal resource. Its above-ground stems and leaves possess significant hemostatic, analgesic, anti-inflammatory, and antibacterial properties, making it a highly valuable medicinal plant in pastoral areas. This invention presents a method for cultivating and transplanting *Lysimachia christinae* seedlings in degraded black soil grasslands. This method not only effectively alleviates the severe shortage of *Lysimachia christinae* resources in pastoral areas and increases the economic income of herders, but also enhances the productivity and vegetation cover of degraded black soil grasslands, providing a reliable artificial restoration technology and achieving a synergistic improvement in ecological restoration and economic benefits. The medicinal part of *Lysimachia christinae* is the above-ground portion. During harvesting, the complete underground root system is preserved, ensuring continued germination and growth in the following year, promoting population establishment and density increase, thus guaranteeing sustainable harvesting and increasing herders' economic income. The germination, seedling cultivation, and transplanting materials and tools used are inexpensive, and the operation and management are simple and easy, possessing strong replicability and application value in degraded black soil grasslands.

[0016] This invention achieves an average seed germination rate of 78.56% by determining the optimal seed treatment method (1% sodium hypochlorite disinfection for 10 min + 150 mg / L gibberellin soaking for 24 h). Combined with techniques such as greenhouse seedling raising, in-situ hardening, reasonable transplanting window (late June to early July), and post-transplanting field management, it can successfully achieve rapid transplanting and effectively solve the problem of seedling overwintering in high-altitude and cold habitats. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The results of transplanting *Impatiens balsamina* to degraded grassland in black soil areas and comparing the following year's grassland without transplantation are shown in the figure. In the figure, A is the comparison of total community biomass, B is the comparison of total vegetation cover, C is the comparison of species richness, and D is the comparison of soil moisture content. Detailed Implementation

[0019] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0020] Example 1: A method for ecological restoration of degraded grassland in black soil areas.

[0021] 1. Seed treatment All *Duwei* seeds used in the experiment were collected in the wild, and mature seeds with plump grains and free from pests and diseases were selected. Due to the physiological dormancy characteristics of *Duwei* seeds, the germination rate is low under natural conditions. Disinfection and artificial dormancy breaking are required before germination. A two-stage step-by-step screening and optimization method was used to establish the optimal germination pretreatment scheme for *Duwei* seeds.

[0022] Phase 1: Determining the optimal sodium hypochlorite concentration and disinfection time. Three sodium hypochlorite concentration gradients were established: 0.5%, 1%, and 1.5%, and four sodium hypochlorite disinfection times were established: 6 min, 8 min, 10 min, and 12 min, to explore the treatment combination with the lowest seed pathogen infection and mortality rates. Table 1 shows that disinfection with 1% sodium hypochlorite for 10 min was the most effective.

[0023] The second stage: Under the optimal disinfection conditions determined in the first stage, the germination-promoting effect of gibberellin on seeds was further investigated. Five gradients of gibberellin concentration were set: 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, and 250 mg / L; four gradients of gibberellin soaking time were set: 10 h, 15 h, 24 h, and 30 h. A systematic comparison of 20 treatment groups revealed (Table 2) that the germination rate of *Ligusticum striatum* showed a clear trend of first increasing and then decreasing with concentration and time. The highest average germination rate, reaching 78.56%, was achieved with a 150 mg / L gibberellin solution soaked for 24 h.

[0024] Table 1. Pathogen infection rate and mortality rate of *Ipomoea purpurea* seeds under different disinfection treatments. In summary, the best treatment for *Ipomoea aquatica* is to disinfect it with 1% sodium hypochlorite for 10 minutes, followed by soaking it in a 150 mg / L gibberellin solution for 24 hours.

[0025] After being soaked in gibberellin for a long time, the surface of the seeds absorbs water and swells, making them difficult to separate. Mix the seeds evenly with wood ash (the mass ratio of seeds to wood ash is 10:3) until the seeds no longer feel slippery and do not stick together. They are then ready for sowing.

[0026] Table 2 Germination rate of *Illicium verum* seeds under different concentrations of gibberellin and soaking times 2. Seedling raising The seedling soil substrate materials and their mass fractions are as follows: 40% peat moss (40 parts), 30% perlite (30 parts), 20% well-rotted organic fertilizer (20 parts), and 10% vermiculite (10 parts). The mixed soil substrate is placed into a sterilization bag and sterilized at 121℃ for 20 minutes. After cooling to 25℃, it is ready for use.

[0027] Seedlings were raised in 50-cell black trays with a diameter of 54 cm × 28 cm × 6 cm. Before sowing, the trays were disinfected by spraying or wiping with 75% alcohol. After the alcohol had completely evaporated, the sterilized soil substrate was evenly filled into each cell. The substrate height in each cell was controlled at 5 cm, with a 1 cm buffer space left at the top to facilitate the removal of the seedling root ball and transplanting in the field later. After the substrate was filled, water was supplied through the bottom tray using the bottom watering method. The surface of the soil substrate was continuously observed until the water was fully absorbed and saturated by capillary action, providing sufficient and uniform moisture for seed germination.

[0028] Sow 4 seeds evenly in each hole of the seedling tray, ensuring a spacing of 2 cm between seeds. Cover with 0.5 cm of soil, just enough to conceal the seeds. After sowing, cover the top of the seedling tray with a transparent film and place it in a greenhouse with a day / night temperature of 22℃ / 10℃. Observe the seeds daily after sowing and spray water to keep the soil substrate moist, avoiding direct sunlight at midday.

[0029] Five to eight days after sowing, the seeds begin to sprout, reaching peak germination between 10 and 15 days, and germination essentially ceases between 20 and 25 days. When the seedlings are close to the plastic film, remove the top film from the seedling tray and water promptly. Observe the seedling growth daily; if any seedlings die, rot, or become infected with disease, replant or remove them immediately to prevent affecting other healthy seedlings. When the seedlings have fully developed one to two true leaves, thin them out to ensure that only one healthy seedling remains in each hole of the seedling tray.

[0030] 3. Seedling transplantation When the seedlings of *Ipomoea aquatica* have grown to 5±1 true leaves, a crown width of 7.5±2.5 cm, and their roots have completely enveloped the soil substrate to form a root ball, they can be transplanted into the wild. Before transplanting, a 10-day in-situ hardening-off treatment is required: the seedling trays are directly transferred to the degraded grassland of the target black soil area, shade nets are erected for physical buffering, and during the hardening-off period, the shaded area is gradually reduced to induce the seedlings to adapt to the strong light and low humidity environment of the plateau.

[0031] After hardening off, seedlings can be transplanted, with the optimal time window being late June to early July. Depending on soil moisture, transplanting on a cloudy or rainy day is most suitable, as the soil moisture content is higher at this time, allowing the seedlings to recover quickly. If there are no cloudy or rainy days, avoid transplanting during periods of strong sunlight and water in advance to prevent seedling burn and death.

[0032] In the bare patches of degraded grassland on the black soil beach, use a professional soil drill with a diameter of 5 cm to pre-drill planting holes 10 cm deep. Then, transplant the seedlings of *Ipomoea aquatica* along with their complete root ball substrate, using a whole-body embedding method, transplanting 2 seedlings per hole, with a plant spacing of 20 cm. After transplanting, gently tamp down the surrounding soil to ensure that the root ball is in close contact with the hole wall.

[0033] 4. Field management after transplantation After transplanting, irrigation strategies should be dynamically adjusted based on weather and rainfall. If the cumulative rainfall within a week exceeds 20 mm, it is considered sufficient natural rainfall and no artificial intervention is needed. If rainfall is insufficient, irrigation should be carried out around the seedlings every two days, ensuring that the water penetrates to a depth of 15 cm. Simultaneously, attention should be paid to drainage to prevent waterlogging and root rot. Thinning should be carried out 15 days after transplanting, removing weaker seedlings from each planting hole according to the principle of "removing the weak and keeping the strong," ensuring concentrated seedlings. If an entire planting hole dies, strong seedlings from other planting holes can be used to replant and maintain population density.

[0034] The first 30 days after transplanting are a critical window for seedling establishment and transplanting. During this period, it is necessary to regularly remove weeds and competing plants around the *Ipomoea aquatica* plants to prevent seedling death due to light blockage and nutrient competition. Once the *Ipomoea aquatica* canopy has stabilized, the leaves are close to the ground, and transplanting has been successful, manual weeding should be stopped. The pioneer species advantage of *Ipomoea aquatica* should be utilized to promote the natural succession process, ultimately leading to the formation of a stable plant community in the degraded grassland.

[0035] *Eclipta prostrata* possesses a strong ability to adapt to its native habitat and a competitive advantage in nutrient availability. After establishment, it requires no additional artificial fertilization. Its extensive root system efficiently utilizes mineral nutrients in degraded black soil grasslands, achieving significant biomass growth and population expansion even under low-nutrient conditions. Furthermore, *Eclipta prostrata* is virtually free of leaf diseases and requires no artificial control, achieving low cost and high sustainability.

[0036] 5. Harvesting of medicinal parts and seeds Five years after planting, *Ipomoea aquatica* begins to flower. The above-ground parts are used medicinally. After flowering, in mid-August of the same year, the above-ground parts are cut horizontally with scissors at a height of 1.5 ± 0.5 cm from the ground. It is crucial to harvest only the above-ground parts and strictly prohibit uprooting the entire plant to ensure the underground root system remains intact, thus avoiding impacting the natural propagation of the *Ipomoea aquatica* population the following year and the continued yield of the medicinal parts. While harvesting the medicinal material, some healthy plants should be retained for seed collection, generally in September when the fruit spikes turn brown. After harvesting, the seeds are air-dried, cleaned until the grains are no longer sticky, and then stored at a low temperature of 4℃.

[0037] 6. Indicator survey and measurement The evaluation of the transplanting effect of *Ligustrum lucidum* was conducted from July to August of the year following the initial transplanting. This period allows for a better assessment of whether *Ligustrum lucidum* successfully overwintered, whether the population was established, and the species composition, quantity, and vegetation cover of the degraded grassland in the black soil area. The specific evaluation method involved using 1 m × 1 m quadrats in the transplanting area to investigate the species count within each quadrat, measuring the cover and aboveground biomass of *Ligustrum lucidum* and other species, and determining the soil moisture content from 0 cm to 10 cm using the oven-drying method. The oven-drying method was as follows: Weigh 30 g of soil sample into an aluminum box (A), weigh the wet soil plus the aluminum box (B), bring it back to the laboratory, dry it in an oven at 105℃ for 8 h, then cool it to room temperature, weigh the dry soil plus the aluminum box (C), and calculate the soil moisture content using the following formula:

[0038] Soil moisture content (%) = (BC) / (CA) × 100%.

[0039] The vegetation survey results showed that the successor species after transplantation exhibited a highly similar pattern. That is, with the successful establishment of *Erigeron breviscapus*, pioneer species with similar ecological niches and physiological characteristics, as well as strong tolerance to poor soil and strong dispersal ability, such as *Elsholtzia ciliata*, *Potentilla biloba*, *Potentilla chinensis*, *Potentilla spp.*, and *Stichopus japonicus*, were the first to migrate and establish themselves. Together with *Erigeron breviscapus*, they reconstructed the species composition of the initial community. The establishment and growth of these pioneer species directly drove the recovery of the initial biomass and cover of the degraded grassland. The experimental results show that the seedling cultivation and transplantation of *Ligustrum lucidum* (a type of wild herb) of this invention have a significant restorative effect on degraded bare-spot grasslands in alpine regions: the average aboveground biomass increased from the initial 8.56 g / m² to 27.69 g / m², of which *Ligustrum lucidum* biomass was 14.35 g / m², accounting for 51.8% of the total biomass; the average vegetation cover increased from the initial 7.32% to 67.34%, of which *Ligustrum lucidum* cover was 39.25%, accounting for approximately 58.3% of the total cover; simultaneously, species richness increased from an average of 2 species to 6 species, and soil moisture content increased from the initial 23.1% to 51.2%. Figure 1 (A~D).

[0040] The method provided by this invention has successfully achieved artificial colonization of *Ipomoea aquatica*. Through significant habitat improvement, it effectively drives the degraded grassland community in the black soil area towards positive succession towards structural stability, species diversity, and high coverage. At the same time, the above-ground parts of *Ipomoea aquatica* can be harvested for medicinal purposes, which can open up a stable income channel for local herders and achieve synergistic improvement in ecological restoration and herders' economic benefits.

[0041] Although preferred embodiments of the invention have been described, those skilled in the art, once they have learned the basic inventive concept, can make other changes and modifications to these embodiments.

[0042] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for ecological restoration of degraded grassland in black soil areas, characterized in that, The method promotes the establishment of Elsholtzia ciliata, Potentilla biloba, Potentilla chinensis, Potentilla spp. or Scutellaria baicalensis by transplanting Eupatorium fortunei, thereby increasing the aboveground biomass, vegetation cover, species richness or soil moisture content of degraded grasslands in black soil areas. Specifically, the following steps are included: After disinfecting the seeds of *Duyiwei*, soak them in a 100 mg / L to 150 mg / L gibberellin solution for 15 to 30 hours to promote germination. Germinated seeds of *Illicium verum* are sown in seedling trays containing seedling substrate for cultivation. After thinning and hardening off, the seedlings are transplanted.

2. The method according to claim 1, characterized in that, The disinfection process involves soaking the seeds of *Erigeron breviscapus* in a 1%–1.5% sodium hypochlorite solution for 8–12 minutes.

3. The method according to claim 1, characterized in that, The seedling substrate consists of 35-45 parts peat moss, 25-35 parts perlite, 15-25 parts well-rotted organic fertilizer, and 5-15 parts vermiculite.

4. The method according to claim 1, characterized in that, The seedling tray contains 3 to 5 seeds per hole, and the soil covering thickness is 0.3 cm to 0.7 cm.

5. The method according to claim 1, characterized in that, Thinning is carried out when the seedlings have grown 1-2 true leaves, with one seedling retained in each hole.

6. The method according to claim 1, characterized in that, The seedling hardening process involves cultivating seedlings until they have 4-6 true leaves, a crown width of 5-10 cm, and a root ball. Then, the seedling trays are transferred to degraded grasslands in black soil areas, and shade nets are erected for 8-12 days of in-situ hardening, gradually reducing the shaded area.

7. The method according to claim 1, characterized in that, The transplanting process involves using a soil drill with a diameter of 4 cm to 6 cm to make planting holes with a depth of 8 cm to 12 cm in the bare patches of degraded grassland. The seedlings, along with the root ball substrate, are then transplanted as a whole, with 1 to 3 seedlings per hole and a plant spacing of 15 cm to 25 cm.

8. The method according to claim 1, characterized in that, After transplanting, supplement irrigation according to rainfall, thin out the seedlings after 13-17 days, and remove weeds around the plants within 28-32 days.

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