Ecological restoration method for saline-alkali soil

Abstract

The invention discloses an ecological restoration method for saline-alkali soil, which comprises the following steps: S1, digging a plurality of mounting grooves in the saline-alkali soil, and arranging spraying liquid recovery devices in the mounting grooves; s2, land leveling is conducted on the saline-alkali soil, sundries are removed, the terrain gradient is made to be smaller than 2 degrees, and the edge of the leveled saline-alkali soil is surrounded to form a cofferdam; s3, irrigating the saline-alkali soil in the cofferdam, and standing for a period of time until irrigation water permeates; s4, ridging is conducted on the irrigated saline-alkali soil, an isolation layer is laid on a ridge table, and planting soil is laid on the isolation layer; s5, covering a mulching film, laying a drip irrigation belt, and planting alkali-resistant crops; s6, irrigating the furrows between the ridges for multiple times, wherein the humic acid magnetic biochar modifier is added into the irrigating water. The saline-alkali soil can be ecologically restored, irrigation water can be recycled, the irrigation water is evaporated through a photo-thermal technology, energy consumption can be effectively reduced, the irrigation water of the saline-alkali soil can be recycled, and waste of water resources is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land restoration, and particularly to an ecological restoration method for saline-alkali land. Background Art

[0002] In the coastal areas of our country, especially at the river estuaries, the groundwater level is shallow, the salinity is high, and the seawater intrusion is obvious. A large area of land is formed by the sediment deposition of rivers and the reclamation of submarine silt. Its soil texture is extremely poor, without soil structure, with a large bulk density, small pores, and strong soil capillary action. Under the evaporation effect, the high-salinity groundwater is easy to migrate to the surface soil layer, leading to the formation of saline-alkali land. And the soil permeability is poor, and the rainfall is relatively concentrated. After a single rainfall, the total amount of soil infiltration is small, and a large amount of rainfall forms surface runoff and is lost without participating in the leaching of saline-alkali soil, resulting in very low efficiency of soil salt leaching by atmospheric rainfall, making the rainfall infiltration amount much less than the soil evaporation amount, and the soil salt content of saline-alkali land continues to rise without being fully leached.

[0003] Generally, physical methods and chemical methods are used for the treatment of saline-alkali soil. The physical improvement technology mainly modifies saline-alkali soil by disrupting the water-salt movement process of saline-alkali soil. On the one hand, it prevents the further increase of soluble salts in saline-alkali soil, and on the other hand, it removes the existing soluble salts. The method generally adopts the leaching method, irrigating saline-alkali soil with a large amount of water to dissolve some of the soluble salts in saline-alkali soil, and then discharging this part of water to achieve the purpose of removing soluble salts from saline-alkali soil. However, when using the leaching method to repair saline-alkali land, it is difficult to treat the irrigation water of saline-alkali land, and the pollutants in it are not easy to separate. Summary of the Invention

[0004] An ecological restoration method for saline-alkali land provided by the present invention can perform ecological restoration on saline-alkali land, can recycle irrigation water, utilize photothermal technology to evaporate irrigation water, can effectively save energy consumption, realize the recycling of irrigation water for saline-alkali land, and reduce water resource waste.

[0005] In order to achieve the above object, the present invention provides an ecological restoration method for saline-alkali land, which includes the following steps:

[0006] S1. Dig a plurality of installation grooves in the saline-alkali land, and arrange a leachate recovery device in the installation grooves;

[0007] S2. Level the saline-alkali land, remove sundries, make the terrain slope less than 2°, and enclose the edge of the leveled saline-alkali land to form a cofferdam;

[0008] S3. Irrigate the saline-alkali land within the cofferdam, and let it stand for a period of time until the irrigation water permeates;

[0009] S4. Ridging the watered saline-alkali land, laying an isolation layer on the ridge platform, and laying planting soil on the isolation layer;

[0010] S5. Covering with plastic film, laying drip irrigation belts, and planting alkali-tolerant crops at the same time;

[0011] S6. Conducting multiple waterings in the furrows between the ridge platforms, and adding humic acid magnetic biochar modifier to the irrigation water;

[0012] S7. After the alkali-tolerant crops are harvested, plowing and sunning the saline-alkali land, then rotary tilling and crushing, and finally repeating steps S3 - S7 in a cycle.

[0013] As a further description of the above technical solution:

[0014] After the irrigation water in steps S3 and S4 has permeated, the land surface needs to be sunned and dried, and the crystallized substances on the land surface are removed.

[0015] As a further description of the above technical solution:

[0016] The bottom of the plastic film extends to the bottom of the planting soil.

[0017] As a further description of the above technical solution:

[0018] The preparation steps of the humic acid magnetic biochar modifier include:

[0019] (1) Mixing biomass, ferric salt, and organic solution in a certain proportion and firing to obtain ferrous biochar powder;

[0020] (2) Conducting oxygen-limited firing or anaerobic firing on the ferrous biochar powder to obtain magnetic biochar;

[0021] (3) Combining the magnetic biochar with activated humic acid, trehalose, betaine, and melatonin to obtain the humic acid magnetic biochar modifier.

[0022] As a further description of the above technical solution:

[0023] Before the magnetic biochar is combined with humic acid, the magnetic biochar needs to be magnetized.

[0024] As a further description of the above technical solution:

[0025] The ferric salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate.

[0026] As a further description of the above technical solution:

[0027] The biomass includes at least one of rice straw, cotton straw, tobacco straw, and reed straw.

[0028] As a further description of the above technical solution:

[0029] The leachate recovery device includes a first water storage tank, a second water storage tank, an evaporation box and a water guide belt. A plurality of water seepage holes are provided on the side wall of the first water storage tank, and the water seepage holes are all closed by water seepage filter materials. The evaporation box is arranged on the outer wall of the first water storage tank. The water guide belt is made of a water-absorbing material and is arranged inside the first water storage tank. One end of the water guide belt passes through the first water storage tank and is connected to the evaporation box, and the evaporation box is connected to the second water storage tank through a water pipe.

[0030] As a further description of the above technical solution:

[0031] At least one heat conduction plate is arranged between the first water storage tank and the second water storage tank.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0033] 1. In the present invention, by building dikes and ridges on saline-alkali land and setting an isolation layer on the ridges, the soil capillary can be effectively cut off, the evaporation of groundwater can be blocked, and salt return can be prevented. By setting a plastic film on the planting soil, the irrigation water can be prevented from entering the planting soil, avoiding the influence of irrigation water on alkali-tolerant crops. And by using the leaching method to leach the saline-alkali land in the furrows for multiple times, the salt in the saline-alkali land can be taken away, so as to achieve the purpose of repairing the saline-alkali land. The saline-alkali land can be planted while being leached and salt flushed.

[0034] 2. In the present invention, a plurality of leachate recovery devices are arranged in the saline-alkali land. When the irrigation water seeps downward, it can dissolve the salt in the saline-alkali land. After the irrigation water seeps into the first water storage tank, the capillary action of the water guide belt is used to migrate the irrigation water entering the first water storage tank upward and transport it to the evaporation box. The evaporation box can evaporate the water in the irrigation water based on the photothermal evaporation effect, so that the crystalline salt of the irrigation water can be obtained on the evaporation surface of the evaporation box. The evaporated water vapor enters the second water storage tank through a pipeline. The second water storage tank is located underground in the saline-alkali land and has a low temperature, which can condense the water vapor into water droplets and store them in the second water storage tank, realizing recycling and saving water resources.

[0035] 3. In the present invention, a humic acid magnetic biochar modifier is added to the irrigation water. By using the high affinity between humic acid and iron oxide, humic acid is loaded on magnetic biochar to prepare humic acid-magnetic biochar, improving the adsorption capacity of biochar and reducing the salinity and alkalinity of saline-alkali soil. Description of the Drawings

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a flowchart of an ecological restoration method for saline-alkali land.

[0038] Figure 2 It is a usage state diagram of a leachate recovery device in an ecological restoration method for saline-alkali land.

[0039] Legend description:

[0040] 1. Saline-alkali land; 2. Installation groove; 3. Leachate recovery device; 31. First water storage tank; 32. Second water storage tank; 33. Evaporation box; 34. Water guiding belt; 4. Ridge platform; 5. Isolation layer; 6. Planting soil; 7. Plastic film; 8. Water seepage hole; 9. Heat conducting plate. Detailed implementation manners

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0043] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0044] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "inner", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0045] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and defined, the terms "set", "install", "connect", and "link" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0046] Please refer to Figure 1-2 , the present invention provides an ecological restoration method for saline-alkali land, including:

[0047] S1. Excavate a plurality of installation grooves 2 in the saline-alkali land 1, and arrange a leachate recovery device 3 in the installation grooves 2;

[0048] S2. Level the saline-alkali land 1, remove sundries, make the terrain slope less than 2°, and enclose the edge of the leveled saline-alkali land 1 to form a cofferdam;

[0049] S3. Irrigate the saline-alkali land 1 within the cofferdam, and let it stand for a period of time until the irrigation water penetrates;

[0050] S4. Ridging the irrigated saline-alkali land 1, laying an isolation layer 5 on the ridge platform 4, and laying planting soil 6 on the isolation layer 5; the isolation layer is composed of plant stalks, specifically it can be straw;

[0051] S5. Cover with a plastic film 7, lay a drip irrigation belt, and at the same time plant alkali-tolerant crops;

[0052] S6. Conduct multiple irrigations in the furrows between the ridge platforms, and add a humic acid magnetic biochar modifier to the irrigation water;

[0053] S7. After the alkali-tolerant crops are harvested, plow and sun the saline-alkali land 1, then rotary till and break it up, and finally repeat steps S3 - S7 in a cycle.

[0054] After the irrigation water penetrates in step S3 and step S4, the land surface needs to be dried in the sun, and the crystallized substances on the land surface are removed.

[0055] The bottom of the plastic film 7 extends to the bottom of the planting soil. This can prevent the irrigation water from soaking the planting soil.

[0056] The preparation steps of the humic acid magnetic biochar modifier include:

[0057] (1) Mix biomass, ferric salt, and organic solution in a certain proportion and then burn to obtain ferrous biochar powder; the organic solution can specifically be ethanol;

[0058] (2) Carry out oxygen-limited firing or anaerobic firing on the ferrous biochar powder to obtain magnetic biochar; the ferrous biochar powder can be fired in a tube furnace;

[0059] (3) Combine the magnetic biochar with activated humic acid, trehalose, betaine, and melatonin to obtain a humic acid magnetic biochar modifier.

[0060] Before the magnetic biochar is combined with humic acid, the magnetic biochar needs to be magnetized. This can improve the magnetism of the magnetic biochar and facilitate the subsequent separation of crystalline salts.

[0061] The trivalent iron salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate.

[0062] The biomass contains at least one of rice straw, cotton straw, tobacco straw, and reed straw.

[0063] The leachate recovery device 3 includes a first water storage tank 31, a second water storage tank 32, an evaporation box 33, and a water guide belt 34. A plurality of water seepage holes 8 are provided on the side wall of the first water storage tank 31, and the water seepage holes 8 are all closed by water seepage filter materials. The evaporation box 33 is arranged on the outer wall of the first water storage tank 31. The water guide belt 34 is made of a water-absorbing material and is built in the first water storage tank 31. One end of the water guide belt 34 passes out of the first water storage tank 31 and is connected to the evaporation box. The evaporation box 33 is connected to the second water storage tank 32 through a water pipe. The water seepage filter material is a water seepage filter cloth: the evaporation box is a transparent box body, and the evaporation box is made of a photothermal base material with a photothermal coating applied thereon. The irrigation water can obtain the crystalline salts of the irrigation water on the evaporation surface of the evaporation box, and the evaporated water vapor enters the second water storage tank through a pipeline. The second water storage tank is located underground in the saline-alkali land and has a low temperature, which can condense the water vapor into water droplets and store them in the second water storage tank, realizing recycling and saving water resources.

[0064] At least one heat conduction plate 9 is arranged between the first water storage tank 31 and the second water storage tank 32. In this way, the heat of the second water storage tank can be transferred to the first water storage tank through the heat conduction plate to increase the temperature of the irrigation water and facilitate evaporation.

[0065] Working principle: By building cofferdams and ridges on saline-alkali land and setting up an isolation layer on the ridge platform, the soil capillary can be effectively cut off, groundwater evaporation can be blocked, and salt return can be prevented. By setting up plastic films on the planting soil, irrigation water can be prevented from entering the planting soil, avoiding the impact of irrigation water on alkali-tolerant crops. In the furrow, the saline-alkali land can be leached multiple times by the leaching method to take away the salt in the saline-alkali land, thus achieving the purpose of repairing the saline-alkali land. The saline-alkali land can be planted while being leached and salt-flushed. Multiple leachate recovery devices are set in the saline-alkali land. When the irrigation water infiltrates downward, it can dissolve the salt in the saline-alkali land. After the irrigation water infiltrates into the first water storage tank, it migrates upward through the capillary action of the water guide belt and is transported to the evaporation box. The evaporation box can evaporate the water in the irrigation water based on the photothermal evaporation effect, so that the crystal salt of the irrigation water can be obtained on the evaporation surface of the evaporation box. Then, through the magnetic attraction method, the magnetic carbon in the crystal salt can be recovered. The evaporated water vapor enters the second water storage tank through a pipeline. The second water storage tank is located underground in the saline-alkali land and has a low temperature, which can condense the water vapor into water droplets and store them in the second water storage tank, realizing recycling and saving water resources. By adding humic acid magnetic biochar modifier to the irrigation water and using the high affinity between humic acid and iron oxide, humic acid is loaded on the magnetic biochar to prepare humic acid-magnetic biochar, improving the adsorption capacity of the biochar and reducing the salinity and alkalinity of the saline-alkali soil.

[0066] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for ecological restoration of saline-alkali land, characterized in that: The following steps are involved: S1. excavating a plurality of installation grooves in the saline-alkali land, and installing a leaching recovery device in the installation grooves; S2. Level the saline-alkali land, remove debris, make the terrain slope less than 2°, and then enclose the edge of the leveled saline-alkali land to form a cofferdam; S3, irrigate the saline-alkali land within the cofferdam, and let it stand for a period of time until the irrigation water penetrates; S4, making ridges on the irrigated saline-alkali land, laying an isolation layer on the ridges, and laying planting soil on the isolation layer; S5. Cover the ground with film, lay drip irrigation tape, and plant alkali-resistant crops; S6. Watering is performed multiple times in the furrows between the ridges, and humic acid magnetic biochar improver is added to the irrigation water; S7, after the alkali-resistant crops are harvested, the saline-alkali land is plowed, turned over, and ridged, then rotary tilled and broken, and finally steps S3-S7 are repeated.

2. The ecological restoration method for saline-alkali land according to claim 1, characterized in that: After the irrigation water has penetrated through step S3 and step S4, the soil surface needs to be air-dried and crystals on the soil surface need to be removed.

3. The ecological restoration method for saline-alkali land according to claim 1, characterized in that: The bottom of the ground film extends to the bottom of the planting soil.

4. The ecological restoration method of saline-alkali land according to claim 1, characterized in that: The preparation steps of the humic acid magnetic biochar modifier include: (1) mixing biomass, trivalent iron salt and organic solution in a certain proportion and then firing to obtain ferrous biochar powder; (2) subjecting the ferrous biochar powder to oxygen-limited or oxygen-free firing to obtain magnetic biochar; (3) Combine magnetic biochar with activated humic acid, trehalose, betaine and melatonin to obtain humic acid magnetic biochar modifier.

5. The ecological restoration method for saline-alkali land according to claim 4, characterized in that: Before the magnetic biochar is combined with humic acid, it needs to be magnetized.

6. The ecological restoration method for saline-alkali land according to claim 4, characterized in that: The trivalent iron salt is at least one of ferric chloride, ferric sulfate and ferric nitrate.

7. The ecological restoration method for saline-alkali land according to claim 4, characterized in that: The biomass comprises at least one of rice straw, cotton straw, tobacco straw and reed straw.

8. The ecological restoration method for saline-alkali land according to claim 1, characterized in that: The liquid recovery device includes a first water storage tank, a second water storage tank, an evaporation box and a water guide belt. A plurality of water seepage holes are arranged on the side wall of the first water storage tank, and the water seepage holes are all closed by water seepage filter materials. The evaporation box is arranged on the outer wall of the first water storage tank. The water guide belt is made of water-absorbing material. The water guide belt is built into the first water storage tank. One end of the water guide belt passes through the first water storage tank and is connected to the evaporation box. The evaporation box is connected to the second water storage tank through a water pipe.

9. The ecological restoration method for saline-alkali land according to claim 8, characterized in that: At least one heat conducting plate is arranged between the first water storage tank and the second water storage tank.

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