Continuous farmland non-point source pollution control system

Abstract

The invention discloses a contiguous farmland non-point source pollution control system, which comprises an ecological ditch, a water-logged compost pool, a fertilizer liquid collection pool and a deep adsorption bed, and is characterized in that the ecological ditch is arranged in a farmland, and is used for collecting rainwater in the farmland and filtering and adsorbing part of pollutants in the rainwater; the water-logged compost pond is communicated with the ecological ditch, the ecological ditch is used for conveying part of rainwater to the water-logged compost pond, and the water-logged compost pond is used for water-logged compost by utilizing rainwater and agricultural wastes; the fertilizer liquid collecting tank is communicated with the water-logged compost tank and is used for collecting fertilizer liquid generated by the water-logged compost tank; the deep adsorption bed is communicated with the ecological ditch, the ecological ditch is used for conveying residual rainwater to the deep adsorption bed, and the deep adsorption bed is used for adsorbing pollutants of the rainwater. The multi-stage interception mode of the ecological ditch, the water-logged compost pool and the deep adsorption bed is adopted, the effect that soluble pollutants are adsorbed, absorbed and reused is achieved, solid pollutants are subjected to resource reutilization, and zero emission of farmland pollutants is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural environmental protection, and in particular to a control system for non-point source pollution of contiguous farmland. Background Art

[0002] According to statistics, my country's annual straw production is 864.2901 million tons, of which about 60% is used for fertilizing fields. In rural areas of my country, straw and crop waste are often used to increase fertilizer in farmland through direct return to the field, carbonization return to the field, composting return to the field, etc. Direct return to the field is prone to cause pests and diseases, carbonization return to the field is prone to cause air pollution and energy waste, and the composting return to the field can kill most of the insect eggs, pathogens and grass seeds in the straw through the composting effect, reducing the occurrence of diseases. Measures need to be taken in the composting return to the field to ensure that it can be started quickly and composted smoothly at appropriate temperature and humidity. Rural areas mostly use chemical fertilizers or farmyard manure for farmland fertilization to promote crop growth and improve soil quality. Some farmlands in mountainous areas of my country are built along gullies and rivers. The slope of farmlands in mountainous areas is large, and agricultural fertilizers can easily enter rivers in the form of surface runoff along with initial rainwater, causing river pollution.

[0003] Patent CN109626723A discloses an ecological treatment system for controlling non-point source pollution in farmland. The system includes an ecological purification pool, a sedimentation pool, a deep purification pool and a water collection pool which are arranged and connected in sequence. The ecological purification pool is connected to the farmland, and a return water pipeline is arranged between the water collection pool and the farmland.

[0004] However, the above-mentioned existing technologies are unable to adsorb, absorb and reuse agricultural waste, resulting in loss of fertility and waste. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and propose a control system for non-point source pollution of contiguous farmland to solve the technical problem that the existing technology cannot adsorb, absorb and reuse agricultural waste, resulting in fertility loss and waste.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The present invention provides a system for controlling non-point source pollution of contiguous farmland, comprising: Ecological ditches are arranged in farmland and are used to collect rainwater in the farmland and filter and absorb some pollutants in the rainwater; A composting pool, the composting pool is connected to the ecological ditch, the ecological ditch is used to transport part of the rainwater to the composting pool, and the composting pool is used to utilize rainwater and agricultural waste to compost; A fertilizer liquid collection tank, the fertilizer liquid collection tank is connected to the composting tank, and the fertilizer liquid collection tank is used to collect the fertilizer liquid generated by the composting tank; and A deep adsorption bed is connected to the ecological ditch, the ecological ditch is used to transport the remaining rainwater to the deep adsorption bed, and the deep adsorption bed is used to adsorb pollutants in the rainwater.

[0007] In some embodiments, the ecological ditch is filled with filter material, and the filter material includes a pebble layer, a first water-storing expanded clay layer and a planting soil layer arranged in sequence from bottom to top, and aquatic vegetables are planted on the planting soil layer.

[0008] In some embodiments, the pebble layer is laid with a thickness of 20 cm to 30 cm and a particle size of 5 cm to 10 cm; The laying thickness of the first water-storage ceramsite layer is 20 cm to 30 cm, the particle size is 1.5 cm to 3.5 cm, and the apparent density is 700 to 900 kg / m 3 , bulk density is 450-500kg / m 3 , the average porosity is greater than or equal to 40%, the mass water absorption rate is greater than 75%, and the compressive strength is 1-2Mpa; The thickness of the planting soil layer is 10 cm.

[0009] In some embodiments, an anti-seepage membrane is also laid on opposite sides of the ecological ditch.

[0010] In some embodiments, one end of the ecological ditch is respectively connected to the composting pool and the deep adsorption bed, and a water retaining barrier is provided at the connection between the ecological ditch and the deep adsorption bed, so that the initial rainwater collected by the ecological ditch enters the composting pool, and the remaining rainwater enters the deep adsorption bed.

[0011] In some embodiments, the composting pond includes a pond body and a sealing canvas, a second water-storing expanded clay layer is laid on the bottom of the pond body, the pond body is also provided with air holes and rainwater collection holes connected to the ecological ditch, and the sealing canvas is laid above the pond body.

[0012] In some embodiments, a partition net is further provided at the rainwater collection hole, the aperture of the partition net is 1 cm to 1.5 cm, and the material of the partition net is 304 stainless steel or other corrosion-resistant materials.

[0013] In some embodiments, the deep adsorption bed is provided with two permeable walls spaced apart along the water flow direction, and the two permeable walls divide the deep adsorption bed into a water distribution area, a water storage area and a water outlet area which are sequentially arranged along the water flow direction. The water distribution area is connected to the ecological ditch, and a third water-storage expanded clay layer is laid in the water storage area. Aquatic vegetables are also planted above the third water-storage expanded clay layer, and the water outlet area is used to connect to the river channel.

[0014] In some embodiments, the effective volume of the third water-storage expanded clay layer = (average daily precipitation at the farmland location - initial rainwater interception amount) / porosity of the water-storage expanded clay, and its filling depth is 1m to 1.5m and its width is 4m to 5m.

[0015] In some embodiments, the composting tank is connected to the fertilizer liquid collecting tank via a fertilizer liquid discharge pipe, the fertilizer liquid discharge pipe is located at the bottom of the composting tank, and the fertilizer liquid discharge pipe is provided with a valve.

[0016] Compared with the prior art, the present invention provides a control system for non-point source pollution of contiguous farmland, wherein the ecological ditch is connected to the composting pool and the deep adsorption bed respectively. When rainfall occurs, rainwater flows into the ecological ditch through surface runoff, and solid impurities are initially filtered through the ecological ditch. The initial rainwater of the first 15 minutes enters the composting pool, and the rainfall other than the initial rainwater enters the deep adsorption bed. This part of rainwater is adsorbed by the deep adsorption bed and then discharged into the river. The livestock and poultry manure of farmers, the straw and waste in the farmland can be harvested and chopped and put into the composting pool. During the initial startup, a composting agent can be added to accelerate the composting of the fertilizer, and during the composting process, Special microorganisms with strong adaptability are enriched. After the initial startup, the enriched special microorganisms can be used to quickly start the composting tank each time straw, livestock and poultry manure, and waste are added, without the need to re-domesticate the microorganisms each time. The leachate fertilizer liquid produced during the composting process can be discharged into the fertilizer liquid collection tank according to the needs of composting. The liquid in the fertilizer liquid collection tank has a high concentration of nitrogen, phosphorus and other elements that can help improve the fertility of farmland. This application adopts the multi-stage interception method of the ecological ditch, the composting tank, and the deep adsorption bed to achieve the effect of adsorption, absorption, and reuse of soluble pollutants, and solid pollutants are recycled and reused to achieve zero emissions of farmland pollutants.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows with reference to the accompanying drawings. The specific implementation of the present invention is given in detail by the following embodiments and their accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an embodiment of a control system for non-point source pollution of contiguous farmland provided by the present invention; Figure 2 yes Figure 1 Schematic diagram of the control system for non-point source pollution in contiguous farmland; Figure 3 yes Figure 2 Sectional view along AA; Figure 4 yes Figure 2 Sectional view along BB; Figure 5 yes Figure 2 Cross-sectional view along CC; Figure 6 yes Figure 2 Cross-sectional view along DD.

[0019] Description of reference numerals: 1-ecological ditch, 11-pebble layer, 12-first water-storing ceramsite layer, 13-planting soil layer, 14-anti-seepage membrane, 15-water retaining ridge, 2-fertilizer pool, 21-pool body, 211-air vent, 212-rainwater collection hole, 22-sealed canvas, 23-second water-storing ceramsite layer, 24-partition, 3-fertilizer liquid collection pool, 31-fertilizer liquid discharge pipe, 32-valve, 4-deep adsorption bed, 41-permeable wall, 42-water distribution area, 43-water storage area, 44-water outlet area, 45-third water-storage ceramsite layer. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] In order to solve the technical problem that the existing technology is unable to adsorb, absorb and reuse agricultural waste, resulting in loss and waste of fertility, the present invention provides a non-point source pollution control system for contiguous farmland, which can achieve the effect of adsorption, absorption and reuse of soluble pollutants, and resource reuse of solid pollutants, thereby achieving zero emission of farmland pollutants.

[0022] See also Figure 1 , Figure 1 It is a schematic diagram of the structure of a control system for non-point source pollution of contiguous farmland in one embodiment of the present invention.

[0023] The present invention provides a control system for non-point source pollution of contiguous farmland, comprising an ecological ditch 1, a composting pool 2, a fertilizer liquid collection pool 3 and a deep adsorption bed 4, wherein the ecological ditch 1 is arranged in the farmland, and the ecological ditch 1 is used to collect rainwater in the farmland and filter and adsorb part of the pollutants in the rainwater; the composting pool 2 is connected with the ecological ditch 1, and the ecological ditch 1 is used to transport part of the rainwater to the composting pool 2, and the composting pool 2 is used to utilize rainwater and agricultural waste for composting; the fertilizer liquid collection pool 3 is connected with the composting pool 2, and the fertilizer liquid collection pool 3 is used to collect the fertilizer liquid generated by the composting pool 2; the deep adsorption bed 4 is connected with the ecological ditch 1, and the ecological ditch 1 is used to transport the remaining rainwater to the deep adsorption bed 4, and the deep adsorption bed 4 is used to adsorb pollutants in the rainwater.

[0024] In this example, see Figure 1and Figure 2 The ecological ditch 1 is connected to the composting pool 2 and the deep adsorption bed 4 respectively. When it rains, the rainwater flows into the ecological ditch 1 through the surface runoff. The rainwater passes through the ecological ditch 1 to initially filter solid impurities. The initial rainwater of the first 15 minutes enters the composting pool 2. The rainfall other than the initial rainwater enters the deep adsorption bed 4. This part of the rainwater is adsorbed by the deep adsorption bed 4 and then discharged into the river. The livestock and poultry manure, straw and waste in the farmland can be harvested and chopped and put into the composting pool 2. At the initial startup, a composting agent can be added to accelerate the composting of the fertilizer. During the composting process, special microorganisms with strong adaptability will be enriched. Biologically, after the initial startup, the enriched special microorganisms can be used to quickly start the composting tank 2 each time straw, livestock and poultry manure, and waste are added, without the need to re-domesticate the microorganisms each time. The leachate fertilizer liquid produced during the composting process can be discharged into the fertilizer liquid collection tank 3 according to the needs of composting. The liquid in the fertilizer liquid collection tank 3 has a relatively high concentration of nitrogen, phosphorus and other elements that can help improve the fertility of farmland. The present application adopts the multi-stage interception method of the ecological ditch 1, the composting tank 2, and the deep adsorption bed 4 to achieve the effect of adsorption, absorption, and reuse of soluble pollutants, and the solid pollutants are recycled and reused to achieve zero emissions of farmland pollutants.

[0025] In one embodiment, see Figure 3 and Figure 5 The ecological ditch 1 is filled with filter material, and the filter material includes a pebble layer 11, a first water-storing ceramsite layer 12 and a planting soil layer 13 arranged in sequence from bottom to top, and aquatic vegetables are planted on the planting soil layer 13.

[0026] In this embodiment, a pebble layer 11, a first water-storage ceramsite layer 12 and a planting soil layer 13 are sequentially laid in the ecological ditch 1 from bottom to top. The pebble layer 11 with a thickness of 20 cm to 30 cm at the bottom of the ecological ditch 1 can effectively ensure the infiltration and discharge of rainwater. The first water-storage ceramsite in the middle can preliminarily absorb some pollutants. The planting soil layer 13 on the top can be used to plant aquatic vegetables, which can absorb the fertilizer in the water-storage ceramsite and provide economic income for farmers.

[0027] In one embodiment, the pebble layer 11 is laid with a thickness of 20 cm to 30 cm, and its particle size is 5 cm to 10 cm; the first water-storage ceramsite layer 12 is laid with a thickness of 20 cm to 30 cm, and its particle size is 1.5 cm to 3.5 cm, and its apparent density is 700-900 kg / m 3 , bulk density is 450-500kg / m 3 , the average porosity is greater than or equal to 40%, the mass water absorption rate is greater than 75%, and the compressive strength is 1-2Mpa; the thickness of the planting soil layer 13 is 10cm.

[0028] In one embodiment, see Figure 3 An anti-seepage membrane 14 is also laid on opposite sides of the ecological ditch 1.

[0029] In this embodiment, in order to ensure that rainwater can be smoothly collected in the ecological ditch 1, an anti-seepage membrane 14 is provided on both sides of the ecological ditch 1. The anti-seepage membrane 14 can prevent rainwater from penetrating and ensure that rainwater flows into the ecological ditch 1.

[0030] In one embodiment, see Figure 2 One end of the ecological ditch 1 is connected to the composting pool 2 and the deep adsorption bed 4 respectively, and a water retaining dam 15 is provided at the connection between the ecological ditch 1 and the deep adsorption bed 4, so that the initial rainwater collected by the ecological ditch 1 enters the composting pool 2, and the remaining rainwater enters the deep adsorption bed 4.

[0031] In this embodiment, the height of the water retaining bank 15 is 5 cm, and it is arranged at the bottom of the ecological ditch 1. Due to the arrangement of the water retaining bank 15, at the beginning of rainfall, rainwater in the ecological ditch 1 flows into the composting pool 2. As the rainfall time increases, a large amount of rainwater is collected in the ecological ditch 1, and its depth will gradually exceed the height of the water retaining bank 15, and then it can cross the water retaining bank 15 and enter the deep adsorption bed 4, and then be discharged into the river channel after further adsorption and filtration in the deep adsorption bed 4.

[0032] In one embodiment, see Figure 3 and Figure 4 The composting pool 2 includes a pool body 21 and a sealing canvas 22. A second water-storing expanded clay layer 23 is laid at the bottom of the pool body 21. The pool body 21 is also provided with air holes 211 and rainwater collection holes 212 connected to the ecological ditch 1. The sealing canvas 22 is laid above the pool body 21.

[0033] In this embodiment, the two opposite sides of the pool body 21 are human-shaped walls with a support beam on the top. The sealing canvas 22 is laid on the human-shaped wall. The air holes 211 are arranged on the human-shaped wall. The number of the air holes 211 can be set according to the width of the human-shaped wall. The human-shaped wall is made of concrete material to achieve the purpose of anti-seepage, or a brick wall material that has been treated for anti-seepage. The effective volume of the composting pool 2 is approximately 1.2% of the cultivated land area served, the composting depth is approximately 1 to 1.5 m, the width is 4 to 5 m, and the length is set according to the terrain.

[0034] The water-storage ceramsite is laid at the bottom of the composting tank 2, which can fully absorb the pollutants in the initial rainwater and provide the required water source for composting. Due to the excellent water retention performance of the water-storage ceramsite, it can ensure that water is continuously evaporated under the composting temperature conditions to supplement the composting humidity and provide living conditions for microorganisms. The high porosity of the water-storage ceramsite at the bottom of the composting tank 2 can also accumulate microorganisms generated during the composting process. Therefore, the water-storage ceramsite can be turned over and thrown on the straw material when the composting is restarted next time, so as to achieve the effect of quickly starting the composting.

[0035] Specifically, the laying volume of the second water-storage ceramsite layer 23 is determined according to the volume of the initial rainwater rainfall in the service area for 15 minutes and the porosity of the water-storage ceramsite. The particle size of the second water-storage ceramsite layer 23 is 1.5 cm-3.5 cm, and the apparent density is 700-900 kg / m 3 , bulk density is 450-500kg / m 3 , the average porosity is greater than or equal to 40%, the mass water absorption is greater than 75%, and the compressive strength is 1-2Mpa.

[0036] In one embodiment, a partition net 24 is further provided at the rainwater collection hole 212 . The aperture of the partition net 24 is 1 cm to 1.5 cm. The material of the partition net 24 is 304 stainless steel or other corrosion-resistant materials.

[0037] In one embodiment, see Figure 2 and Figure 6 The deep adsorption bed 4 is provided with two permeable walls 41 spaced apart along the water flow direction. The two permeable walls 41 divide the deep adsorption bed 4 into a water distribution area 42, a water storage area 43 and a water outlet area 44 which are sequentially arranged along the water flow direction. The water distribution area 42 is connected to the ecological ditch 1. A third water storage ceramsite layer 45 is laid in the water storage area 43. Aquatic vegetables are also planted above the third water storage ceramsite layer 45. The water outlet area 44 is used to connect with the river.

[0038] In this embodiment, the volume of the deep adsorption bed 4 is designed to further adsorb and purify relatively clean rainwater except for the initial rainwater in a precipitation, which can ensure that the overall rainwater residence time is up to 1 day. Combined with the adsorption effect of water-storage expanded clay and the absorption capacity of aquatic vegetables, it can ensure the decontamination capacity while taking into account economic benefits.

[0039] In one embodiment, the effective volume of the third water-storage ceramsite layer 45 = (average daily precipitation at the farmland location - initial rainwater interception amount) / porosity of the water-storage ceramsite, and the filling depth is 1m to 1.5m and the width is 4m to 5m.

[0040] In this embodiment, the particle size of the third water-storage ceramsite layer 45 is 1.5 cm-3.5 cm, and the apparent density is 700-900 kg / m 3 , bulk density is 450-500kg / m 3 , the average porosity is greater than or equal to 40%, the mass water absorption is greater than 75%, and the compressive strength is 1-2Mpa.

[0041] In one embodiment, see Figure 4 and Figure 5 The composting tank 2 is connected to the fertilizer liquid collecting tank 3 through a fertilizer liquid discharge pipe 31 . The fertilizer liquid discharge pipe 31 is located at the bottom of the composting tank 2 . The fertilizer liquid discharge pipe 31 is provided with a valve 32 .

[0042] In this embodiment, the fertilizer liquid collection pool 3 can collect the fertilizer liquid at the bottom of the quick-start composting pool 2, and the fertilizer liquid can be used for farmland irrigation. The effective volume of the fertilizer liquid collection pool 3 is twice the volume of the initial rainwater. One end of the fertilizer liquid discharge pipe 31 is arranged corresponding to the partition net 24. The material of the fertilizer liquid discharge pipe 31 is corrosion-resistant plastic such as UPVC, and the minimum diameter of the fertilizer liquid discharge pipe 31 is 200 mm.

[0043] In order to better understand the present invention, the following Figures 1 to 6 The technical solution of the present invention is described in detail: When it rains, rainwater flows into the ecological ditch 1 through surface runoff. Solid impurities are initially filtered out by the rainwater through the ecological ditch 1. The first water-storing expanded clay layer 12 can absorb some pollutants and moisture to ensure the growth of aquatic vegetables in the ecological ditch 1.

[0044] The initial rainwater of the first 15 minutes that infiltrates along the pebble layer 11 of the ecological ditch 1 enters the composting pool 2 under the action of the water retaining bank 15, and the pollutants in the initial rainwater are adsorbed by the second water-storing ceramsite layer 23. The humidity required for the composting process can be provided by the evaporation of water in the second water-storing ceramsite layer 23.

[0045] Rainfall other than the initial rainwater passes over the water retaining dam 15 and enters the deep adsorption bed 4. This part of rainwater is adsorbed by the third water-storage expanded clay layer 45 and then discharged into the river. The pollutants in the third water-storage expanded clay layer 45 are taken away by aquatic vegetables.

[0046] Farmers' livestock and poultry manure, straw in farmland and aquatic vegetable waste can be harvested and chopped and put into the composting pool 2. During the first start-up, a composting agent can be added to accelerate the composting of the fertilizer. During the composting process, special microorganisms with strong adaptability will be enriched on the second water-storage ceramsite layer 23. After the initial start-up, each time straw, livestock and poultry manure and waste are added, the second water-storage ceramsite layer 23 can be turned over to quickly start the composting pool 2 using the enriched special microorganisms, without the need to re-domesticate the microorganisms each time.

[0047] The leachate fertilizer liquid produced during the composting process can be used to increase humidity or ventilation according to the needs of composting, and the gate can be closed or opened to discharge into the fertilizer liquid collection pool 3. The liquid in the fertilizer liquid collection pool 3 has a relatively high concentration of nitrogen, phosphorus and other elements, which can help improve the fertility of farmland.

[0048] Take a 1-hectare farmland in Wuhan as an example:

[0049] The comprehensive utilization rate of agricultural waste in this embodiment reaches 100%, and there is no burning or stacking of agricultural waste, which effectively reduces pollutants entering the atmosphere or rivers. During rainfall, the effluent from the deep purification bed in this embodiment reaches the Class III surface water standard, effectively reducing soil erosion and fertility loss in farmland.

[0050] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A control system for non-point source pollution in contiguous farmland, characterized in that: It includes: Ecological ditches are arranged in farmland and are used to collect rainwater in the farmland and filter and absorb some pollutants in the rainwater; A composting pool, the composting pool is connected to the ecological ditch, the ecological ditch is used to transport part of the rainwater to the composting pool, and the composting pool is used to utilize rainwater and agricultural waste to compost; A fertilizer liquid collection tank, the fertilizer liquid collection tank is connected to the composting tank, and the fertilizer liquid collection tank is used to collect the fertilizer liquid generated by the composting tank; as well as A deep adsorption bed is connected to the ecological ditch, the ecological ditch is used to transport the remaining rainwater to the deep adsorption bed, and the deep adsorption bed is used to adsorb pollutants in the rainwater.

2. The contiguous farmland non-point source pollution control system according to claim 1 is characterized in that: The ecological ditch is filled with filter material, which includes a pebble layer, a first water-storing ceramsite layer and a planting soil layer arranged in sequence from bottom to top, and aquatic vegetables are planted on the planting soil layer.

3. The non-point source pollution control system for contiguous farmland according to claim 2 is characterized in that: The pebble layer has a paving thickness of 20 cm to 30 cm and a particle size of 5 cm to 10 cm; The laying thickness of the first water-storage ceramsite layer is 20 cm to 30 cm, the particle size is 1.5 cm to 3.5 cm, and the apparent density is 700 to 900 kg / m 3 , bulk density is 450-500kg / m 3 , the average porosity is greater than or equal to 40%, the mass water absorption rate is greater than 75%, and the compressive strength is 1-2Mpa; The thickness of the planting soil layer is 10 cm.

4. The non-point source pollution control system for contiguous farmland according to claim 1 is characterized in that: The opposite sides of the ecological ditch are also paved with anti-seepage membranes.

5. The contiguous farmland non-point source pollution control system according to claim 1 is characterized in that: One end of the ecological ditch is connected to the composting pool and the deep adsorption bed respectively, and a water retaining barrier is provided at the connection between the ecological ditch and the deep adsorption bed, so that the initial rainwater collected by the ecological ditch enters the composting pool, and the remaining rainwater enters the deep adsorption bed.

6. The non-point source pollution control system for contiguous farmland according to claim 1 is characterized in that: The composting pond comprises a pond body and a sealing canvas. A second water-storing ceramsite layer is laid on the bottom of the pond body. The pond body is also provided with air holes and rainwater collection holes connected to the ecological ditch. The sealing canvas is laid above the pond body.

7. The non-point source pollution control system for contiguous farmland according to claim 6 is characterized in that: A partition net is also provided at the rainwater collection hole. The aperture of the partition net is 1 cm to 1.5 cm. The material of the partition net is 304 stainless steel or other corrosion-resistant materials.

8. The non-point source pollution control system for contiguous farmland according to claim 1 is characterized in that: The deep adsorption bed is provided with two permeable walls arranged at intervals along the water flow direction, and the two permeable walls divide the deep adsorption bed into a water distribution area, a water storage area and a water outlet area which are arranged in sequence along the water flow direction. The water distribution area is connected with the ecological ditch, and a third water-storage expanded clay layer is laid in the water storage area. Aquatic vegetables are also planted above the third water-storage expanded clay layer, and the water outlet area is used to connect with the river channel.

9. The non-point source pollution control system for contiguous farmland according to claim 8, characterized in that: The effective volume of the third water-storage ceramsite layer = (average daily precipitation at the farmland location - initial rainwater interception volume) / porosity of the water-storage ceramsite, and the filling depth is 1m to 1.5m and the width is 4m to 5m.

10. The non-point source pollution control system for contiguous farmland according to claim 1, characterized in that: The composting tank is connected to the fertilizer liquid collecting tank through a fertilizer liquid discharge pipe, the fertilizer liquid discharge pipe is located at the bottom of the composting tank, and the fertilizer liquid discharge pipe is provided with a valve.

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