Ecological restoration method for salinized land in semi-arid region based on natural solution

Abstract

The application discloses a natural solution-based ecological restoration method for salinized land in a semi-arid area, which comprises the following steps: S1, demarcating a plurality of ecological restoration areas; S2, planting plants; in each ecological restoration area, high-level plants are planted in a circle at the edge of the ecological restoration area, and medium-level plants and low-level plants are sequentially planted in circles towards the inside of the ecological restoration area; and S3, setting the ecological restoration area; the application can form an ecological restoration area with multi-level plant distribution, which is helpful to restore and improve biodiversity; through the setting of the first groove, the sand barrier and the spacing therebetween, the seeds of plants at various levels can be deposited in the first groove or nearby along with the wind in subsequent years to achieve the purpose of sowing and growth, multi-level plants along the first groove are formed, the ecological restoration effect is strengthened, subsequent sowing by using wind power is facilitated, and manual dense planting is not needed.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology, specifically to a method for ecological restoration of saline-alkali land in semi-arid regions based on natural solutions. Background Technology

[0002] Saline land, also known as saline-alkali land, refers to a type of land where excessive accumulation of soluble salts alters the soil's properties, making it unfavorable for plant growth. In semi-arid regions, where evaporation exceeds precipitation, soil salts easily rise to the surface via capillary water and accumulate, forming saline land.

[0003] Due to global warming, inland lakes in semi-arid regions are shrinking, resulting in the creation of large areas of bare land around these lakes in the past two to three years. Simultaneously, lake retreat leads to the accumulation of salts in the soil, exacerbating soil salinization. Salinized land in semi-arid regions is mainly distributed in Northeast and Northwest China. The climate, topography, and hydrogeological conditions of these areas collectively determine the distribution characteristics of salinized land. Excessive salt content in salinized land damages soil structure, leading to decreased soil fertility, adversely affecting plant growth, and ultimately causing crop yield reduction or even death. In severe cases, salinization can lead to farmland abandonment, causing significant losses to agricultural production. Furthermore, the expansion of salinized land leads to ecosystem degradation, reduced biodiversity, and disruption of ecological balance. Simultaneously, salinization exacerbates environmental problems such as desertification and soil erosion, affects groundwater quality, and poses a threat to human health.

[0004] Therefore, effective prevention and control measures are needed to address salinization in semi-arid regions. Existing technologies commonly employ soil improvement, rational irrigation, planting salt-tolerant plants, establishing drainage systems, and bioremediation. However, these methods are generally costly and rarely utilize favorable natural environmental factors, resulting in a lack of synergistic effects between artificial and natural restoration, and the overall ecological restoration effect needs improvement. Planting salt-tolerant plants is the most common method; however, many transplanted plants often struggle to survive on salinized lakeshore land due to their own reproductive capacity. To improve restoration effectiveness, dense artificial planting is frequently employed. However, current methods simply involve transplanting plants without adjusting planting height and density to create a multi-layered structure suitable for plant survival. This results in unreliable survival rates for transplanted plants and the inability to create a suitable environment for plant growth, making it difficult for plants to propagate through seed and leading to challenges in subsequent management. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for ecological restoration of saline-alkali land in semi-arid regions based on natural solutions.

[0006] A natural-solution-based method for ecological restoration of saline-alkali land in semi-arid regions includes the following steps:

[0007] S1. Delineate multiple ecological restoration zones;

[0008] Within the study area with strong winds, exposed saline land near the lake that needs restoration was selected and divided into multiple ecological restoration zones.

[0009] S2, Plant cultivation;

[0010] In each of the ecological restoration zones, a ring of tall plants is planted around the edge of the ecological restoration zone, followed by a ring of mid-level plants and a ring of low-level plants along the edge of the ecological restoration zone toward the interior; the planting density of the tall plants is less than the planting density of the mid-level plants and the planting density of the low-level plants.

[0011] Among them, the upper-level plants are one or more of reeds, Suaeda salsa, and Acer palmatum; the middle-level plants are Leymus chinensis or Tartary buckwheat; and the lower-level plants are Saussurea involucrata.

[0012] S3, Ecological Restoration Zone Establishment;

[0013] Within the ecological restoration area, multiple parallel first trenches are constructed along a direction perpendicular to the prevailing wind direction or the shoreline. A row of sand barriers is set in the center of each trench. Then, at least one second trench is constructed within the ecological restoration area that is perpendicular to and connected to the first trenches. The first trenches have a sloped inner bottom surface. The depth of the first trench at one end of the connection with the second trench is greater than the depth at the other end of the first trench.

[0014] Explanation: The above methods can create an ecological restoration zone with multi-layered plant distribution. These multi-layered plants absorb soil salts through their roots, and as they grow and metabolize, they effectively reduce soil salt accumulation, thus improving soil salinity balance. Using salt-tolerant plants as a biological framework improves saline-alkali soil, reduces surface water evaporation, helps loosen the soil, improves soil structure, and enhances soil aeration and permeability. The multi-layered plant distribution provides suitable ecological niches for different types of plants, animals, and microorganisms, contributing to the restoration and enhancement of ecosystem diversity. The placement of the first trench, sand barriers, and their spacing allows seeds from various layers to be carried by the wind to the first trench or its vicinity for sowing and growth in subsequent years, forming a multi-layered plant structure along the first trench and strengthening the aforementioned ecological restoration effects. However, due to abundant groundwater in the saline-alkali land along the lake shore, rainwater accumulation in the trenches during rainfall increases the salinity of the near-surface soil, affecting plant growth. To avoid the impact of excessive rainwater, a first and a second ditch are set up. Rainwater in the first ditch can be drained to avoid affecting the plants in the first ditch.

[0015] Furthermore, the selected exposed saline land near the lake with strong winds and requiring restoration is divided into multiple ecological restoration zones. This includes selecting exposed saline land near the lake in the semi-arid area with an average soil pH value of 10.30 to 10.68 and an average wind force of level 3 or higher but below level 6. Then, the exposed saline land near the lake is divided into multiple ecological restoration zones according to an area of ​​50×50 to 200×200m for each ecological restoration zone.

[0016] Note: The above-described delineation of ecological restoration areas enhances the relevance of this plan.

[0017] Furthermore, the upper-layer plants are one or more of reeds, Suaeda salsa, and Acer palmatum; the middle-layer plants are Leymus chinensis or Tartary buckwheat; and the lower-layer plants are Saussurea involucrata.

[0018] Furthermore, the planting density of the upper-level plants is such that the distance between each two upper-level plants is 30-70cm; the planting density of the middle-level plants is such that the distance between each two middle-level plants is 20-28cm; and the planting density of the lower-level plants is such that the distance between each two lower-level plants is 5-18cm.

[0019] Explanation: The density design described above makes the hierarchical structure between individual plants more obvious, which helps to form a small structure, increases the resistance to wind and sand, and helps the ecological restoration process.

[0020] Furthermore, the distance between the upper-level plants and the middle-level plants is 10-20cm, and the distance between the middle-level plants and the lower-level plants is 5-15cm.

[0021] Note: The above intervals are reasonable and can enhance the survival ability of each plant.

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

[0023] Note: The depth design described above is conducive to the growth of seeds that fall into the first groove and on the edge of the first groove, so as to form a plant composite layer structure.

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

[0025] Note: The above design allows rainwater from the first ditch to flow into the second ditch and be discharged.

[0026] Furthermore, the sand barriers are made of straw or harvested, dried local salt-tolerant plants.

[0027] Note: The sand barrier used above is a common sand barrier, which can block seeds blown away by the wind, causing the seeds to fall into or near the first trench.

[0028] Furthermore, the sand barrier near the edge of the first ditch of the ecological restoration area consists of planted mid-level plants, while the sand barrier near the center of the first ditch of the ecological restoration area consists of planted low-level plants.

[0029] Explanation: By setting up the sand barriers described above, the plant layer structure can be further optimized to achieve the effect that the seeds of the upper layer plants fall into the first groove corresponding to the middle layer plants, and the seeds of the middle layer plants fall into the first groove of the lower layer plants, thus optimizing the plant layer effect in the ecological restoration area.

[0030] Furthermore, the second trenches between every two of the aforementioned ecological restoration zones are interconnected.

[0031] Explanation: The interconnection of the second ditch between the two ecological restoration areas can enhance the hydrological connectivity between the two ecological restoration areas, promote the flow and drainage of rainwater (preventing rainwater from remaining in the ditch for a long time, which would cause salt leaching from the soil and harm plants), help maintain and restore the health of the aquatic ecosystem. At the same time, the interconnected ditch 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 trenches (the distance between two adjacent first trenches is also equal to the perpendicular 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 trenches; W is the wind force (measured by a certain standard, such as meters per second); M is the seed mass; H is the height difference between the upper and middle layers of plants or between the upper and lower layers of plants; Cd is the seed drag coefficient; A is the windward area of ​​the seed; ρ is the air density; ε is other drag terms, such as drag that changes during rainy or foggy periods, which are obtained empirically; and g is the acceleration due to gravity.

[0035] Explanation: The above method can be used to calculate the location of the first furrow that is most favorable for wind-driven seeding. Using this location, the plants in each first furrow can form a more optimized multi-layered structure, which can promote the ecological restoration process and avoid problems such as long experimental cycles caused by relying on experience.

[0036] The beneficial effects of this invention are:

[0037] This invention creates a multi-layered plant distribution ecological restoration zone, improving soil salinity and reducing salt accumulation. Simultaneously, using salt-tolerant plants as a biological framework improves saline-alkali soil, reduces surface water evaporation, helps loosen the soil, improves soil structure, and enhances aeration and permeability. The multi-layered plant distribution provides suitable ecological niches for different types of plants, animals, and microorganisms, contributing to the restoration and enhancement of ecosystem diversity. Furthermore, the placement of the first trench, sand barriers, and their spacing allows seeds from various plant layers to be carried by the wind to remain in or near the first trench in subsequent years, achieving sowing and growth, forming multiple layers of plants along the first trench (creating a simple competitive environment), thus strengthening the aforementioned ecological restoration effects. In addition, the saline land along the lake shore has abundant groundwater; during rainfall, rainwater accumulates in the trenches, increasing the salinity of the near-surface soil and affecting plant growth. To avoid the impact of excessive rainwater, the first and second trenches are set up to drain rainwater from the first trench, preventing it from affecting the plants within it. By setting the spacing of the first trench, the arrangement of each plant can be made more reasonable, which facilitates subsequent sowing using wind power and solves the problem of the plants' difficulty in surviving. Attached Figure Description

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

[0039] Figure 2 This is one of the restored on-site images according to an embodiment of the present invention;

[0040] Figure 3 This is the second image of the repaired site from an embodiment of the present invention. Detailed Implementation

[0041] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.

[0042] Example 1: As Figure 1 As shown, a natural solution-based ecological restoration method for saline-alkali land in semi-arid regions includes the following steps:

[0043] S1. Delineate multiple ecological restoration zones;

[0044] Within the study area with strong winds, exposed saline land near the lake that needs restoration was selected and divided into multiple ecological restoration zones.

[0045] The selection of exposed saline land near the lake with strong winds and requiring restoration, and the division of it into multiple ecological restoration zones, includes: selecting exposed saline land near the lake with an average soil pH value of 10.30 to 10.68 in the semi-arid saline land, and an average wind force of level 5 on the exposed saline land near the lake; and then dividing the exposed saline land near the lake into multiple ecological restoration zones according to an area of ​​100×100m for each ecological restoration zone.

[0046] S2, Plant cultivation;

[0047] In each ecological restoration zone, a ring of tall plants is planted around the edge of the zone, followed by a ring of mid-level plants and a ring of low-level plants along the edge towards the interior of the zone. The tall plants consist of equal numbers of reeds, Suaeda salsa, and Acer palmatum; the mid-level plants are Leymus chinensis; and the low-level plants are Saussurea involucrata. The planting density of the tall plants is less than the planting density of the mid-level plants, which is less than the planting density of the low-level plants.

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

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

[0050] S3, Ecological Restoration Zone Establishment;

[0051] Within the ecological restoration area, multiple parallel first trenches are constructed perpendicular to the prevailing wind direction or the shoreline. A row of sand barriers is placed in the center of each trench. Then, at least one second trench, perpendicular to and connected to the first trenches, is constructed within the ecological restoration area. The bottom of the first trench is sloped, and the depth of the first trench at the point of connection with the second trench is greater than the depth at the other end. The first trench is 20 cm deep and 5 cm wide, and the second trench is 25 cm deep. The sand barriers are constructed using straw or harvested, dried local salt-tolerant plants. The second trenches between every two ecological restoration areas are interconnected.

[0052] Example 2: The difference between this example and Example 1 is that the middle layer plants are buckwheat, the sand barrier near the edge of the first ditch of the ecological restoration area is the planted middle layer plants, and the sand barrier near the center of the first ditch of the ecological restoration area is the planted low layer plants.

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

[0054]

[0055] In the formula, D is the distance between two adjacent first trenches; W is the wind force (measured by a certain standard, such as meters per second); M is the seed mass; H is the height difference between the upper and middle layers of plants or between the upper and lower layers of plants; Cd is the seed drag coefficient; A is the seed's windward area; ρ is the air density; ε is other drag terms, such as those for rainy or foggy periods, which need to be greater than 0; and g is the acceleration due to gravity. After calculation, the distance between two adjacent first trenches is found to be 0.8m.

[0056] Example 3: This example differs from Example 1 in that the planting density of the upper-layer plants is 30cm between every two upper-layer plants; the planting density of the middle-layer plants is 28cm between every two middle-layer plants; and the planting density of the lower-layer plants is 18cm between every two lower-layer plants. The interval between the upper-layer and middle-layer plants is 20cm, and the interval between the middle-layer and lower-layer plants is 5cm. The first trench is 25cm deep and 3cm wide. The second trench is deeper than the first trench. The sand barriers are made of straw or harvested, dried local salt-tolerant plants. The second trenches between every two ecological restoration zones are interconnected.

[0057] Example 4: This example differs from Example 1 in that the planting density of the upper-layer plants is 70cm between every two upper-layer plants; the planting density of the middle-layer plants is 20cm between every two middle-layer plants; and the planting density of the lower-layer plants is 5cm between every two lower-layer plants. The interval between the upper-layer and middle-layer plants is 10cm, and the interval between the middle-layer and lower-layer plants is 15cm. The first trench is 35cm deep and 7cm wide. The second trench is deeper than the first trench. The sand barriers are made of straw or harvested, dried local salt-tolerant plants. The second trenches between every two ecological restoration zones are interconnected.

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

[0059] Table 1. Vegetation growth status

[0060]

[0061] Vegetation cover refers to the proportion of vegetation covering the ground, usually expressed as a percentage. It reflects the density and coverage of vegetation on the ground 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 two aspects: species richness and species evenness, and can reflect the level of species diversity in a community or ecosystem. The higher the Shannon-Wiener index value, the higher the species diversity in the community.

[0063] As shown in Table 1, compared with the direct transplanting method in Comparative Example 1, the plants, ditches, and sand barriers established in this embodiment of the invention can combine with 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 saline-alkali land in semi-arid regions based on natural solutions, characterized in that, Includes the following steps: S1. Delineate multiple ecological restoration zones; Within the study area with high wind speeds, exposed saline land near the lake that needs restoration was selected and divided into multiple ecological restoration zones. S2, Plant cultivation; In each of the ecological restoration zones, a ring of tall plants is planted around the edge of the ecological restoration zone, followed by a ring of mid-level plants and a ring of low-level plants along the edge of the ecological restoration zone toward the interior; the planting density of the tall plants is less than the planting density of the mid-level plants and the planting density of the low-level plants. The upper-level plants are one or more of reeds, Suaeda salsa, and Acer palmatum; the middle-level plants are Leymus chinensis or Tartary buckwheat; and the lower-level plants are Saussurea involucrata. S3, Ecological Restoration Zone Establishment; Within the ecological restoration area, multiple parallel first trenches are constructed along a direction perpendicular to the prevailing wind direction or the shoreline. A row of sand barriers is set in the center of each trench. Then, within the ecological restoration area, at least one second trench is constructed that is perpendicular to and connected to the first trenches. The bottom surface of the first trench is designed with a slope, and the depth of the first trench at one end where it connects to the second trench is greater than the depth of the other end of the first trench. The distance between two adjacent first trenches is: ； In the formula, D is the distance between two adjacent first furrows, W is the wind force, M is the seed mass, H is the height difference between upper and middle layer plants or between upper and lower layer plants, and C is the seed mass. d ρ is the drag coefficient of the seed, A is the windward area of ​​the seed, and ρ is the density of the air. Other resistance terms, It is gravitational acceleration.

2. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 1, characterized in that, The selected exposed saline land near the lake with strong winds and requiring restoration is divided into multiple ecological restoration zones. These zones include: selecting exposed saline land near the lake in the semi-arid area with an average soil pH of 10.30 to 10.68 and an average wind force of level 3 to level 6 on the exposed saline land. Then, the exposed saline land near the lake is divided into multiple ecological restoration zones according to an area of ​​50×50 to 200×200m for each ecological restoration zone.

3. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 1, characterized in that, The planting density of the upper-level plants is 30-70cm between every two upper-level plants; the planting density of the middle-level plants is 20-28cm between every two middle-level plants; and the planting density of the lower-level plants is 5-18cm between every two lower-level plants.

4. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 3, characterized in that, The distance between the upper-level plants and the middle-level plants is 10-20cm, and the distance between the middle-level plants and the lower-level plants is 5-15cm.

5. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 1, characterized in that, The first trench has a depth of 25-35cm and a width of 3-7cm; the second trench has a greater depth than the first trench.

6. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 1, characterized in that, The sand barriers are made of straw or harvested, dried local salt-tolerant plants.

7. The method for ecological restoration of saline-alkali land in semi-arid areas based on natural solutions as described in claim 1, characterized in that, The sand barriers in the first ditch near the edge of the ecological restoration area are planted with mid-level plants, while the sand barriers in the first ditch near the center of the ecological restoration area are planted with low-level plants.

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