An apparatus for simulation of a system for reclamation of saline soils and a method of using the same

Abstract

The application relates to a device for simulation of a saline-alkali soil improvement system and a use method thereof, which comprises a water storage column (1) and a soil column (2), the inside of the soil column (2) is provided with water-permeable and air-permeable layers (3) and salt-alkali resisting material layers (4) stacked in an up-down mode, the inside of the soil column (2) is divided into an upper salt discharging cavity and a lower salt resisting cavity, ion exchange holes (5) are formed in the adjacent wall surfaces of the water storage column (1) and the soil column (2), the ion exchange holes (5) of the two columns are connected by a hose, a sampling hole (6) is formed in the outer side wall surface of the soil column (2), conductivity test sensors are arranged at different depths of the soil column (2) and the water storage column (1), and the use method comprises two stages of upper salt discharging and lower salt resisting. Compared with the prior art, the device has the advantages of small land occupation, small operation difficulty, easy implementation, intuitive and accurate display of salt water migration in the saline-alkali soil improvement system and significant advantages compared with a qualitative research device.

Description

Technical Field

[0001] This invention belongs to the field of saline-alkali land improvement technology, and relates to a device for simulating saline-alkali land improvement systems and its usage method. Background Technology

[0002] Land resources directly impact national economic construction, social development, and people's living standards. Saline-alkali soil, as one of my country's most important reserve land resources, has the potential to become high-quality agricultural and ecological land. Therefore, the rational improvement and utilization of saline-alkali land is of great significance for improving the human living environment, achieving sustainable agricultural development, and promoting vigorous economic growth. Traditional methods for water and salt management in saline-alkali land typically rely on leaching soil salts with freshwater, adjusting tillage practices to regulate water and salt transport, and using surface covering materials to reduce soil moisture evaporation and salt accumulation. These measures often suffer from high costs, short-term effectiveness, poor results, and water waste.

[0003] Patent CN 213337245 U discloses a salt rock test permeation migration simulation device, comprising: a permeation migration device, which includes a demolding connection mechanism, a permeation migration column, a brine storage tank, and a temperature and humidity control chamber; a brine pressurization supply system for providing pressurized brine, which includes a brine tank, a pressure storage tank, and a heat-insulated brine pipe, one end of which is fixedly connected to the bottom side of the brine tank, and the other end of which is connected to the brine storage tank; the pressure storage tank is equipped with a pressure transmission pipe, one end of which is connected to the pressure storage tank; and a temperature control system including a data acquisition instrument and a moisture temperature controller. Patent CN 112858626 A discloses an apparatus and method for simulating the migration patterns of nutrients and pollutants in soil. The apparatus includes an experimental simulation column, a sampling device, a leachate collection device, and a water level control system. The experimental simulation column is filled with culture soil, and an observation tube is inserted into the culture soil. The water level control system is connected to the observation tube via a rubber hose to inject water into the culture soil. The water level control system can provide constant water supply or alternating wet and dry water supply. The sampling device collects soil solutions from different depths within the experimental simulation column, and the leachate collection device collects the soil leachate from the bottom of the culture soil. However, these patented devices are relatively complex and cumbersome to operate. Summary of the Invention

[0004] The purpose of this invention is to overcome at least one of the shortcomings of existing saline-alkali land improvement systems and provide a device and its usage method for simulating saline-alkali land improvement systems. This invention combines a modified drainage system with a storage system and a layer of salt-alkali barrier materials to construct an indoor experimental device for simulating a long-term saline-alkali land improvement system. The device can explore the saltwater migration process of the improvement system based on changes in the stored water and soil salinity.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The present invention provides an apparatus for simulating a saline-alkali land reclamation system. The apparatus includes a water storage column and a soil column. The soil column is internally equipped with a water-permeable and air-permeable layer and a salt-blocking material layer stacked vertically, which divides the interior of the soil column into an upper salt drainage chamber and a lower salt suppression chamber. Ion exchange pores are opened on the adjacent walls of the water storage column and the soil column, and the ion exchange pores of the two columns are connected by a rubber hose. Sampling holes are opened on the outer wall of the soil column.

[0007] Furthermore, the adjacent walls of the water storage column and the soil column are provided with ion exchange pores of 1-2 cm in diameter every 3-5 cm from top to bottom, providing channels for ion exchange and simulating the contact between soil and water.

[0008] Furthermore, a filter screen is bonded to the inner wall of the ion exchange pores to prevent soil from entering the water.

[0009] Furthermore, the sampling holes are sealed with putty during non-testing periods to prevent moisture leakage and evaporation.

[0010] Furthermore, conductivity testing sensors are installed on the water storage column and soil column.

[0011] Furthermore, conductivity testing sensors are laid at different depths of the soil column.

[0012] As an optional technical solution, a conductivity testing sensor is laid every 8-10 cm in depth on the soil column.

[0013] Furthermore, the height of the water storage column and the soil column is 30-60cm, the inner diameter is 15-20cm, the outer diameter is 16-25cm, and the material is plexiglass. The material of the water-permeable and air-permeable layer is crushed stone, and the material of the salt-alkali barrier layer is hydrophobic modified sand.

[0014] The second aspect of the present invention provides a method of using an apparatus for simulating a saline-alkali land improvement system, the method comprising two stages: upper layer salt removal and lower layer salt suppression.

[0015] Furthermore, the upper desalination stage specifically involves: filling the soil column, injecting water into the water storage column until the water level in the water storage column drops to a stable level, at which point the moisture content of the saline-alkali soil in the soil column reaches saturation; sealing the surfaces of the soil column and the water storage column with a plastic film to prevent water evaporation; sealing the ion exchange pores below the salt-alkali barrier material layer to prevent water from entering and causing ion exchange; leaving only the ion exchange pores above the salt-alkali barrier material layer open; the time when the water level drops to a stable level is the start time of the experiment; and monitoring the changes in the conductivity of the aqueous solution in the water storage column and the soil leachate in the soil column.

[0016] Furthermore, the lower salt suppression stage specifically involves: once the conductivity values ​​of the solution inside the water column and the soil in the soil column have stabilized, removing the thin film from the surface of the water column and soil column to allow the aqueous solution inside the water column to evaporate. When the water level inside the water column drops to the position of the salt-barrier material layer (the water surface is no longer in contact with the upper soil layer), opening the ion exchange pores below the salt-barrier material layer to allow the aqueous solution to contact the saline-alkali soil below, until the aqueous solution inside the water column is completely evaporated, and continuously monitoring the changes in conductivity of the aqueous solution inside the water column and the leachate from the soil in the soil column.

[0017] The salt migration process in the device is as follows: In the upper salt discharge stage, a certain amount of water is stored in the reservoir. At this time, the salt concentration of the water is low, while the salt concentration of the soil column is high, and salt diffuses from the saline-alkali soil to the reservoir. As water infiltrates, the salt in the soil migrates downwards. The salt-blocking material layer inhibits water infiltration, and salt transfer only occurs between the upper saline-alkali soil and the reservoir, significantly increasing the moisture content of the upper soil. In the lower salt suppression stage, water in the reservoir evaporates rapidly due to evaporation, lowering the water level and increasing the salt concentration in the reservoir. When the salt concentration exceeds the soil salt concentration, salt diffuses from the water to the lower soil layer, and the salt concentration in the upper soil layer does not increase.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) This invention designs a long-term transformation system for saline-alkali land under water storage conditions, changing drainage to storage, simulating the water-salt migration process, with a small experimental area, simple device configuration, and easy operation.

[0020] (2) This invention quantitatively demonstrates the water and salt migration in the saline-alkali land improvement system by measuring the soil conductivity at different depths, which is more accurate than other qualitative research devices. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the device used for simulating a saline-alkali land improvement system in an embodiment of the present invention.

[0022] Explanation of markings in the diagram:

[0023] 1—Water storage column, 2—Soil column, 3—Permeable and breathable layer, 4—Salt-resistant material layer, 5—Ion exchange pore, 6—Sampling hole. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0025] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0026] Example:

[0027] A device for simulating a saline-alkali land reclamation system includes a water-storage column 1 and a soil column 2. The soil column 2 contains stacked permeable and breathable layers 3 and a salt-blocking material layer 4, dividing its interior into an upper salt-draining chamber and a lower salt-suppressing chamber. Ion exchange pores 5 with a diameter of 2 cm are opened every 5 cm from top to bottom on the adjacent walls of the water-storage column 1 and the soil column 2. A filter screen is bonded to the inner wall of each ion exchange pore 5. The ion exchange pores 5 of the two columns are connected by a rubber hose. Sampling holes 6 are opened on the outer wall of the soil column 2, and these holes are sealed with modeling clay during non-testing periods. Conductivity testing sensors are installed on the water-storage column 1, and conductivity testing sensors are installed at different depths on the soil column 2, with five conductivity testing sensors installed at depths of 10 cm, 20 cm, 30 cm, 40 cm, and 50 cm. The water storage column 1 and soil column 2 are 50cm high, 17cm in inner diameter and 18cm in outer diameter, and are made of plexiglass. The permeable and breathable material 3 is made of crushed stone, and the salt-alkali barrier material layer 4 is made of modified hydrophobic sand.

[0028] A method of using an apparatus for simulating a saline-alkali land reclamation system, the method comprising the following steps:

[0029] During the upper salt removal stage, soil column 2 was filled with self-prepared saline soil with an electrical conductivity of 3200±100 μs / cm. Deionized water with a conductivity of 3 μs / cm was injected into water column 1 until the water level in water column 1 stabilized. The surfaces of soil column 2 and water column 1 were then sealed with a plastic film. The ion exchange pores 5 below the salt-barrier material layer 4 were closed, while the ion exchange pores 5 above the salt-barrier material layer 4 were opened. Timing began when the water level stabilized, and the changes in the electrical conductivity of the aqueous solution in water column 1 and the soil leachate in soil column 2 were monitored.

[0030] In the lower salt suppression stage, once the electrical conductivity values ​​of the solution in water column 1 and the soil in soil column 2 have stabilized, the thin film on the surface of water column 1 and soil column 2 is removed, allowing the aqueous solution in water column 1 to evaporate. When the water level in water column 1 drops to the position of the salt-barrier material layer 4, the ion exchange pores 5 below the salt-barrier material layer 4 are opened until the aqueous solution in water column 1 is completely evaporated. The changes in the electrical conductivity of the aqueous solution in water column 1 and the leachate from the soil in soil column 2 are continuously monitored.

[0031] In the upper layer desalination stage, the initial soil conductivity was high, while the water conductivity was low. Therefore, after the upper saline-alkali soil came into contact with the water, salt diffused from the soil into the water. After 160 hours, the conductivity of both the water and the saline-alkali soil stabilized at approximately 2200±200 μS / cm. In the lower layer salt suppression stage, the conductivity of the upper saline-alkali soil remained relatively stable, while salt transferred between the lower soil and water layers. Water evaporation caused the conductivity of both the lower soil and water layers to eventually rise to 4200±200 μS / cm. These results demonstrate that this invention provides a direct and quantitative representation of saltwater migration in a saline-alkali land remediation system.

[0032] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method of using a device for simulating a saline-alkali land reclamation system, characterized in that, The device includes a water storage column and a soil column. The soil column is filled with a water-permeable and air-permeable layer and a salt-resistant material layer stacked on top of each other, which divides the interior of the soil column into an upper salt drainage chamber and a lower salt suppression chamber. Ion exchange pores are opened on the adjacent walls of the water storage column and the soil column to provide channels for ion exchange and simulate the contact between soil and water. The ion exchange pores of the two columns are connected by a flexible tube. Sampling holes are opened on the outer wall of the soil column. Electrical conductivity testing sensors were installed on water storage columns and soil columns. The permeable and breathable layer is made of crushed stone, and the salt and alkali barrier layer is made of hydrophobic modified sand. The usage method includes two stages: upper layer salt removal and lower layer salt inhibition. The upper salt removal stage is as follows: After filling the soil column, water is injected into the water storage column until the water level in the water storage column drops to a stable level. At this time, the water content of the saline-alkali soil in the soil column reaches saturation. The surfaces of the soil column and the water storage column are sealed with a membrane to prevent water evaporation. The ion exchange pores below the salt-alkali barrier material layer are sealed to prevent water from flowing in and causing ion exchange. Only the ion exchange pores above the salt-alkali barrier material layer are left open. The time when the water level drops to a stable level is the start time of the experiment. The changes in the conductivity of the aqueous solution in the water storage column and the soil leachate in the soil column are monitored. The specific steps of the lower salt suppression stage are as follows: once the conductivity values ​​of the solution in the water storage column and the soil in the soil column have stabilized, the surface film of the water storage column and the soil column is removed to allow the aqueous solution in the water storage column to evaporate. When the water level in the water storage column drops to the position of the salt-alkali barrier material layer, the water surface is no longer in contact with the upper soil layer. The ion exchange pores below the salt-alkali barrier material layer are opened to allow the aqueous solution to contact the saline-alkali soil below until the aqueous solution in the water storage column is completely evaporated. The changes in conductivity of the aqueous solution in the water storage column and the leachate in the soil in the soil column are continuously monitored. The salt migration process of the device: In the upper salt discharge stage, water is stored in the water column. At this time, the salt concentration of the water is low, while the salt concentration of the soil column is high. Salt diffuses from the saline-alkali soil to the water column. As water infiltrates, the salt in the soil migrates downwards. The salt-blocking material layer inhibits the downward infiltration of water, and salt transfer only occurs between the upper saline-alkali soil and the water column, increasing the water content of the upper soil. In the lower salt suppression stage, water in the water column evaporates due to evaporation, the water level drops, and the salt concentration in the water column increases. When the salt concentration increases to a level higher than that of the soil, salt diffuses from the water body to the lower soil, and the salt concentration in the upper soil does not increase.

2. The method of using the device for simulating a saline-alkali land improvement system according to claim 1, characterized in that, The adjacent walls of the water storage column and the soil column have ion exchange pores with a diameter of 1-2 cm every 3-5 cm from top to bottom.

3. The method of using the device for simulating a saline-alkali land improvement system according to claim 1, characterized in that, A filter screen is bonded to the inner wall of the ion exchange pores to prevent soil from entering the water.

4. The method of using the device for simulating a saline-alkali land improvement system according to claim 1, characterized in that, The sampling holes were sealed with putty during non-testing periods.

5. The method of using the device for simulating a saline-alkali land improvement system according to claim 1, characterized in that, Conductivity testing sensors were laid at different depths of the soil column.

6. The method of using the device for simulating a saline-alkali land improvement system according to claim 5, characterized in that, A conductivity test sensor is laid every 8-10 cm in depth on the soil column.

7. The method of using the device for simulating a saline-alkali land reclamation system according to claim 1, characterized in that, The water storage column and soil column are 30-60 cm high, with an inner diameter of 15-20 cm and an outer diameter of 16-25 cm, and are made of plexiglass.

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