CN111328489A - A system and method for efficient rainwater improvement of coastal sticky and heavy saline soil - Google Patents

Abstract

The invention discloses a system and method for efficiently improving coastal sticky and heavy saline soil by rainwater. The system includes a soil body, a water storage well and an intelligent control system; the soil body includes heavy sticky salts to be improved that are arranged in sequence from top to bottom Alkaline soil, permeable membrane layer, water storage layer, waterproof layer and saline-alkali soil layer; the bottom of the water storage well is provided with a water intake pit, and a water intake pipe is provided in the water storage well, and the water intake of the water intake pipe is provided with a pumping pump and is continuously Extending into the water intake socket, the outlet end of the water intake pipe is horizontally arranged below the surface of the sticky and heavy saline-alkali soil to be improved. The system and method of the invention can circulate the water infiltrated into the water storage well to wash the saline soil, the operation is simple and the automatic control, the recycling of water resources is realized, the rainfall can be efficiently used to wash the saline-alkali soil, and the saline-alkali soil can be washed in one rainy season. The effect of improvement is that the rain period is used to save the construction period, fresh water resources are saved, and the improvement cost is low.

Description

A system and method for efficient rainwater improvement of coastal sticky and heavy saline soil

technical field

The invention belongs to the technical field of water resource utilization and saline-alkali land improvement engineering, and in particular relates to a system and method for efficiently improving coastal sticky and heavy saline soil by rainwater.

Background technique

The total area of coastal saline soil in China is 500×104hm ² . With the increasingly urgent demand for land resources in economic development and urban construction, the improvement and utilization of saline-alkali land has become an important direction for the development of reserve land resources. Blowing and filling works are booming. By the end of 2007, the area of reclamation nationwide had reached 540km ² , and by 2015, the area of reclamation in China had reached more than 1,500km ² . Only Tianjin Binhai New Area and Caofeidian in Hebei planned to reclaim 600km 2 by 2020. area further expanded. Coastal saline soils, especially heavy-heavy saline soils, are characterized by high salt content, heavy soil texture, extremely low permeability (generally, the order of magnitude does not exceed 10 ^-7 cm/s), and high soil sodium adsorption ratio (soil particles after water saturation) Expansion structure destroys pores and closes, impermeable, gas and salt are difficult to wash.), nutrient-poor, easy to alkalize, groundwater with high salinity and shallow burial, etc., seriously affect urban greening and agricultural and forestry production. Greening has always been an internationally recognized "worldwide problem".

In order to explore the construction paths of sponge cities under different natural environments and urban forms, the country has carried out two batches of pilot construction of 30 sponge cities. At present, the construction of sponge cities has been carried out in full swing across the country. Different types of rainwater are used for different underlying surfaces. Technologies and products for collection, purification and utilization emerge in an endless stream. Rainwater is a very precious freshwater resource, especially for coastal saline-alkali land, which is severely water-deficient, collecting and utilizing rainwater is even more valuable. In saline-alkali land, salt damage occurs because the salt content in the soil exceeds the capacity of plants. Salt comes and goes with water. Therefore, freshwater resources must be fully collected and efficiently utilized to achieve sustainable utilization of saline land resources.

The method of irrigation, drainage, washing and salt control used in farmland is not suitable for urban greening due to the limited improvement depth and easy repetition. At present, the engineering measures of “project salt avoidance + foreign soil replacement” are generally adopted in urban greening of saline-alkali land in my country. Salt avoidance in engineering generally uses physical measures to improve soil salinity, that is, by changing soil physical structure to achieve the purpose of regulating soil water and salt movement, inhibiting soil evaporation, and improving infiltration and leaching of salt. The method of combining the salt barrier with the blind pipe is the most commonly used physical improvement measure at present. The salt barrier by setting the medium with large pores promotes the salt discharge from the soil and cuts off the way for the salt to rise with the capillary water, thereby avoiding the The role of soil salinization. Underdrain salt drainage is to set underdrain under the coating layer, and place plastic corrugated underdrain in the underditch to discharge the salt through the drainage effect of the underdrain. The replacement of foreign soil is to replace the original saline soil with purchased planting soil, so as to ensure that the salt content reaches the standard, and greening can be directly carried out. The technology of drenching the salt layer, draining the salt through the hidden pipe, and planting the foreign soil is a mature saline-alkali land treatment method, which has quick effect, good effect and moderate cost.

Although the engineering measures of "project salt avoidance + foreign soil replacement" can achieve the effect of salt discharge and salt reduction to a certain extent, this technology has the following shortcomings.

First, although this technology adopts the measures of physical separation and discharge of salt, it mainly relies on foreign soil resources. By excavating planting soil in other places, it can meet the needs of greening construction in saline-alkali areas. Planting soil resources are a kind of precious soil resources. Once excavation is a major damage to the local ecological environment, especially the soil environment, this is an unecological construction method.

Second, this technology did not reduce the salinity of the undisturbed saline soil. The utilization of undisturbed saline soil has been abandoned, resulting in the waste of a large amount of saline soil resources.

Third, with the current urban greening construction in saline-alkali areas, the original less passenger and soil resources, the longer the purchase distance, the higher the cost.

Fourth, the application range of this technology is above the groundwater level. If the burial depth exceeds the groundwater level, it cannot resist the reverse osmosis and lateral seepage of the underground salt water, and cannot play the role of salt discharge and salt reduction. The groundwater level in coastal areas is affected by climate, seawater and other factors, and often fluctuates greatly.

Fifth, the currently used technology of underground salt drainage for soil planting still has the problem of insufficient utilization of rainwater resources. After the rainwater penetrates into the soil, it is directly discharged into the municipal drainage pipe network through the stone chip layer or seeps into the underground salt. Soil layer, rainwater cannot be used effectively,

Sixth, during the fertilization process, a large amount of nitrogen, phosphorus, potassium and other nutrients are also discharged into the municipal rainwater system with the brine, resulting in insufficient plant nutrients, poor growth, and eutrophication of downstream water bodies.

In addition, in engineering, the method of raising the terrain is often combined with the method of raising the terrain on the basis of the technology of planting the underground pipe to solve the problem of the groundwater level being too shallow and fluctuating. Raise it by 1-2m, further away from underground high-salinity groundwater, and reduce the influence of high-salt capillary water, so as to ensure that the guest soil is no longer salinized and can be greened normally. However, this method has the following disadvantages. The elevation of green space requires an increase in the amount of earthwork, which is uneconomical, and after the elevation of green space, rainwater will flow into surrounding roads and other surrounding facilities during rainfall, increasing road drainage pressure and the risk of waterlogging. road surface, resulting in runoff pollution problems such as mud left on the road after rain.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the present invention provides a system and method for efficiently improving the coastal sticky and heavy saline soil with rainwater, which solves the problems of poor permeability, large water consumption, and lack of nutrients in the coastal sticky and heavy saline soil. Technical saline soils suffer from shortage of guest soil resources, high cost, waste of saline soil resources, great influence by groundwater, insufficient utilization of rainwater resources, nutrient loss and runoff pollution.

The technical scheme of the present invention is as follows: a system for efficiently improving coastal sticky and heavy saline soil by rainwater, comprising a soil body, a water storage well and an intelligent control system; the soil body comprises the sticky and heavy salt to be improved sequentially arranged from top to bottom soaking soil, permeable membrane layer, water storage layer, waterproof layer, saline soil layer and ventilation device; the lower surface of the aquifer layer is provided with a groove protruding into the saline soil layer, and a hidden pipe is arranged in the groove; The hidden pipes are connected to the water storage wells in the slope direction; the water storage wells are arranged in the soil body at intervals, and the depth of the water storage wells extends from top to bottom to the bottom of the groove; Air holes; the system elevation is 5-20cm lower than the surrounding ground, or the system is ridged, the ridge height is 5-20cm, and the junction with the surrounding buildings or structures is reverse-wrapped with a lateral waterproof layer; the well of the water storage well There is a water intake hole at the bottom, and a water intake pipe is arranged in the water storage well. The water intake of the water intake pipe is provided with a pump and extends into the water intake pocket. One end of the outlet end of the water intake pipe is provided with a sprinkler irrigation device extending upwards for the sticky and heavy saline soil to be improved, and the other end is provided with a discarding device; the intelligent control system includes an information collection module, an analysis module, a discarding module and a rinsing module The information acquisition module includes an online collector of salinity and PH value of soil and water storage, and the control analysis module includes an information processor, a comparison processor and a controller. Carry out comparison, make decisions on rinsing and discarding, and transmit control signals to the discarding module and the rinsing module; To be improved soil water supply and leaching, the abandoned flow module is used to receive the open or closed signal of the control analysis module to control the abandoned flow valve to perform the abandonment of the excess water; the intelligent control system is suspended on the side wall of the water storage well or stands on the water storage Beside the well, the probe of the online collector is inserted into the soil and the bottom water of the water intake well.

The viscous and heavy saline soil to be improved is mixed with a permeability modifier. The permeability modifier is river sand and organic matter, and the mixing ratio is: saline soil: river sand: organic matter (0.5-0.85): (0.1-0.3): (0.05-0.3), and the organic matter can be coconut bran , One or more combinations of greening waste branches and trunks, wood debris, etc.

The thickness of the sticky and heavy saline soil to be improved is 60-140 cm.

A ventilation hole is also provided, and the ventilation hole extends downward from the sticky heavy saline soil to be improved in the soil body to the water permeable membrane layer.

A method for efficiently improving coastal sticky and heavy saline soil with rainwater, comprising the following steps:

(1) Permeability improvement of the coastal sticky and heavy saline soil to be improved;

(2) Collect rainwater through the water storage well when it rains. When the water level in the water storage well reaches the upper edge of the control water level, the intelligent control system turns on the rinsing module to perform the leaching of the sticky and heavy saline soil to be improved, and the rainwater passes through the infiltration again. Washed into the aquifer and water storage well, so that the watering and rinsing is repeated in a cycle to improve the sticky and heavy saline soil;

(3) When the intelligent control system shows that the salt content of the water in the aquifer exceeds the salt content of the saline soil to be improved, the abandoned flow device is activated, and the abandoned flow is discharged to the municipal drainage system or the surrounding saline-alkali wetland lakes and other water systems. After the first rainfall, the leaching cycle can be repeated until the soil salinity index is less than or equal to 3g/kg, and the leaching is completed to achieve the purpose of desalination;

(4) Finally, a soil nutrient improver is added to the desalinated soil to achieve the purpose of improvement, and suitable plants are planted.

In the step (1), the permeability improvement of the sticky and heavy saline soil to be improved includes mixing a permeability modifier or a deep ridge.

The permeability modifier is river sand and organic matter, and the mixing ratio is: saline soil: river sand: organic matter (0.5-0.85): (0.1-0.3): (0.05-0.3), and the organic matter can be coconut bran , One or more combinations of greening waste branches and trunks, wood debris, etc.

The soil nutrient modifier in the step (4) includes cow dung, vinegar lees, edible fungus residue and greening crushed waste. The proportion of nutrient improver in the soil to be improved should not be less than 1%, and it should be mixed with the surface soil evenly.

The volume ratio of the cow dung, vinegar lees, edible fungus residue and greening pulverized waste is (15-30):(15:45):(30-45):(15:45).

Beneficial effects of the present invention: 1. Rapid and efficient leaching of saline soil, realizing the recycling of water resources and saving water resources to the greatest extent. 2. The technology of the present invention is simple in operation and intelligently controlled. After the system is constructed, it is automatically processed and can be realized without manual duty. 3. The present invention is suitable for saline soil with a salt content of more than 3 g/kg. The higher the salt content, the more significant the effect. 4. The economic benefit of the present invention is remarkable, and the cost is lower compared to the prior art. 5. The construction period is short, and the saline soil improvement can be completed in only one rainy season, without delaying the construction period. 6. The system can be reused to continuously rinse different saline soils. 7. The system can also be directly used as a long-term greening structure, which will not allow the lower saline soil and groundwater salt to return to the system, and can well achieve nutrient retention, which is beneficial to plant growth.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

FIG. 2 is a schematic structural diagram of another embodiment of the present invention with ventilation holes;

Among them: 1-water storage well; 2-intelligent control system; 3-viscous and heavy saline soil to be improved; 4-permeable membrane layer; 5-water storage layer; 6-waterproof layer; 7-water intake hole; 8-water intake pipe ;9-water pump;10-sprinkler irrigation device;11-sprinkler irrigation valve;12-discharge device valve;13-first salinity and PH value collector; 14-second salinity and PH value collector; 15-ditch tank; 16-dark pipe; 17-water; 18-saline soil layer; 19-liquid level gauge; 20-vent hole.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below with reference to the preferred embodiments. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

Referring to FIG. 1 , a system for efficiently improving coastal clay-heavy saline soil by rainwater according to the present invention includes a soil body, a water storage well 1 and an intelligent control system 2; Saline soil 3, permeable membrane layer 4, aquifer layer 5, waterproof layer 6, saline soil layer 18;

The lower surface of the water storage layer 5 is provided with a groove 15 protruding into the saline soil layer 18, and a hidden pipe 16 is arranged in the groove 15; the hidden pipe 16 is connected to the water storage well 1 in the slope direction; The well 1 is arranged in the soil body at intervals, and its depth extends from top to bottom to the bottom of the groove 15, and the wall of the well 1 in contact with the aquifer 5 is a vent structure; in the system elevation is lower than the surrounding 5-20cm on the ground or ridges around the system, the height of the ridge is 5-20cm, and the junction with surrounding buildings or structures adopts a lateral waterproof layer to be reversed; The water well 5 is provided with a water intake pipe 8, and the water intake of the water intake pipe 8 is provided with a pump 9 and extends into the water intake pocket 7, and the outlet end of the water intake pipe 8 is horizontally arranged below the surface of the sticky and heavy saline soil 3 to be improved. The outlet end of the water intake pipe 8 is provided with a tee, and one end is provided with a sprinkler irrigation device 10 extending upward for the sticky and heavy saline soil to be improved, and the other end is provided with a discarding device. The intelligent control system includes an information acquisition module, an analysis module, a discarded flow module and rinse module. The information acquisition module includes an online collector of salinity and pH of soil and water storage, and the control and analysis module includes an information processor, a comparison processor and a controller, by processing the collected information and comparing it with a set threshold. Yes, make decisions on rinsing and discarding, and transmit the control signal to the discarding module and the rinsing module; When the soil to be improved is supplied with water for leaching, the discarding flow module is used to receive the open or close signal of the control analysis module to control the discarding flow valve, so as to carry out the discarding of the excess water. The intelligent intelligent control system 2 is suspended on the side wall of the water storage well 1 or stands beside the water storage well 1, and the online collector probes 13 and 14 are respectively inserted into the soil and the water at the bottom of the water storage well.

According to a preferred embodiment of the present invention, the water-permeable membrane layer 4 is a water-permeable nonwoven fabric.

According to a preferred embodiment of the present invention, the aquifer 5 is a 18-60 cm thick stone chip or crushed stone or pp module and other macroporous materials.

According to a preferred embodiment of the present invention, the waterproof layer 6 is preferably a breathable and impermeable layer, including an upper waterproof geotextile layer, a waterproof membrane layer and a lower waterproof geotechnical layer, extending to the bottom of the well at the water storage well 1; the waterproof layer The setting of 6 can not only ensure that the rainwater penetrates into the aquifer 5 and is discharged into the water storage well 1 through the hidden pipe 16, so that the rainwater will not directly penetrate into the saline soil layer 18 below to be lost; Salt water does not reverse seep into the aquifer 5, even reverse osmosis to the saline soil 3 to be improved, thereby causing damage to the saline soil 3 to be improved; the waterproof layer 6 also isolates the aquifer 5 at the water storage well 1 Mutual seepage between the soil layer and the saline soil layer 18. In addition, the upper waterproof geotextile layer also helps to strengthen the toughness and strength of the waterproof layer, preventing the crushed stone on the upper layer from damaging the waterproof membrane layer; similarly, the lower waterproof geotextile layer helps to prevent the lower saline soil layer from 18 pairs of waterproof membrane layers of damage.

According to a preferred embodiment of the present invention, the hidden pipes 16 are arranged at intervals of 6-8 meters; the hidden pipes 16 are PVC seepage pipes and are connected to the water storage well 1 in a 2% slope direction; in order to prevent the seepage holes of the hidden pipes from being blocked, the The hidden pipe 16 is covered with water-permeable geotextile; the circumference of the hidden pipe 16 of the present invention can be opened with multiple rows of narrow strip-shaped water seepage holes, which can meet the requirements of different ring stiffness and permeability by controlling the opening rate; outside the hidden pipe 16 Covering the water-permeable geotextile can not only play the role of water infiltration, but also prevent sediment from entering the hidden pipe 16 and causing blockage.

According to a preferred embodiment of the present invention, at the junction of the system and surrounding buildings or structures, in order to prevent water loss and the impact of water seepage on other structures, etc., a lateral waterproof layer 6 is used at the boundary of the system to protect water and prevent water. seep.

According to a preferred embodiment of the present invention, when the green space is very large, in order to facilitate management and control, the system can be divided into multiple catchment areas, and different catchment areas can be separated by reverse wrapping with waterproof geotextiles; More than 50cm above the aquifer 5.

Preferably, the viscous and heavy saline soil 3 to be improved is mixed with a permeability modifier.

Preferably, the permeability modifier is river sand and organic matter (coconut chaff, sawdust, and crushed green waste branches, etc.), and the mixing ratio is: saline soil: river sand: organic matter (0.5-0.7): (0.2 -0.3): (0.1-0.3).

Preferably, the thickness of the sticky and heavy saline soil to be improved is 60-140 cm.

Preferably, as shown in FIG. 2, the system can also be provided with ventilation holes, which extend downward from the sticky and heavy saline soil layer 3 of the soil body to be improved to the permeable membrane layer 4; Too much water, it is no longer convenient to exhaust, which will cause the water resources on the surface of the soil body to no longer penetrate downward, and ventilation holes are required for exhausting; the ventilation holes in the present invention can be directly punched in the soil body, or use a ventilation The hole is achieved by inserting the pipe into the soil body.

A method for efficiently improving coastal sticky heavy saline soil by rainwater of the present invention comprises the following steps:

(1) Permeability improvement of coastal sticky and heavy saline soil to be improved; including mixing permeability improver, which is river sand and organic matter, organic matter includes coconut bran, sawdust, green waste branch and trunk crushed material, etc. The mixing ratio is: saline soil: river sand: organic matter (0.5-0.7): (0.2-0.3): (0.1-0.3).

(2) Collect rainwater through the water storage well when it rains. When the water level in the water storage well 1 rises and reaches the set water level threshold—the upper edge of the aquifer, the intelligent control system 2 issues an instruction to open the rinsing module, and the pump 9 valve At the same time, the sprinkler irrigation valve 11 is opened, the water pump is opened, and the sprinkler irrigation device 10 starts to spray and water the saline soil to be improved; when the water level drops to 15 cm below the set water level threshold, the intelligent control system 2 sends out a rinsing end command, and the pump The valve is closed and the suction pump 9 stops running. When the water level in the water storage well 1 rises again to the set water level threshold—the upper edge of the aquifer, the intelligent control system 2 starts the rinsing module again to perform the rinsing of the sticky and heavy saline soil to be improved. Washed to improve sticky heavy saline soil;

(3) When the intelligent control system shows that the salt content of the water in the aquifer 5 exceeds the saline soil to be improved, and the water level reaches the upper limit of the set flow abandonment threshold, the flow abandonment command will be issued, the flow abandonment module will be activated, and the water supply pipeline will be switched to abandon flow. A flow device is used to discharge the excess rainwater to the municipal drainage system or the surrounding saline-alkali wetland lakes and other water systems. After the next rainfall comes, it can be recycled again until the salt content reaches 0.3%, and the leaching is completed to achieve the purpose of desalination;

(4) Finally, a soil nutrient improver is added to the desalinated soil, and plants are finally planted. The proportion of nutrient improver in the soil to be improved should not be less than 1%, and it should be mixed with the surface soil evenly. Soil nutrient amendments include cow dung, vinegar residue, edible fungus residue and greening and crushed waste. The volume ratio of the cow dung, vinegar waste, edible fungus residue and greening pulverized waste is (15-30):(15:45):(30-45):(15:45).

The rainwater leaching used in the present invention can also be replaced by other fresh water such as tap water, lake water, river water, etc., and the effect of improving saline soil can also be realized.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, other changes or modifications in different forms can also be made on the basis of the above description. Not all implementations can be exhaustive here. Any obvious changes or changes derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims (10)

1. a system for the efficient improvement of coastal sticky and heavy saline soil by rainwater, is characterized in that, comprises soil body, water storage well and intelligent control system; Described soil body comprises the sticky and heavy saline soil to be improved that is set sequentially from top to bottom soil, permeable membrane layer, water storage layer, waterproof layer, saline soil layer and ventilation device; the lower surface of the aquifer layer is provided with a groove protruding into the saline soil layer, and a hidden pipe is arranged in the groove; the The hidden pipes are connected to the water storage wells in the slope direction; the water storage wells are arranged in the soil body at intervals, and the depth of the water storage wells extends from top to bottom to the bottom of the groove; the ventilation device includes a ventilation pipe provided in the soil and a ventilation hole provided in the well ; The system elevation is 5-20cm lower than the surrounding ground or ridges are raised around the system, the ridge height is 5-20cm, and the junction with the surrounding buildings or structures adopts a lateral waterproof layer to reverse the package; the bottom of the water storage well There is a water intake pit, a water intake pipe is arranged in the water storage well, the water intake of the water intake pipe is provided with a pump and extends into the water intake pit, and the outlet end of the water intake pipe is horizontally arranged above the surface of the sticky and heavy saline soil to be improved. One end of the outlet end of the water intake pipe is provided with a sprinkler irrigation device extending upwards for the sticky and heavy saline soil to be improved, and the other end is provided with a discarding device; the intelligent control system includes an information collection module, an analysis module, a discarding module and a rinsing module; The information acquisition module includes an online collector of salinity and PH value of soil and water storage, and the control analysis module includes an information processor, a comparison processor and a controller. Compare, make decisions on rinsing and discarding, and transmit the control signal to the discarding module and the rinsing module; the rinsing module is used to receive the opening or closing signal of the control analysis module to control the rinsing valve to execute the control signal to the rinsing valve. Improve soil water supply and leaching, the abandonment module is used to receive the open or close signal of the control analysis module to control the abandonment valve to perform the abandonment of the excess water; the intelligent control system is suspended on the side wall of the water storage well or stands on the water storage well Next to it, the probes of the online collector are inserted into the soil and the bottom water of the water well. 2 . The system for efficiently improving coastal viscous and heavy saline soil according to claim 1 , wherein the to-be-improved viscous and heavy saline soil is mixed with a permeability modifier. 3 . 3. the system that rainwater efficiently improves coastal sticky heavy saline soil according to claim 2, is characterized in that, described permeability modifier is river sand and organic matter, and the mixing ratio is: saline soil: river sand: organic matter ( 0.5-0.85): (0.1-0.3): (0.05-0.3), and the organic matter includes one or more combinations of coconut bran, green waste branch and trunk pulverized material, and wood debris. 4 . The system for efficiently improving coastal sticky and heavy saline soil according to claim 1 , wherein the thickness of the sticky and heavy saline soil to be improved is 60-140 cm. 5 . 5. The system for efficiently improving coastal viscous and heavy saline soil by rainwater according to claim 1, characterized in that, a vent hole is also provided, and the vent hole extends downward from the sticky and heavy saline soil to be improved in the soil body to the water permeable film layer. 6. a method of rainwater efficient improvement of coastal sticky heavy saline soil, is characterized in that, comprises the following steps: (1) Permeability improvement of the coastal sticky and heavy saline soil to be improved; (2) Collect rainwater through the water storage well when it rains. When the water level in the water storage well reaches the upper edge of the control water level, the intelligent control system turns on the rinsing module to perform the leaching of the sticky and heavy saline soil to be improved, and the rainwater passes through the infiltration again. Washed into the aquifer and water storage well, so that the watering and rinsing is repeated in a cycle to improve the sticky and heavy saline soil; (3) When the intelligent control system shows that the salinity content of the water in the aquifer or the salinity content of the saline soil does not change, start the waste flow device and discharge the waste flow to the municipal drainage system or the surrounding saline-alkali wetland lake water system. After the rainfall comes, the leaching cycle can be repeated again and again, until the soil salinity index is less than or equal to 3g/kg, the leaching is completed, and the purpose of desalination is achieved; (4) Finally, a soil nutrient improver is added to the desalinated soil to achieve the purpose of improvement, and suitable plants are planted. 7. The method for efficiently improving coastal sticky and heavy saline soil by rainwater according to claim 6, wherein the step (1) to improve the permeability improvement of the sticky and heavy saline soil comprises mixing a permeability modifier or a deep ridge . 8. the method for the efficient improvement of coastal viscous saline soil by rainwater according to claim 7, is characterized in that, described permeability modifier is river sand and organic matter, and the mixing ratio is: saline soil: river sand: organic matter ( 0.5-0.85): (0.1-0.3): (0.05-0.3), and the organic matter can be one or more combinations of coconut bran, green waste branch and trunk pulverized material, and wood debris. 9. the method for the efficient improvement of coastal sticky saline soil by rainwater according to claim 6, is characterized in that, described step (4) soil nutrient modifier comprises cow dung, vinegar lees, edible fungus residue and greening pulverized waste, The application amount is not less than 1% of the volume of the soil to be improved, and it is evenly mixed with the surface soil. 10. according to the described method of claim 9, rainwater efficient improvement coastal sticky heavy saline soil is characterized in that, the volume ratio of described cow dung, vinegar grains, edible fungus residue and greening pulverized waste is (15-30): (15:45):(30-45):(15:45).

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