Semi-arid region salinized land ecological restoration method based on natural solution

Abstract

The invention discloses an ecological restoration method for salinized land in a semi-arid region based on a natural solution. The ecological restoration method comprises the following steps: S1, defining a plurality of ecological restoration regions; s2, planting plants; in each ecological restoration area, high-layer plants are planted on a circle of the edge of the ecological restoration area, and a circle of middle-layer plants and a circle of low-layer plants are sequentially planted into the ecological restoration area; s3, arranging an ecological restoration area; according to the invention, an ecological restoration area with multi-layer plant distribution can be formed, the restoration and improvement of biodiversity are facilitated, and through the arrangement of the first groove, the sand barrier and the spacing between the first groove and the sand barrier, the purpose that seeds of plants in each layer stay in or near the first groove along with wind to achieve sowing and growth can be achieved in the subsequent year; multiple layers of plants along the first grooves are formed, the ecological restoration effect is enhanced, subsequent sowing through wind power is facilitated, and manual close planting is not needed any more.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological restoration, and in particular to a method for ecological restoration of salinized land in semi-arid areas based on natural solutions. Background Art

[0002] Salinized land, also known as saline-alkali land, refers to land that has accumulated too much soluble salt, causing the soil properties to change and is not conducive to plant growth. In semi-arid areas, because evaporation is greater than precipitation, the salt in the soil easily rises to the surface with capillary water and accumulates, forming salinized land.

[0003] Affected by climate warming, inland lakes in semi-arid areas have retreated, and a large amount of bare land has been newly generated around the lakes in the past 2 to 3 years. At the same time, the retreat of lakes has led to the easy accumulation of salt in the soil, which has aggravated the degree of soil salinization. The salinized land in semi-arid areas is mainly distributed in Northeast and Northwest China. The climatic conditions, topography and hydrogeological conditions in these areas jointly determine the distribution characteristics of salinized land. Excessive salt content in salinized land will destroy the soil structure, lead to a decrease in soil fertility, have an adverse effect on plant growth, and then cause crop yield reduction or even death. In severe cases, salinized land will lead to the abandonment of farmland and cause huge losses to agricultural production. In addition, the expansion of salinized land will lead to ecosystem degradation, reduction of biodiversity, and destruction of ecological balance. At the same time, salinized land will also aggravate environmental problems such as land desertification and soil erosion, affect the quality of groundwater, and pose a threat to human health.

[0004] Therefore, effective prevention and control measures are needed to solve the salinization of land in semi-arid areas. In the prior art, improving soil, reasonable irrigation, planting salt-tolerant plants, establishing drainage systems and bioremediation are common means. However, these methods are generally costly, and there are few restoration plans that utilize favorable factors of the natural environment, so that artificial restoration and natural recovery do not produce good synergistic effects, and the ecological restoration effect needs to be improved. Planting salt-alkali tolerant plants is the most commonly used method. However, since many transplanted plants are usually difficult to survive on the salinized land on the lakeshore by their own reproductive ability, in order to improve the restoration effect, artificial dense planting is often used for restoration. However, the existing artificial dense planting only transplants plants, and does not construct a multi-level structure suitable for plant survival by adjusting the planting height and density. The survival rate of transplanted plants cannot be guaranteed, and a good environment suitable for plant growth cannot be formed, so that plants are difficult to use themselves for sowing and reproduction, and later management is difficult. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for ecological restoration of salinized land in semi-arid areas based on natural solutions.

[0006] A method for ecological restoration of salinized land in semi-arid areas based on natural solutions, comprising the following steps:

[0007] S1. Designate multiple ecological restoration areas;

[0008] In the study area with strong winds, the exposed salinized land near the lake that needs to be restored is selected and divided into several ecological restoration areas;

[0009] S2, plant cultivation;

[0010] In each ecological restoration area, a circle of high-rise plants is planted at the edge of the ecological restoration area, and a circle of middle-rise plants and a circle of low-rise plants are planted in sequence along the edge of the ecological restoration area toward the inside of the ecological restoration area; the planting density of the high-rise plants is less than the planting density of the middle-rise plants and less than the planting density of the low-rise plants;

[0011] The high-layer plants are one or more of Phragmites australis, Suaeda salsa, and Atriplex canescens, the middle-layer plants are Leymus chinensis or Fagopyrum tartari, and the low-layer plants are Saussurea salsa;

[0012] S3. Setting up ecological restoration areas;

[0013] In the ecological restoration area, a plurality of mutually parallel first grooves are opened along a direction perpendicular to the dominant wind direction or the lake shoreline, a row of sand barriers are set in the center of the grooves, and then at least one second groove perpendicular to and connected to the first grooves is set in the ecological restoration area, the first groove has an inner bottom surface designed with a slope, and the depth of the first groove at one end of the connection of the second groove is greater than the depth of the other end of the first groove.

[0014] Description: Through the above method, an ecological restoration area with multi-layered plant distribution can be formed. Multi-layered plants absorb salt in the soil through their roots, and with the growth and metabolism of plants, they effectively reduce the accumulation of salt in the soil, thereby improving the balance of soil salt; using salt-tolerant plants as biological frameworks can improve saline-alkali soil, reduce water evaporation on the soil surface, help loosen the soil, improve soil structure, and increase soil aeration and water permeability; multi-layered plant distribution can provide suitable ecological niches for different types of plants, animals and microorganisms, which helps to restore and enhance the diversity of ecosystems; through the setting of the first trench, sand barriers and their spacing, in subsequent years, the seeds of plants at each layer can be left in or near the first trench by the wind to achieve the purpose of sowing and growth, forming multi-layered plants along the first trench, and strengthening the above ecological restoration effect. Since there is sufficient groundwater in the salinized land on the lakeshore, when precipitation occurs, the accumulation of rainwater in the trench will increase the salt content of the soil near the surface, affecting plant growth. In order to avoid the influence of excessive rainwater, a first groove and a second groove are provided, so that rainwater in the first groove can be discharged to avoid affecting the plants in the first groove.

[0015] Furthermore, the selected exposed salinized land near the lake with strong wind force and in need of restoration is divided into multiple ecological restoration areas, including: selecting the exposed salinized land near the lake with an average soil pH value of 10.30-10.68 in the salinized land in the semi-arid area, and the average wind force on the exposed salinized land near the lake is above level 3 and below level 6, and then dividing the exposed salinized land near the lake into multiple ecological restoration areas according to the area of ​​each ecological restoration area of ​​50×50~200×200m.

[0016] Note: Through the above-mentioned delineation of ecological restoration areas, the targeted nature of this plan can be increased.

[0017] Furthermore, the high-layer plants are one or more of Phragmites australis, Suaeda salsa, and Atriplex canescens, the middle-layer plants are Leymus chinensis or Fagopyrum tartari, and the low-layer plants are Saussurea ovata.

[0018] Furthermore, the planting density of the high-rise plants is 30 to 70 cm between every two high-rise plants; the planting density of the middle-rise plants is 20 to 28 cm between every two middle-rise plants; and the planting density of the low-rise plants is 5 to 18 cm between every two low-rise plants.

[0019] Note: Through the above-mentioned density design, the hierarchical structure formed between the plants can be more obvious, which is helpful to form a small structure, increase the ability to resist wind and sand, and help the process of ecological restoration.

[0020] Furthermore, the distance between the high-layer plants and the middle-layer plants is 10 to 20 cm, and the distance between the middle-layer plants and the low-layer plants is 5 to 15 cm.

[0021] Note: The above spacing is more reasonable and can enhance the survival ability of each plant.

[0022] Furthermore, the first groove has a depth of 25 to 35 cm and a width of 3 to 7 cm.

[0023] Note: The above-mentioned depth design can facilitate the growth of seeds falling in the first groove and on the edge of the first groove to form a plant composite layer structure.

[0024] Furthermore, a depth of the second groove is greater than a depth of the first groove.

[0025] Note: The above design enables the precipitation in the first groove to flow into the second groove for discharge.

[0026] Furthermore, the sand barrier is made of straw or harvested dry local salt-alkali tolerant plants.

[0027] Note: The sand barrier used above is a common sand barrier, which can block the seeds blown down by the wind, so that the seeds fall inside or near the first groove.

[0028] Furthermore, the sand barrier of the first groove near the edge of the ecological restoration area is planted with middle-layer plants, and the sand barrier of the first groove near the center of the ecological restoration area is planted with low-layer plants.

[0029] Note: Through the setting of the above-mentioned sand barriers, the plant layer structure can be further optimized to form an effect in which the seeds of high-layer plants fall in the first groove corresponding to the middle-layer plants, and the seeds of the middle-layer plants fall in the first groove of the low-layer plants, which can optimize the plant layer effect in the ecological restoration area.

[0030] Furthermore, the second grooves between every two of the ecological restoration areas are interconnected.

[0031] Note: The interconnected second trenches between the two ecological restoration areas can enhance the hydrological connectivity between the two ecological restoration areas, promote the flow and discharge of rainwater (avoiding the long-term presence of rainwater in the trenches, which can cause salt analysis in the soil and harm to plants), and help maintain and restore the health of the aquatic ecosystem. At the same time, the connected trenches can enhance the resilience of the ecosystem, making it more resistant to external disturbances and changes, such as climate change.

[0032] Furthermore, the present invention also provides a method for calculating the distance between two adjacent first grooves (the distance between two adjacent first grooves is also equal to the vertical distance between the first structure closest to the edge of the ecological restoration area and the edge of the ecological restoration area), the calculation method comprising:

[0033]

[0034] In the formula, D is the distance between two adjacent first grooves; W is the wind force (measured by some standard, such as meters per second); M is the mass of the seed; H is the height difference between high-level plants and middle-level plants or the height difference between high-level plants and low-level plants; Cd is the resistance coefficient of the seed; A is the windward area of ​​the seed; ρ is the density of the air; ε is other resistance terms, such as the resistance will change during rainy and foggy periods, which is obtained through experience, and g is the acceleration of gravity.

[0035] Note: Through the above method, the position of the first groove that is most conducive to current wind seeding can be calculated. Using this position, the multi-layer structure formed by plants in each first groove can be more optimized, which can promote the ecological restoration process and avoid problems such as long test cycles caused by relying on experience.

[0036] The beneficial effects of the present invention are:

[0037] The method of the present invention can form an ecological restoration area with multi-level plant distribution, which can improve soil salinity and reduce salt accumulation in the soil; at the same time, using salt-tolerant plants as a biological framework can improve saline-alkali soil, reduce water evaporation on the soil surface, help loosen the soil, improve soil structure, and improve soil permeability and water permeability. The multi-level plant distribution provides a suitable niche for different types of plants, animals and microorganisms, which helps to restore and enhance the diversity of the ecosystem. In addition, by setting the first groove, sand barriers and their spacing, it can be achieved in subsequent years that the seeds of plants at all levels stay in or near the first groove with the wind to achieve the purpose of sowing and growth, forming multi-layer plants along the first groove (forming a simple competitive environment), and strengthening the above-mentioned ecological restoration effect. In addition, the lakeshore salinized land has sufficient groundwater, and when precipitation occurs, rainwater gathers in the groove, which will increase the salt content of the near-surface soil and affect plant growth. In order to avoid the influence of excessive rainwater, the first groove and the second groove are set, and the rainwater in the first groove can be discharged to avoid affecting the plants in the first groove. By setting the spacing of the first grooves, the arrangement of the plants can be made more reasonable, which is convenient for subsequent sowing using wind power and solves the problem of the difficulty of survival of the above-mentioned plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of an embodiment of the present invention;

[0039] Figure 2 This is one of the site pictures after restoration according to an embodiment of the present invention;

[0040] Figure 3 This is the second on-site picture after restoration according to the embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to further illustrate the method adopted by the present invention and the effect achieved, the technical solution of the present invention will be clearly and completely described in combination with experiments below.

[0042] Example 1: Figure 1 As shown, a method for ecological restoration of salinized land in semi-arid areas based on natural solutions includes the following steps:

[0043] S1. Designate multiple ecological restoration areas;

[0044] In the study area with strong winds, the exposed salinized land near the lake that needs to be restored is selected and divided into several ecological restoration areas;

[0045] The method of selecting exposed salinized land near a lake with strong wind force and in need of restoration and dividing it into a plurality of ecological restoration areas comprises: selecting exposed salinized land near a lake with an average soil pH value of 10.30 to 10.68 in the salinized land in the semi-arid area, and the average wind force on the exposed salinized land near the lake is level 5, and then dividing the exposed salinized land near the lake into a plurality of ecological restoration areas with an area of ​​100×100m for each ecological restoration area.

[0046] S2, plant cultivation;

[0047] In each of the ecological restoration areas, a circle of high-rise plants are planted at the edge of the ecological restoration area, and a circle of middle-rise plants and a circle of low-rise plants are planted in sequence along the edge of the ecological restoration area toward the interior of the ecological restoration area; wherein the high-rise plants are equal numbers of reeds, salsa sedge, and atriplex, the middle-rise plants are sheep fescue, and the low-rise plants are saussurea ovata; the planting density of the high-rise plants is less than the planting density of the middle-rise plants and less than the planting density of the low-rise plants.

[0048] The planting density of the high-level plants is 40 cm between every two high-level plants; the planting density of the middle-level plants is 24 cm between every two middle-level plants; and the planting density of the low-level plants is 10 cm between every two low-level plants.

[0049] The distance between the high-level plants and the middle-level plants is 15 cm, and the distance between the middle-level plants and the low-level plants is 10 cm.

[0050] S3. Setting up ecological restoration areas;

[0051] In the ecological restoration area, a plurality of mutually parallel first grooves are opened along the direction perpendicular to the dominant wind direction or the lake shoreline, a row of sand barriers are set in the center of the grooves, and then at least one second groove perpendicular to and connected to the first groove is set in the ecological restoration area, the bottom surface of the first groove is designed as a slope, and the depth of the first groove at one end of the connection with the second groove is greater than the depth of the other end of the first groove, the first groove has a depth of 20 cm and a width of 5 cm, and the second groove has a depth of 25 cm. The sand barriers are made of straw or harvested dry local salt-alkali tolerant plants. The second grooves between every two ecological restoration areas are connected to each other.

[0052] Example 2: This example is different from Example 1 in that the middle layer plants are bitter buckwheat, the sand barrier in the first groove near the edge of the ecological restoration area is the planted middle layer plants, and the sand barrier in the first groove near the center of the ecological restoration area is the planted low layer plants;

[0053] A method for calculating the distance between two adjacent first grooves (the distance between two adjacent first grooves is also equal to the vertical distance between the first groove closest to the edge of the ecological restoration area and the edge of the ecological restoration area), the calculation method comprising:

[0054]

[0055] Wherein, D is the distance between two adjacent first grooves; W is the wind force (measured by some standard, such as meters per second); M is the mass of the seed; H is the height difference between high-level plants and middle-level plants or the height difference between high-level plants and low-level plants; Cd is the resistance coefficient of the seed; A is the windward area of ​​the seed; ρ is the density of the air; ε is other resistance terms, for example, the resistance terms in rainy and foggy periods need to be greater than 0, g is the acceleration of gravity. For example, after calculation, the distance between two adjacent first grooves is 0.8m.

[0056] Example 3: This example is different from Example 1 in that the planting density of the high-rise plants is 30 cm between every two high-rise plants; the planting density of the middle-rise plants is 28 cm between every two middle-rise plants; and the planting density of the low-rise plants is 18 cm between every two low-rise plants. The distance between the high-rise plants and the middle-rise plants is 20 cm, and the distance between the middle-rise plants and the low-rise plants is 5 cm. The first groove has a depth of 25 cm and a width of 3 cm. The depth of the second groove is greater than the depth of the first groove. The sand barrier uses straw or harvested dry local salt-alkali tolerant plants. The second grooves between every two ecological restoration areas are interconnected.

[0057] Example 4: This example is different from Example 1 in that the planting density of the high-rise plants is 70 cm between every two high-rise plants; the planting density of the middle-rise plants is 20 cm between every two middle-rise plants; and the planting density of the low-rise plants is 5 cm between every two low-rise plants. The spacing between the high-rise plants and the middle-rise plants is 10 cm, and the spacing between the middle-rise plants and the low-rise plants is 15 cm. The first groove has a depth of 35 cm and a width of 7 cm. The depth of the second groove is greater than the depth of the first groove. The sand barrier uses straw or harvested dry local salt-alkali tolerant plants. The second grooves between every two ecological restoration areas are interconnected.

[0058] Experimental Example: The description of this experimental example is based on the scheme described in Example 1, and is intended to illustrate the practical application effect of the present invention. A plot of land was selected and divided into two treatment plots. One plot was repaired according to the method of Example 1, and the other was repaired according to the direct transplantation method. After 2 years, Figure 2 , Figure 3As shown, the number of plants and the Shannon-Wiener index of the two treatment plots were obtained; as shown in Table 1;

[0059] Table 1 Vegetation growth

[0060]

[0061] Among them, vegetation coverage refers to the proportion of vegetation covering the ground, usually expressed as a percentage. It reflects the distribution density and coverage of vegetation on the surface, and is one of the important indicators for measuring vegetation growth and ecosystem health;

[0062] The Shannon-Wiener index is one of the indicators used in ecology to measure species diversity. It combines species richness and species evenness, and can reflect the species diversity level of a community or ecosystem. The higher the value of the Shannon-Wiener index, the higher the species diversity in the community.

[0063] It can be seen from Table 1 that, compared with the direct transplanting method of Comparative Example 1, the plants, trenches and sand barriers set up in the embodiment of the present invention can combine the wind conditions to form an ecological environment suitable for plant growth, and are conducive to ecological restoration.

Claims

1. A method for ecological restoration of salinized land in semi-arid areas based on natural solutions, characterized in that: The following steps are involved: S1. Designate multiple ecological restoration areas; In the study area with high wind speed, the exposed salinized land near the lake that needs to be restored is selected and divided into several ecological restoration areas; S2, plant cultivation; In each ecological restoration area, a circle of high-rise plants is planted at the edge of the ecological restoration area, and a circle of middle-rise plants and a circle of low-rise plants are planted in sequence along the edge of the ecological restoration area toward the inside of the ecological restoration area; the planting density of the high-rise plants is less than the planting density of the middle-rise plants and less than the planting density of the low-rise plants; The high-layer plants are one or more of Phragmites australis, Suaeda salsa, and Atriplex canescens, the middle-layer plants are Leymus chinensis or Fagopyrum tartari, and the low-layer plants are Saussurea salsa; S3. Setting up ecological restoration areas; In the ecological restoration area, a plurality of mutually parallel first grooves are opened along a direction perpendicular to the dominant wind direction or the lake shoreline, a row of sand barriers are set in the center of the grooves, and then at least one second groove perpendicular to and connected to the first grooves is set in the ecological restoration area, the bottom surface of the first groove is designed with a slope, and the depth of the first groove at one end of the connection with the second groove is greater than the depth of the other end of the first groove.

2. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The selected exposed salinized land near the lake with strong wind force and in need of restoration is divided into multiple ecological restoration areas, including: selecting the exposed salinized land near the lake with an average soil pH value of 10.30-10.68 in the salinized land in the semi-arid area, and the average wind force on the exposed salinized land near the lake is above level 3 and below level 6, and then dividing the exposed salinized land near the lake into multiple ecological restoration areas according to the area of ​​each ecological restoration area of ​​50×50~200×200m.

3. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The high-layer plants are one or more of Phragmites australis, Suaeda salsa, and Atriplex canescens, the middle-layer plants are Leymus chinensis or Fagopyrum tartari, and the low-layer plants are Saussurea salsa.

4. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The planting density of the high-level plants is 30 to 70 cm between every two high-level plants; the planting density of the middle-level plants is 20 to 28 cm between every two middle-level plants; and the planting density of the low-level plants is 5 to 18 cm between every two low-level plants.

5. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 4, characterized in that: The distance between the high-layer plants and the middle-layer plants is 10 to 20 cm, and the distance between the middle-layer plants and the low-layer plants is 5 to 15 cm.

6. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The first groove has a depth of 25 to 35 cm and a width of 3 to 7 cm; the depth of the second groove is greater than the depth of the first groove.

7. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The sand barrier is made of straw or harvested dry local salt-alkali tolerant plants.

8. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The sand barrier of the first groove near the edge of the ecological restoration area is planted with middle-layer plants, and the sand barrier of the first groove near the center of the ecological restoration area is planted with low-layer plants.

9. The method for ecological restoration of salinized land in semi-arid areas based on natural solutions according to claim 1, characterized in that: The distance between two adjacent first grooves is: Where D is the distance between two adjacent first grooves, W is the wind force, M is the mass of the seeds, H is the height difference between the high-level plants and the middle-level plants or the height difference between the high-level plants and the low-level plants, and C is d is the drag coefficient of the seed, A is the windward area of ​​the seed, ρ is the density of the air, ε is other drag terms, and g is the acceleration due to gravity.

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