A saline-alkali soil structure with cyclic salt flushing and multi-layer synergistic desalination function

Abstract

This utility model discloses a saline-alkali land structure with cyclic salt flushing and multi-layer synergistic desalination functions. It includes an ecological cover layer on the surface, beneath which are sequentially arranged a slow-release conditioning layer, a salt-blocking isolation layer, and a salt-draining layer. The salt-draining layer contains several porous salt-draining conduits, which are connected to an underground collection well via a collection and drainage device. It also includes a water return system, one end of which is connected to the collection and drainage device in the collection well, and the other end returns the water to the ecological cover layer, slow-release conditioning layer, salt-blocking isolation layer, and salt-draining layer. This application achieves systematic management of soil salinity migration, dispersion, isolation, and removal through the synergistic interaction of multiple layers of functions, including ecological cover, slow-release conditioning, physical barrier, and salt-draining. This effectively overcomes the drawbacks of traditional single-method improvement methods, such as low desalination efficiency and frequent salt return.

Description

Technical Field

[0001] This utility model relates to the field of agricultural water and soil conservation and soil environment management technology, specifically to a saline-alkali land structure with cyclic salt flushing and multi-layer synergistic desalination functions. Background Technology

[0002] Saline-alkali land is widely distributed in coastal mudflats, inland arid areas, and alluvial plains of my country. It is characterized by high salt content, strong alkalinity, loose or compacted soil structure, and difficulty in plant survival, severely restricting the development and utilization of land resources and sustainable agricultural development. Current methods for improving saline-alkali land mainly include physical flushing, soil covering, chemical conditioning, and shallow desalination. However, these traditional techniques all have limitations in practical application.

[0003] Among these methods, salt flushing is the most commonly used physical remediation technique, relying on large amounts of fresh water to flush salts out into deeper soil layers or to the surface. While it provides quick short-term results, this method is highly dependent on water resources, making it unsuitable for arid or semi-arid regions and prone to water waste. Furthermore, in areas with high groundwater levels or low-lying terrain, salts can easily rise back to the surface due to capillary action, resulting in a "salt return" phenomenon, making it difficult to maintain the remediation effect in the long term.

[0004] The soil covering method suppresses salt by covering the soil with imported soil or crop straw, which is suitable for certain closed or localized improvement scenarios. However, it has problems such as high construction costs, difficulty in obtaining imported soil, and complicated post-maintenance. In addition, it cannot fundamentally improve the physical and chemical properties of the soil, has poor regional adaptability, and is difficult to promote.

[0005] Chemical conditioning methods involve applying conditioners such as desulfurized gypsum and sodium humate to react with soil salinity, thereby improving soil structure and permeability. However, their effectiveness is limited by moisture conditions, has a short duration of effect, and excessive application may lead to soil compaction or environmental pollution risks. Their stability and environmental friendliness are difficult to guarantee.

[0006] Shallow drainage structures, such as drainage ditches or blind pipe systems, can divert saline water to areas outside the land parcel. However, the drainage path is shallow and singular, making them prone to blockage, requiring significant maintenance, and exhibiting poor operational stability. Furthermore, these structures are often isolated from irrigation systems, failing to achieve coordinated flushing and drainage, resulting in low overall desalination efficiency, particularly in the treatment of moderate to severe saline-alkali land, where they struggle to meet the demands for continuous and efficient desalination. In summary, existing saline-alkali land treatment technologies still have significant shortcomings in terms of desalination efficiency, resource utilization, salt return control, and ecological restoration. Utility Model Content

[0007] The technical problem to be solved by this utility model is: how to overcome the problems of single structure and function, low desalination efficiency, serious waste of water resources, and frequent salt return in existing saline-alkali land treatment technologies.

[0008] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0009] A saline-alkali land structure with cyclic salt flushing and multi-layer synergistic desalination functions includes an ecological cover layer on the surface, and below the ecological cover layer are arranged a slow-release conditioning layer, a salt-blocking isolation layer and an infiltration and salt-draining layer in sequence. The infiltration and salt-draining layer is provided with a number of porous salt-draining pipes, which are connected to a collection well located underground through a collection and drainage device.

[0010] It also includes a water return system, one end of which is connected to the collection and drainage device in the water collection well, and the other end flows back to the ecological cover layer, the slow-release conditioning layer, the salt barrier layer and the salt drainage layer.

[0011] This application aims to propose a saline-alkali land improvement structure with reasonable structure, synergistic function, and high resource recycling efficiency, featuring cyclic salt flushing and multi-layer synergistic desalination. Through the synergistic linkage of multiple functions such as ecological coverage, slow-release conditioning, physical barrier and salt drainage, this application achieves systematic management of soil salt migration, dispersion, isolation and extraction, effectively overcoming the drawbacks of traditional single improvement methods such as low desalination efficiency and frequent salt return.

[0012] As a further embodiment of this utility model: the sprinkler return system includes a water delivery pump, a water pump, a purified water storage tank, and a reverse osmosis device installed on the ground surface;

[0013] The inlet of the water pump is connected to the collection and drainage device through the water pumping pipe, and the outlet is connected to the reverse osmosis equipment. The reverse osmosis equipment is connected to the purified water storage tank. The purified water storage tank is connected to the sprinkler pipe through the water pump. The sprinkler pipe is introduced into the ecological cover layer, the slow-release conditioning layer, the salt barrier layer, and the infiltration and salt drainage layer.

[0014] As a further aspect of this utility model, a salt content detector is provided inside the water collection well.

[0015] As a further embodiment of this utility model, the arrangement of the porous salt drainage conduits is either parallel or staggered in a grid pattern.

[0016] As a further embodiment of this utility model, the porous salt drainage conduit is made of polyethylene perforated flexible tubing or ceramic porous tubing.

[0017] As a further embodiment of this utility model, the thickness of the ecological covering layer is 5cm to 8cm.

[0018] As a further aspect of this utility model, the thickness of the sustained-release conditioning layer is 20cm to 30cm.

[0019] As a further embodiment of this utility model, the thickness of the salt barrier layer is 15cm to 25cm.

[0020] As a further embodiment of this utility model, the thickness of the salt drainage layer is 15cm to 20cm.

[0021] As a further embodiment of this utility model: the permeation and salt drainage layer includes a lower gravel pad layer and an upper coarse sand layer, with a porous salt drainage conduit laid in the gravel pad layer or the coarse sand layer.

[0022] Compared with the prior art, the beneficial effects of this utility model are:

[0023] First, compared with existing saline-alkali land treatment methods, the saline-alkali land improvement structure with cyclic salt flushing and multi-layer synergistic desalination functions provided in this application has achieved significant improvements in structural configuration and treatment effect;

[0024] This application achieves systematic management of soil salinity migration, dispersion, isolation and extraction through the synergistic linkage of multiple functions such as ecological coverage, slow-release conditioning, physical barrier and salt drainage, effectively overcoming the drawbacks of traditional single improvement methods such as low desalination efficiency and frequent salt return.

[0025] Secondly, the high density design of the salt barrier layer can effectively block the upward path of salt and ensure the long-term stability of the treatment effect; the closed-loop operation mechanism of the collection and drainage system and the sprinkler return system realizes the recycling and reuse of saline resources and re-irrigation to flush out salt, which greatly reduces the amount of irrigation water used and alleviates the pressure on water resources.

[0026] Finally, the amendments in the slow-release conditioning layer are continuously released under suitable conditions, which can stably improve the physical and chemical properties of the soil and enhance its tillage performance. The whole structure is easy to construct, stable to operate, easy to maintain, and has good regional adaptability. The design parameters can be flexibly adjusted according to different salinity types. It is widely applicable to various complex landform types such as coastal mudflats, inland soda saline-alkali land, and seasonal salinization areas, and has significant engineering application value and promotion potential. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the saline-alkali land with the functions of cyclic salt flushing and multi-layer synergistic desalination in an embodiment of the present invention;

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Water pump; 2. Sprinkler pipe; 3. Ecological cover layer; 4. Slow-release conditioning layer; 5. Salt barrier layer; 6. Infiltration and salt removal layer; 7. Collection and drainage device; 8. Salt content detector; 9. Water collection well; 10. Pumping pipe; 11. Pump; 12. Reverse osmosis equipment. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] A saline-alkali land structure with cyclic salt flushing and multi-layer synergistic desalination functions is constructed by building a four-layered improvement system consisting of "ecological cover layer 3 - slow-release conditioning layer 4 - salt barrier layer 5 - infiltration and salt drainage layer 6" and combined with the synergistic operation mechanism of "collection and drainage device 7 + sprinkler return system". This achieves efficient migration and discharge of soil salts, effective blocking of deep salt return, slow release of conditioning agents, and recycling of irrigation water.

[0032] The improved structure and surface water treatment equipment constitute a closed-loop system. The whole system achieves multi-stage collection, treatment and ecological reuse of saline content through the logic of "infiltration-guidance-drainage-purification-recharge". The structure has good physical isolation, chemical conditioning, ecological control and system circulation capabilities, which can significantly improve the sustainability and resource utilization rate of saline-alkali land management.

[0033] This invention is applicable to the remediation and improvement of various types of moderately to severely saline soils, and is particularly suitable for application in typical and complex areas such as coastal mudflats, soda saline-alkali lands, and periodically saline areas. It has significant application and promotion value and ecological environment governance significance.

[0034] Reference Figure 1 The saline-alkali land improvement structure of this utility model consists of multiple functional layers and a circulation system. Its design concept is to achieve full-process control of salinity through the linkage of mechanisms such as physical isolation, chemical conditioning, water and salt drainage, and resource recovery. The specific technical implementation steps are as follows:

[0035] I. Construction Area Preparation: Select a representative moderately saline-alkali land plot as the application site, mechanically clean and level the surface, mark the depth boundaries of each functional layer, and control the overall excavation depth in the range of 90cm to 110cm (it should be noted that the recommended depth for slightly saline-alkali land is about 90cm to 100cm, and for moderate to severe saline-alkali land it is 100cm to 110cm) to ensure the complete layout of the functional layers.

[0036] II. Constructing Ecological Cover Layer 3: First, lay an ecological cover layer 3 on the soil surface, 5cm-8cm thick, to regulate the microenvironment of the soil surface. This layer can be made of breathable and moisture-retaining agricultural materials, such as biodegradable mulch film, rice husks, wheat straw, or corn stalks. The function of this layer is to inhibit water evaporation and stabilize soil temperature, creating a suitable microenvironment for root growth, reducing surface salt accumulation, and mitigating diurnal temperature variations, thus creating a stable surface environment. This not only facilitates the slow-release effect of underlying conditioners but also provides favorable microclimate conditions for crop root growth.

[0037] At the same time, this covering layer, together with the subsequent sprinkler pipes, forms a protective umbrella-shaped water film layer. This water film can evenly cover the surface, reduce the local evaporation gradient, inhibit capillary rise, and reduce the risk of salt return.

[0038] 3. Constructing a slow-release conditioning layer 4: A 25cm thick slow-release conditioning layer 4 is laid under the ecological cover layer 3. The conditioning material is a mixture of humic acid organic fertilizer, desulfurized gypsum, fly ash and zeolite in a certain proportion for landfilling. This ratio has been verified in field simulation experiments to effectively regulate pH and increase the aggregate ratio. After mechanical mixing on site, it is backfilled in layers and lightly compacted to form an active soil layer with continuous conditioning capacity.

[0039] The main function of this layer is to gradually release conditioners under irrigation conditions, thereby achieving long-term and stable improvement of soil physical and chemical properties by neutralizing soil salinity, adjusting pH value, and promoting the formation of aggregate structure. The slow-release nature of the conditioner ensures that its effect is sustainable and will not be lost due to short-term rainfall or excessive irrigation.

[0040] IV. Constructing a salt barrier layer 5; A salt barrier layer 5 with a thickness of about 20cm is set under the slow-release conditioning layer 4. It is made of bentonite and clay mixed in a 1:3 ratio and compacted to form a continuous and dense layer. This layer mainly blocks the upward movement of deep salt through capillary action and is a key structure for preventing salt return. At the same time, it has good water stability and crack resistance to ensure long-term effective operation.

[0041] This layer forms a dense, impermeable barrier, effectively preventing deep salt from rising to the cultivated layer with capillary water. It is the key to suppressing the "salt return" phenomenon in the entire structure. The presence of this layer can significantly improve the stability and effectiveness of the upper conditioning structure, preventing the treatment effect from repeatedly failing due to the rise of deep salt.

[0042] 5. Laying out the salt drainage layer 6; Below the salt barrier layer 5, the salt drainage layer 6 is laid out, consisting of a 5cm bottom gravel cushion layer and a 10-15cm top coarse sand layer; porous salt drainage pipes are evenly laid out in this layer, with PE perforated flexible tubing or ceramic drainage pipes recommended. The layout can be parallel or grid-like staggered, with a spacing of 2.5-3.5cm (the spacing should be fine-tuned according to the plot area and salt distribution characteristics); the pipes converge into the collection well 9, which is equipped with a salt detector 8 to quickly collect the migrated saline solution; this layer is configured with "high permeability + low clogging" to ensure drainage stability;

[0043] This layer can quickly collect and guide saline water migrating down from the upper part, forming a clear and controllable salt discharge path, effectively improving desalination efficiency and avoiding secondary pollution caused by saline water remaining in the soil.

[0044] VI. The collection and drainage device 7 and filtration module are installed. A conduit installed within the salt drainage layer 6 is connected to the collection and drainage device 7, which can be in the form of a salt collection well. A gravel filter layer is installed at the bottom of the collection and drainage device 7 to prevent soil particles from clogging the conduit. This device is mainly used to collect and store the discharged saline water, providing a water source for the subsequent sprinkler return system, while preventing surface saline water from overflowing and negatively impacting the surrounding environment. This part of the design must ensure anti-clogging, anti-seepage, and easy maintenance for long-term operation and management.

[0045] The salt discharge pipes centrally divert the water to the collection well 9, which is located underground or in the edge area. The well is about 1.5m deep and has a gravel and filter screen combination filter layer at the bottom. The saline solution is pumped to the collection well 9 for purification. This design ensures the orderly outward diversion of underground saline solution and avoids surface seepage.

[0046] VII. Construct a surface water treatment and reinjection system; install an integrated water treatment and reinjection module on the surface (e.g., Figure 1 The equipment shown includes a filter pretreatment tank, a reverse osmosis membrane module, a purified water storage tank, and a sprinkler pump set.

[0047] The sprinkler system is a seepage irrigation network laid across four layers: an ecological cover layer (3), a slow-release conditioning layer (4), a salt-barrier layer (5), and a salt-draining layer (6). This system pumps a portion of the collected saline solution back to the surface for irrigation and flushing, achieving a closed-loop management process of "flushing—drainage—collection—re-irrigation." Simultaneously, the sprinkler frequency and intensity can be automatically adjusted via soil moisture sensors or a timer controller, enabling precise control and water conservation.

[0048] The system operates and dynamically adjusts in this application. During the entire structural operation, the functions of each layer work together and can be dynamically adjusted according to seasonal changes, soil salinity, and crop water requirements. The parameters of each layer of the system (such as thickness, material ratio, and pipe spacing) can be customized and optimized according to the regional soil type and crop needs to ensure the maximum treatment effect. For severely saline-alkali land, the concentration of conditioner or the thickness of the conditioner layer can be appropriately increased.

[0049] The workflow is as follows:

[0050] The saline water extracted from the collection well 9 is pumped by the water pump 11 and enters the surface water treatment for primary filtration. After primary filtration, it enters the reverse osmosis membrane treatment unit 12.

[0051] The desalinated water enters a ground-level water storage device;

[0052] The water is pumped into the sprinkler pipe 2 via a variable frequency pump and then injected into the four layers: ecological cover layer 3, slow-release conditioning layer 4, salt barrier layer 5, and infiltration and salt drainage layer 6.

[0053] This system creates a "purified water-re-spray-re-infiltration" cycle, reducing the amount of fresh water used and improving overall water resource utilization efficiency. It can also be paired with a humidity sensor and controller for intelligent control of irrigation time and intensity.

[0054] Once the entire system is built, operational strategies are set based on soil salinity, electrical conductivity, crop type, and other factors. For example:

[0055] Perform a high-frequency rinse before spring irrigation or planting;

[0056] Sprinkle water to flush away salt at noon every day during the crop's growing season;

[0057] Reduce spraying frequency after rain to minimize excess accumulation. Regularly sample and monitor the pH, salinity, and crop growth status of the slow-release conditioner layer. Adjust the conditioner replenishment frequency and sprinkler pipe operating time based on the analysis results to achieve precise, energy-saving, and long-term dynamic control.

[0058] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A saline-alkali land structure with cyclic salt flushing and multi-layer synergistic desalination functions, characterized in that, It includes an ecological cover layer (3) located on the surface, and below the ecological cover layer (3) are arranged a slow-release conditioning layer (4), a salt barrier layer (5) and a salt drainage layer (6) in sequence. The salt drainage layer (6) is provided with a number of porous salt drainage pipes, and the number of porous salt drainage pipes are connected to the underground water collection well (9) through the collection and drainage device (7). It also includes a water return system, one end of which is connected to the collection and drainage device (7) in the collection well (9), and the other end flows back to the ecological cover layer (3), the slow-release conditioning layer (4), the salt barrier layer (5), and the infiltration and salt drainage layer (6).

2. The saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination function according to claim 1, characterized in that: The sprinkler return system includes a water delivery pump (1), a water pump (11), a purified water storage tank, and a reverse osmosis device (12) installed on the ground surface; The inlet of the water pump (11) is connected to the collection and drainage device (7) through the water pumping pipe (10), and the outlet is connected to the reverse osmosis equipment (12). The reverse osmosis equipment (12) is connected to the water purification tank. The water purification tank is connected to the sprinkler pipe (2) through the water delivery pump (1). The sprinkler pipe (2) is inserted into the ecological cover layer (3), the slow-release conditioning layer (4), the salt barrier layer (5), and the infiltration and salt drainage layer (6).

3. The saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination function according to claim 1, characterized in that: The water collection well (9) is equipped with a salt content detector (8).

4. The saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination function according to claim 1, characterized in that: The porous salt drainage conduits are arranged in parallel or in a grid-like staggered pattern.

5. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 4, characterized in that: The porous salt drainage conduit is made of polyethylene perforated flexible tubing or ceramic porous tubing.

6. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 1, characterized in that: The thickness of the ecological cover layer (3) is 5cm to 8cm.

7. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 1, characterized in that: The thickness of the sustained-release conditioning layer (4) is 20cm to 30cm.

8. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 1, characterized in that: The thickness of the salt barrier layer (5) is 15cm to 25cm.

9. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 1, characterized in that: The thickness of the salt drainage layer (6) is 15cm to 20cm.

10. A saline-alkali land structure with circulating salt flushing and multi-layer synergistic desalination functions according to claim 1, characterized in that: The permeation and salt drainage layer (6) includes a gravel cushion layer at the bottom and a coarse sand layer at the top, with porous salt drainage pipes laid in the gravel cushion layer or the coarse sand layer.

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