Ecological restoration method for saline-alkali improvement of river (sea) shore

Abstract

The invention discloses an ecological restoration method for saline-alkali improvement of a river (sea) bank. The ecological restoration method comprises the following steps: (1) excavating a saline-alkali soil body downwards for 1.5-2.5 m in a dry season; (2) preparing a hydrophobic microporous salt-isolating material, laying the hydrophobic microporous salt-isolating material at the excavation position to serve as a hydrophobic microporous salt-isolating layer, and earthing and tamping after laying; (3) a composite salt-resistant material layer is laid from the bottom of the slope to the hydrophobic microporous salt isolation layer along the upstream slope surface and attached to the slope surface; (4) an embedded micropore drainage belt is laid above the composite salt-resistant material layer and attached to the slope surface, the bottom of the drainage belt is connected with a water collecting pipe, and a drainage net is formed; (5) uniformly covering soil on the surfaces of the composite salt-resistant material layer and the embedded microporous drainage belt, paving geocells on the slope surface, and filling soil in a layered manner from the bottom of the slope to the top of the slope; and (6) carrying out plant configuration after improvement, and establishing an ecological functional area. According to the method, salt migration can be effectively blocked, the soil structure is improved, salt accumulation in soil is avoided, a plant community is configured, and the ecological function is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the comprehensive treatment and ecological restoration of saline-alkali soil, and in particular to an ecological restoration method for improving saline-alkali soil on river (sea) shores. BACKGROUND

[0002] Saline-alkali soil is one of the important types of soil degradation that affects agricultural production and ecological environment worldwide. In particular, in high-salt and water-active areas such as river and sea shores and reservoirs, due to the uplift of groundwater by lateral seepage, salt is transported to the surface soil by capillary action, leading to excessive accumulation of soil salt, and thus causing problems such as soil salinization and vegetation degradation. Not only does it reduce soil fertility and affect crop growth, but it also damages the ecological environment and reduces the sustainable use value of the land.

[0003] Current treatment methods for saline-alkali soil mainly include irrigation leaching, chemical improvement, and engineering measures. For example, the irrigation leaching method reduces the salt content of the surface soil by irrigating with a large amount of fresh water to dissolve and transport the salt downward with the seepage water. The chemical improvement method mainly uses gypsum, phosphogypsum, and other improvers to replace sodium ions in the soil, thereby improving the soil structure. Engineering measures such as underground drainage systems can artificially lower the groundwater level and reduce capillary uplift. However, these traditional treatment methods still have many shortcomings, such as: the traditional irrigation leaching method can reduce the salt content of the surface soil in the short term, but it fails to block the coupled transport mechanism of water and salt, so the salt in the groundwater continues to rise, leading to salt accumulation and affecting the long-term effectiveness of the treatment; the use of chemical improvers such as gypsum may cause soil pH imbalance, affect the soil microbial community structure, and possibly pollute the surrounding water; and engineering measures such as underground drainage networks require high construction and maintenance costs, and their impact on the groundwater level may not be easily controlled, leading to excessive drying or soil structure damage in local areas.

[0004] Since the essence of soil salinization is water migration, the accumulation of salt is closely related to water movement, therefore, how to effectively block the upward channel of groundwater and reduce the accumulation of salt on the surface is the key to improving saline-alkali soil on river (sea) shores. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the present application provides a kind of river (sea) coast saline-alkali improvement ecological restoration method, can effectively block groundwater rising channel, inhibit salt migration to surface, while according to water level change, through the setting of slope surface drainage facilities and the layout of slope bottom composite salt-resistant material layer, the problem of salt migration is solved. By setting ecological function area, according to water level gradient and function division into embankment area, high water level area and low water level area, plant configuration is carried out in the three regions respectively, salt-tolerant plants are selected, the number of species is relatively large, has the characteristics of anti-interference and strong stability, can play the role of long-term enrichment of saline-alkali, so as to realize the long-term stable improvement of river (sea) coast saline-alkali soil. Plant configuration in different water level areas can ensure the landscape effect in different seasons, a variety of arbor and shrub are selected in embankment area according to proportion and certain density for mixed planting, the developed root system of plants can stabilize the embankment, enhance the ability of flood resistance and embankment protection, mainly use color-leaf plants, match evergreen trees and a small amount of flowering shrubs, have landscape effect, and restore the ecological function of the area.

[0006] To achieve the above object, the present application provides the following technical scheme: a kind of river (sea) coast saline-alkali improvement ecological restoration method, comprising the following steps:

[0007] (1) in dry season, saline-alkali soil of the river (sea) coast to be treated is excavated downward by 1.5-2.5 m;

[0008] (2) prepare hydrophobic microporous salt barrier material, lay the hydrophobic microporous salt barrier material at the excavation position, the laying thickness is 4-5 cm, as a hydrophobic microporous salt barrier layer, after laying, cover the hydrophobic microporous salt barrier layer with soil and tamp;

[0009] (3) along the river (sea) embankment slope, match the slope, lay a composite salt-resistant material layer from the slope bottom to the hydrophobic microporous salt barrier layer;

[0010] (4) embed the microporous drainage belt on the composite salt-resistant material layer, form a plurality of longitudinal parallel drainage channels, and connect the drainage belt bottom to the water collection pipe to form a drainage network;

[0011] (5) after uniformly covering soil on the surface of the composite salt-resistant material layer and the embedded microporous drainage belt, lay geocell on the slope surface and fill the soil culture medium;

[0012] (6) plant configuration is carried out in the improved river (sea) coast area, and an ecological function area is established.

[0013] Preferably, the material of the hydrophobic microporous salt barrier layer includes fine sand, kaolin, thermosetting solution fluorocarbon resin, acetone, blocked isocyanate resin crosslinking agent, silane modified silicon dioxide, rice husk biochar, and sodium bicarbonate pore former.

[0014] Preferably, in the hydrophobic microporous salt barrier material, the fine sand has a fineness modulus of 1.6-2.2 and a particle size range of 0.25-0.35 mm.

[0015] Preferably, in the hydrophobic microporous salt barrier material, the kaolin has a particle size of 5-20 μm.

[0016] Preferably, in the hydrophobic microporous salt barrier material, the silane-modified silica has a particle size of 10-100 nm.

[0017] Preferably, in the hydrophobic microporous salt barrier material, the sodium bicarbonate pore former has a particle size of 5-50 μm.

[0018] Preferably, the method for preparing the hydrophobic microporous salt barrier comprises: mixing fine sand, kaolin, silane-modified silica, rice husk biochar, and sodium bicarbonate pore former in a mass ratio of 50:25:10:10:5 to form dry mixed powder as material A; mixing thermosetting solution fluorocarbon resin, acetone, blocked isocyanate resin, and crosslinking agent in a mass ratio of 100:15:10 to form resin mixed wet material as material B; adding material B to material A in a mass ratio of 70:30 while stirring until a uniform slurry without obvious particles is formed; and performing 120°C thermosetting treatment on the slurry for 45-60 min to form the hydrophobic microporous salt barrier.

[0019] Preferably, the hydrophobic microporous salt barrier has a hydrophobic microporous structure with a pore size of 0.5-5 mm, a thickness of 4-5 cm, and a liquid contact angle with the hydrophobic microporous salt barrier of ≥120°.

[0020] Preferably, the microgroove holes on the embedded microporous drainage belt are frustoconical, the inner walls of the microgroove holes are uniformly distributed with micro-membrane sheets for preventing backflow, the porosity of the microgroove holes is 50%, the upper end of the microgroove holes has a pore size of 50 μm, and the lower end of the microgroove holes has a pore size of 100 μm.

[0021] Preferably, the embedded microporous drainage belt is laid along the water-facing slope surface of the embankment, has a height corresponding to the position of the buried depth of the hydrophobic microporous salt barrier, and forms multiple longitudinal parallel drainage channels on the slope surface.

[0022] Preferably, the water collection pipes are distributed transversely, have openings at both ends, have a diameter of 5 cm, and are connected to the pipe diameter of the embedded microporous drainage belt at the bottom, forming a parallel drainage network on the slope surface.

[0023] Preferably, the composite salt-resistant material layer is composed of a layer of polyurethane sprayed on the surface of a non-woven fabric, has a thickness of 2-3 mm, is laid in the area between the bottom of the water-facing slope surface of the embankment along the river (sea) and the bottom end of the water collection pipe, and is covered with 5-7 cm of soil after the composite salt-resistant material layer is laid.

[0024] Preferably, the geocell is filled with soil culture medium, and the soil culture medium is prepared by mixing clay, fermented wood powder, agricultural and forestry waste and soil stabilizer at a volume ratio of 10:5:3:1.

[0025] Preferably, the ecological function area is divided into a dike area, a high water level area and a low water level area according to a water level gradient and a function, and plants are configured in the three areas respectively.

[0026] Preferably, the plant configuration scheme of the dike area is to select at least three kinds from bamboo willow, tamarisk, pearl beauty begonia, white wax, oleander, pear willow, purple pagoda tree, lilac, and plum leaf, and mix and plant them. 2 The planting density of the woody plants is 1-2 plants / m The ratio of arbor and shrub mixed planting is 1:3.

[0027] Preferably, the plant configuration scheme of the high water level area is to select alfalfa, wild soybean, awnless brome and sesbania and mix and sow them at a seed mass ratio of 6:2:2:1.

[0028] Preferably, the plant configuration scheme of the low water level area is to select one or more of bulrush, cattail, water onion, alternanthera, alocasia, saltmarsh rush and yellow iris and sow them.

[0029] The present application has the following beneficial effects:

[0030] The hydrophobic microporous salt separation layer is arranged at a certain depth of the river (sea) shore saline-alkali soil, which cuts off the upward transportation path of the salt in the deep soil through capillary action, prevents the upward migration of water carrying salt, and effectively blocks capillary back salt. The reasonable configuration of the slope active drainage facility composed of the embedded microporous drainage belt and the composite salt blocking material layer can further adjust the migration path of water and salt. When the water level in the river rises in the wet season, the salt concentration in the water body is relatively low at this time, and part of the water in the soil above the salt separation layer will be transferred to the outside through the embedded microporous drainage belt by capillary action; another part of the water will be transferred downward through the microporous salt separation layer, which can effectively alleviate soil waterlogging. When the water level in the river decreases in the dry season, the salt concentration in the river water is high, and the high-salt water is blocked by the composite salt blocking material layer and cannot enter the soil below the salt separation layer, which can ensure that the salt transfer between the water body and the soil is effectively managed at different water levels, and prevent the accumulation of salt in the soil. The ecological function area formed by the configuration selects salt-tolerant plants, the number of species is relatively large, and has the characteristics of strong anti-interference and stability, which can play a long-term role in enriching salt and alkali, and realize long-term stable improvement of river (sea) shore saline-alkali soil. The plant configuration in different water level areas can ensure the landscape effect in different seasons, and a variety of trees and shrubs are selected in the embankment area according to the proportion and certain density for mixed planting, the developed root system of the plants can stabilize the embankment and enhance the flood resistance and embankment protection capacity, the main color-leaf plants are matched with evergreen trees and a small amount of flowering shrubs, which have landscape effect and restore the ecological function of the area. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic diagram of salt migration in the wet season of the application;

[0032] Figure 2 It is a schematic diagram of preventing salt migration in the dry season of the application;

[0033] Figure 3 It is a transverse sectional view of the embedded microporous drainage belt of the application;

[0034] Figure 4 It is a vertical sectional view of the drainage net of the application.

[0035] In the figure: 1, water level line in the wet season; 2, embedded microporous drainage belt; 3, water collecting pipe; 4, composite salt blocking material layer; 5, river (sea) shore saline-alkali soil; 6, hydrophobic microporous salt separation layer; 7, salt migration path; 8, deep soil; 9, water level line in the dry season; 10, low water level area; 11, high water level area; 12, embankment area; 13, micro-groove hole; 14, micro-membrane piece. DETAILED DESCRIPTION

[0036] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0037] Please refer to Figures 1-4 As shown in the drawings, an ecological restoration method for improving saline-alkali soil of a river (sea) bank is used to improve the saline-alkali soil 5 of the river (sea) bank, solve problems such as vegetation degradation, improve the ecological environment, and restore the ecological function of the region.

[0038] The method comprises the following steps.

[0039] The fine sand 350 kg, kaolin 175 kg, silane-modified silicon dioxide 70 kg, rice husk biochar 70 kg, and sodium bicarbonate pore-forming agent 35 kg are stirred and mixed uniformly to form dry mixed powder. The fine sand has a fineness modulus of 2.1 and a particle size of 0.35 mm, the kaolin has a particle size of 10 μm, the silane-modified silicon dioxide has a particle size of 50 nm, and the sodium bicarbonate pore-forming agent has a particle size of 30 μm.

[0040] The thermosetting solution fluorocarbon resin 240 kg, acetone 36 kg, and blocked isocyanate resin crosslinking agent 24 kg are mixed uniformly to form resin mixed wet material.

[0041] The dry mixed powder is slowly added to the resin mixed wet material, and stirring is performed while adding until a uniform slurry without obvious particles is formed; the prepared slurry is cured at a high temperature of 120°C for 60 min to form the hydrophobic microporous salt-blocking layer 6.

[0042] The saline-alkali soil layer is excavated along the river bank to a width of 10 m and a depth of 2 m, and the hydrophobic microporous salt-blocking layer 6 is laid and tamped after covering with soil.

[0043] A 3 mm polyurethane is sprayed on the surface of the non-woven fabric to form a composite salt-blocking material layer 4, which is attached to the slope soil and laid in the area between the bottom of the water-facing slope of the river embankment and the bottom end of the catchment pipe 3.

[0044] Along the water-facing slope of the river (sea) embankment, the catchment pipe 3 is laid transversely at the position of the hydrophobic microporous salt-blocking layer 6, and the catchment pipe 3 is open at both ends for drainage, and the upper end is notched to be connected to the embedded microporous drainage belt 2.

[0045] An embedded microporous drainage strip 2 is laid on the soil above the slope. The micro-grooves 13 on the embedded microporous drainage strip 2 are frustoconical in shape. Micro-membranes 14 are evenly distributed on both sides of the inner wall of the micro-grooves 13 to prevent backflow. The porosity of the micro-grooves 13 is 50%, with an upper pore diameter of 50 μm and a lower pore diameter of 100 μm. The bottom of the drainage strip is connected to the pipe diameter through the groove of the water collection pipe 3 to form a drainage network.

[0046] A 5cm thick layer of soil is uniformly covered on the surface of the composite salt barrier material layer 4 and the embedded microporous drainage strip 2. After the soil covering is completed, geocells are laid flat on the slope. Soil culture medium is prepared by mixing clay, fermented wood powder, agricultural and forestry waste and soil stabilizer in a volume ratio of 10:5:3:1 and then filling it into the geocells.

[0047] After the improvement, the river (sea) shore area was divided into three areas: low water level zone 10, high water level zone 11, and dike zone 12 for vegetation configuration. The low water level zone 10 is located between the high water level line 1 and the low water level line 9, while the high water level zone 11 is located above the low water level line 9 to the dike zone 12.

[0048] Among them, the plant configuration scheme for the low water level area is to select cattail, water onion, loosestrife, sweet flag and yellow iris for clump sowing.

[0049] In the high-water-level area, the plant configuration scheme for Project 11 is as follows: alfalfa, wild soybean, awnless bromegrass, and sesbania are selected and evenly mixed and sown in a seed weight ratio of 6:2:2:1, with an alfalfa sowing rate of 6 kg / hm². 2 The sowing rate for wild soybean is 2 kg / hm². 2 The sowing rate for awnless bromegrass is 2 kg / hm. 2 The seeding rate for sesbania is 1 kg / hm². 2 .

[0050] The planting scheme for the 12 sections of the dike area involves selecting three woody plants—Fraxinus chinensis, Amorpha fruticosa, and Syringa vulgaris—and planting them in a triangular pattern. The planting density of the woody plants is 1-2 plants / m². 2 The ratio of trees to shrubs is 1:3. The planting holes for trees are 60cm×60cm×60cm, and the planting holes for shrubs are 40cm×40cm×40cm.

[0051] During the wet season, the salt and alkali in the soil above the hydrophobic microporous salt barrier 6 can be effectively reduced by rain washing. During the dry season, the hydrophobic microporous salt barrier 6 cuts off the path of salt in the deep soil 8 transported upward by capillary action, preventing water from carrying salt upward. High-salt river water is blocked by the composite salt-resistant material layer 4, cutting off the path of salt in the water transported laterally to the underlying soil. The configuration of salt-tolerant plants can play a long-term role in enriching salt and alkali, achieving long-term stable improvement of the river (sea) shore saline soil 5. Plant configuration in different water level areas can ensure the landscape effect in different seasons. In the embankment area 12, a variety of trees and shrubs are mixed and planted in proportion and at a certain density. The developed root system of the plants can stabilize the embankment and enhance the ability to resist floods and protect the embankment. The plant configuration is mainly based on colorful leaf plants, supplemented by evergreen trees and a small amount of flowering shrubs, which have both landscape effects. The ecological function of the restoration area is restored.

[0052] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An ecological restoration method for improving salinity and alkalinity along river (sea) banks, characterized in that, Includes the following steps: (1) During the dry season, the saline-alkali soil of the river (sea) bank to be treated should be excavated downwards by 1.5-2.5m; (2) Prepare hydrophobic microporous salt barrier material, lay the hydrophobic microporous salt barrier material at the excavation location with a thickness of 4-5cm as the hydrophobic microporous salt barrier layer, and cover the hydrophobic microporous salt barrier layer with soil and compact it after laying. (3) Along the water-facing slope of the river (sea) embankment, a composite salt barrier material layer is laid from the bottom of the slope to the hydrophobic microporous salt barrier layer. (4) Above the composite salt barrier material layer, an embedded microporous drainage strip is laid in line with the slope to form multiple longitudinal parallel drainage channels. The bottom of the drainage strip is connected to a water collection pipe to form a drainage network. (5) After uniformly covering the surface of the composite salt barrier material layer and the embedded microporous drainage strip with soil, the geocells are laid flat on the slope and the soil is filled in layers from the bottom of the slope to the top of the slope. (6) Planting is carried out in the improved river (sea) shore area to establish an ecological functional zone.

2. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 1, characterized in that: The materials of the hydrophobic microporous salt barrier layer include fine sand, kaolin, thermosetting fluorocarbon resin, acetone, blocked isocyanate resin crosslinking agent, silane-modified silica, rice husk biochar, and sodium bicarbonate pore-forming agent.

3. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 2, characterized in that: Fine sand, kaolin, silane-modified silica, rice husk biochar, and sodium bicarbonate pore-forming agent are mixed evenly in a mass ratio of 50:25:10:10:5 to form a dry powder, which is designated as material A. Thermosetting fluorocarbon resin, acetone, blocked isocyanate resin, and crosslinking agent are mixed evenly in a mass ratio of 100:15:10 to form a resin mixture wet material, which is designated as material B. Materials A and B are mixed and stirred in a mass ratio of 70:30 to form a slurry. The slurry is then heat-cured at 120℃ for 45-60 minutes to form a hydrophobic microporous salt barrier layer.

4. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 1, characterized in that: The micro-grooves on the embedded microporous drainage strip are frustum-shaped, and micro-membranes to prevent backflow are evenly distributed on both sides of the inner wall of the micro-grooves. The porosity of the micro-grooves is 50%, the upper end diameter of the micro-grooves is 50μm, and the lower end diameter of the micro-grooves is 100μm.

5. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 1, characterized in that: The water collection pipes are distributed horizontally, with openings at both ends. The bottom of the embedded microporous drainage strip is connected to the diameter of the water collection pipe, forming a parallel drainage network on the slope.

6. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 1, characterized in that: The composite salt barrier material layer is made by spraying a layer of polyurethane onto the surface of a nonwoven fabric, and the thickness of the composite salt barrier material layer is 2-3 mm.

7. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 1, characterized in that: The ecological functional zones are divided into dike zones, high-water-level zones, and low-water-level zones according to water level gradients and functions, and plant configurations are carried out in each of the three zones.

8. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 7, characterized in that: The plant configuration scheme within the dike area is as follows: at least three species should be selected from bamboo willow, tamarisk, Malus spectabilis, ash, oleander, pear, Amorpha fruticosa, lilac, and Prunus triloba for mixed planting, with the planting density of woody plants being 1-2 plants / m². 2 The ratio of trees to shrubs is 1:

3.

9. The ecological restoration method for improving salinity and alkalinity along river (sea) banks according to claim 7, characterized in that: The plant configuration scheme in the high water level area is as follows: alfalfa, wild soybean, awnless brome, and sesbania are selected and mixed in a ratio of 6:2:2:

1.

10. The ecological restoration method for improving saline-alkali riverbanks according to claim 7, characterized in that, The plant configuration scheme for the low water level area is as follows: select one or more of the following for sowing: cattail, bulrush, water onion, loosestrife, sweet flag, saltwort, and yellow iris.

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