A phased and classified integrated management method for degraded grassland

Abstract

This invention provides a phased and categorized integrated management method for degraded grassland, belonging to the field of ecological restoration technology. Based on vegetation cover, this invention divides grassland into four stages: severely degraded grassland, moderately degraded grassland, moderately restored grassland, and basically restored grassland. According to the dominant factors of different degradation stages and types, it adopts a phased and categorized integrated management method of supplementation, stimulation, promotion, and adjustment, significantly improving the targeting, efficiency, and stability of degradation management.

Description

Technical Field

[0001] This invention belongs to the field of ecological restoration technology, and in particular relates to a phased and classified integrated management method for degraded grassland. Background Technology

[0002] Grasslands are the most widely distributed renewable resource in the world and the largest terrestrial ecosystem. They not only directly provide humans with essential resources like meat, eggs, and dairy products, but also offer various indirect services, such as climate and gas regulation, water conservation, soil and water retention, air purification, windbreak and sand fixation, and maintaining carbon-oxygen balance. In recent years, with the increase in global population and the rapid development of heavy industry and the economy, while focusing on economic development, humans have neglected the ecological restoration function of grasslands and the balance between ecosystems, overusing grassland resources for production and daily life, such as large-scale grassland reclamation, overgrazing by herders, and improper management practices. Therefore, how to curb grassland degradation and accelerate ecological restoration has become an urgent global issue.

[0003] Grassland restoration techniques are a crucial component of grassland ecosystem recovery. In my country, over 20 degraded grassland restoration techniques are known, including commonly used methods such as fencing, no-till reseeding, root pruning, fertilization, and the addition of microbial agents. Unique techniques include grass checkerboard barriers, fish-scale pits, and rodent control. While these grassland ecological restoration techniques have achieved some success in my country, most studies are affected by regional differences, lacking broad applicability and a comprehensive assessment of the overall ecological environment restoration effect. Although these measures can increase grassland cover, height, and aboveground biomass to a certain extent in the short term, the restoration level may rebound or even decrease compared to the original level over time. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a phased and classified integrated management method for degraded grasslands. This method is highly applicable and widely used. While taking into account both ecology and production, it follows the concept of near-natural restoration with natural restoration as the main approach and artificial intervention as a supplement, ultimately achieving efficient restoration of degraded grasslands.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A phased and categorized integrated management method for degraded grassland includes the following steps:

[0007] Based on vegetation cover, grasslands are divided into four stages: severely degraded grasslands, moderately degraded grasslands, moderately restored grasslands, and basically restored grasslands.

[0008] For severely degraded grasslands, a "replenishment" approach is adopted, including reseeding with native grass species and applying fertilizers to improve soil fertility;

[0009] For moderately degraded grasslands, the "stimulation" measures are adopted, including breaking the sod or harrowing the land, applying different gradients of water, and applying water-retaining and fertilizer-locking agents and plant growth regulators to stimulate the activity of the soil seed bank.

[0010] For moderately restored grasslands, "promotion" measures are adopted, including fencing or root pruning, fertilization and irrigation management, to promote the growth of dominant species;

[0011] For grasslands that have been basically restored, the "adjustment" measures are adopted, including the rational use of resources and the ecological restoration and reconstruction of damaged plots, in order to optimize the function of the ecosystem.

[0012] Preferably, the vegetation coverage of the severely degraded grassland is <30%, the vegetation coverage of the moderately degraded grassland is 30%-60%, the vegetation coverage of the moderately restored grassland is 60%-85%, and the vegetation coverage of the basically restored grassland is >85%.

[0013] Preferably, the reseeding of native grass species includes the following steps: selecting grass species according to the actual condition of the degraded grassland, reseeding before the summer rains arrive, and using broadcasting, row sowing, hole sowing or aerial sowing methods.

[0014] Preferably, the application of fertilizer includes the following steps: fertilizing in the early stage of plant growth; the type of fertilizer is determined based on the results of the soil physicochemical property survey, selecting one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer, and the specific amount of fertilizer is determined through the "3414" fertilization experiment or orthogonal experiment.

[0015] Preferably, the specific operation of breaking the turf is to use a root cutter or manual trenching, with a breaking depth of 3-5cm and a row spacing of 10-15cm.

[0016] Preferably, the alternating application of different gradient water includes: in arid or semi-arid regions, simulating rainfall through artificial irrigation, and alternately applying different gradient water to stimulate soil seed bank activity.

[0017] Preferably, the applied plant growth regulator includes naphthaleneacetic acid, gibberellin, brassinolide, or sodium nitrophenolate and chlorpyrifos; the application concentration is determined by germination test and sprayed on the soil surface to promote seed germination.

[0018] Preferably, the root cutting, fertilization, and irrigation management include: root cutting depth of 3-5 cm; and application of nitrogen fertilizer at 100-150 kg / hm². 2 and phosphate fertilizer 60-90 kg / hm 2 Irrigation volume is 500-1000m³ 3 / hm 2 .

[0019] Preferably, the rational use of resources includes: implementing fencing to prohibit grazing, grazing rest or rotational grazing, and optimizing grassland resource utilization by coordinating grazing management and nutrient management.

[0020] Preferably, the ecological restoration and reconstruction includes: collecting, preserving and protecting native grass species, screening varieties that are drought-resistant, cold-resistant, have high germination rates and high biomass yields; and establishing breeding bases and resource nurseries in suitable areas to provide seed source guarantees for grassland ecological restoration.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention systematically considers the dominant factors of degraded grasslands at different stages and types of degradation, and adopts a phased and typed comprehensive management method of replenishment, stimulation, promotion and adjustment, which significantly improves the targeting, efficiency and stability of degradation management.

[0023] This invention systematically improves the harsh native environment of degraded grasslands, stimulates the activity of soil seed banks, promotes natural vegetation regeneration, and has outstanding ecological functions. It enhances the grasslands' ability to prevent wind erosion and sand fixation, conserve water and soil, and provide ecological services, effectively consolidating and improving the regional ecological barrier function, and greatly improving the stability and sustainability of grassland ecosystems.

[0024] The restoration measures of this invention are simple and easy to implement, with low investment costs, short duration, quick results, and significant economic benefits. They can be applied and promoted in the restoration of degraded grassland vegetation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the phased and classified integrated management method for degraded grassland according to the present invention;

[0026] Figure 2 Effects of NAA, BR, sodium nitrophenolate + chlorpyrifos, and gibberellin on total community biomass;

[0027] Figure 3 The impact of comprehensive measures on vegetation community cover;

[0028] Figure 4 The impact of integrated measures on the species number of vegetation communities

[0029] Figure 5 The impact of comprehensive measures on the existing above-ground vegetation;

[0030] Figure 6 The impact of comprehensive measures on soil ammonium nitrogen;

[0031] Figure 7The impact of comprehensive measures on available phosphorus in the soil;

[0032] Figure 8 The seasonal variation of available phosphorus content in the soil after fertilization;

[0033] Figure 9 The seasonal variation of soil available nitrogen content after fertilization;

[0034] Figure 10 This refers to the seasonal changes in soil organic matter content after fertilization;

[0035] Figure 11 The seasonal variation in soil electrical conductivity after fertilization;

[0036] Figure 12 This represents the seasonal variation in soil pH after fertilization. Detailed Implementation

[0037] This invention provides a phased and classified integrated management method for degraded grasslands, such as... Figure 1 As shown, it includes the following steps:

[0038] Based on vegetation cover, grasslands are divided into four stages: severely degraded grasslands, moderately degraded grasslands, moderately restored grasslands, and basically restored grasslands.

[0039] In this invention, it is preferred that the vegetation coverage of severely degraded grassland is <30%, the vegetation coverage of moderately degraded grassland is 30%-60%, the vegetation coverage of moderately restored grassland is 60%-85%, and the vegetation coverage of basically restored grassland is >85%. It is further preferred that the vegetation survey be carried out during the peak growing season of grassland degradation (mid-August). The method is to randomly select 1m×1m quadrats in a “Z” or “S” pattern for each plot, with a replication number of ≥5, and determine the vegetation coverage by visual estimation.

[0040] For severely degraded grasslands, a "replenishment" approach is adopted, including reseeding with native grass species and applying fertilizers to improve soil fertility. In the stage of severe grassland degradation, primary productivity, soil quality, and plant diversity all decline, with large areas of bare vegetation. The grassland ecosystem can no longer self-recover through its own succession; therefore, timely replenishment with native grass species and soil fertility is necessary. Fertilization improves grassland soil nutrition, promotes seed source and plant growth, and improves grass community structure. Reseeding replenishes the soil seed bank, enhances seed renewal capacity, promotes the progressive succession of degraded grasslands, maintains grassland stability, improves grassland productivity, and enhances forage quality.

[0041] In this invention, reseeding with native grass seeds includes the following steps:

[0042] (1) Grass species should be selected based on the actual conditions of the degraded grassland. Furthermore, native grass species that promote community growth should be selected for reseeding, with local varieties being preferred. As an implementation method, in areas with severe wind erosion and desertification, where water is scarce and planting is difficult, plant species with well-developed root systems, strong water absorption capacity, and strong drought resistance should be selected. For saline-alkali degraded grasslands, salt-tolerant plant species should be chosen. For crops used in grazing areas or for economic purposes such as mowing, low-lying grasses should be the primary choice.

[0043] (2) It is preferable to reseed before the summer rains arrive, so as to ensure sufficient moisture and good light conditions. Sowing methods include broadcasting, row sowing, hole sowing or aerial sowing.

[0044] (3) It is preferable to use a mixed sowing method of grass and legume in the early stage of planting, with grass as the main species, in a ratio of 2:1 or 1.5:1 (m / m), and to select bare patches and vacant positions for re-sowing.

[0045] In this invention, applying fertilizer includes the following steps:

[0046] (1) It is preferable to apply fertilizer in the early stage of plant growth, and even more preferable to implement it first in the most severely degraded soil, so as to improve the physical and chemical properties of the soil, help the formation of aggregate structure, and meet the nutrient needs of plants at all stages of growth and development.

[0047] (2) The preferred fertilizer type is determined based on the results of the soil physicochemical property survey. Choose one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer. Applying nitrogen fertilizer is more conducive to the growth of grass plants. Applying phosphorus fertilizer and potassium fertilizer is suitable for the growth and development of legumes. Applying organic fertilizer is slow to take effect and is mainly used as base fertilizer, while inorganic fertilizer is fast to take effect and is mainly used as top dressing.

[0048] (3) The specific amount of fertilizer should be determined through the “3414” fertilization experiment or orthogonal experiment, and further optimized through specific experimental data results to comprehensively formulate fertilization methods suitable for the local area.

[0049] For moderately degraded grasslands, a "stimulation" approach is adopted, including breaking up the sod or harrowing the land, applying different gradients of water, and applying water-retaining fertilizers and plant growth regulators to stimulate the activity of the soil seed bank. Compared to severely degraded stages, while reseeding and fertilization can increase plant yields in moderately degraded stages, their effects are short-lived and prone to "rebound" or even "regression." Therefore, "replenishment" measures are not used. Considering the sustainable use and development of grasslands, stimulating the soil seed bank preserved in degraded grasslands becomes crucial.

[0050] (1) Breaking the turf or harrowing the soil: Breaking the turf helps retain moisture and allow air to enter, providing a prerequisite for the germination of the seed bank in the surface soil. In this invention, the preferred specific operation for breaking the turf is to use a root cutter or manual trenching, with a breaking depth of 3-5cm, more preferably 4cm; and a row spacing of 10-15cm, more preferably 12cm.

[0051] (2) Alternating application of different water gradients: In arid and semi-arid regions, the stimulating effect of water on the soil seed bank is far more significant than that of other environmental factors such as sunlight and altitude. In this invention, it is preferable to use alternating application of different water gradients instead of rainfall to stimulate the activity of the soil seed bank.

[0052] (3) Apply water-locking and fertilizer-retaining agents: By replenishing the water around the seeds and the soil nutrients, conditions are provided for seed germination.

[0053] (4) Application of plant growth regulators: Applying appropriate concentrations of plant growth regulators to stimulate the vitality of the soil seed bank and promote rapid seed germination. In this invention, preferred plant growth regulators include naphthaleneacetic acid, gibberellin, brassinolide, or sodium nitrophenolate and chlorpyrifos; further preferred application concentrations are determined by germination tests and sprayed onto the soil surface to promote seed germination.

[0054] For moderately restored grasslands, a "promotion" approach is adopted, including fencing or root pruning, fertilization, and irrigation management, to promote the growth of dominant species. In the moderate restoration stage, dominant species play a crucial role in the plant community and are key to maintaining the stability of community structure and function. Dominant species possess high ecological adaptability and can largely determine the environmental conditions within the community, influencing the survival and growth of other species. In a relatively resource-rich environment, tall plants become dominant, reducing species competitiveness and increasing heterogeneity, providing significant opportunities for invasive species and vegetation reorganization, thereby increasing species richness. For the moderate restoration stage of grasslands, a single restoration measure is insufficient to positively regulate the complex community; a combination of multiple approaches is necessary.

[0055] (1) Enclosure: Enclosure can eliminate interference from human activities and livestock, which is conducive to the restoration of the dominance of perennial grasses as the community recovers, reducing the ecological niche occupied by weeds. At the current stage, enclosure has the best effect on the restoration of plant primary productivity and soil quality.

[0056] (2) Root pruning, fertilization, and irrigation management: In this invention, the root pruning depth is preferably 3-5 cm, and more preferably 4 cm. Unlike fertilization during the severe degradation stage, the purpose of fertilization at this stage is to regulate the plant, acting around the dominant plant. The amount used is small but must be precise, with nitrogen fertilizer preferably applied at 100-150 kg / hm².2 and phosphate fertilizer 60-90 kg / hm 2 Further optimization of nitrogen fertilizer application: 150 kg / hm 2 And phosphate fertilizer 90kg / hm 2 The preferred irrigation volume is 500-1000 m³. 3 / hm 2 Further preferred is 750m 3 / hm 2 Comprehensive measures can increase grassland fertility and composition in multiple ways, enhance soil microbial function and metabolism, and promote soil nutrient cycling through the secreted chemical substances, thereby improving soil fertility and vegetation productivity, promoting the growth and development of dominant vegetation, and thus better maintaining the stability of the community and its functions.

[0057] For grasslands that have been basically restored, a "regulation" approach is adopted, including the rational use of resources and the ecological restoration and reconstruction of damaged areas to optimize ecosystem functions. When utilizing grassland ecosystem resources, we should not only consider the economic benefits brought by livestock production, but also pay attention to the various service functions that grassland ecosystems provide to humans. Adhering to the principle of "adapting to local conditions and implementing differentiated policies," we should scientifically and systematically utilize grassland ecological restoration technologies to coordinate ecosystem functions as a whole.

[0058] (1) Rational use of resources: In the management of grassland ecosystems, we must adhere to the concept of development and protection, rationally utilize water resources, soil resources and vegetation resources, and avoid over-exploitation and over-utilization that could lead to resource depletion and ecosystem dysfunction. Therefore, by coordinating grazing management and nutrient management, and adopting a fenced "grazing ban / restoration / rotational grazing" restoration model, we can optimize the utilization of grassland resources.

[0059] (2) Ecological restoration and reconstruction of damaged areas: Prioritize methods such as replanting local plants, restoring natural vegetation, and repairing aquatic ecosystems to help restore ecosystem functions. As an feasible approach, native grass species are the first choice for reseeding in ecological restoration. However, insufficient seed sources are a significant constraint on grassland restoration. Specific methods include collecting, preserving, and protecting native grass species, while comprehensively evaluating the traits of potential and valuable grass germplasm resources, such as stress resistance, germination rate, plant height, and grass yield. Conduct research on stress resistance, seed germination treatment, and artificial propagation to achieve grass germplasm innovation. Select native ecological grass varieties with drought resistance, cold resistance, high germination rate, high biomass yield, and suitable growth cycle. Establish breeding bases and resource nurseries in suitable areas to provide seed source guarantees for grassland ecological restoration.

[0060] In this invention, preferably after adopting the above-mentioned measures of "supplementation, stimulation, promotion, and adjustment," regular maintenance and management are carried out, including operations to prevent diseases, pests, and rodents. Finally, effectiveness analysis is conducted based on feedback results, and strategies are adjusted promptly for problems encountered during the process, ultimately achieving efficient restoration of degraded grassland. Further preferably, during maintenance and management, patrols are strengthened to monitor the condition of grassland fencing in real time, preventing illegal grazing during grazing ban periods. If any damage to fencing is discovered, responsibility is investigated, and repairs are required within a specified timeframe. Rodent control is achieved using chemical pesticides. Disease and pest control requires regular surveys of grassland health; upon identifying problems, biological, chemical, and physical control methods are combined to achieve control. More preferably, after completing the above steps, a statistical analysis of the vegetation and soil conditions of the restored grassland should be conducted annually during the peak growing season. Local meteorological data should be retrieved, and statistical analysis should be performed using interannual data. Adjustments should be made promptly and accurately based on the results.

[0061] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0062] Example 1

[0063] A phased and categorized integrated management method for degraded grassland includes the following steps:

[0064] The experimental grassland was divided into four zones based on vegetation coverage: severely degraded zone (vegetation coverage <30%); moderately degraded zone (vegetation coverage 30%-60%); moderately restored zone (vegetation coverage 60%-85%); and basically restored zone (vegetation coverage >85%).

[0065] (1) Severely degraded areas – “Replenishment” measures

[0066] Objective: To replenish grass seeds and soil fertility, and restore primary productivity.

[0067] Specific implementation steps:

[0068] (1.1) Reseeding with native grass seeds:

[0069] Grass species selection: Select wind-resistant and drought-tolerant grasses (sheepgrass, ice grass) and leguminous grasses (almond grass) for mixed sowing at a ratio of 2:1.

[0070] Reseeding time: mid-June (before the rainy season), using aerial seeding technology, with a seeding rate of 15 kg / hm² for grasses. 2 Leguminosae 7.5 kg / hm 2 .

[0071] Reseeding area: Select a bare patch area (patch diameter > 1m).

[0072] (1.2) Soil fertilization:

[0073] Fertilizer selection: Based on soil test results (alkaline nitrogen <50mg / kg, available phosphorus <10mg / kg), apply nitrogen-phosphorus compound fertilizer (N:P2O5=2:1).

[0074] Fertilizer application rate: 100 kg / hm² of nitrogen fertilizer 2 Phosphate fertilizer 50 kg / hm 2 Mechanical application was used.

[0075] (2) Moderately degraded area – “stimulation” measures

[0076] Objective: To stimulate the activity of the soil seed bank and promote natural regeneration.

[0077] Specific implementation steps:

[0078] (2.1) Break the turf: Use a root cutter to break the turf to a depth of 4cm and a row spacing of 12cm to create micro-topographical gullies.

[0079] Time: After the spring thaw (early April).

[0080] (2.2) Alternating irrigation: Simulate the natural rainfall cycle and irrigate alternately every 10 days (mild: 10mm, severe: 30mm).

[0081] (2.3) Plant growth regulators: Agent: Spray brassinolide (BR) 0.2 mg / L, 200 L per hectare.

[0082] Time: Grass seed germination period (late May).

[0083] (3) Moderate recovery zone – “Promotion” measures

[0084] Objective: To promote the growth of dominant species and stabilize the community structure.

[0085] Specific implementation steps:

[0086] (3.1) Enclosure management: Set up wire fences to prohibit grazing and human interference, and the enclosure period is 3 years.

[0087] or

[0088] (3.1) Root pruning + precision fertilization: Root pruning depth: 4cm, row spacing 15cm, loosen the soil. Fertilization plan: Apply nitrogen fertilizer (urea, 50kg / hm) around the roots of the dominant species (sheepgrass). 2 ) and phosphate fertilizer (superphosphate, 30 kg / hm) 2 ).

[0089] (3.2) Drip irrigation system: irrigation volume 750m 3 / hm 2Irrigation is carried out three times: during the greening stage, the jointing stage, and the heading stage.

[0090] (4) Basic recovery area – “adjustment” measures

[0091] Objective: To optimize ecosystem functions and achieve sustainable use.

[0092] Specific implementation steps:

[0093] (4.1) Rotational grazing management: Divide the area into 3 rotational grazing zones, with each zone having a grazing cycle of 30 days, and control the carrying capacity.

[0094] (4.2) Conservation of native grass species:

[0095] Germplasm resource bank construction: Collect local high-quality grass species (such as sheepgrass and needlegrass) and establish a 10-mu resource nursery.

[0096] Artificial breeding: Select drought-resistant and high-yielding varieties, with an annual output of 500 kg of grass seeds.

[0097] Example 2

[0098] A degradation restoration experimental platform was established in 2014 on the southern slope of Argalangtu, Xilinhot, a moderately degraded grassland. Five plant growth regulators screened through previous indoor seed germination experiments were applied to the platform to improve the germination rate of seeds from the native soil seed bank. The five plant growth regulators screened indoors were formulated into four treatments (including one combination) and a control. Each treatment contained three concentrations: naphthaleneacetic acid (NAA) 20 mg / L, 100 mg / L, 200 mg / L; gibberellin (GA3) 10 mg / L, 50 mg / L, 100 mg / L; brassinolide (BR) 0.02 mg / L, 0.2 mg / L, 2 mg / L; and sodium nitrophenolate + chlorpyrifos (10 mg / L + 0.5 mg / L, 50 mg / L + 2.5 mg / L, 100 mg / L + 5 mg / L), with five replicates. Plant biomass was measured for two consecutive years during the vigorous growth period.

[0099] Implementation effect monitoring:

[0100] like Figure 2 As shown, after NAA spraying, two measurements of community biomass both indicated that the biomass was highest under the 20 mg / L treatment. The two BR survey results were inconsistent, which is related to the time effect. The results for sodium nitrophenolate + chlorpyrifos treatment are as follows: both surveys showed that the biomass was highest under the 10 mg / L sodium nitrophenolate + 0.5 mg / L chlorpyrifos treatment. The gibberellin treatment results showed that the 10 mg / L treatment had the best effect on biomass in both surveys. The results of the two-year follow-up study indicate that appropriate plant growth regulator treatments can promote plant community growth and increase grassland plant biomass.

[0101] Example 3

[0102] Experimental location: Typical grassland of Xilinhot

[0103] A survey of the soil and vegetation conditions in the study area determined that the degradation was at a moderate recovery stage, and comprehensive regulation was adopted for remediation. From 2015 to 2017, comprehensive regulation experiments with optimized combinations of regulation technologies were conducted in the experimental area of ​​the degradation recovery experimental platform. The experiment adopted a three-factor combination orthogonal experiment. The specific experimental scheme and orthogonal array design are shown in Table 1. The comprehensive regulation experiment was designed with 5 treatment levels, with 5 replicates for each treatment, and the experiment adopted a Latin square setup.

[0104] Table 1. Orthogonal experimental design table and specific experimental schemes

[0105]

[0106] Implementation effect monitoring:

[0107] (1) Optimization of regulatory measures

[0108] By analyzing the orthogonal experimental results of the survey data (Table 2), the optimal ratio of each factor can be determined based on the average value (k) of the corresponding index results at each level. Vegetation survey indicators include a series of indicators such as community cover, species composition, species height, species density, species biomass, productivity, and litter. The results show that community cover and height are significantly affected by plant regulation, and both are influenced by optimal and suboptimal plant regulation schemes, respectively. Grazing optimization is the main factor affecting community density, fresh weight, and biomass, while soil conservation has the most significant impact on litter.

[0109] Table 2 Range Analysis of Experimental Results

[0110]

[0111]

[0112] Note: In the experimental factors, 1: optimal level; 2: suboptimal level; k1: average of the optimal level; k2: average of the suboptimal level; R: |k1-k2|.

[0113] (2) The impact of comprehensive regulation on dominant species of Leymus chinensis and Stipa krychnifedipin

[0114] As shown in Tables 3 and 4, the comprehensive regulation treatments all had some impact on the dominant species of Leymus chinensis and Stipa krusei. For Leymus chinensis, treatment 3 had the best effect on its height, number of clumps, and aboveground biomass. Orthogonal analysis revealed that plant regulation had the most significant effect, ranking first. Soil conservation and grazing optimization measures had different effects on Leymus chinensis. Soil conservation had a greater effect on all Leymus chinensis indicators than grazing optimization, while grazing optimization was superior to soil conservation in its impact on Stipa krusei. Overall, N 100 kg / hm 2 +P₂O₅60kg / hm 2 The optimal combination of sodium nitrophenolate 50 mg / L, chlorpyrifos 2.5 mg / L, and 8 sheep units / plot showed the best effect on Leymus chinensis; N 150 kg / hm 2 +P2O590kg / hm 2 The combined regulatory combination of sodium nitrophenolate 50 mg / L, chlorpyrifos 2.5 mg / L, and 4 sheep units / plot showed the best effect on *Stipa kryne*.

[0115] Table 3. Impact of comprehensive regulation on dominant Leymus chinensis species

[0116] deal with Height (cm) <![CDATA[Number of clusters (number / m 2 )]]> <![CDATA[Fresh weight (g / m 2 )]]> <![CDATA[Dry weight (g / m 2 ) <!-- 8 -->]]> 1 22.56 21.07 8.36 5.16 2 19.34 9.53 8.24 4.42 3 23.9 34.53 18.21 10.52 4 22.82 22.87 12.43 6.74

[0117] Table 4. The impact of comprehensive regulation on dominant species of *Stipa krychnifolia*

[0118] deal with Height (cm) <![CDATA[Number of clusters (number / m 2 )]]> <![CDATA[Fresh weight (g / m 2 )]]> <![CDATA[Dry weight (g / m 2 )]]> 1 24.09 18.87 65.24 43.37 2 27.6 14.93 60.67 40.24 3 30.44 20.33 69.91 47.46 4 28.87 21.47 87.55 57.77

[0119] (3) The impact of comprehensive regulation measures on vegetation communities

[0120] like Figure 3-5 As shown, in 2015, with favorable hydrothermal conditions, the various integrated control measures played a significant role. Compared with the control, the control measures increased vegetation cover by an average of 14%, density by 10%, and total aboveground biomass by 160%. Furthermore, the control measures increased the number of species by an average of 20%. The results indicate that integrated control measures not only improve grassland vegetation productivity but also enhance the species diversity of degraded grasslands, achieving the expected goals. In 2016, with relatively arid conditions, compared with the control, the vegetation cover under the control measures increased slightly, density decreased by 10%, and total aboveground biomass increased by 9%. Even under relatively arid conditions, integrated control measures could increase plant biomass accumulation. In 2017, with extremely arid conditions, only a few treatment combinations showed improvement in cover and density compared to the control, producing positive effects; other treatments and indicators did not achieve effective results.

[0121] like Figure 6 and Figure 7As shown, among the comprehensive control measures, plant growth regulators promoted plant growth, significantly increasing plant height and biomass, and improving many physiological indicators. After the addition of soil nutrients, the content of readily available soil nutrients such as available nitrogen and available phosphorus showed an increasing trend. Soil microbial communities changed, improving soil nutrient supply capacity and laying an important foundation for improving vegetation productivity.

[0122] Example 4

[0123] The experimental area is located in Argalangtu, Xilingol League, Inner Mongolia Autonomous Region, 15 km from Xilinhot City. The average annual precipitation over the past 50 years is 350 mm, the average annual temperature is 1.7℃, and the soil type is sandy soil. Prior to 2014, the grassland showed severe degradation due to long-term heavy grazing. A fertilization experiment was conducted in June of that year. The experiment included two fertilization treatments: inorganic fertilizer and organic fertilizer. The inorganic fertilizer treatment was a two-factor (nitrogen and phosphorus) four-level three-replicated design (N0 and P0 were no fertilization, N1, N2, and N3 were 50 kg / hm²). 2 100kg / hm 2 150kg / hm 2 ;

[0124] P1, P2, and P3 are each 30 kg / hm² 2 60kg / hm 2 90kg / hm 2 Organic fertilizer was treated with sheep manure (2 levels, 3 replicates, M1 was 2000 kg / hm² of well-rotted sheep manure). 2 M2 is 4000 kg / hm² of well-rotted sheep manure. 2 Soil samples were collected from the experimental plots during the two growing months of July and August each year, with soil samples collected at depths of 0-10 cm and 10-20 cm, and brought back to the laboratory for testing. One month after fertilization each year, the grassland vegetation composition, aboveground biomass, and belowground biomass of each plot were measured.

[0125] Implementation effect monitoring:

[0126] like Figure 8 As shown, fertilization results indicate that applying inorganic phosphate fertilizer can increase the available phosphorus content in the soil, while applying nitrogen fertilizer can increase the available nitrogen content, especially in the top 0-10 cm layer where the change is more significant than that in the 10-20 cm layer. The available phosphorus content in the soil shows a trend of rapid increase after fertilization followed by a rapid decrease, with the content in July (one month after fertilization) being higher than in June and August. Overall, the available phosphorus content shows an increasing trend from year to year.

[0127] like Figure 9As shown, fertilization has a significant impact on the available nitrogen content in the 0-10cm soil layer, but a smaller impact on the 10-20cm soil layer. Under the same fertilization treatment, the available nitrogen content in the 0-10cm soil layer is significantly higher than that in the 10-20cm soil layer. In the 0-10cm soil layer, the available nitrogen content generally increases with increasing nitrogen fertilizer application. There is no significant change in available nitrogen content under different sheep manure levels. The available nitrogen content in June and July is generally higher than that in August.

[0128] like Figure 10 As shown, although the organic matter varied between plots, the changes were irregular, and fertilization failed to affect the level of organic matter in the short term. The difference in organic matter content between the 0-10cm soil layer and the 10-20cm soil layer was also not significant.

[0129] like Figure 11 As shown, soil electrical conductivity changed significantly after fertilization. In July, it increased overall with increasing nitrogen application, and at the same nitrogen application rate, it also increased with increasing phosphorus application. The electrical conductivity of the 0-10 cm soil layer was higher than that of the 10-20 cm layer, and the conductivity in July was generally higher than in June and August. This indicates that some of the ions increased by fertilization were fixed over time.

[0130] like Figure 12 As shown, the soil pH level did not change significantly overall and did not respond obviously to fertilization. The soil pH in the 0-10cm and 10-20cm soil layers was basically 7.5-8.0.

[0131] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A phased and categorized integrated management method for degraded grassland, characterized in that, Includes the following steps: Based on vegetation cover, grasslands are divided into four stages: severely degraded grasslands, moderately degraded grasslands, moderately restored grasslands, and basically restored grasslands. For severely degraded grasslands, a "replenishment" approach is adopted, including reseeding with native grass species and applying fertilizers to improve soil fertility; For moderately degraded grasslands, a "stimulating" approach is adopted, including breaking the sod or harrowing the land, alternating the application of different water gradients, and applying water-retaining and fertilizer-locking agents and plant growth regulators to stimulate soil seed bank activity. The alternating application of different water gradients includes, in arid or semi-arid regions, simulating rainfall through artificial irrigation, and alternating the application of different water gradients to stimulate soil seed bank activity. The application of plant growth regulators includes naphthaleneacetic acid, gibberellin, brassinolide, or sodium nitrophenolate combined with chlorpyrifos; the application concentration is determined through germination tests and sprayed onto the soil surface to promote seed germination. For moderately restored grasslands, "promotion" measures are adopted, including fencing or root pruning, fertilization, and irrigation management, to promote the growth of dominant species. The root pruning, fertilization, and irrigation management include: root pruning depth of 3-5 cm; and application of nitrogen fertilizer at 100-150 kg / hm². 2 and phosphate fertilizer 60-90 kg / hm 2 Irrigation volume is 500-1000m³ 3 / hm 2 ; For grasslands that have been basically restored, the "adjustment" measures are adopted, including the rational use of resources and the ecological restoration and reconstruction of damaged plots to optimize ecosystem functions. The rational use of resources includes: implementing fencing and grazing bans, grazing rest or rotational grazing models, and optimizing grassland resource utilization by coordinating grazing management and nutrient management. The vegetation coverage of severely degraded grassland is <30%, that of moderately degraded grassland is 30%-60%, that of moderately restored grassland is 60%-85%, and that of basically restored grassland is >85%.

2. The method according to claim 1, characterized in that, The reseeding of native grass species includes the following steps: selecting grass species according to the actual condition of the degraded grassland, and reseeding before the summer rains arrive, using broadcasting, row sowing, hole sowing or aerial sowing methods.

3. The method according to claim 1, characterized in that, The application of fertilizer includes the following steps: fertilizing in the early stage of plant growth; the type of fertilizer is determined based on the results of the soil physicochemical property survey, selecting one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer, and the specific amount of fertilizer is determined through the "3414" fertilization experiment or orthogonal experiment.

4. The method according to claim 1, characterized in that, The specific operation of breaking the turf involves using a root cutter or manually opening trenches, with a breaking depth of 3-5cm and a row spacing of 10-15cm.

5. The method according to claim 1, characterized in that, The ecological restoration and reconstruction include: collecting, preserving and protecting native grass species, and screening varieties that are drought-resistant, cold-resistant, have high germination rates and high biomass yields; and establishing breeding bases and resource nurseries in suitable areas to provide seed source guarantees for grassland ecological restoration.

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