System and method for purifying and recycling farmland non-point source pollution in polder and farmland wetland

Abstract

The present application provides a kind of polder farmland wet complex source pollution purification system, method and resource utilization process, applied in polder area;Including root hole wetland unit, plant polder ridge unit, natural ecological ditch, ecological gravel purification unit, and wetland pond unit;The farmland drainage containing agricultural non-point source pollution flows through root hole wetland unit, plant polder ridge unit, natural ecological ditch, ecological gravel purification unit in turn from farmland and collects into wetland pond unit, completes the ecological purification treatment of agricultural non-point source pollution.The present application constructs root hole wetland unit, plant polder ridge unit, natural ecological ditch, ecological gravel purification unit, wetland pond unit multistage ecological system, based on the characteristics of the concentration of polder area, developed water system, with existing land conditions, realize the farmland wet complex ecological management of water body, solve the problem of unsatisfactory management effect or high investment, lack of systematic control, wide land area etc. in the process of one-way ecological management of polder area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ecological purification of agricultural non-point source pollution, in particular to a polder agricultural wetland non-point source pollution purification system, method and resource utilization process. BACKGROUND

[0002] The polder area has the characteristics of low-lying terrain, developed water system, and concentrated farmland. During the process of large-scale agricultural planting in the polder area, the farmland drainage generated by it forms a relatively obvious non-point source pollution. Rural non-point source pollution refers to the dissolved or solid pollutants, such as soil particles, nitrogen, phosphorus, pesticides, heavy metals, rural livestock manure and household garbage, etc. organic or inorganic substances, from non-specific regions, under the action of rainfall and runoff, through farmland surface runoff, farmland drainage and underground seepage, so that a large amount of pollutants enter the receiving water body (river, lake, reservoir, bay), agricultural non-point source pollution is easy to cause eutrophication of river water, large-scale reproduction of algae, reduction of aquatic biodiversity, destruction of water ecological balance, and even may cause red tide, water bloom and other phenomena, affecting water safety. In the process of agricultural non-point source pollution control, the relatively mature 4R technology is formed, that is, source reduction, process blocking, nutrient recycling and ecological restoration. In the process of ecological governance, ecological purification technology can effectively control the non-point source pollution formed by farmland drainage.

[0003] Under the traditional agricultural production and land use mode, the polder area agriculture faces many ecological and environmental problems, such as serious farmland non-point source pollution, ecological function degradation, low water resource utilization efficiency, etc. These problems not only affect the local agricultural production and ecological environment quality, but also restrict the sustainable development of regional economy. In actual use, the effect of some single ecological governance is not ideal, or the investment is high, the system is lack of systematic regulation and control, the land occupation is wide, and the maintenance is difficult, which are important factors restricting the development of the technology. At the same time, in the actual application of ecological technology, the resource utilization rate of plant stems and water is low, or the resource utilization technology is difficult to implement due to land and single technology. The non-point source pollution in the polder area needs to be controlled by a low-cost, in-situ multi-level, easy-to-maintain and high-resource technology system, which can effectively improve the ecological governance efficiency. SUMMARY

[0004] In view of the shortcomings of the prior art described above, the purpose of the present application is to provide a polder agricultural wetland non-point source pollution purification system, method and resource utilization process, which is used for purifying the water quality of agricultural non-point source pollution in the polder area, and constructing a water body and plant resource recycling system.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a polder agricultural wetland non-point source pollution purification system, which is applied to a polder area, comprising:

[0006] a root-hole wetland unit, wherein natural root-hole forming aquatic plants and hygrophytes are planted, and the root-hole wetland unit reduces organic matter and suspended solids in farmland runoff through capturing, root-hole area filtering, plant absorption, substrate interception, and microbial degradation;

[0007] a plant dike unit, wherein aquatic plants are planted, and the plant dike unit reduces organic matter in farmland runoff through root interception of aquatic plants;

[0008] an ecological gravel purification unit for purifying organic matter, nitrogen, and phosphorus pollutants in farmland runoff;

[0009] a wetland pond unit, wherein emergent plants and submerged plants are planted, for purifying organic matter in farmland runoff, and the wetland pond unit is used for standing and depositing farmland runoff;

[0010] A natural ecological ditch is further arranged between the plant dike unit and the ecological gravel purification unit. Farmland runoff containing agricultural non-point source pollution flows through the root-hole wetland unit, the plant dike unit, the natural ecological ditch, the ecological gravel purification unit, and is collected in the wetland pond unit, thereby completing ecological purification treatment of agricultural non-point source pollution.

[0011] Preferably, the natural ecological ditch is built based on an irrigation ditch or a drainage ditch, and aquatic plants are further planted in the natural ecological ditch for purifying water quality and reducing nitrogen and phosphorus pollutant content in farmland runoff.

[0012] Preferably, plant stems are embedded in the substrate of the root-hole wetland unit, and aquatic plants and hygrophytes are planted in the substrate. After the plant stems in the substrate rot, artificial root holes are formed, which simulate a natural wetland reed root hole system for purifying farmland runoff containing agricultural non-point source pollution.

[0013] Preferably, the root-hole wetland unit is arranged between the farmland and the plant dike unit, and a planting stake is arranged on the side of the root-hole wetland unit close to the farmland, which is used to distinguish farmland planting areas and ecological purification areas.

[0014] Preferably, a water head difference between two sides of the root-hole wetland unit is 2 cm-6 cm.

[0015] Preferably, the ecological gravel purification unit is embedded below the ground, and the ecological gravel purification unit comprises a water inlet area, a gravel area, a water outlet area, and a water collection area, wherein the water inlet area is communicated with the natural ecological ditch through a gravity flow pipeline; the water collection area is communicated with the wetland pond unit; farmland runoff in the natural ecological ditch flows into the water inlet area through the gravity flow pipeline, is filtered and purified in the gravel area, and then flows into the water outlet area, and then flows into the wetland pond unit after being collected in the water collection area.

[0016] Preferably, the height of the gravel area is 0.6-1.0 m; the particle size of the gravel in the gravel area is 10-30 mm.

[0017] Preferably, the wetland pond unit can also be configured with fish and benthic animals to form an ecological system in the wetland pond unit.

[0018] To achieve the above object or other objects, the application further discloses a polder and farmland combined source pollution purification method, which adopts the polder and farmland combined source pollution purification system, and the steps are as follows:

[0019] S1: a root-hole wetland unit, a plant polder ridge unit, a natural ecological ditch, an ecological gravel purification unit and a wetland pond unit are planned and built on the periphery of the farmland;

[0020] S2: after farmland irrigation or rainfall, a water head difference is formed between the farmland and the root-hole wetland unit, farmland runoff containing agricultural source pollution flows through the root-hole wetland unit, the plant polder ridge unit, the natural ecological ditch and the ecological gravel purification unit in sequence to the wetland pond unit, and the ecological purification treatment of the agricultural source pollution is completed.

[0021] To achieve the above object or other objects, the application further discloses a polder and farmland combined source pollution purification resource utilization process, which adopts the polder and farmland combined source pollution purification system, and the substrate of the root-hole wetland unit is embedded with plant stems, and the sources of the plant stems include aquatic plants planted on the root-hole wetland unit, the plant polder ridge unit and the wetland pond unit.

[0022] The wetland pond unit has a water storage function and can collect farmland runoff and rainwater; the farmland runoff and rainwater can be used for farmland crop irrigation after purification by the wetland pond unit.

[0023] As described above, the polder and farmland combined source pollution purification system, method and resource utilization process have the following beneficial effects:

[0024] 1. The application constructs a multi-stage ecological system of the root-hole wetland unit, the plant polder ridge unit, the natural ecological ditch, the ecological gravel purification unit and the wetland pond unit, realizes farmland and wetland combined ecological management of water bodies based on the characteristics of concentration and developed water system in the polder area, and solves the problems of unsatisfactory management effect, high investment, lack of systematic regulation and control, wide occupation area and difficult maintenance in the process of one-way ecological management of the polder area.

[0025] 2、The substrate of the root hole wetland unit in the application can adopt the stems of aquatic plants planted in the plant dike unit and the stems of aquatic plants planted in the wetland pond unit, realizes the resource utilization of plant stems, and the wetland pond unit also has the water storage function and can collect farmland runoff and rainwater; the farmland runoff and rainwater can be used for farmland irrigation water after purification by the wetland pond unit, realizes the resource utilization of water resources, realizes pollution-free discharge and highly cyclic utilization of resources. The initial construction and later maintenance cost is low, and the application has strong popularization.

[0026] 3、The application mainly constructs composite ecological technical measures to control agricultural non-point source pollution in the polder area based on the existing terrain and natural conditions, improves the resource utilization of plant stems and water, does not need large-scale additional land, and has low maintenance cost and gravity operation of water flow without power consumption. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a general schematic view of the polder agricultural wet composite non-point source pollution purification system.

[0028] Figure 2 It is a schematic view of the root hole wetland unit, the plant dike unit and the natural ecological ditch in the application.

[0029] Figure 3 It is a schematic view of the ecological gravel purification unit of the polder agricultural wet composite non-point source pollution purification system.

[0030] Figure 4 It is a schematic view of the wetland pond unit of the polder agricultural wet composite non-point source pollution purification system.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] 1, root hole wetland unit; 2, plant dike unit; 3, natural ecological ditch; 4, ecological gravel purification unit; 401, water inlet area; 402, gravel area; 403, water outlet area; 404, water collection area; 5, wetland pond unit; 501, emergent plant; 502, submerged plant; 6, planting stake; 7, farmland. DETAILED DESCRIPTION

[0033] The following specific embodiments illustrate the embodiments of the application, and those skilled in the art can easily understand other advantages and effects of the application from the disclosed content.

[0034] It is to be understood that the structures, proportions, sizes, etc. shown in the drawings accompanying the present specification are merely intended to facilitate understanding and reading of the content disclosed by the present specification for those skilled in the art, and are not intended to limit the conditions under which the present application can be implemented, and therefore do not have technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in the present specification are merely for the convenience of clear description, and are not intended to limit the scope of the present application, and the change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present application.

[0035] As shown in Figures 1-4 The present application provides a polder farmland wetland composite non-point source pollution purification system, which is applied to a polder area; comprising:

[0036] a root hole wetland unit 1, aquatic plants and hygrophytes capable of forming natural root holes are planted on the root hole wetland unit 1, and the root hole wetland unit 1 reduces organic matter and suspended solids in farmland runoff through capture, root hole area filtration, plant absorption, substrate interception, and microbial degradation;

[0037] a plant polder dike unit 2, aquatic plants are planted on the plant polder dike unit 2, and the plant polder dike unit 2 releases and retards organic matter in farmland runoff through the root system of the aquatic plants;

[0038] an ecological gravel purification unit 4, which is used for purifying organic matter, nitrogen, and phosphorus pollutants in farmland runoff;

[0039] a wetland pond unit 5, emergent plants 501 and submerged plants 502 are planted in the wetland pond unit 5, which is used for purifying organic matter in farmland runoff, and the wetland pond unit 5 is used for standing and depositing farmland runoff;

[0040] A natural ecological ditch 3 is further arranged between the plant polder dike unit 2 and the ecological gravel purification unit 4; farmland runoff containing agricultural non-point source pollution flows through the root hole wetland unit 1, the plant polder dike unit 2, the natural ecological ditch 3, the ecological gravel purification unit 4 in sequence from the farmland 7, and is collected in the wetland pond unit 5, to complete ecological purification treatment of the agricultural non-point source pollution.

[0041] The polder farmland wetland composite non-point source pollution purification system disclosed by the present application comprises a root hole wetland unit 1, a plant polder dike unit 2, a natural ecological ditch 3, an ecological gravel purification unit 4, and a wetland pond unit 5, and when farmland runoff flows in the above multi-level ecological system, organic matter, nitrogen, and phosphorus pollutants contained in the farmland runoff are filtered, intercepted, purified, and decomposed by each unit, so that the source of agricultural non-point source pollution is treated.

[0042] Preferably, as shown in Figure 1 , Figure 2 , the natural ecological ditch 3 is built on the basis of irrigation ditches or drainage ditches; aquatic plants are also planted in the natural ecological ditch 3 for purifying water quality and reducing the content of nitrogen and phosphorus pollutants in farmland runoff.

[0043] Further, the irrigation ditches or drainage ditches are existing facilities for the area of the polder farmland 7; the aquatic plants in the natural ecological ditch 3 have a purifying effect, which can enhance water quality purification, save land, play the ecological role of the ditch, and have low investment cost and convenient maintenance. The purifying effect of the aquatic plants is fully utilized, and the content of nitrogen, phosphorus and other pollutants in the farmland runoff is reduced.

[0044] Preferably, in this embodiment, plant stems (which can be appropriately matched with crop straws) are buried in the substrate of the root hole wetland unit 1, and aquatic plants and hygrophytes are planted in the substrate; after the plant stems in the substrate rot, artificial root holes are formed, simulating the reed root hole system of natural wetlands, for purifying farmland runoff containing agricultural non-point source pollution.

[0045] The root hole wetland unit 1 is constructed by simulating the reed root hole system of natural wetlands, using plant stems as the filler / medium of the substrate, effectively changing the macropore structure of the wetland bed. At the initial stage of construction of the root hole wetland unit 1, plant stems are buried in the subsoil layer of the wetland, and aquatic plants and hygrophytes capable of forming natural root holes are planted thereon. After the plant stems rot, artificial root holes are formed in the wetland.

[0046] Preferably, as shown in Figure 2 , the root hole wetland unit 1 is arranged between the farmland 7 and the plant polder ridge unit 2, and a planting stake 6 is arranged on the side of the root hole wetland unit 1 close to the farmland 7. The planting stake 6 is used to distinguish the planting area of the farmland 7 and the ecological purification area. The water head difference between the two sides of the root hole wetland unit 1 is 2-6 cm.

[0047] Further, the planting stake 6 is used to prevent irregular growth of aquatic plants, effectively distinguishing the crops of the farmland 7 from the aquatic plants, and also blocks the soil of the farmland 7, fully plays the ecological role of the ridge, and effectively prevents water and soil loss of the farmland 7.

[0048] Preferably, in this embodiment, the plant polder ridge unit 2 is based on a natural ridge, and forms natural alternating growth of aquatic plants by planting aquatic plants. The aquatic plants can be harvested to pile fillers according to the needs of the substrate of the root hole wetland unit 1, and the root system of the aquatic plants in the plant polder ridge unit 2 can further enhance the interception and release of farmland runoff, and at the same time solidify the plant polder ridge unit 2.

[0049] Preferably, as shown inFigure 1 , Figure 4 As shown, the ecological gravel purification unit 4 is buried underground. The ecological gravel purification unit 4 includes an inlet area 401, a gravel area 402, an outlet area 403, and a collection area 404. The inlet area 401 is connected to the natural ecological ditch 3 via a gravity flow pipe; the collection area 404 is connected to the wetland pond unit 5. Farmland runoff from the natural ecological ditch 3 flows into the inlet area 401 through the gravity flow pipe, is filtered and purified in the gravel area 402, flows into the outlet area 403, and then is collected in the collection area 404 before flowing into the wetland pond unit 5. Furthermore, the height of the gravel area 402 is 0.6m-1.0m; the particle size of the gravel in the gravel area 402 is 10mm-30mm.

[0050] In this embodiment, the ecological gravel purification unit 4 is a fully underground purification unit primarily composed of gravel filler, installed in existing road shoulders, drainage outlets, and other geographical locations. This saves floor space and significantly improves cold resistance. The ecological gravel purification unit 4 has high resistance to impact loads and a strong ability to purify pollutants such as organic matter, nitrogen, and phosphorus from water bodies, while its cost is lower than similar technologies. The ecological gravel purification unit 4 achieves "zero land occupation," high purification function, and restores the original land use characteristics of the surface portion.

[0051] Preferred, such as Figure 1 , Figure 4 As shown, in this embodiment, the wetland pond unit 5 can also be equipped with fish and benthic animals to form an ecosystem within the wetland pond unit 5. The wetland pond unit 5 can be constructed by modifying existing pits, ponds, river / lake boundary wetlands, etc., and planted with emergent plants 501 (such as reeds and cattails) and submerged plants 502 (such as Vallisneria natans) and other aquatic plants with purifying effects. Through sedimentation and deep purification, suspended solids, nitrogen, phosphorus, and other pollutants in the water are further removed. Furthermore, multiple wetland pond units 5 can be set according to actual conditions, and adjacent wetland pond units 5 can be connected in parallel or series, eliminating the need for large-scale construction of new wetland pond units 5 and saving land area.

[0052] In the embodiment, the multi-stage ecological purification system is relied on to save land and control the farmland non-point source pollution of the check dam. The wetland pond unit 5 can be used for farmland flood control in the rainy season, rainwater storage, and interception and purification of irrigation return water in dry days, and can greatly realize the water storage, water purification, soil conservation, carbon sequestration and other abilities in the system, and promote the balanced development of ecology. The root hole wetland unit 1 and the plant check dam unit 2 can enhance the water conservation capacity of the farmland wetland system in the check dam area, and at the same time purify the water, reduce the turbidity of the farmland return water, and reduce the degree of soil erosion in the farmland. At the same time, the aquatic plants on the plant check dam unit 2 and the aquatic plants in the wetland pond unit 5 can effectively purify the farmland pollution, and the stems and stalks after harvesting can be used as the filler / medium of the pre-ecological technology to realize the resource utilization in the aquatic plant system. The farmland return water and rainwater collected in the wetland pond unit 5 can be used for farmland irrigation after purification, improve the water resource utilization efficiency, and realize the near-zero emission in the local ecological system.

[0053] To achieve the above object or other objects, the application further discloses a check dam farmland wetland composite non-point source pollution purification method using the check dam farmland wetland composite non-point source pollution purification system, and the steps are as follows:

[0054] A1: The root hole wetland unit 1, the plant check dam unit 2, the natural ecological ditch 3, the ecological gravel purification unit 4 and the wetland pond unit 5 are planned and built on the outer circumferential side of the farmland 7, wherein the root hole wetland unit 1 is adjacent to the farmland 7, and the root hole wetland unit 1 and the farmland 7 are further provided with the planting stake 6;

[0055] A2: After irrigation or rainfall of the farmland 7, a water head difference is formed between the farmland 7 and the root hole wetland unit 1, the farmland return water containing agricultural non-point source pollution flows from the farmland 7 to the root hole wetland unit 1, the plant check dam unit 2, the natural ecological ditch 3, the ecological gravel purification unit 4 and the wetland pond unit 5 in sequence, and the ecological purification treatment of the agricultural non-point source pollution is completed;

[0056] Wherein, the farmland runoff is formed after irrigation or rainfall in the farmland, a water head difference is formed between the planting stake 6 and the root hole wetland unit 1 on the basis of water conservation, and the soil loss caused by excessive erosion is avoided, the root hole wetland unit 1 captures, filters, absorbs, intercepts and degrades the organic matter and suspended solids in the farmland return water, and realizes the primary purification of the farmland return water;

[0057] The farmland return water after the primary purification flows into the plant check dam unit 2, the root system of the aquatic plants planted on the plant check dam unit 2 further intercepts and releases the organic matter in the farmland return water, and realizes the secondary purification of the farmland return water;

[0058] The farmland runoff after secondary purification flows into the natural ecological ditch 3, the natural ecological ditch 3 collects the farmland runoff after secondary purification, and aquatic plants planted in the natural ecological ditch 3 further purify organic matters in the farmland runoff, reduce the content of nitrogen and phosphorus pollutants in the farmland runoff, and achieve three-stage purification of the farmland runoff.

[0059] The farmland runoff after three-stage purification flows into the ecological gravel purification unit 4 through a gravity flow pipeline, gravel fillers filled in the ecological gravel purification unit 4 further purify organic matters, nitrogen, phosphorus and other pollutants in the farmland runoff, and four-stage purification of the farmland runoff is achieved.

[0060] The farmland runoff after four-stage purification flows into the wetland pond unit 5, the wetland pond unit 5 performs sedimentation on the farmland runoff, and emergent plants 501 and submerged plants 502 in the wetland pond unit 5 further purify the farmland runoff, a complete ecological system is formed among fish, benthic animals and microorganisms configured in the wetland pond unit 5, and purification of the farmland runoff is achieved.

[0061] To achieve the above object or other objects, the application further discloses a resource utilization process for polder farmland wetland combined non-point source pollution purification, which adopts the polder farmland wetland combined non-point source pollution purification system, plant stems are embedded in the substrate of the root hole wetland unit 1, and the plant stems are derived from aquatic plants planted on the root hole wetland unit 1, aquatic plants planted on the plant polder ridge unit 2 and aquatic plants planted in the wetland pond unit 5; the wetland pond unit 5 has a water storage function and can collect farmland runoff and rainwater; after the farmland runoff and rainwater are purified by the wetland pond unit 5, the farmland runoff and rainwater can be used as irrigation water for a planting area of a farmland 7.

[0062] The resource utilization process in the application mainly embodies the following two aspects:

[0063] 1. Treatment and reuse of farmland runoff and rainwater runoff; the water resource reuse mainly utilizes the water storage function of the wetland pond unit 5 to collect farmland runoff and rainwater, which can reduce the risk of flood disasters to a certain extent, and the purified water can be used as irrigation water for farmland crops.

[0064] 2. Resource utilization of stems of aquatic plants after harvesting or part of crop straws; the stems of aquatic plants are mainly derived from stems of aquatic plants after harvesting of the root hole wetland unit 1, the plant polder ridge unit 2 and the wetland pond unit 5, and can be used as the substrate filler of the root hole wetland unit 1, which can effectively improve the root hole purification effect of the root hole wetland unit 1 and realize resource utilization, and crop straws can be used as the filler according to actual needs.

[0065] The present application relates to the invention of the wet complex source pollution purification system, method and resource utilization process of the paddy field, combined with multi-stage ecological purification treatment measures, saving land, realizing the wetland ecological control technology of paddy field agricultural non-point source pollution, solving the shortcomings of single ecological management effect being not ideal or investment being higher, lacking of systematic regulation and control, occupying large area, being difficult to maintain, and low resource utilization rate, and the farmland backwater and aquatic plant stems after multi-stage ecological purification treatment can be fully utilized, realizing pollution zero discharge, resource high cycle utilization, low initial construction and later maintenance cost, and strong popularization.

[0066] Therefore, the present application effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.

[0067] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A paddy field and wetland complex source pollution purification system applied to a paddy field area; characterized in that, It comprises: a root-hole wetland unit (1) on which natural root-hole forming aquatic plants and hygrophytes are planted, the root-hole wetland unit (1) reducing organic matter and suspended solids in farmland runoff through capturing, root-hole area filtering, plant absorption, substrate interception and microbial degradation; a plant dike unit (2) on which aquatic plants are planted, the plant dike unit (2) intercepting and slowly releasing organic matter in farmland runoff through the root system of aquatic plants; an ecological gravel purification unit (4) for purifying organic matter, nitrogen and phosphorus pollutants in farmland runoff, the ecological gravel purification unit (4) being buried underground, the ecological gravel purification unit (4) comprising a water inlet area (401), a gravel area (402), a water outlet area (403) and a water collecting area (404), the water inlet area (401) being communicated with a natural ecological ditch (3) through a gravity flow pipe; the water collecting area (404) being communicated with a wetland pond unit (5); farmland runoff in the natural ecological ditch (3) flows into the water inlet area (401) through the gravity flow pipe, is filtered and purified in the gravel area (402) and then flows into the water outlet area (403), and then flows into the wetland pond unit (5) after being collected in the water collecting area (404); the wetland pond unit (5) in which emergent plants (501) and submerged plants (502) are planted for purifying organic matter in farmland runoff, and at the same time the wetland pond unit (5) is used for standing and depositing farmland runoff; a natural ecological ditch (3) is further arranged between the plant dike unit (2) and the ecological gravel purification unit (4); farmland runoff containing agricultural non-point source pollution flows through the root-hole wetland unit (1), the plant dike unit (2), the natural ecological ditch (3) and the ecological gravel purification unit (4) in sequence from a farmland (7) and is collected in the wetland pond unit (5), so that ecological purification treatment of the agricultural non-point source pollution is completed; the root-hole wetland unit (1) is arranged between the farmland (7) and the plant dike unit (2), a planting stake (6) is arranged on the side of the root-hole wetland unit (1) close to the farmland (7), the planting stake (6) is used for distinguishing a planting area and an ecological purification area of the farmland (7), and at the same time the planting stake (6) blocks the soil of the farmland (7) to play an ecological role of a dike and effectively prevent water and soil loss of the farmland (7); a water head difference between the two sides of the root-hole wetland unit (1) is 2cm-6cm.

2. The system according to claim 1, wherein the system is characterized in that: The natural ecological ditch (3) is built on the basis of an irrigation ditch or a drainage ditch; aquatic plants are further planted in the natural ecological ditch (3) for purifying water quality and reducing the content of nitrogen and phosphorus pollutants in farmland runoff.

3. The system according to claim 1, wherein the system is characterized in that: Plant stems are buried in the substrate of the root-hole wetland unit (1), and aquatic plants and hygrophytes are planted in the substrate; after the plant stems in the substrate rot, artificial root holes are formed to simulate a natural wetland reed root hole system for purifying farmland runoff containing agricultural non-point source pollution.

4. The system according to claim 1, wherein the system is characterized in that: The height of the gravel area (402) is 0.6-1.0 m; the particle size of the gravel in the gravel area (402) is 10-30 mm.

5. The system according to claim 1, wherein the system is characterized in that: The wetland pond unit (5) is also provided with fish and benthic animals to form an ecological system in the wetland pond unit (5).

6. A method for purifying farmland and wetland combined non-point source pollution, using the farmland and wetland combined non-point source pollution purification system according to any one of claims 1-5, characterized in that: The steps are as follows: S1: planning and constructing the root-hole wetland unit (1), the plant dike unit (2), the natural ecological ditch (3), the ecological gravel purification unit (4), and the wetland pond unit (5) on the peripheral side of the farmland (7); S2: after irrigation or rainfall of the farmland (7), a water head difference is formed between the farmland (7) and the root-hole wetland unit (1), and the farmland runoff containing agricultural non-point source pollution flows from the farmland (7) through the root-hole wetland unit (1), the plant dike unit (2), the natural ecological ditch (3), and the ecological gravel purification unit (4) in sequence and is collected in the wetland pond unit (5), thereby completing the ecological purification treatment of the agricultural non-point source pollution.

7. A resource utilization process for purifying and treating the agricultural non-point source pollution in a dike-farmland wetland composite system, which adopts the dike-farmland wetland composite non-point source pollution purification system according to any one of claims 1-5, characterized in that: The root-hole wetland unit (1) is provided with plant stems in the substrate, and the plant stems are derived from the aquatic plants planted on the root-hole wetland unit (1), the plant dike unit (2), and the wetland pond unit (5); The wetland pond unit (5) has a water storage function and can collect farmland runoff and rainwater; the farmland runoff and rainwater can be used for crop irrigation after purification by the wetland pond unit (5).

Images