Staged and classified comprehensive treatment method for degraded grassland

Abstract

The invention provides a staged and classified comprehensive treatment method for degraded grassland, and belongs to the technical field of ecological restoration. According to the vegetation coverage, the grassland is divided into four stages, namely a seriously degraded grassland, a moderately degraded grassland, a moderately recovered grassland and a basically recovered grassland, and according to dominant factors of the degraded grassland in different degradation stages and types, a comprehensive treatment method of supplementing, exciting, promoting and regulating in stages and types is adopted. And the target performance, efficiency and stability of degradation treatment are obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological restoration, and in particular relates to a method for comprehensive management of degraded grasslands by stages and categories. Background Art

[0002] Grassland is the most widely distributed renewable resource in the world and the largest ecosystem on land. It not only directly provides humans with production and living materials such as meat, eggs and milk, but also provides humans with various indirect services, such as gas and climate regulation, water conservation, soil and water conservation, air purification, wind and sand fixation, and carbon oxygen balance. Ecosystem and service functions. In recent years, with the increase in the global population and the rapid development of heavy industry and economy, while focusing on economic development, humans have neglected the ecological restoration function of grasslands and the balance between ecosystems, and over-utilized grassland production and living materials, such as large-scale grassland reclamation, overgrazing by herders, and improper management measures, resulting in grasslands degrading to varying degrees around the world, seriously restricting the sustainable development of the national economy. At the same time, a large amount of forage needs to be introduced from abroad, which has placed a serious burden on the national fiscal economy. Therefore, how to curb the degradation of grasslands and accelerate ecological restoration has become a global problem that needs to be solved urgently.

[0003] The restoration technology of degraded grassland is an extremely important component of grassland ecosystem restoration. There are more than 20 known degraded grassland restoration technologies in my country. Commonly used technologies include fencing, no-tillage reseeding, root cutting, adding fertilizers, adding microbial agents, etc. Special technologies include grass grid sand barriers, fish scale pits, rodent control, etc. Although different grassland ecological restoration technologies in my country have achieved certain results, most of the studies are affected by regional differences, lack wide adaptability, and lack an overall evaluation of the restoration effect of the entire ecological environment. Although these measures can increase the coverage, height, and aboveground biomass of the grassland to a certain extent in a short period of time, as the recovery time goes by, the degree of recovery will rebound to a certain extent, and even decrease compared with the original level. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for comprehensive management of degraded grassland in a phased and classified manner. The method has strong applicability and wide application. While taking into account ecology and production, it follows the concept of near-natural restoration with natural restoration as the main and artificial intervention as the auxiliary, and ultimately achieves efficient restoration of degraded grassland.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for comprehensive management of degraded grassland by stages and categories, comprising the following steps:

[0007] According to the vegetation coverage, grasslands are divided into four stages: severely degraded grassland, moderately degraded grassland, moderately restored grassland and basically restored grassland.

[0008] For severely degraded grasslands, measures to improve soil fertility are taken, including reseeding native grass species and applying fertilizers;

[0009] For moderately degraded grasslands, "stimulation" measures are taken, including scratching the turf or harrowing the ground, applying different gradients of water alternately, 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 cutting, fertilization and irrigation management, to promote the growth of dominant species;

[0011] In order to basically restore the grassland, "adjustment" measures are taken, including rational use of resources, ecological restoration and reconstruction of damaged land, 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 seeds comprises the following steps: selecting grass seeds according to the actual conditions of the degraded grassland, and reseeding before the arrival of summer rains, using broadcasting, row sowing, hole sowing or aerial sowing.

[0014] Preferably, the application of fertilizers includes the following steps: fertilizing in the early stage of plant growth; the type of fertilizer is determined based on the results of a survey of the physical and chemical properties of the soil, and one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer are selected, and the specific amount of fertilizer is determined by a "3414" fertilization test or an orthogonal test.

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

[0016] Preferably, the alternating application of different gradients of moisture includes: in arid or semi-arid areas, simulating rainfall through artificial irrigation, and alternatingly applying different gradients of moisture to stimulate soil seed bank activity.

[0017] Preferably, the applied plant growth regulators include naphthylacetic acid, gibberellins, brassinolide or sodium nitrophenolate and chlorfenapyr; the applied 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 includes: root cutting depth of 3-5 cm; nitrogen fertilizer application of 100-150 kg / hm 2 and phosphate fertilizer 60-90kg / hm 2 ; irrigation volume is 500-1000m 3 / hm 2 .

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

[0020] Preferably, the ecological restoration and reconstruction include: collecting, preserving and protecting native grass seeds, screening varieties that are drought-resistant, cold-resistant, have high germination rates and high biological yields; establishing breeding bases and resource gardens 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] The present invention systematically considers the dominant factors of degraded grasslands at different degradation stages and types, and adopts a comprehensive management method of supplementation, stimulation, promotion and adjustment in different stages and types, which significantly improves the targeting, efficiency and stability of degradation management.

[0023] The present invention systematically improves the harsh native environment of degraded grassland, stimulates the activity of soil seed banks, promotes natural renewal of vegetation, and has outstanding ecological functions. It enhances the ability of grassland to prevent wind and sand, maintain water and soil, and provide ecological services, effectively consolidates and enhances the regional ecological barrier function, and greatly improves the stability and sustainability of grassland ecosystems.

[0024] The restoration measures of the present invention are simple and easy to implement, with low investment cost, short duration, quick effect, and huge economic benefits, and can be applied and promoted in the process of restoring degraded grassland vegetation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the method for comprehensive management of degraded grassland in stages and categories according to the present invention;

[0026] Figure 2 The effects of NAA, BR, sodium nitrophenolate + chlorfenapyr and gibberellin on the total biomass of the community;

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

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

[0029] Figure 5The impact of comprehensive measures on the aboveground stock of vegetation communities;

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

[0031] Figure 7 The effects of comprehensive measures on soil available phosphorus;

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

[0033] Fig. 9 It is the seasonal change of soil alkaline nitrogen content after fertilization;

[0034] Fig.10 seasonal changes in soil organic matter content after fertilization;

[0035] Fig.11 is the seasonal variation of soil electrical conductivity after fertilization;

[0036] Fig.12 It is the seasonal change of soil pH after fertilization. DETAILED DESCRIPTION

[0037] The present invention provides a method for comprehensive management of degraded grassland by stages and categories, such as Figure 1 As shown, the following steps are included:

[0038] According to the vegetation coverage, grassland is divided into four stages: severely degraded grassland, moderately degraded grassland, moderately recovered grassland and basically recovered grassland.

[0039] In the present 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 recovered grassland is 60%-85%, and the vegetation coverage of basically recovered grassland is >85%; it is further preferred to conduct vegetation surveys in the peak growing season of grassland degradation (early to mid-August), by randomly selecting 1m×1m plots in a "Z" or "S" shape for each sample plot, with a repetition number ≥5, and selecting a visual estimation method to determine the vegetation coverage.

[0040] For severely degraded grasslands, "replenishment" measures are taken, including reseeding native grass seeds and applying fertilizers to improve soil fertility. In the stage of severe grassland degradation, grassland primary productivity, soil quality, and plant diversity have all declined, the area of ​​bare surface plants is large, and the grassland ecosystem can no longer recover according to its own succession. Therefore, it is necessary to replenish native grass seeds and soil fertility in a timely manner. Fertilization improves the nutritional status of grassland soil, promotes the growth of seed sources and plants, and improves the structure of grass communities; reseeding grass seeds replenishes the soil seed bank, improves the ability of seed renewal, promotes the progressive succession of degraded grasslands, maintains the sustained stability of grasslands, improves the production capacity of grasslands and improves the quality of forage.

[0041] In the present invention, reseeding native grass seeds comprises the following steps:

[0042] (1) It is preferred to select grass species according to the actual conditions of the degraded grassland, and it is further preferred to select native grass species that have a promoting effect on the community, and more preferably local varieties with strong resistance. As an implementation method, in areas with severe wind erosion and desertification, where there is a lack of water and it is difficult to establish a plant, plant varieties with well-developed root systems, strong water absorption capacity, and strong drought resistance should be selected; in the selection of salinized and degraded grasslands, salt-alkali tolerant plant varieties should be selected; in the selection of crops for economic purposes such as grazing land or mowing land, plant varieties that are mainly low-lying grass should be selected.

[0043] (2) It is best to carry out overseeding before the arrival of summer rains to ensure sufficient moisture and good light conditions, using broadcast sowing, row sowing, hole sowing or aerial sowing.

[0044] (3) It is preferred to choose a mixed sowing method of Gramineae and Leguminosae in the early stage of planting, with Gramineae as the main species in a ratio of 2:1 or 1.5:1 (m / m), and select bare patches and vacant positions for overseeding.

[0045] In the present invention, applying fertilizer comprises the following steps:

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

[0047] (2) The preferred type of fertilizer is determined based on the results of the soil physical and chemical properties survey, and one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer can be selected; nitrogen fertilizer is more conducive to the growth of grass plants; phosphorus fertilizer and potassium fertilizer are suitable for the growth and development of leguminous plants; organic fertilizer has a slow effect and is mainly used as base fertilizer, while inorganic fertilizer has a fast effect and is mainly used as topdressing.

[0048] (3) It is preferred that the specific amount of fertilizer be determined through a "3414" fertilization test or an orthogonal test, and it is further preferred that a comprehensive fertilization method adapted to the local situation be formulated based on specific test data results.

[0049] For moderately degraded grasslands, "stimulation" measures are taken, including scratching the turf or raking the ground, applying different gradients of water alternately, and applying water-retaining and fertilizer-locking agents and plant growth regulators to stimulate the activity of the soil seed bank. Compared with the severe degradation stage, reseeding and fertilization can increase plant yields in the moderately degraded stage, but the duration is short and it is very easy to "rebound" or even "regress". Therefore, "supplement" measures are not adopted. Considering the sustainable use and development of grasslands, stimulating the soil seed bank retained in degraded grasslands becomes the key.

[0050] (1) Scratching the turf or raking the ground: Scratching the turf is conducive to the retention of moisture and the entry of air, providing a prerequisite for the germination of the surface soil seed bank. In the present invention, the specific operation of scratching the turf is preferably to use a root cutter or manual furrowing, with a scratching depth of 3-5 cm, more preferably 4 cm; the row spacing is 10-15 cm, more preferably 12 cm.

[0051] (2) Alternating application of different gradients of water: In arid and semi-arid areas, the stimulating effect of water on the soil seed bank is far more significant than other environmental factors such as light and altitude. In the present invention, it is preferred to alternately apply different gradients of water instead of rainfall to stimulate the activity of the soil seed bank.

[0052] (3) Apply water-locking and fertilizer-retaining agents: This provides conditions for seed germination by replenishing the moisture around the seeds and the soil nutrients.

[0053] (4) Applying plant growth regulators: Apply plant growth regulators at appropriate concentrations to stimulate the vitality of the soil seed bank and promote rapid seed germination. In the present invention, preferably, the plant growth regulators include naphthylacetic acid, gibberellins, brassinolide or sodium nitrophenolate and chlorfenapyr; further preferably, the application concentration is determined by germination tests and sprayed on the soil surface to promote seed germination.

[0054] For moderately restored grasslands, "promotion" measures are taken, including fencing or root cutting, fertilization and irrigation management, to promote the growth of dominant species. In the moderate recovery stage, dominant species occupy an important position in the plant community and are the key to maintaining the stability of community structure and function. Dominant species have a high degree of ecological adaptability and can largely determine the environmental conditions within the community, affecting the survival and growth of other species. In an environment with relatively rich resources, tall plants become dominant species, which will reduce the competitiveness of species in the environment and increase the heterogeneity of the environment, providing great opportunities for the invasion of alien species and the reorganization of vegetation, thereby increasing species richness. For the moderate recovery stage of grasslands, a single restoration measure is difficult to have a positive regulation on complex communities, and a combination of multiple methods must be adopted.

[0055] (1) Fencing: Fencing can eliminate interference from human activities and livestock, which is conducive to the restoration of perennial grass plants as the community recovers through succession, reducing the ecological niches occupied by weeds. At the current stage, fencing has the best effect on the restoration of plant primary productivity and soil quality.

[0056] (2) Root cutting, fertilization and irrigation management: In the present invention, the preferred root cutting depth is 3-5 cm, and more preferably 4 cm. Different from fertilization in the severe degeneration stage, the purpose of fertilization in this stage is to regulate and act around the dominant plants. The amount is not large but must be accurate. Preferably, 100-150 kg / hm2 of nitrogen fertilizer is applied. 2 and phosphate fertilizer 60-90kg / hm 2 , further preferably nitrogen fertilizer 150kg / hm 2 and phosphate fertilizer 90kg / hm 2 ; The preferred irrigation volume is 500-1000m 3 / hm 2 , more preferably 750m 3 / hm 2 Comprehensive measures can increase grassland fertility and composition structure from multiple aspects, enhance the functional metabolism of soil microorganisms, and secrete chemical substances that promote soil nutrient circulation, thereby improving soil fertility and vegetation productivity, and promoting the growth and development of dominant vegetation, so as to better maintain the stability of the community and function.

[0057] For the basic restoration of grassland, "adjustment" measures are taken, including rational use of resources, ecological restoration and reconstruction of damaged plots, to optimize the function of the ecosystem. When utilizing grassland ecosystem resources, we should not only consider the economic benefits brought by animal husbandry production, but also pay attention to the various service functions provided by grassland ecosystems to humans. Based on the principle of "adapting measures to local conditions and implementing policies in a classified manner", we should scientifically and systematically use grassland ecological restoration technologies to coordinate the functions of the ecosystem as a whole.

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

[0059] (2) Ecological restoration and reconstruction of damaged plots: Replanting local plants, restoring natural vegetation, and repairing aquatic ecosystems are preferred to help the ecosystem restore its functions. As a feasible implementation method, native grass seeds are the first choice for ecological restoration and reseeding grass seeds, but the lack of seed sources has become an important constraint on grassland restoration. Specific practices include collecting, preserving, and protecting native grass seeds. At the same time, comprehensive evaluation of the characteristics of potential and important grass germplasm resources such as stress resistance, germination rate, plant height, and grass yield is carried out. Research on artificial domestication such as stress resistance, seed germination treatment, and artificial breeding is carried out to achieve grass germplasm innovation, screen out rural ecological grass varieties with drought resistance, cold resistance, high germination rate, high biological yield, and suitable growth cycle, and establish breeding bases and resource gardens in suitable areas to provide seed source guarantee for grassland ecological restoration.

[0060] In the present invention, it is preferred to adopt the above-mentioned "supplement, stimulation, promotion, and adjustment" measures, and then regularly carry out maintenance management, prevent pests and diseases, rodents and other operations, and finally conduct effectiveness analysis based on the feedback results, and timely adjust the strategy planning for problems that arise in the process, and finally achieve efficient restoration of degraded grasslands. It is further preferred that during the maintenance and management period, inspections are strengthened to grasp the status of grassland fences in real time to prevent the occurrence of stealing grazing during the grazing ban period. Once the fence facilities are found to be damaged, the responsibility must be clarified and repaired within a time limit; rodent damage is controlled by drugs; the control of pests and diseases requires regular surveys of the health status of the grassland. After problems are found, biological control, chemical control, physical control and other methods are combined for use to achieve the purpose of control. It is more preferred that after completing the above steps, the vegetation and soil conditions of the restored grassland should be counted once during the peak season of plant growth each year, and local meteorological data should be retrieved, combined with inter-annual data for statistical analysis, and adjustment measures should be made in a timely and accurate manner according to the results.

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

[0062] Example 1

[0063] A method for comprehensive management of degraded grassland by stages and categories, comprising the following steps:

[0064] The experimental grassland was divided into four areas according to vegetation coverage: severely degraded area (vegetation coverage <30%); moderately degraded area (vegetation coverage 30%-60%); moderately restored area (vegetation coverage 60%-85%); and basically restored area (vegetation coverage >85%).

[0065] (1) Severely degraded areas: “supplementary” measures

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

[0067] Specific implementation steps:

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

[0069] Grass seed selection: Choose wind-resistant and drought-tolerant grasses (leepgrass, wheatgrass) and legumes (Astragalus) for mixed sowing in a ratio of 2:1.

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

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

[0072] (1.2) Soil fertilization:

[0073] Fertilizer selection: According to the soil test results (alkaline nitrogen <50mg / kg, available phosphorus <10mg / kg), apply nitrogen-phosphorus compound fertilizer (N:P 2 O 5 =2:1).

[0074] Fertilizer application amount: Nitrogen fertilizer 100kg / hm 2 , phosphate fertilizer 50kg / hm 2 , use mechanical spreading.

[0075] (2) Moderately degraded areas: “stimulating” measures

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

[0077] Specific implementation steps:

[0078] (2.1) Scrape the turf: Use a root cutter to scratch the turf to a depth of 4 cm and a row spacing of 12 cm to form micro-topography gullies.

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

[0080] (2.2) Alternating irrigation: Simulate the natural rainfall cycle and alternate irrigation every 10 days (light: 10 mm, heavy: 30 mm).

[0081] (2.3) Plant growth regulators: Agents: 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: Promote the growth of dominant species and stabilize community structure.

[0085] Specific implementation steps:

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

[0087] or

[0088] (3.1) Root cutting + precision fertilization: Root cutting depth: 4cm, row spacing 15cm, loose soil. Fertilization plan: Apply nitrogen fertilizer (urea, 50kg / hm2) in holes around the roots of the dominant species (Leymus chinensis). 2 ) and phosphate fertilizer (superphosphate, 30kg / hm 2 ).

[0089] (3.2) Drip irrigation system: irrigation volume 750m 3 / hm 2 , irrigation should be carried out three times: at the greening stage, jointing stage and 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: The farm is divided into three rotational grazing areas, each with a grazing cycle of 30 days and controlled livestock carrying capacity.

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

[0095] Germplasm resource bank construction: collect local high-quality grass seeds (such as Leymus chinensis and Stipa krylovii) and establish a 10-acre resource garden.

[0096] Artificial breeding: Screen drought-resistant and high-yield varieties, with an annual grass seed production of 500kg.

[0097] Example 2

[0098] In 2014, a degradation restoration test platform was established on the southern slope of Arigalangtu in Xilinhot, which is a moderately degraded grassland. Five plant growth regulators selected through the previous indoor seed germination test were used on the degradation restoration experimental platform to improve the germination rate of seeds in the native soil seed bank. The five plant growth regulators selected indoors were mixed into four treatments (including one combination) and one control, each treatment containing three concentrations, including naphthaleneacetic acid (NAA20mg / L, 100mg / L, 200mg / L), gibberellin (GA 3 10mg / L, 50mg / L, 100mg / L), brassinolide (BR 0.02mg / L, 0.2mg / L, 2mg / L), sodium nitrophenolate + chlorfenapyr (10mg / L+0.5mg / L, 50mg / L+2.5mg / L, 100mg / L+5mg / L), 5 replicates. Plant biomass was measured during the vigorous growth period for two consecutive years.

[0099] Implementation effect monitoring:

[0100] like Figure 2 As shown in the figure, after NAA spraying, the two measurements of community biomass showed that the biomass under the 20mg / L treatment was the highest; the two survey results of BR were inconsistent, which was related to the time effect; the results of sodium nitrophenolate + chlorfenapyr treatment were as follows, and the biomass under the 10mg / L sodium nitrophenolate + 0.5mg / L chlorfenapyr treatment was the largest in both results; the treatment results of gibberellin showed that the biomass effect under the 10mg / L treatment was the best in both surveys. The results of the two consecutive years of research showed that appropriate plant growth regulator treatment can promote the growth of plant communities and increase the biomass of grassland plants.

[0101] Example 3

[0102] Test location: Typical grassland in Xilinhot

[0103] The soil and vegetation conditions in the study area were investigated, and it was determined that the degradation stage was at the moderate recovery stage, and comprehensive control measures were adopted for governance. From 2015 to 2017, a comprehensive control test study on the optimization combination of control technologies was carried out in the test area of ​​the degradation restoration test platform. The test adopted a three-factor combination orthogonal experiment. The specific test plan and orthogonal table design are shown in Table 1. The comprehensive control test designed a total of 5 treatment levels, each with 5 replicates, and the test adopted a Latin square setting.

[0104] Table 1 Orthogonal test design table and specific test plan

[0105]

[0106] Implementation effect monitoring:

[0107] (1) Optimal selection of control measures

[0108] Through the orthogonal test results analysis of the experimental survey data (Table 2), the optimal ratio of each factor can be determined according to the size of the average value (k) of the index results corresponding to each level of each factor. Vegetation survey indicators include community coverage, species composition, species height, species density, species biomass, productivity and litter. The results show that community coverage and height are significantly affected by plant regulation, and both are affected by the optimal and suboptimal regulation schemes of plants, respectively. Grazing optimization is the main factor affecting community density, fresh weight and biomass, and soil conservation has the most significant effect on litter.

[0109] Table 2 Experimental results range analysis table

[0110]

[0111]

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

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

[0114] As shown in Tables 3 and 4, each treatment of comprehensive regulation has a certain degree of impact on the dominant species of Leymus chinensis and Stipa krylovii. For Leymus chinensis, treatment 3 has the best effect on its height, number of clusters and aboveground stock. In the orthogonal analysis, it was found that the effect of plant regulation was the most obvious and ranked first, while the effects of soil conservation and grazing optimization measures on Leymus chinensis were different. The effect of soil conservation on the various indicators of Leymus chinensis was greater than that of grazing optimization, while grazing optimization was better than soil conservation in terms of its impact on Stipa krylovii. In comprehensive comparison, N 100kg / hm 2 +P 2 O 5 60kg / hm 2 + sodium nitrophenolate 50mg / L+ chlorfenapyr 2.5mg / L+8 sheep units / plot had the best effect on Leymus chinensis; N 150kg / hm 2 +P 2 O 5 90kg / hm 2 The comprehensive control combination of + sodium nitrophenolate 50mg / L+ chlorfenapyr 2.5mg / L+ 4 sheep units / plot has the best effect on Stipa krylovii.

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

[0116] deal with Height (cm) <![CDATA[Number of clumps (pcs / 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 Effects of comprehensive regulation on dominant species of Stipa krylovii

[0118] deal with Height (cm) <![CDATA[Number of clumps (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) Impact of comprehensive control measures on vegetation communities

[0120] like Figure 3-5 As shown in the results, in 2015, the water and heat conditions were good, and the comprehensive control measures played a significant role. Compared with the control, the various control measures increased the vegetation community coverage by 14%, density by 10%, and the total aboveground stock by 160%. In addition, the control measures increased the number of species by 20% on average. The results show that the comprehensive control measures can not only improve the productivity of grassland vegetation, but also improve the species diversity of degraded grasslands, achieving the expected purpose. In 2016, the climate was relatively dry. Compared with the control, the vegetation community coverage under the control measures increased slightly, the density decreased by 10%, and the total aboveground stock increased by 9%. Even under relatively dry conditions, the comprehensive control measures can increase the accumulation of plant biomass. In 2017, the climate was very dry. Compared with the control, only a few treatment combinations could improve the coverage and density, producing positive effects, and other treatments and indicators did not achieve effective effects.

[0121] like Figure 6 and Figure 7 As shown in the data, among the comprehensive control measures, plant regulators promoted plant growth, plant height and biomass increased significantly, and a number of physiological indicators were also improved. After the addition of soil nutrients, the content of soil fast-acting nutrients such as alkaline nitrogen and available phosphorus tended to increase, the soil microbial population changed, and the soil nutrient supply capacity was improved, laying an important foundation for improving vegetation productivity.

[0122] Example 4

[0123] The experimental area is located in Arigalangtu, Xilin Gol League, Inner Mongolia Autonomous Region, 15km away from Xilinhot City. The average annual precipitation in the past 50 years is 350mm, the average annual temperature is 1.7℃, and the soil type is sandy soil. Before 2014, due to long-term heavy grazing, the grassland showed serious degradation, and a fertilization experiment was carried out in June of the same year. The experiment set up two fertilization treatments, inorganic fertilizer and organic fertilizer, of which the inorganic fertilizer treatment was a 2-factor (nitrogen and phosphorus) 4-level 3-replication design (N0, P0 is no fertilizer, N1, N2, N3 are 50kg / hm 2 、100kg / hm 2 、150kg / hm 2 ;

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

[0125] Implementation effect monitoring:

[0126] like Figure 8 As shown in the figure, the fertilization results show that the application of inorganic phosphorus fertilizer can increase the content of soil available phosphorus, and the application of nitrogen fertilizer can increase the content of soil alkaline nitrogen, especially the change in the surface layer 0-10cm is more significant than that in 10-20cm. The change in soil available phosphorus content shows a trend of rapid increase after fertilization and then rapid decrease. The content in July (one month after fertilization) is higher than that in June and August. Between years, the content of available phosphorus shows an overall increasing trend.

[0127] like Fig. 9 As shown in the figure, fertilization has a greater effect on the alkaline nitrogen content of the 0-10cm soil layer, and a smaller effect on the 10-20cm soil layer. Under the same fertilization treatment, the alkaline nitrogen content of the 0-10cm soil layer is significantly higher than that of the 10-20cm soil layer. In the 0-10cm soil layer, with the increase in the amount of nitrogen fertilizer applied, the alkaline nitrogen content of the soil showed an overall increasing trend. There was no significant change in the alkaline nitrogen content of the soil under different sheep manure levels. The alkaline nitrogen content of the soil in June and July was generally higher than that in August.

[0128] like Fig.10 As shown, although organic matter varied among the plots, the changes were irregular, fertilization failed to affect the level of organic matter in the short term, and there was little difference in organic matter content between the 0-10 cm soil layer and the 10-20 cm soil layer.

[0129] like Fig.11 As shown in the figure, soil conductivity changed significantly after fertilization. In July, it increased with the increase of nitrogen application, and at the same nitrogen fertilizer application rate, it increased with the increase of phosphorus fertilizer application rate. The 0-10cm soil conductivity was higher than that of 10-20cm, and the conductivity in July was higher than that in June and August. This shows that as time goes by, some of the ions added by fertilization are fixed.

[0130] like Fig.12 As shown, there is no major change in the overall soil pH level, and there is no obvious response to fertilization. In the 0-10cm and 10-20cm soil layers, the soil pH is basically 7.5-8.0.

[0131] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for comprehensive management of degraded grassland by stages and categories, characterized in that: The following steps are involved: According to the vegetation coverage, grasslands are divided into four stages: severely degraded grassland, moderately degraded grassland, moderately restored grassland and basically restored grassland. For severely degraded grasslands, measures to improve soil fertility are taken, including reseeding native grass species and applying fertilizers; For moderately degraded grasslands, "stimulation" measures are adopted, including scratching the turf or harrowing the ground, applying different gradients of water alternately, and applying water-retaining and fertilizer-locking agents and plant growth regulators to stimulate the activity of the soil seed bank; For moderately restored grasslands, "promotion" measures are adopted, including fencing or root cutting, fertilization and irrigation management, to promote the growth of dominant species; In order to basically restore the grassland, "adjustment" measures are taken, including rational use of resources, ecological restoration and reconstruction of damaged plots, so as to optimize the function of the ecosystem.

2. The method according to claim 1, characterized in that 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%.

3. The method according to claim 1, characterized in that The reseeding of native grass seeds comprises the following steps: selecting grass seeds according to the actual situation of the degraded grassland, and reseeding before the arrival of summer rains, using broadcasting, row seeding, hole seeding or aerial seeding.

4. The method according to claim 1, characterized in that: The application of fertilizers comprises the following steps: applying fertilizers in the early stage of plant growth; the type of fertilizer is determined according to the results of the soil physical and chemical property investigation, and one or more of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer and organic fertilizer are selected, and the specific amount of fertilizer is determined by a "3414" fertilization test or an orthogonal test.

5. The method according to claim 1, characterized in that The specific operation of scarifying the turf is to use a root cutter or manual ditching, with a scarification depth of 3-5 cm and a row spacing of 10-15 cm.

6. The method according to claim 1, characterized in that The alternate application of different gradients of water includes: in arid or semi-arid areas, artificial irrigation is used to simulate rainfall, and different gradients of water are alternately applied to stimulate soil seed bank activity.

7. The method according to claim 1, characterized in that The applied plant growth regulator includes naphthylacetic acid, gibberellin, brassinolide or sodium nitrophenolate and chlorfenapyr; the applied concentration is determined by germination test and sprayed on the soil surface to promote seed germination.

8. The method according to claim 1, characterized in that The root cutting, fertilization and irrigation management include: root cutting depth of 3-5cm; nitrogen fertilizer application of 100-150kg / hm 2 and phosphate fertilizer 60-90kg / hm 2 ; irrigation volume is 500-1000m 3 / hm 2 .

9. The method according to claim 1, characterized in that: The rational use of resources includes: implementing fenced grazing bans, grazing breaks or rotational grazing models, and optimizing grassland resource utilization by coordinating grazing management and nutrient management.

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

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