Method for reseeding medicago ruthenica in degraded alpine meadow

Abstract

The invention belongs to the technical field of medicago ruthenica reseeding, and discloses a method for reseeding medicago ruthenica in degraded alpine meadow, which comprises the following steps: selecting a proper area and grassland; selecting medicago ruthenica seeds; carrying out hardening treatment; applying phosphate fertilizer and nitrogen fertilizer; no-tillage reseeding is carried out; and performing management after reseeding. According to the method, a certain amount of medicago ruthenica is resown, and a certain amount of fertilizer is applied, so that the proportion of leguminous forage in the degraded alpine grassland community can be increased, the grassland vegetation coverage can be improved, the forage quality can be improved, the nutrition of nitrogen and phosphorus in grassland soil can be increased, and the utilization and circulation of nitrogen and phosphorus in a grassland ecosystem can be promoted; the grassland coverage and yield are improved, grassland nutrition and soil fertility are improved, and the method plays an important role in animal husbandry production and stability and sustainability of a grassland ecosystem and has a wide application prospect. The technology is simple to operate, low in cost and easy for large-area popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of Medicago truncatula reseeding, and in particular relates to a method for reseeding Medicago truncatula on a degraded alpine meadow. Background Art

[0002] The vast natural grasslands in the alpine areas of the Qinghai-Tibet Plateau are the basis for the survival and generational management of local herdsmen. They are an important base for the development of animal husbandry, and are also an important area for building ecological barriers in the upper reaches of the Yangtze River and the Yellow River. Animal husbandry in the alpine areas of the Qinghai-Tibet Plateau is mainly based on grazing, but the lack of high-quality leguminous forage in the grassland has caused serious protein "hunger" problems in livestock. Leguminosae account for a small proportion of the community, and the nitrogen brought into the system through biological nitrogen fixation by leguminous plants is small. In addition, a large amount of nitrogen is lost every year due to overgrazing, soil erosion, etc., resulting in grassland nitrogen nutrition not enough. Therefore, reseeding leguminous forage is an important way to increase the crude protein content of grassland, use the nitrogen fixation characteristics of leguminous forage to improve soil fertility, and then increase grassland biomass and community diversity.

[0003] In alpine areas, degraded grasslands are mostly reseeded with grasses with strong adaptability, such as bluegrass, alkali grass, fescue, old sedge and other more cold-resistant grass species, to achieve the effect of ecological restoration and reconstruction of degraded grasslands. Most of the research on leguminous forage in alpine areas is limited to artificial grasslands, and mainly focuses on the construction of artificial grasslands mixed with annual leguminous plants, such as peas and arrow peas and grasses. There are also examples of scientific and technological workers trying to use leguminous forage to reseed degraded natural grasslands in alpine areas, such as reseeding with alfalfa, red bean grass, sand sorghum, and clover. The study found that the reseeding treatments of red bean grass, sand sorghum and clover could not survive the winter well, and the reseeding of alfalfa had a better effect. In general, reseeding leguminous plants in warm areas has a higher effect on grassland restoration, while reseeding degraded grasslands in alpine areas is mainly dominated by grasses.

[0004] Our team has attempted to conduct alfalfa reseeding research in the alpine meadows of the Qinghai-Tibet Plateau. In the year of reseeding, the seedlings emerged well, but in late summer and early autumn, alfalfa was sporadically visible in the grass, and the remaining alfalfa leaves were obviously yellow. This shows that the reseeded alfalfa is easily excluded by competition from the native meadow vegetation and has a clear competitive disadvantage. It is speculated that it may be mainly due to weak competitiveness for water and fertilizer, especially the serious lack of nitrogen and phosphorus. After reseeding, alfalfa also faces the problem of difficulty in wintering. Although the alfalfa seedlings emerged well that year, the alfalfa overwintering rate was almost zero.

[0005] Therefore, in view of the extremely complex ecological environment in the alpine areas, the production potential of forage grass is limited by a variety of harsh environmental conditions such as cold and drought. In addition, there are few high-yield and high-quality leguminous forage grasses in my country that are highly cold-resistant and drought-resistant. The introduction price is expensive and difficult to adapt to the environment in the plateau area. How to successfully establish leguminous forage grasses under the natural conditions of the alpine areas, and maintain a high proportion of leguminous grasses in natural grasslands for a long time through appropriate management measures, and select leguminous germplasm that is suitable for the harsh natural conditions in the alpine areas and has strong competitiveness is the key to successful reseeding.

[0006] The main companion grass species of alpine meadows, Alfalfa, is the only species in the genus Alfalfa that can adapt to extreme environments. It is very outstanding in terms of drought resistance, cold resistance, salt and alkali resistance, high protein content, and no saponin. It is conducive to the rapid fattening of livestock and improves the quality of dairy products. It is an excellent forage grass. The varieties introduced and domesticated using plateau wild Alfalfa have strong adaptability to local adverse climate and soil conditions. They are of great significance for improving natural grasslands, establishing and cultivating grasslands, and preventing and controlling soil erosion, especially ideal materials for improving natural grasslands in high-altitude drought and poor soil.

[0007] There are sporadic reports on the reseeding of flat alfalfa and related technologies in alpine areas. The research mainly targets severely degraded grasslands, poor soils, and areas with low vegetation coverage. The combination of flat alfalfa and grasses is used. The roots of legumes are deep in the soil, which can coexist with rhizobia and complete nitrogen fixation, while the roots of grasses are shallow in the soil, with a large specific surface area, which is conducive to nutrient absorption. For lightly or lightly to moderately degraded grasslands that are mowed or used for both mowing and grazing, from the perspective of production, ecology and economy, the reseeding of flat alfalfa can increase the proportion of legume forage in the community, increase the nutritional value of the grassland, improve the soil environment, and solve the bottleneck problem of lack of protein forage for livestock.

[0008] Nitrogen and phosphorus are one of the essential elements that cannot be missing in the emergence and establishment of leguminous forage. Available nitrogen and phosphorus in the soil are the main factors driving the growth and maintenance of leguminous forage in natural grasslands. Soil nitrogen and phosphorus deficiency is common in grasslands in northern my country, but the more nitrogen and phosphorus, the better. Exceeding the threshold will inhibit plant growth and development and affect the soil and ecological environment. Therefore, it is crucial to find the appropriate nitrogen and phosphorus application rate, which can effectively promote the initial growth and long-term maintenance of leguminous forage in the reseeding period.

[0009] Through the above analysis, the problems and defects of the prior art are as follows:

[0010] Leguminosae account for a small proportion of the community, and the nitrogen brought into the system through biological nitrogen fixation by leguminous plants is small. In addition, a large amount of nitrogen is lost every year due to overgrazing, soil erosion, etc., resulting in a shortage of grassland nitrogen nutrition. There are sporadic reports on the reseeding of leguminous forage. Sandy land generally chooses super-xerophytes such as Astragalus membranaceus that can prevent wind and fix sand. For reseeding in arid areas, drought-resistant forage grasses such as alfalfa are selected. Low-lying grasslands should choose barren-resistant, moisture-resistant, and shade-tolerant forage grasses such as Lotus japonicus. For saline land, salt-tolerant forage grasses such as alfalfa, Sainfoin, and Sweet Clover should be selected. However, although there are relevant studies on the reseeding of leguminous forage grasses in natural grasslands in alpine areas, they have not been well applied in practice. At present, the reseeding of degraded natural grasslands in alpine areas is mainly based on grasses with strong adaptability. The technical issues such as variety selection, reseeding method and time, and management of reseeding leguminous forage grasses in natural grasslands in alpine areas play an important role in improving the productivity of natural grasslands after reseeding and the stability of grassland communities. Summary of the invention

[0011] In view of the problems existing in the prior art, the present invention provides a method for reseeding Medicago truncatula on degraded alpine meadows.

[0012] The present invention is achieved by a method for reseeding Medicago truncatula in a degraded alpine meadow, comprising:

[0013] Step 1, select suitable areas and grasslands;

[0014] Step 2, select Medicago truncatula seeds;

[0015] Step 3, hardening treatment;

[0016] Step 4, applying phosphorus fertilizer and nitrogen fertilizer;

[0017] Step 5, no-till reseeding;

[0018] Step 6: Management after reseeding.

[0019] Further, the method for selecting suitable areas and grasslands is as follows:

[0020] Alpine meadows on the Qinghai-Tibet Plateau, slightly or slightly to moderately degraded grasslands with Medicago truncatula as the companion species.

[0021] Further, the selection of Medicago truncatula seeds:

[0022] The Medicago truncatula is a wild cultivated species that is cold-resistant, drought-resistant and barren-resistant, and is suitable for planting in areas with an altitude of 3000-3200m on the Qinghai-Tibet Plateau.

[0023] Further, the hardening treatment:

[0024] Before use, lightly grind the seeds of Medicago truncatula with sandpaper until the surface is rough and fuzzy, then soak them in 70-80℃ hot water for 10-15 minutes, and dry them naturally for use; or soak the seeds in 98% concentrated sulfuric acid for 30 minutes, then rinse with running water for 10 minutes, and dry them naturally.

[0025] Further, the application of phosphate fertilizer and nitrogen fertilizer:

[0026] Phosphate fertilizer dosage is 75-200 kg P ha -1 , nitrogen fertilizer dosage is 100 kg N ha -1 The specific amount of fertilizer is determined according to the measured value of soil fertility status; fertilizer can be applied twice, the first time is before the grass turns green and at the same time of reseeding, and fertilization is carried out with a no-till reseeding fertilizer machine for precise fertilization; the second time is when the grass turns green in the second year, and it is applied manually before it is cloudy and rainy, and each time half of the annual fertilizer amount is applied.

[0027] Further, the no-tillage overseeding:

[0028] On the basis of fencing and artificial rodent control, around mid-April before the natural grassland in the alpine areas of the Qinghai-Tibet Plateau turns green, the turf is scratched with a no-tillage seeder. The scratching process uses machine-driven discs with a spacing of 15 to 20 cm between the discs and a harrowing depth of 1.5 to 2 cm. The soil is covered and suppressed with the pressing wheels that come with the no-tillage seeder. Appropriate grazing can be allowed one week after sowing, with animal hooves trampling the seeds so that the seeds can come into good contact with the soil. Grazing is prohibited after one week to facilitate seedling emergence and deep rooting of the current year.

[0029] The theoretical sowing rate of flat clover is 15~22.5kg / hm 2 It is advisable to conduct a germination rate test on the treated seeds before reseeding and calculate the actual sowing amount based on the germination rate.

[0030] Further, the post-reseeding management:

[0031] It is best not to graze in the year of reseeding. If grazing is necessary, the grazing time is from October when the grass turns yellow in the first year to April before the grass turns green in the second year. After the second year, autumn mowing or winter grazing can be carried out in mid-to-late September. Derat control is very important in the year of reseeding and the second year. In places where conditions permit, it is recommended to carry out derat control every year before the grass turns green.

[0032] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0033] First, the key to the success of leguminous forage reseeding technology in high-altitude cold areas lies in: first, choosing excellent leguminous forage varieties that are adapted to the harsh local climate and soil conditions; second, adopting appropriate reseeding technology; and third, taking effective management measures.

[0034] The alpine areas of the Qinghai-Tibet Plateau are at high altitudes, with long and cold winters. Few legumes can safely overwinter in this area. This technology uses Longzhong No. 1 flat clover introduced and domesticated from wild flat clover on the alpine grasslands of the Qinghai-Tibet Plateau for overseeding. Through exploration of different overseeding rates, it was found that 15kg / hm2 of flat clover can effectively protect the slightly degraded grassland. 2 Reseeding amount, moderately degraded grassland 22.5kg / hm 2 The amount of reseeding is appropriate, and the seeds should comply with the provisions of GB 6141. Reseeding is best carried out in mid-April after the soil thaws and before the grass turns green. In order to prevent some places from being suppressed inaccurately, especially in the mouse hills, appropriate grazing can be allowed one week after reseeding, and the seeds can be trampled by animal hooves so that the seeds can be well in contact with the soil. Grazing is prohibited after one week, which is conducive to seedling emergence and deep rooting of the current year.

[0035] Previous studies have found that alpine grasslands generally have low levels of effective nitrogen and phosphorus and slow nutrient turnover. In order to ensure the effectiveness of reseeding, the appropriate addition of effective nitrogen and phosphorus is very important, especially phosphorus is more important for leguminous forage seed germination and seedling growth, but a certain amount of nitrogen is also needed before nodules form in the seedling stage. Studies have found that for mildly degraded grasslands, 75kg / hm 2 Phosphorus is more suitable, 200kg / hm2 for moderately degraded grassland 2 Phosphorus, 100kg / hm 2 Nitrogen is more suitable. Considering the production, economy and ecology, it is recommended to apply fertilizer twice, preferably at the time of seed sowing and the greening period of the second year. It is best not to graze in the year of reseeding. If grazing is necessary, the grazing time is from October when the grass turns yellow in the first year to April before the grass turns green in the second year. After the second year, autumn mowing and grass cutting can be carried out in mid-to-late September or it can be used as winter pasture for grazing. Prairie zokors and prairie pikas prefer to eat the roots of legumes, so rodent control is very important for the morphological establishment of reseeded alfalfa.

[0036] Reseeding a certain amount of ferns and beans + applying appropriate nitrogen and phosphorus fertilizers combined with reasonable management measures can not only increase the proportion of legume forage in degraded alpine grassland communities and improve grassland vegetation coverage, especially the restoration of bare mouse hill vegetation, but also improve forage quality, increase the nutrition of nitrogen and phosphorus in grassland soil, and promote the utilization and circulation of nitrogen and phosphorus in grassland ecosystems.

[0037] Supplementing Medicago truncatula with a certain amount of phosphorus and nitrogen fertilizers can promote the good growth of Medicago truncatula and give full play to its nitrogen fixation function. It can increase the coverage of grassland communities to more than 98% in a short period of time, increase grass production by more than 52.64% compared with the control, increase the crude protein of forage by more than 18.6%, and increase the content of soil organic matter by more than 20.08%. This technology has a significant inhibitory effect on weeds, especially, and promotes the growth of high-quality forage. The present invention not only improves grassland coverage and yield, but also improves forage nutrition and soil fertility, plays an important role in the stability and sustainability of animal husbandry production and grassland ecosystems, and has broad application prospects. This technology is simple to operate, low in cost, and easy to promote on a large scale.

[0038] Second, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0039] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0040] The alpine areas of the Qinghai-Tibet Plateau are mainly grazing, and grassland is the most important means of production for herders. High-quality forage and livestock products are extremely important to the lives of local herders. Reseeding native grass species is easy to succeed. After reseeding, grassland vegetation can be restored, and grassland yield and quality can be significantly improved. In particular, leguminous forage can be used to improve natural grasslands. Leguminous forage fixes nitrogen in the atmosphere and converts it into usable nitrogen nutrition, thereby improving the nutritional value of the entire grassland community, providing high-quality forage for livestock, increasing the quantity and quality of livestock products, and improving market competitiveness. It plays an important role in promoting the healthy development of animal husbandry in alpine areas, national food security, and economic development in pastoral areas.

[0041] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0042] Using no-till overseeding technology, while minimizing the damage to native vegetation, varieties bred from wild native clover are used to overseed degraded grasslands. Through rodent control, addition of nitrogen and phosphorus fertilizers, and certain management measures, the establishment and growth of the overseeded clover are promoted, filling the technical bottleneck of the difficulty in establishing legume forage in natural grasslands in high-altitude areas and the lack of high-quality legume forage in the community.

[0043] (3) The technical solution of the present invention solves the technical problems that people have been eager to solve but have never been able to solve successfully:

[0044] Due to the harsh natural environment in the alpine areas, there are extremely high requirements for reseeding grass seeds, especially reseeding leguminous forage grass is easily excluded by competition from native vegetation and affected by low temperatures in the alpine areas. How to successfully establish leguminous forage grass under natural conditions and maintain a higher proportion of leguminous grass in natural grasslands through appropriate management measures is a difficult problem faced by alpine grasslands in improving quality and efficiency. Using flat alfalfa beans bred from wild native grass seeds in the alpine areas for reseeding, screening out the more suitable reseeding amount for mildly to moderately degraded grasslands in the alpine areas, not only solves the problem of difficulty and lack of leguminous forage grass in natural grasslands in the alpine areas, significantly improves the nutritional value of forage grass, and significantly improves livestock production capacity. To ensure a higher emergence rate and growth of reseeded leguminous forage grass and maintain a higher proportion of leguminous forage grass in natural grasslands, reasonable phosphorus and nitrogen application is crucial. The combination of appropriate sowing amount and phosphorus and nitrogen can not only help the reconstruction of degraded grasslands by reseeding leguminous forage grass, but also improve grassland productivity and the proportion of leguminous forage grass.

[0045] Third, in alpine areas, the grassland ecological environment is fragile and the natural conditions are harsh, so traditional grassland restoration and yield increase methods are difficult to work. The main technical problems include:

[0046] 1) Low seed germination rate: The climate in high-altitude and cold regions is harsh, the temperature is low, the seed germination rate is low, and the survival rate is difficult to guarantee.

[0047] 2) Poor soil: The soil in alpine grasslands has low organic matter content and insufficient fertility, which affects plant growth.

[0048] 3) Traditional farming destroys grassland ecology: Traditional farming methods can easily destroy the surface soil structure of grasslands, causing soil erosion and further deteriorating the grassland ecological environment.

[0049] 4) Rodent and pest problems: Rodent pests are rampant in high-altitude areas. Use traditional bow and arrow methods to kill rodents and prevent other methods from polluting the grassland. Pests and diseases occasionally occur, and timely detection and taking certain measures can protect the healthy growth of grassland.

[0050] The present invention has achieved remarkable technical progress in the following aspects:

[0051] 1) Improve seed germination rate and survival rate: Through hardening treatment, the germination rate and survival rate of Medicago truncatula seeds are greatly improved, allowing them to adapt to the harsh climatic conditions in high-altitude and cold areas.

[0052] 2) Enhance soil fertility: Applying phosphorus fertilizer and nitrogen fertilizer improves soil nutritional status and promotes the healthy growth of plants.

[0053] 3) Protect grassland ecology: The use of no-tillage reseeding technology reduces the damage to the surface soil of the grassland, protects the grassland ecological environment, and prevents soil erosion.

[0054] 4) Efficient use of resources: Through reasonable reseeding quantity and scientific post-reseeding management, the efficiency of resource utilization is improved and the maximization of reseeding effect is ensured.

[0055] 5) Rodent and pest control: Scientific rodent control measures are used to reduce the impact of rodents on Medicago truncatula during the seedling stage. Regularly check the grassland to detect and control pests and diseases in time to ensure the healthy growth of Medicago truncatula.

[0056] In summary, the present invention not only solves the main problems in the prior art, but also achieves significant technical progress in the restoration and yield increase of alpine grasslands, and has important application value and promotion significance.

[0057] Fourthly, the method for reseeding Medicago truncatula in alpine degraded meadows of the present invention overcomes many difficulties in the prior art by selecting suitable areas and seeds, carrying out hardening treatment, applying fertilizers, no-till reseeding and post-reseeding management, and achieves significant technical progress, which is specifically manifested in the following aspects:

[0058] 1) Improve seed germination rate and survival rate: Hardening the seeds of Medicago truncatula by mechanical treatment, hot water treatment or chemical treatment effectively improves the germination rate and survival rate of the seeds and adapts to the harsh climatic conditions in high-altitude and cold areas. Through experiments, it was found that this treatment method can significantly improve the germination speed and germination rate of seeds.

[0059] 2) Enhance soil fertility and promote plant growth: Applying phosphorus and nitrogen fertilizers, especially in batches, can provide the nutrients needed for plant growth and promote root development and aboveground growth. Studies have shown that reasonable fertilizer application amount and application time can significantly increase grassland yield and quality.

[0060] 3) Protect grassland ecological environment: The use of no-tillage and reseeding technology avoids the damage to the grassland surface soil caused by traditional farming methods, reduces soil erosion, and protects the grassland ecological environment. No-tillage and reseeding technology preserves the surface structure of the grassland and improves the resistance and sustainability of the grassland.

[0061] 4) Rational use of resources and improved economic benefits: By scientifically determining the amount of reseeding, the effective use of seeds is ensured, avoiding waste of resources. At the same time, scientific arrangements for post-reseeding management, such as appropriate grazing or mowing, improve the efficiency of grassland utilization and economic benefits.

[0062] 5) In the management after reseeding, scientific rodent control measures are adopted to reduce the impact of rodents on Medicago truncatula and grassland, ensuring the healthy growth and high yield of grassland. Regularly check the grassland to detect and control pests and diseases in time. Various methods such as biological control and chemical control can be adopted to ensure the healthy growth of Medicago truncatula.

[0063] 6) Adapting to the specific environment of high-cold areas: The present invention is specifically designed for the special environment of the high-cold areas of the Qinghai-Tibet Plateau. Cold-resistant, drought-resistant, and barren-resistant flat alfalfa seeds are selected to ensure the applicability and effectiveness of the method in specific areas. Experiments have shown that the method has significant effects on grassland restoration and yield increase in high-cold areas.

[0064] In summary, the method for reseeding Medicago truncatula in alpine degraded meadows of the present invention not only solves the main technical problems in the prior art, but also achieves significant technical progress in ecological restoration and yield increase of alpine grasslands, and has important application value and promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The present invention is a flowchart of a method for reseeding Medicago truncatula in alpine grasslands provided by an embodiment of the present invention.

[0066] Figure 2 It is a data diagram of the implementation effect provided by an embodiment of the present invention; Figure A shows the effect of the technology on the biomass of grasslands with different degrees of degradation; Figure B shows the effect on the crude protein content of grassland; Figure C shows the effect on organic matter, available phosphorus and alkaline nitrogen in the 0-15cm soil layer; Figure D shows the effect on organic matter, available phosphorus and alkaline nitrogen in the 15-30cm soil layer.

[0067] Figure 3 This is a diagram of the effect of reseeding of Medicago truncatula provided by an embodiment of the present invention (the left picture shows reseeding in mouse hills, 2023.6.13, and the right picture shows the growth of Medicago truncatula in the community, 2023.7.2).

[0068] Figure 4 This is a comparison (2023.9.20) of the unreseeded Medicago truncatula (left picture) and the reseeded Medicago truncatula (right picture) provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] like Figure 1 As shown, a method for reseeding Medicago truncatula in an alpine meadow provided by an embodiment of the present invention comprises the following steps:

[0071] S101, select suitable areas and grasslands; select Medicago truncatula seeds;

[0072] S102, hardening treatment;

[0073] S103, application of phosphorus and nitrogen fertilizers;

[0074] S104, no-tillage overseeding;

[0075] S105, overseeding amount;

[0076] S106, management after reseeding.

[0077] The detailed working principle of the method for reseeding clover and bean in alpine grassland provided by the embodiment of the present invention is as follows:

[0078] S101: Select suitable areas and grasslands; select clover seeds

[0079] 1) Select suitable areas and grasslands: Select suitable reseeding areas based on the climate, soil conditions and grassland status of the alpine grassland. The ideal area should have appropriate moisture, light and temperature conditions to support the growth of Medicago truncatula.

[0080] 2) Selecting alfalfa seeds: Select high-quality, high-yield, and stress-resistant alfalfa seeds. The seeds should meet the requirements to ensure their purity and germination rate.

[0081] S102: Hard treatment

[0082] Seed hardening treatment: There is a hard seed coat on the surface of Medicago truncatula seeds, which affects seed germination. Hardening treatment can be performed by physical or chemical methods to improve seed germination rate. Common methods include:

[0083] Mechanical treatment: Use sandpaper or a sander to gently sand the seed coat to thin it.

[0084] Hot water treatment: Soak the seeds in 70-80℃ hot water for 10-15 minutes, then cool immediately.

[0085] Chemical treatment: Use sulfuric acid to treat the seed coat, but pay attention to the treatment time and concentration to avoid seed damage.

[0086] S103: Apply phosphorus and nitrogen fertilizers

[0087] Fertilization: Before sowing, apply appropriate amounts of phosphorus fertilizer and nitrogen fertilizer according to soil fertility. Phosphorus fertilizer helps promote root growth and early plant growth, while nitrogen fertilizer helps increase the chlorophyll content of plants, promote photosynthesis and growth. Fertilization can be done by broadcasting or striping.

[0088] S104: No-till reseeding

[0089] No-tillage reseeding: Use no-tillage sowing technology to reseed without destroying the original grassland vegetation and soil structure. Use a no-tillage seeder to evenly sow the treated clover seeds on the grassland, and control the sowing depth to 1.5-2cm to ensure that the seeds are fully in contact with the soil, which is conducive to seed germination and rooting.

[0090] S105: Reseeding amount

[0091] Determine the amount of overseeding: According to the current situation of the grassland and the characteristics of the clover seeds, determine the reasonable amount of overseeding. The general overseeding amount is 15-22.5kg / hm 2 The specific amount can be adjusted appropriately according to soil fertility, climatic conditions and grassland density.

[0092] S106: Post-seeding management

[0093] 1) Derat control: The period before and during the green period is when plateau zokors and pikas are rampantly active. Derat control during this period is very important to help prevent them from grazing on the green period pastures.

[0094] 2) Check the grassland regularly to find and control pests and diseases in time. You can use biological control, chemical control and other methods to ensure the healthy growth of Medicago.

[0095] 3) Appropriate grazing or mowing: The grazing time is from October when the grass turns yellow in the first year to April before the grass turns green again in the second year. After the second year, autumn mowing or winter grazing can be carried out in mid-to-late September.

[0096] Through the above steps, Medicago truncatula can be effectively reseeded on alpine grasslands to improve grassland productivity and ecological benefits.

[0097] The method for selecting suitable areas and grasslands provided by the embodiment of the present invention is as follows:

[0098] Alpine meadow on the Qinghai-Tibet Plateau, slightly or moderately degraded meadow with Medicago truncatula as the companion species.

[0099] The embodiment of the present invention provides the selection of Medicago truncatula seeds:

[0100] The Medicago truncatula is a wild cultivated species that is cold-resistant, drought-resistant and barren-resistant, and is suitable for planting in areas with an altitude of 3000-3200m on the Qinghai-Tibet Plateau.

[0101] The hardening process provided by the embodiment of the present invention:

[0102] Before use, lightly grind the seeds of Medicago truncatula with sandpaper until the surface is rough and fuzzy, then soak them in 70-80℃ hot water for 10-15 minutes, and dry them naturally for use; or soak the seeds in 98% concentrated sulfuric acid for 30 minutes, then rinse with running water for 10 minutes, and dry them naturally.

[0103] The application of phosphorus fertilizer and nitrogen fertilizer provided in the embodiment of the present invention:

[0104] Phosphate fertilizer dosage is 75-200 kg P ha -1 , nitrogen fertilizer dosage is 100 kg N ha -1The specific amount of fertilizer is determined according to the measured value of soil fertility status; fertilizer can be applied twice, the first time is before the grass turns green and at the same time of reseeding, and the fertilization is carried out by a no-till reseeding fertilizer machine to scratch the turf for precise fertilizer application; the second time is when the grass turns green in the second year, and it is applied manually before it is cloudy and rainy, and each time half of the annual fertilizer amount is applied.

[0105] The no-tillage overseeding provided by the embodiment of the present invention:

[0106] On the basis of fencing and artificial rodent control, in the mid-April before the natural grassland in the alpine areas of the Qinghai-Tibet Plateau turns green, the turf is scratched with a no-tillage seeding machine. The scratching process uses a machine-driven disc with a spacing of 15 to 20 cm between the discs and a harrowing depth of 1.5 to 2 cm. The soil is covered and pressed with the pressing wheel of the no-tillage seeding machine. Appropriate grazing can be allowed one week after the sowing, and the seeds can be trampled by animal hooves so that they can have good contact with the soil. Grazing is prohibited after one week to facilitate the emergence of seedlings and the deep rooting of the root system in the current year.

[0107] The theoretical sowing rate of flat clover is 15~22.5kg / hm 2 It is advisable to conduct a germination rate test on the treated seeds before reseeding and calculate the actual sowing amount based on the germination rate.

[0108] The post-rebroadcasting management provided by the embodiment of the present invention:

[0109] Investigate and control rodent and disease pests in a timely manner; it is best not to graze in the year of reseeding. If grazing is necessary, the grazing time should be from October when the grass is withering in the first year to April before the grass turns green in the second year; after the second year, autumn mowing and grass cutting can be carried out in mid-to-late September or it can be used as winter pasture for grazing.

[0110] The invention is mainly used for ecological restoration of degraded alpine meadows on the Qinghai-Tibet Plateau, and improvement and maintenance of grassland productivity and quality. The no-tillage reseeding technology is used to reseed and repair degraded alpine meadows without damaging the grassland as much as possible, and the morphological establishment and maintenance of reseeded Medicago truncatula are promoted by adding a certain amount of phosphorus and nitrogen and combining corresponding management measures.

[0111] The alpine areas of the Qinghai-Tibet Plateau are at high altitudes, with long and cold winters, and there are few legumes that can safely overwinter in this area. Through demonstration research, it was found that this technology used the Longzhong No. 1 flat clover variety introduced and domesticated from the wild flat clover of the Qinghai-Tibet Plateau alpine grassland to reseed, and the seedlings emerged quickly, especially the reseeding rate of naked mouse mounds was high, which had a significant promoting effect on the morphological establishment of naked mouse mound vegetation ( Figure 3 ), and the reseeding of flat lilac has a strong competitiveness in the community structure. The application of flat lilac with a certain amount of nitrogen and phosphorus fertilizer can promote the good growth of flat lilac and give full play to its nitrogen fixation function. This technology has a significant inhibitory effect on weeds and promotes the growth of high-quality forage grass ( Figure 4The invention not only improves grassland coverage and yield, but also improves grassland nutrition and soil fertility, plays an important role in the stability and sustainability of animal husbandry production and grassland ecosystem, and has broad application prospects. The technology is simple to operate, low in cost, and easy to promote on a large scale.

[0112] 1. Mildly degraded grassland: reseeding 15kg / hm2 of Medicago truncatula 2 + 75kg ha -1 Phosphorus +100kg ha -1 Nitrogen: Compared with the control, the biomass of grass and beans, forbs and total biomass increased by 74%, 80.9% and 77.7% respectively. For moderately degraded grassland: 22.5 kg / hm2 of Medicago truncatula was planted 2 + 200kg ha -1 Phosphorus +100kg ha -1 Compared with the control, nitrogen increased the biomass of grass and bean, weeds and total biomass by 68.47%, 39.71% and 52.64%, respectively. This restoration model significantly increased grass production.

[0113] Table 1 Effects of reseeding on plant cover and yield in the community

[0114]

[0115]

[0116] Note: T1 is mild degeneration, T2 is moderate degeneration, CK is the control, the same below.

[0117] 2. The crude protein, crude fat, calcium and phosphorus content of treatment T1 increased by 18.6%, 37.1%, 6.9% and 33.3% respectively compared with the control. The crude protein content of treatment T2 increased by 44.22%, crude fat increased by 20.79%, calcium increased by 20.83%, and phosphorus content increased by 13.33% compared with the control, all of which significantly improved the nutritional quality of forage.

[0118] Table 2 Effects of reseeding on the nutritional quality of grassland

[0119]

[0120] In the 3.0-15cm soil layer, the organic matter content increased by 47.61% and 47.50% under the T1 and T2 treatments, the available phosphorus had no significant change, and the alkaline nitrogen increased by 22.43% and 27.76%; in the 15-30cm soil layer, the organic matter content increased by 20.08% and 35.70% under the T1 and T2 treatments, the alkaline nitrogen increased by 9.12% and 26.35%, and the available phosphorus was 38.79% under the T1 treatment.

[0121] Table 3 Effect of reseeding on soil fertility

[0122]

[0123] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for reseeding Medicago truncatula in alpine degraded meadows, characterized in that: The following steps are involved: S101, select suitable areas and grasslands; select Medicago truncatula seeds; S102, hardening treatment; Treat the seeds of Medicago truncatula to harden; S103, application of phosphorus and nitrogen fertilizers; Apply phosphorus and nitrogen fertilizers before planting; S104, no-tillage overseeding; Adopt no-till seeding technology for reseeding, evenly spread the clover seeds on the grassland, and evenly sow the treated clover seeds on the grassland, with the sowing depth controlled at 1.5-2cm; S105, overseeding amount; Determine the appropriate amount of overseeding, which should be 15-22.5 kg per hectare of grassland; S106, post-reseeding management; After reseeding, carry out rodent control, pest control and moderate grazing or mowing.

2. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The hardening process comprises the following steps: Mechanical treatment: Use sandpaper or a sander to gently sand the seed coat to make it thinner; Hot water treatment: Soak the Medicago truncatula seeds in hot water at 70-80℃ for 10-15min, then cool immediately; Chemical treatment: Use sulfuric acid to treat the seed coat for 30 minutes, and then rinse the seeds thoroughly with clean water.

3. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The method for selecting suitable areas and grasslands is as follows: Degraded alpine meadows on the Qinghai-Tibet Plateau, slightly or moderately degraded meadows with Medicago truncatula as the companion species.

4. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: Choosing Medicago truncatula seeds: The Medicago truncatula is a wild cultivated species that is cold-resistant, drought-resistant and barren-resistant, and is suitable for planting in areas with an altitude of 3000-3200m on the Qinghai-Tibet Plateau.

5. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The hardening treatment: Before use, lightly grind the seeds of Medicago truncatula with sandpaper until the surface is rough and fuzzy, then soak them in hot water at 70-80℃ for 10-15 minutes, and dry them naturally for use; or soak the seeds in 98% concentrated sulfuric acid for 30 minutes, then rinse with running water for 10 minutes, and dry them naturally.

6. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The application of phosphorus fertilizer and nitrogen fertilizer: Phosphate fertilizer dosage is 75-200 kg P ha -1 , nitrogen fertilizer dosage is 100 kg N ha -1 The specific amount of fertilizer is determined according to the measured value of soil fertility status; fertilizer can be applied twice, the first time is before the grass turns green and at the same time of reseeding, and fertilization is carried out with a no-till reseeding fertilizer machine for precise fertilization; the second time is when the grass turns green in the second year, and it is applied manually before it is cloudy and rainy, and each time half of the annual fertilizer amount is applied.

7. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The no-tillage overseeding: On the basis of fencing and artificial rodent control, in the natural grasslands of the Qinghai-Tibet Plateau, before the grass turns green again: around mid-April, use a no-tillage seeding machine to scratch the turf. The scratching process uses a machine-driven disc with a spacing of 15 to 20 cm between the discs and a harrowing depth of 1.5 to 2 cm. Use the pressing wheel of the no-tillage seeding machine to cover the soil and press it down. One week after the seeding, grazing can be done appropriately, and the hooves of livestock can be used to trample the seeds so that the seeds can have good contact with the soil. After one week, grazing is prohibited to facilitate the emergence of seedlings and the deep rooting of the root system in the current year. The theoretical sowing rate of flat clover is 15~22.5kg / hm 2 It is advisable to conduct a germination rate test on the treated seeds before reseeding and calculate the actual sowing amount based on the germination rate.

8. The method for reseeding Medicago truncatula in alpine grassland according to claim 1, characterized in that: The post-reseeding management: It is best not to graze in the year of overseeding. If grazing is really necessary, the grazing time should be from October when the grass is withering in the first year to April before the grass turns green in the second year. After the second year, autumn mowing and grass cutting can be carried out in mid-to-late September or it can be used as winter pasture for grazing.

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