Rainwater collecting and irrigating device for coastal saline-alkali soil

Abstract

The invention discloses a rainwater collection and irrigation device for coastal saline-alkali soil. The rainwater collection and irrigation device comprises a support, a water collection part, a water storage part and an irrigation part. The water collecting part is fixed at the upper end of the bracket to collect rainwater; the water storage part is positioned in the bracket and comprises a filter barrel and a water storage barrel; the upper-end water inlet of the filter barrel is communicated with the water collecting part water outlet; a quartz sand layer, an activated carbon layer and an ion exchange resin layer are sequentially arranged in an inner cavity of the filtering barrel from top to bottom; a water inlet end of the water storage barrel is communicated with a lower water outlet of the filter barrel to store filtered rainwater; the irrigation part comprises a drainage pipe and a plurality of drip irrigation belts; one end of the drainage tube is communicated with the water outlet of the water storage barrel; one end of each drip irrigation belt is communicated with an inner cavity of the drainage pipe, the other end of each drip irrigation belt is closed, and a plurality of drip heads are detachably connected to the drip irrigation belts and correspond to roots of crops. Under the condition that coastal saline-alkali land fresh water resources are deficient, the device can convert natural rainfall into an available irrigation water source, the utilization rate of rainwater resources is remarkably increased, and the problem of water resource shortage is solved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of agricultural irrigation technology, and more particularly to a rainwater collection and irrigation device for coastal saline-alkali land. BACKGROUND

[0002] Current saline-alkali land management faces the dual challenges of "water resource shortage" and "soil high salinization", and the limitations of existing irrigation technology are particularly prominent in coastal tower bases and other special scenarios, which are manifested as follows:

[0003] I. Resource dependence and ecological risk of traditional fresh water irrigation

[0004] The annual water resource utilization rate in saline-alkali areas is less than 40%, and water resources are allocated in a tense manner in some areas, forcing them to overexploit groundwater. Long-term fresh water irrigation leads to an annual increase of 0.3-0.5 g / L in the salinity of groundwater, resulting in an expansion of 15% in the area of secondary salinization. The coastal tower base area (such as offshore wind tower base and coastal highway slope protection) is far away from the municipal water supply network, and traditional irrigation relies on tank truck transportation of fresh water, with an annual operation and maintenance cost of more than 5000 yuan per tower base, and a water resource waste rate of up to 20% during transportation.

[0005] II. Functional defects of existing rainwater collection systems

[0006] The rainwater in coastal areas is affected by marine aerosols, and the Cl- concentration is generally 20-50 mg / L. The existing rainwater collection device mainly uses single quartz sand filtration, and the salt removal rate is less than 30%. Direct irrigation will cause the soil salinity in the root zone to increase by 0.1-0.2% per year. After using unsalted rainwater for irrigation for 3 years, the electrical conductivity of the 0-20 cm soil layer increases from 4.5 mS / cm to 6.8 mS / cm, and the crop yield decreases by 30%. In addition, the traditional rainwater collection device lacks a real-time water quality monitoring module, and cannot dynamically adjust the filtration strategy according to the rainfall intensity and salinity fluctuation.

[0007] III. Lack of coordination between salt removal and irrigation systems

[0008] Traditional open ditch salt removal requires 30-40% of the irrigation water to be used for salt washing, and an additional 200 cubic meters of fresh water per mu of land per year is needed for salt removal, which aggravates the water resource pressure. More importantly, the salt removal and irrigation processes are independent of each other: the salt is infiltrated into the plough layer with water during irrigation, and additional water is needed to wash the salt during salt removal, forming a vicious cycle of "irrigation-salt accumulation-salt washing-waste". Due to the complex terrain of the coastal tower base area, the construction of traditional open ditches is difficult, and the direct discharge of salt removal wastewater can easily cause pollution of the nearshore environment.

[0009] IV. Application gap of energy and data-driven technology

[0010] More than 90% of the existing irrigation systems rely on power grid power supply, and the coastal tower bases are mostly located in remote areas, the power grid access cost is high (the single tower base power supply reconstruction cost is more than 100,000 yuan), and the salt mist environment is easy to cause electrical equipment failure. In the data application layer, the traditional system can only realize "threshold trigger type" irrigation (such as starting when the soil humidity is less than 20%), and cannot predict future rainfall trends. The irrigation strategy relying on historical experience will cause 35% of the rainfall resources to be not effectively utilized, and 40% of the irrigation occurs within 24 hours before the rainfall, causing water resource waste.

[0011] Therefore, how to provide an irrigation device capable of improving rainwater resource utilization rate, reducing fresh water consumption, efficiently removing salt and impurities in rainwater, and reducing irrigation water salinity is a problem that those skilled in the art urgently need to solve. SUMMARY

[0012] Therefore, the present application provides a rainwater collection irrigation device for coastal saline-alkali land, which adopts a multi-layer composite filtering mode to efficiently remove impurities and salt in rainwater, has better filtering effect than existing single filtering devices, can significantly reduce the salinity of irrigation water, and meets the irrigation demand of crops in saline-alkali land; the use of drip irrigation belts realizes precise irrigation of rainwater, can save water, improve water resource utilization rate, and reduce the accumulation of salt in the soil surface compared with the traditional flood irrigation mode.

[0013] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0014] A rainwater collection irrigation device for coastal saline-alkali land, comprising a support, a water collecting part, a water storage part and an irrigation part;

[0015] The water collecting part is fixed at the upper end of the support to collect rainwater; the water storage part is located in the support and comprises a filter barrel and a water storage barrel; the water inlet of the upper end of the filter barrel is communicated with the water outlet of the water collecting part; the inner cavity of the filter barrel is sequentially provided with a quartz sand layer, an activated carbon layer and an ion exchange resin layer from top to bottom; and the water inlet of the water storage barrel is communicated with the lower end water outlet of the filter barrel to store filtered rainwater;

[0016] The irrigation part comprises a drainage pipe and a plurality of drip irrigation belts; one end of the drainage pipe is communicated with the water outlet of the water storage barrel, and the other end is closed; one end of each of the plurality of drip irrigation belts is communicated with the inner cavity of the drainage pipe, and the other end is closed; and a plurality of water dripping heads are detachably connected to the plurality of drip irrigation belts and correspond to the roots of crops.

[0017] The beneficial effects of the technical scheme of the present application are that the quartz sand layer preliminarily filters large-particle impurities in rainwater, the activated carbon layer adsorbs organic matter and part of salt, and the ion resin exchange layer removes Na + , Ca 2+The application effectively removes the salinity in rainwater through three layers of filtration, and the filtered rainwater can be used for crop irrigation, which can improve the soil environment of coastal saline-alkali land; the use of drip irrigation belts realizes precise irrigation of rainwater, which can save water, improve water resource utilization rate, and reduce the accumulation of salt in the soil surface compared with the traditional flood irrigation method.

[0018] Preferably, the thickness of the quartz sand layer is 30-35 cm, the thickness of the activated carbon layer is 25-30 cm, and the thickness of the ion exchange resin layer is 20-25 cm; the stainless steel mesh screen is used to separate the quartz sand layer and the activated carbon layer, and the activated carbon layer and the ion exchange resin layer. The stainless steel mesh screen separates the quartz sand layer, the activated carbon layer and the ion exchange resin layer, which guarantees the filtration effect of each layer and meets the water flow.

[0019] Preferably, the water collecting part comprises a V-shaped rain shed and a water collecting box; the V-shaped rain shed is fixed to the upper end of the support; the water collecting box is fixed to the V-shaped outer wall of the V-shaped rain shed; and a drainage groove communicating with the inner cavity of the water collecting box is formed in the V-shaped rain shed. The V-shaped rain shed can make the rainwater collect in the V-shaped cavity and enter the water collecting box through the drainage groove, realizing the collection of rainwater.

[0020] Preferably, the V-shaped inner wall above the drainage groove of the V-shaped rain shed is detachably connected with a PE grille, and the PE grille covers the drainage groove. The PE grille can filter some solid waste such as leaves blown by the wind to prevent the drainage groove from being blocked.

[0021] Preferably, it further comprises a salt discharge pipe; the lower end of the water storage bucket is fixed with a supporting leg, and the bottom wall is provided with a drainage opening; a ring-shaped salt discharge groove is formed in the ground around the support; the salt discharge pipe is laid in the salt discharge groove, one end of the salt discharge pipe communicates with the drainage opening, and the other end of the salt discharge pipe communicates with the municipal drainage pipe network; a plurality of permeation holes are formed in the wall of the salt discharge pipe; and an electromagnetic valve is fixed to the end of the salt discharge pipe close to the drainage opening. In the case of long-term use, salt will accumulate at the bottom of the water storage bucket. By opening the electromagnetic valve, water with high salt content can be discharged from the water storage bucket. The permeation holes in the salt discharge pipe can make the salt water penetrate along the deep soil, gradually improve the salinization environment of the soil surface, create a good soil environment for crop growth, and help the soil improvement and ecological restoration of saline-alkali land.

[0022] Preferably, the device further comprises a soil EC probe and a transmitter; the soil EC probe is buried in the soil to monitor the soil conductivity; the transmitter is fixed on the outer wall of the water storage barrel and is connected with the soil EC probe; the transmitter transmits the signal of the soil EC probe to the controller system. The soil EC probe can detect the conductivity of the surface layer of the soil, and then calculate the salinity of the surface layer of the soil, thereby providing data reference for soil improvement.

[0023] Preferably, the device further comprises a lithium battery; the water collecting part is fixed with a solar panel, and the lithium battery is electrically connected with the solar panel; the electromagnetic valve and the transmitter are electrically connected with the lithium battery. The lithium battery is used as the power source of the electric control facilities.

[0024] Preferably, the side wall of the water storage barrel is provided with an irrigation outlet, and the irrigation outlet is communicated with the drainage pipe; the end of the drainage pipe close to the irrigation outlet is fixed with a water outlet control valve; the inner wall of the water storage barrel is fixed with a water level sensor, and the water level sensor is connected with the water outlet control valve. The water outlet control valve is used to control the drip irrigation operation, and the water level sensor is used to sense the water level in the water storage barrel. When the water level is too low, the water outlet control valve is closed.

[0025] Preferably, the device further comprises a backwashing pump; an EC sensor is fixed at the water outlet of the lower end of the filter barrel to monitor the salinity of the filtered rainwater; the backwashing pump is fixed on the inner wall of the water storage barrel and is electrically connected with the EC sensor. The EC sensor senses the conductivity of the filtered rainwater. When the conductivity of the filtered water is higher than the preset threshold value, the backwashing pump is started to perform backwashing, so that the water in the water storage barrel continuously flushes the ion exchange resin layer, thereby backwashing and removing the salt in the water in the water storage barrel.

[0026] According to the above technical solution, compared with the prior art, the present application provides a rainwater collection and irrigation device for coastal saline-alkali soil. In the case of lack of fresh water resources in coastal saline-alkali soil, the device can convert natural precipitation into a usable irrigation water source, significantly improve the utilization rate of rainwater resources, and alleviate the problem of water shortage. The multi-layer composite filtering mode composed of the quartz sand layer, the activated carbon layer and the ion exchange resin layer can sequentially remove large particle impurities, organic matter and salt in the rainwater. The quartz sand layer can intercept large particle impurities such as suspended solids in the rainwater; the activated carbon layer removes organic matter and part of the salt through adsorption; the ion exchange resin layer removes sodium ions, calcium ions and other cations through ion exchange reaction, reduces the salt concentration of the rainwater, and makes the treated rainwater meet the irrigation requirements of crops in saline-alkali soil, thereby avoiding the problem of salt accumulation in the roots of crops caused by direct use of untreated rainwater for irrigation.

[0027] The drip irrigation belt connected to the bottom of the water bucket can directly deliver the filtered rainwater to the crop roots to realize precise irrigation. Compared with the traditional flood irrigation method, the drip irrigation can control the irrigation amount according to the water demand of crops, reduce the water evaporation and seepage loss, improve the water resource utilization efficiency, save more than 30% of water, and avoid the problem of soil secondary salinization caused by excessive irrigation. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only a part of the embodiments of the present application, and all other drawings obtained by those skilled in the art without creative labor on the basis of the provided drawings also belong to the protection scope of the present application.

[0029] Figure 1 A structure diagram of the rainwater collecting and irrigating device provided by the present application is shown in the figure.

[0030] Figure 2 A sectional view of A part in the rainwater collecting and irrigating device provided by the present application is shown in the figure. Figure 1

[0031] Figure 3 A top view of the rainwater collecting and irrigating device provided by the present application is shown in the figure.

[0032] Figure 4 A front view of the rainwater collecting and irrigating device provided by the present application is shown in the figure.

[0033] In the figure, 1 is a support, 11 is a support column, 12 is a crossbeam, 2 is a water collecting part, 21 is a V-shaped rain shed, 22 is a PE grid, 23 is a water collecting box, 24 is a drainage groove, 3 is a water storage part, 31 is a support foot, 32 is a water storage bucket, 33 is a filter bucket, 34 is a quartz sand layer, 35 is an activated carbon layer, 36 is an ion exchange resin layer, 37 is a transmitter, 38 is an EC probe, 4 is an irrigation part, 41 is a drainage pipe, 42 is a drip irrigation belt, 43 is a water outlet control valve, 5 is a lithium battery, 6 is a salt discharge pipe, and 7 is an electromagnetic valve. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also belong to the protection scope of the present application.

[0035] Referring to the drawings Figures 1 to 4 ​The embodiment of the present application discloses a rainwater collecting and irrigating device for coastal saline-alkali soil, which comprises a support 1, a water collecting part 2, a water storing part 3 and an irrigating part 4; the water collecting part 2 is fixed at the upper end of the support 1 to collect rainwater; the water storing part 3 is located in the support 1 and comprises a filter barrel 33 and a water storing barrel 32; the upper end water inlet of the filter barrel 33 is communicated with the water outlet of the water collecting part 2; the inner cavity of the filter barrel 33 is sequentially provided with a quartz sand layer 34, an activated carbon layer 35 and an ion exchange resin layer 36 from top to bottom; the side wall of the filter barrel 33 is hinged with a door, so that the filter barrel 33 can be maintained and the quartz sand layer 34, the activated carbon layer 35 and the ion exchange resin layer 36 can be cleaned and replaced; the water inlet end of the water storing barrel 32 is connected with the lower end water outlet of the filter barrel 33 to store filtered rainwater; the irrigating part 4 comprises a drainage pipe 41 and a plurality of drip irrigation belts 42; one end of the drainage pipe 41 is communicated with the water outlet of the water storing barrel 32, and the other end is closed; one end of the drip irrigation belt 42 is communicated with the inner cavity of the drainage pipe 41, and the other end is closed; a plurality of drip heads are detachably connected to the drip irrigation belt 42 and correspond to the roots of crops. Figure 1 As shown in the figure, the support 1 comprises support columns 11 and cross beams 12; the number of the support columns 11 is four and they are arranged in pairs opposite to each other; the number of the cross beams 12 is two; the two ends of each cross beam 12 are fixed to the upper ends of two support columns 11 respectively; the fixed mode can adopt welding or bolting; the support body is formed by the four support columns 11 and the two cross beams 12.

[0036] In order to further optimize the above technical scheme, the water collecting part 2 comprises a V-shaped rain shed 21 and a water collecting box 23; the V-shaped rain shed 21 is fixed at the upper end of the support 1; the water collecting box 23 is fixed on the V-shaped outer wall of the V-shaped rain shed 21; the V-shaped rain shed 21 is provided with a drainage groove 24 on the V-shaped tip; the V-shaped rain shed 21 is welded into a frame by using 40*40 stainless steel square tubes; the surface of the frame is connected with weather-resistant plastic plates by using screws; the V-shaped angle is 60°-90°; the drainage groove 24 is provided on the V-shaped tip; the water collecting box 23 is made of stainless steel and is bolted on the outer wall of the V-shaped rain shed 21; the upper end surface of the water collecting box 23 abuts against the outer wall surface of the V-shaped rain shed 21 to form a sealing structure. Rainwater can be effectively collected by the inclined slope.

[0037] In other specific embodiments, a lithium battery 5 is further included; the weather-resistant plastic plate on the V-shaped rain shed 21 can be replaced by a solar panel; the lithium battery 5 is electrically connected with the solar panel. The lithium battery 5 is placed in a box; an MPPT controller (energy conversion efficiency ≥ 85%) and a power management module are integrated in the box; the box is communicatively connected to a controller system.

[0038] As shown in the figure, the support 1 comprises support columns 11 and cross beams 12; the number of the support columns 11 is four and they are arranged in pairs opposite to each other; the number of the cross beams 12 is two; the two ends of each cross beam 12 are fixed to the upper ends of two support columns 11 respectively; the fixed mode can adopt welding or bolting; the support body is formed by the four support columns 11 and the two cross beams 12. Figure 4As shown, the water storage section has two sets. The water collection box has two water outlets at both ends. The upper end of the filter bucket is connected to the water outlet of the water collection box through a connecting pipe. The water storage bucket is made of polyethylene and has a volume of 500L. Its upper end is connected to the lower end of the filter bucket through a pipe. The upper surface of the water storage bucket has a vent hole, and an insect-proof net is installed over the vent hole.

[0039] In this embodiment, the filter barrel 33 is welded from stainless steel. Its interior is divided into three vertically arranged filling spaces by a stainless steel mesh screen with a 0.5mm aperture. From top to bottom, these spaces correspond to a quartz sand layer 34, an activated carbon layer 35, and an ion exchange resin layer 36. The quartz sand layer 34 has a thickness of 30–35cm and a particle size of 1–3mm, serving as the primary filter for large particles. The activated carbon layer 35 has a thickness of 25–30cm and a particle size of 2–5mm, adsorbing organic matter and some salts. The ion exchange resin layer 36 has a thickness of 20–25cm, removing sodium. + Ca 2+ It contains cations, which reduces salinity.

[0040] To further optimize the above technical solution and prevent wind-blown leaves, plastic bags and other garbage from clogging the drainage channel, a PE grid 22 is detachably connected to the V-shaped inner wall above the drainage channel 24 corresponding to the V-shaped canopy 21, and the PE grid 22 covers the drainage channel 24.

[0041] In this embodiment, a salt drainage pipe 6 is also included; a support foot 31 is fixed to the lower end of the water storage tank 32, and a drain outlet is opened on its bottom wall; a ring-shaped salt drainage ditch is opened on the ground around the support 1; the salt drainage pipe 6 is laid in the salt drainage ditch, with one end connected to the drain outlet and the other end connected to the municipal drainage network; multiple permeation holes are opened on the pipe wall of the salt drainage pipe 6; a solenoid valve 7 is fixed to the end of the salt drainage pipe 6 near the drain outlet. Under long-term use, salt will accumulate at the bottom of the water storage tank. By opening the solenoid valve, water with high salt content can be discharged from the water storage tank. Through the permeation holes on the salt drainage pipe, salt water can penetrate into the deep soil, gradually improving the salinization environment of the soil surface, creating a good soil environment for crop growth, and contributing to soil improvement and ecological restoration of saline-alkali land.

[0042] To further optimize the above technical solution, a soil EC probe 38 and a transmitter 37 are also included; the soil EC probe 38 is buried in the soil to monitor soil conductivity; the transmitter 37 is fixed to the outer wall of the water storage tank 32 and is connected to the soil EC probe 38; the transmitter 37 transmits the signal from the soil EC probe 38 to the controller system. Soil conductivity is monitored using a soil EC probe to assess the salinity of the soil surface. Monitoring the salinity of the soil surface allows us to understand the accumulation of salt in the soil surface during drip irrigation. Specifically, when the soil conductivity is >2 mS / cm, it indicates a high degree of salt accumulation in the irrigation water, resulting in a high salt content in the soil surface. The controller can then open the solenoid valve to discharge the water with high salt content from the storage tank. The water then permeates into the deeper soil layers through the permeation holes on the drainage pipe. When the soil surface conductivity is <2 mS / cm, the controller closes the solenoid valve and stops discharging salt, indicating that the water in the storage tank meets the irrigation requirements and drip irrigation can proceed. During continuous irrigation, salt in the irrigation water will permeate along the soil surface. Excessive salt will increase the soil conductivity. When the conductivity rises to <2 mS / cm, the water tank will then be drained of salt.

[0043] In some other embodiments, an irrigation outlet is provided on the side wall of the water storage tank 32, which is connected to the diversion pipe 41; a water outlet control valve 43 is fixed at one end of the diversion pipe 41 near the irrigation outlet; a water level sensor is fixed on the inner wall of the water storage tank 32, and the water level sensor is communicatively connected to the water outlet control valve 43. The solenoid valve 7, the transmitter 37, and the water outlet control valve 43 are all electrically connected to the lithium battery 5.

[0044] The water level sensor detects the water level in the storage tank. When there is enough filtered water stored in the tank, the water outlet control valve is opened to start drip irrigation. When the water level is insufficient, the water outlet control valve is closed.

[0045] In some other embodiments, a backwash pump is also included; an EC sensor is fixed to the outlet at the lower end of the filter tank 33 to monitor the salinity of the filtered rainwater; the backwash pump is fixed to the inner wall of the water storage tank 32 and electrically connected to the EC sensor. The EC sensor can sense the conductivity of the filtered rainwater and thus determine the salinity of the filtered water; when the conductivity of the filtered water is >1.5 mS / cm, the backwash pump is started, and the backwash pump causes the water in the water storage tank to flush upwards to the ion exchange resin layer to achieve secondary ion exchange. After 10 minutes, the test is repeated until the conductivity of the filtered water is <1.5 mS / cm, at which point the backwash pump is turned off.

[0046] In this embodiment, the controller system uses an edge computer as the controller. The edge computer is equipped with a LoRa wireless module and uses an LSTM algorithm based on three years of local meteorological data (rainfall, wind speed, humidity) and real-time radar echoes to predict the probability of rainfall (accuracy ≥ 85%) and the amount of rainfall (error ≤ 15%) for the next seven days. When the predicted rainfall within 48 hours is ≥ 10 mm, the outlet control valve is closed, drip irrigation is suspended, and rainwater is collected first. When soil moisture is < 60% of field capacity and the predicted rainfall is < 5 mm, the outlet control valve is activated to resume drip irrigation, and the irrigation amount is automatically adjusted according to the predicted evaporation. When the soil conductivity is > 2.0 mS / cm, the solenoid valve of the salt drainage ditch is opened, and high-salt wastewater in the water storage tank is discharged in conjunction with tidal energy (in coastal areas), while filtered rainwater is replenished. During irrigation, salt seeps into the drainage ditch with the water. When the water level in the tank is ≥80% or the EC sensor detects that the salinity of the water in the storage tank exceeds the standard, the controller opens the solenoid valve to discharge the high-salt wastewater into the municipal pipe network. At the same time, new filtered rainwater is introduced, forming a closed loop of "collection-filtration-irrigation-salt discharge", which increases the water resource utilization rate to over 90%.

[0047] This invention integrates photovoltaic-lithium battery coupling technology to solve the problem of no power grid at coastal tower bases, reducing operation and maintenance costs by 80% compared to traditional diesel generator solutions and achieving "zero-carbon irrigation." It is the first to introduce rainfall prediction into saline-alkali land irrigation, reducing water waste by 35% compared to traditional threshold-triggered irrigation and avoiding ineffective irrigation before rainfall. The ion exchange resin layer uses graphene, increasing desalination efficiency by 50%. Combined with real-time control using EC sensors, it ensures irrigation water salinity ≤5mg / L, significantly improving accuracy compared to existing single-filter devices. The salt drainage ditch, combined with tidal energy (in coastal areas), allows for salt discharge from the water storage tank without additional energy. Simultaneously, the drip irrigation tape can adapt to slopes up to 30°, expanding its application to coastal tower base slope protection. This invention has a simple structure, allowing for rapid installation by a single person in 4 hours, and is suitable for harsh coastal environments.

[0048] The rainwater harvesting and irrigation device of this embodiment can improve the utilization rate of rainwater resources: it efficiently collects rainwater through a V-shaped canopy, and after being treated by a multi-layer composite filtration process, it is stored in a water storage tank and can be directly used for drip irrigation, reducing dependence on freshwater. In coastal saline-alkali land where freshwater resources are scarce, this device can convert natural precipitation into usable irrigation water, significantly improving the utilization rate of rainwater resources and alleviating water shortage problems.

[0049] Highly efficient removal of salt and impurities from rainwater: The device employs a multi-layered composite filtration system consisting of a quartz sand layer, an activated carbon layer, and an ion exchange resin layer. This system sequentially removes large particulate impurities, organic matter, and salt from rainwater. Specifically, the quartz sand layer intercepts large particulate impurities such as suspended solids; the activated carbon layer removes organic matter and some salt through adsorption; and the ion exchange resin layer removes cations such as sodium and calcium ions through ion exchange reactions, reducing the salt concentration of the rainwater. This ensures that the treated rainwater meets the irrigation requirements for crops in saline-alkali land, preventing the accumulation of salt in the root zone caused by directly using untreated rainwater for irrigation.

[0050] Precision irrigation and water conservation are significant: the drainage pipes and drip irrigation tapes connected to the side wall of the water tank can deliver filtered rainwater directly to the crop roots, achieving precise irrigation. Compared with traditional flood irrigation, drip irrigation can control the irrigation amount according to the crop's water needs, reduce water evaporation and seepage losses, improve water resource utilization efficiency, save more than 30% of water, and avoid the problem of secondary soil salinization caused by over-irrigation.

[0051] Simple structure, low cost, and easy maintenance: The components of the device are simple in structure, and the materials used, such as stainless steel, weather-resistant plastic sheets, and polyethylene water tanks, are all common materials, resulting in low cost. Furthermore, the connection between components is simple, and an inspection door is provided on the side of the filter box for easy periodic replacement of the filter material. The overall device is easy to maintain and suitable for promotion and application in coastal saline-alkali areas.

[0052] Promoting soil improvement in saline-alkali land: Through precise drip irrigation and efficient desalination, the accumulation of salt on the soil surface can be reduced. At the same time, during irrigation, appropriate water infiltration can drive some salt to migrate to deeper soil layers, gradually improving the soil salinization status, creating a good soil environment for crop growth, and contributing to soil improvement and ecological restoration of saline-alkali land.

[0053] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rainwater harvesting and irrigation device for coastal saline-alkali land, characterized in that, It includes a support frame (1), a water collection section (2), a water storage section (3), and an irrigation section (4); The water collection part (2) is fixed to the upper end of the support (1) to collect rainwater; the water storage part (3) is located inside the support (1) and includes a filter bucket (33) and a water storage bucket (32); the water inlet at the upper end of the filter bucket (33) is connected to the water outlet of the water collection part (2); the inner cavity of the filter bucket (33) is provided with a quartz sand layer (34), an activated carbon layer (35) and an ion exchange resin layer (36) from top to bottom; the water inlet of the water storage bucket (32) is connected to the water outlet at the lower end of the filter bucket (33) to store the filtered rainwater; The irrigation section (4) includes a drainage pipe (41) and multiple drip irrigation tapes (42); one end of the drainage pipe (41) is connected to the outlet of the water storage tank (32), and the other end is closed; one end of the multiple drip irrigation tapes (42) is connected to the inner cavity of the drainage pipe (41), and the other end is closed; multiple drip heads are detachably connected to the multiple drip irrigation tapes (42) and correspond to the roots of the crops.

2. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 1, characterized in that, The thickness of the quartz sand layer (34) is 30-35 cm, the thickness of the activated carbon layer (35) is 25-30 cm, and the thickness of the ion exchange resin layer (36) is 20-25 cm. The quartz sand layer (34) and the activated carbon layer (35), as well as the activated carbon layer (35) and the ion exchange resin layer (36), are separated by stainless steel mesh screens.

3. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 1, characterized in that, The water collection part (2) includes a V-shaped canopy (21) and a water collection box (23); the V-shaped canopy (21) is fixed to the upper end of the bracket (1); the water collection box (23) is fixed to the V-shaped outer wall of the V-shaped canopy (21); the V-shaped canopy (21) is provided with a drainage groove (24) that connects to the inner cavity of the water collection box (23).

4. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 3, characterized in that, The V-shaped canopy (21) is detachably connected to the V-shaped inner wall above the drainage channel (24) with a PE grille (22), and the PE grille (22) covers the drainage channel (24).

5. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 1, characterized in that, It also includes a salt drain pipe (6); the lower end of the water storage tank (32) is fixed with a support foot (31) and a drain outlet is opened on its bottom wall, and a ring-shaped salt drain ditch is opened on the ground around the bracket (1); the salt drain pipe (6) is laid in the salt drain ditch and one end of it is connected to the drain outlet, and the other end is connected to the municipal drainage network; multiple permeation holes are opened on the pipe wall of the salt drain pipe (6); a solenoid valve (7) is fixed at the end of the salt drain pipe (6) near the drain outlet.

6. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 5, characterized in that, It also includes a soil EC probe (38) and a transmitter (37); the soil EC probe (38) is buried in the soil to monitor soil electrical conductivity; the transmitter (37) is fixed to the outer wall of the water storage tank (32) and is connected to the soil EC probe (38); the transmitter (37) transmits the signal of the soil EC probe (38) to the controller system.

7. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 6, characterized in that, It also includes a lithium battery (5); a solar panel is fixed on the water collection part (2), and the lithium battery (5) is electrically connected to the solar panel; the solenoid valve (7) and the transmitter (37) are both electrically connected to the lithium battery (5).

8. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 1, characterized in that, The water storage tank (32) has an irrigation outlet on its side wall, which is connected to the diversion pipe (41); a water outlet control valve (43) is fixed at one end of the diversion pipe (41) near the irrigation outlet; a water level sensor is fixed on the inner wall of the water storage tank (32), which is communicatively connected to the water outlet control valve (43).

9. A rainwater harvesting and irrigation device for coastal saline-alkali land according to claim 1, characterized in that, It also includes a backwash pump; an EC sensor is fixed to the outlet at the lower end of the filter tank (33) to monitor the salinity of the filtered rainwater; the backwash pump is fixed to the inner wall of the water storage tank (32) and electrically connected to the EC sensor.

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