CN107853121A - A kind of sloping upland agricultural non-point source pollution integrated control system and method - Google Patents

Abstract

The invention provides a system and method for comprehensive prevention and control of agricultural non-point source pollution on sloping farmland. The system includes a soil erosion control system, an ecological ditch system, a cascaded water storage system and a terminal purification system. The soil erosion control system can prevent and control the production, migration and export of agricultural non-point source substances at the source; the ecological ditch system can effectively deposit sediment, purify water quality, and reduce the concentration of pollutants; the cascade water storage system can store water from above and deposit sediment , purify the water quality, and provide irrigation water for the lower slope farmland; the terminal purification system consists of sedimentation tanks, anaerobic digestion tanks and artificial wetlands, which are used to ecologically intercept and purify the water entering the river and storage. The invention makes full use of the topographical conditions of the slope farmland, and adopts effective prevention and control measures and methods for the key process and different stages of non-point source pollution in the agricultural farming process, improves the recycling efficiency of water and fertilizer resources in the slope farmland, and reduces soil erosion on the slope surface and surface source pollution output.

Description

A system and method for comprehensive prevention and control of agricultural non-point source pollution on sloping farmland

technical field

The invention relates to the fields of ecological protection, prevention and control of non-point source pollution, and water and soil conservation, in particular to a system and method for comprehensive prevention and control of agricultural non-point source pollution on sloping farmland.

Background technique

Sloping cultivated land refers to the land used by farming on the slope of the mountain. Due to the large slope and undulating terrain, it has problems such as low productivity, poor water and fertilizer retention capacity, serious soil erosion and non-point source pollution output. The Three Gorges Reservoir area is one of the areas with the most concentrated slope cultivated land in my country. The slope cultivated land area is about 35.8 million mu, accounting for more than 80% of the cultivated land area in the region, which is much higher than the national average of 20%. These sloping farmlands are the basis for the survival of the people in the Three Gorges Reservoir area, and they are also the main sources of sediment and non-point source pollution in the Three Gorges Reservoir area.

The process of ground source pollution in slope farming is usually accompanied by the process of soil erosion. Due to the high inclination of slope cultivated land, after the rainfall reaches the surface, under the combined influence of gravity and slope support force, it is easy to form rapid surface runoff along the slope, scouring the soil and nutrients, and making the nutrients needed for crop growth With runoff and sediment output, non-point source pollution is formed. Taking the Three Gorges Reservoir area as an example, the losses of soil nitrogen and phosphorus in the slope farmland during the rainy season were 1.038kg/hm ² and 0.509kg/hm ² , which were much higher than the losses in the plains of the same region.

Experiments show that the nitrogen in the surface runoff of sloping farmland mainly includes nitrate nitrogen and ammonium nitrogen, and the output of nitrate nitrogen is the main one; the phosphorus includes soluble phosphorus and granular phosphorus, and the granular phosphorus is the main one. At present, domestic ground source pollution prevention and control technologies for slope farming mainly include methods such as changing slopes to terraces, plant hedges, applying slow-release fertilizers, and improving farming measures; Source control-process control-end treatment" to prevent source pollution of cultivated land in low mountain and hilly areas. The application of these technologies has played an important role in the prevention and control of soil erosion and non-point source pollution in my country.

Although we have conducted in-depth research on individual technologies for the prevention and control of non-point source pollution and made great progress, my country still lacks effective methods and control systems for the comprehensive prevention and control of agricultural non-point source pollution on sloping farmland. In particular, the combined analysis of non-point source pollution and soil erosion process for the prevention and control of non-point source pollution is rare.

Based on the process and mechanism of source pollution of slope farmland in the Three Gorges Reservoir area and the upper reaches of the Yangtze River, and comprehensively considering the advantages and disadvantages of water and soil resources of slope farmland, a comprehensive system including soil erosion and non-point source pollution prevention, land productivity improvement, and efficient use of water and fertilizer resources is formed. The control system and method have important practical significance. The comprehensive control system and method for the prevention and control of agricultural non-point source pollution in the Three Gorges Reservoir area, where the contradiction between man and land is prominent, with heavy rainfall and steep terrain, is more practical.

Contents of the invention

The present invention is to provide a system and method for comprehensive prevention and control of agricultural non-point source pollution on sloping farmland, which can recycle the slope runoff as a resource, realize the maximum interception of nitrogen and phosphorus in the slope runoff, and realize the prevention and cleanliness of non-point source pollution Production is of great significance to the prevention and control of ground source pollution on slope farms.

In order to realize the foregoing invention object, the present invention adopts following technical scheme:

A comprehensive prevention and control system for agricultural non-point source pollution on sloping farmland, including a soil erosion control system, an ecological ditch system, a cascade water storage system, and a terminal purification system. Plant hedges for erosion control step sills, the ecological ditch system includes intercepting drainage ditches and grit chambers, the cascade water storage system includes water storage tanks distributed at different heights, and the terminal purification system includes sediment sedimentation tanks, exhaust Oxygen digester, artificial wetland and ecological floating bed; the rill erosion control step sill is formed by building step sills along the contour line on the slope at the interval of the critical slope length of rill erosion; the intercepting drainage The ditch is divided into two levels. The surface of the first-level intercepting drainage ditch is laid with grass-planting bricks, and the low-lying part of the slope is arranged perpendicular to the slope contour line. The second-level intercepting drainage ditch is arranged along the slope contour line. The first-level intercepting drainage ditch It is connected with the second-level intercepting drainage channel through the grit chamber arranged in the middle, and the ecological grass ditch is formed after planting wet plants in the first-level drainage ditch; the upper end of the reservoir is provided with a spillway connected to the drainage ditch. The entrance of the reservoir is connected with the ecological grass ditch, and the exit is connected with the irrigation canal of the cultivated land below.

Further, the width of the rill erosion control step sill is 10-20 cm, and the height is 15-20 cm.

Further, the hedgerows are mainly perennial herbaceous plants with broad applicability, and the species types include day lily, honeysuckle and amorpha.

Further, the first-stage intercepting drainage ditch and the second-stage intercepting drainage ditch are inverted trapezoidal, the upper end width of the first-stage intercepting drainage ditch is 30-50 cm, the lower end width is 10-20 cm, and the depth is greater than 50 cm; The width of the upper end of the secondary cut-off ditch described above is 10-20cm, and the depth is 10-20cm.

Further, the grit chamber is a conical deceleration grit chamber, with an upper port radius of 15-25 cm, a lower port radius of 5-10 cm, and a depth of 30-50 cm, installed on the path of the cut-off drainage ditch.

Further, the wet plant is one of cress, wild water chestnut, water spinach, bermudagrass or a combination thereof.

Further, one of the reservoirs is set according to the average confluence range of 20-50 mu of land, the reservoir is cylindrical, the radius of the pool mouth is 0.8-1.0m, and the depth is 1.5-3.0m.

Further, the terminal purification system is composed of a pretreatment unit and a main treatment unit. The pretreatment unit is mainly a sedimentation tank and anaerobic digestion tank; the main unit includes a constructed wetland and an ecological floating bed.

A method for comprehensive prevention and control of farmland agricultural non-point source pollution, comprising the following steps:

Taking the critical slope length of rill erosion as an interval, build ridges along the contour line on the slope to form rill erosion control ridges, and plant hedgerows on the rill erosion control ridges to form soil erosion control system;

Adopt the form of open ditch on the sloping cultivated land, lay out the slope runoff output path, set up the intercepting drainage ditch, the grit chamber and the ecological grass ditch. The intercepting drainage ditch is divided into two levels, and the surface of the first-level intercepting drainage ditch is laid with grass planting bricks. The low-lying part of the slope is arranged perpendicular to the contour line of the slope surface, and the secondary intercepting drainage ditch is arranged along the contour line of the slope surface. The ecological grass ditch is formed after planting wet plants in the level drainage ditch;

A cascaded water storage system is set on the slope, and the cascade water storage system is connected by a plurality of water storage tanks distributed from high to low and from top to bottom on the slope where the sloping cultivated land is located. The overflow port connected with the drainage ditch, the entrance of the reservoir is connected with the ecological grass ditch, and the exit is connected with the cultivated land irrigation ditch below;

Set up a terminal purification system to carry out ecological interception and purification of the water entering the river and storage. The terminal purification system is composed of a pretreatment unit and a main treatment unit. The pretreatment unit is mainly a sediment sedimentation tank and an anaerobic digestion tank. , the main unit includes a constructed wetland and an ecological floating bed

Further, the hedgerows are mainly perennial herbaceous plants with broad applicability, and the species types include day lily, honeysuckle and amorpha.

Compared with the existing agricultural non-point source pollution prevention and control technology for sloping farmland, the present invention has the following remarkable features and advantages:

The invention prevents the occurrence of water and soil loss and the output of non-point source pollution through the soil erosion prevention and control system on the slope surface, filters the sediment and nutrients in the surface runoff through the ecological ditch system, and realizes the redistribution of water resources on the slope surface through the cascade water storage system. Promote the recycling of water and fertilizer resources, and realize the re-filtration and clean output of slope runoff through the terminal purification system. The invention has the advantages of simple operation, low construction cost, convenient management and maintenance, reusability, low operation management and maintenance cost, wide application range, ecological cleanness, and high social and economic benefits and ecological benefits. The slope of the system "Tikan rill erosion control-grit chamber-reservoir-sedimentation tank" control can be compared with single technology to improve the degree of sediment filtration, "plant hedge-ecological ditch-constructed wetland-biological floating The "island" can significantly improve the interception rate and absorption rate of nitrogen and phosphorus in slope runoff; the cascade storage tank can increase the redistribution and utilization of water and fertilizer resources on the slope surface more than the traditional method, and at the same time, it can be used as emergency irrigation for seasonal drought on slope farmland source of water.

Description of drawings

Fig. 1 is the structure schematic diagram of the comprehensive prevention and control system of agricultural non-point source pollution of sloping farmland of the present invention;

Fig. 2 is the flow chart of the method for comprehensive prevention and control of agricultural non-point source pollution in sloping farmland of the present invention;

Fig. 3 is the structural representation of soil erosion control system and ecological ditch system in the present invention;

Fig. 4 is the schematic layout diagram of the cut-off drainage system of the present invention;

Fig. 5 is a schematic structural view of the water storage tank of the cascade water storage system in the present invention.

Detailed ways

The technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention.

The present invention provides a system and method for comprehensive prevention and control of agricultural non-point source pollution on sloping farmland. Combining high-efficiency recycling of water, soil and fertilizer resources on sloping farmland with prevention and control of agricultural non-point source pollution is an important key to alleviating the contradiction between man and land in hilly areas. Technical Support.

Please refer to Figure 1 and Figure 2, the comprehensive control system includes a soil erosion control system, an ecological ditch system, a cascaded water storage system and a terminal purification system. Among them, the soil erosion control system includes rill erosion control terraces and plant hedges planted on the rill erosion control terraces, which can prevent and control the production, migration and output of agricultural non-point source pollutants at the source; the ecological ditch system includes intercepting Drainage ditches and grit chambers can effectively deposit sediment, purify water quality, and reduce pollutant concentration; the cascade water storage system includes reservoirs distributed at different heights, and each reservoir can store water from above and deposit Sediment, purifies water quality, and provides irrigation water source for the lower slope cultivated land; the terminal purification system includes sediment sedimentation tank, anaerobic digestion tank, constructed wetland and ecological floating bed.

As shown in Fig. 3, with the critical slope length (L) at which rill erosion occurs as an interval, step ridges are built along the contour lines on the slope to form the rill erosion control step ridges. The critical slope length is shown in Table 1, the width of the step sill is 10-20 cm, and the height is 15-20 cm. The rill erosion control step sill reduces the output of non-point source pollutants by preventing the formation of rills and the occurrence of slope soil erosion.

Table 1 Statistical table of critical slope length for rill erosion on typical sloping cultivated land

Plant hedgerows on the rill erosion control step sill, the hedgerows are mainly perennial herbaceous plants with wide adaptability, and the species types include daylily, honeysuckle and amorpha, forming a micro-filter zone to retain surface runoff The sediment in the soil absorbs the nutrients in the surface runoff, and forms interception and filtration before the surface runoff leaves the slope.

The planting of the hedgerow is preferably specifically: planting on the slope in spring, loosening the soil on the slope before sowing, and then planting by sowing or cuttings. If it is necessary to sow the seeds, the sowing planting density is 300-300 500 grains/m ² , if cuttings are required, the cutting density should be 50-100 plants/m ² . After the planting is completed, the present invention needs to manage the hedgerow, and the hedgerow management includes management at the seedling stage and harvesting management. In the present invention, the management at the seedling stage is preferably weed removal; the harvesting management is mainly the harvesting of flowers and fruits, and the pruning of the hedgerows, and the pruning of the hedgerows is mainly when the height of the hedgerows is greater than When the height is 0.5m, the hedge needs to be pruned, and the pruning method is to cut off the branches and leaves higher than 30cm.

Adopt the form of open ditch on the sloping cultivated land, lay out the runoff output path on the slope, set up the intercepting drainage ditch, the grit chamber and the ecological grass ditch, and the said intercepting drainage ditch, the grit chamber and the ecological grass ditch are connected together through the diversion channel, A continuous treatment system is formed to control the runoff process.

As shown in Figure 4, the cut-off drainage ditch is divided into two levels, wherein the first-level cut-off drainage ditch is an inverted trapezoid, and the surface is laid with grass-planting bricks, which have drainage and biological filtration functions, and the low-lying parts along the slope are perpendicular to the slope contour Line layout; the second-level interception ditch is an inverted trapezoid, which has the functions of collecting surface runoff, intercepting soil midflow and drainage, and is arranged along the slope contour. The upper end width of the first-stage intercepting drainage ditch is 30-50 cm, the lower end width is 10-20 cm, and the depth is greater than 50 cm; the upper end width of the second-stage intercepting drainage ditch is 10-20 cm, and the depth is 10-20 cm. The first-stage cut-off drainage ditch and the second-level cut-off drainage ditch are connected through a grit chamber arranged in the middle.

The grit chamber is a small grit chamber, which is a conical deceleration grit chamber. The conical deceleration grit chamber has an upper port radius of 15-25 cm, a lower port radius of 5-10 cm, and a depth of 30-50 cm. It is made of plastic The detachable grit chamber is installed on the path of the cut-off ditch. The small-sized grit chamber needs to be regularly cleaned of sediment, and the cleaning time is within 3-5 days before or after the next rainstorm, and can continue to be used after cleaning the sediment.

The ecological grass ditch is a non-point source pollution filtering, absorption and adsorption comprehensive system formed after wet plants are planted in the first-level drainage ditch, and is mainly used for further blocking the sediment in the runoff, absorbing nitrogen, phosphorus and other agricultural surfaces. source pollutants. The ecological grass ditch is composed of two parts: ditch structure and wet plants, and the ditch structure is the first-level drainage ditch; the wet plants are strong in adsorption, have certain stress resistance, and have Herbs with certain economic value, the specific plants are: cress, wild water chestnut, water spinach, bermudagrass, etc. The ecological grass ditch is arranged between the grit chamber and the reservoir, which can further intercept runoff sediment and absorb non-point source substances such as nitrogen and phosphorus.

In the present invention, a cascaded water storage system is arranged on the slope to store runoff on the slope and to redistribute water and fertilizer resources on the slope. The cascaded water storage system is connected by a plurality of reservoirs distributed from high to low and from top to bottom on the slope where the sloping cultivated land is located, and one of the reservoirs is set according to the confluence range of an average 20-50 mu of land , the reservoir is cylindrical, the radius of the pool mouth is 0.8-1.0m, and the depth is 1.5-3.0m. The inner wall and bottom of the reservoir are treated with anti-seepage. Gutter connected. As shown in Figure 5, the inlet of the reservoir is connected to the ecological grass ditch, the outlet is connected to the irrigation canal of the cultivated land below, and the different reservoirs are connected through the ecological ditch system.

In the present invention, a terminal purification system is set up to carry out ecological interception and purification of the water entering the river and storage. The terminal purification system is composed of a pretreatment unit and a main processing unit. The pretreatment unit is mainly a sediment deposition tank, An anaerobic digester; the main unit includes an artificial wetland and an ecological floating bed.

Preferably, the sediment deposition tank can be constructed according to the width of 2m, length of 3-5m, and depth of 1m. With filter material, the upper layer adopts large particle size stone filter material, and the lower layer adopts small particle size crushed sand filter material. The thickness ratio of the upper and lower layers is 2:1. The incoming water can enter the sedimentation tank through the upper part. After double-layer filtration, Excluded from below into the anaerobic digester.

Preferably, the anaerobic digestion tank is 2m wide, 3-5m long, and 0.5m deep, and the tank wall is treated with anti-seepage.

Preferably, the constructed wetland is composed of a constructed wetland with a width of 3m and a length of 20-50m. The constructed wetland is planted with wet herbs, and the plant species are composed of bermudagrass, reed, cattail, onion orchid, radix radix, etc. , according to equal proportion mixed planting (seed particle number ratio);

Preferably, the ecological floating bed is composed of floating islands and aquatic plants. The floating islands are wet floating islands with frames. The plants are selected from aquatic plants such as canna and cattail. The ecological floating beds are arranged between artificial wetlands At the junction of rivers or lakes, the ecological floating bed needs to be regularly maintained and managed, and aquatic plants can be harvested to reduce the total amount of non-point source pollution such as nitrogen and phosphorus entering the river water.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily imagined by those skilled in the art within the technical scope disclosed in the present invention, All should be covered within the protection scope of the present invention.

Claims (10)

1. A kind of 1. sloping upland agricultural non-point source pollution integrated control system, it is characterised in that：Including Soil Erosion Prevention and Cure system, ecology Sewerage, step water storage system and terminal purifying system, the Soil Erosion Prevention and Cure system include rill erosion control terraced bank, And the plant hedge that terraced bank is controlled in rill erosion is planted, the ecological canal system includes drain dyke, setting pot, the ladder Level water storage system includes the cistern for being distributed in different height, and the terminal purifying system includes sedimentation pond, anaerobic digestion Pond, artificial swamp and biological floating bed；The rill erosion control terraced bank be using rill erosion occur critical plane method as interval, Terraced bank is built along contour and formed on domatic；Described drain dyke is divided into two-stage, and wherein one-level drain dyke surface is laid Grass-planting brick, laid along domatic low-lying place perpendicular to domatic contour, two level drain dyke is laid along domatic contour, the one-level The setting pot that drain dyke and two level drain dyke are laid by centre is connected, and shape after hygrophyte is planted in one-level gutter Into ecological grass ditch；The cistern upper end is provided with the spillway being connected with gutter, the cistern entrance and ecological grass Ditch is connected, and exit is connected with lower section arable land Irrigation Ditch.
2. 2. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The rill erosion It is 10~20cm to control terraced bank width, is highly 15~20cm.
3. 3. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The plant hedge with Based on eurytopicity herbaceos perennial, species include day lily, honeysuckle and false indigo.
4. 4. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The one-level cuts row Ditch and the two level drain dyke are inverted trapezoidal, and described one-level drain dyke upper end width is 30~50cm, lower end width For 10~20cm, depth is more than 50cm；Described two level drain dyke upper end width is 10~20cm, depth 10-20cm.
5. 5. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The setting pot is Conical deceleration setting pot, upper end port radius 15-25cm, lower end port radius 5-10cm, depth 30-50cm, it is installed on and cuts draining On ditch path.
6. 6. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：Described humidogene is planted Thing is Chinese celery, wild water chestnut, water spinach, one kind in Bermuda grass or its combination.
7. 7. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The cistern is pressed 1 is set according to average 20~50 mu of ground scope of confluxing, the cistern is cylinder, and pond port radius are 0.8~1.0m, and depth is 1.5~3.0m.
8. 8. sloping upland agricultural non-point source pollution integrated control system as claimed in claim 1, it is characterised in that：The terminal purifying System is made up of pretreatment unit and main body processing unit two parts, and the pretreatment unit is mainly sedimentation pond, anaerobism Digester；The main unit includes artificial swamp and biological floating bed.
9. 9. a kind of arable land farming pollution of area source method for integrated control, it is characterised in that comprise the following steps：

   The critical plane method occurred using rill erosion is built terraced bank along contour on domatic, that is, forms rill erosion control as interval Terraced bank is made, controls planting plants hedge on terraced bank to form Soil Erosion Prevention and Cure system in the rill erosion；

   Bright ditch form is used on sloping upland, lays slope runoff outgoing route, drain dyke, setting pot and ecological grass are set Ditch, described drain dyke is divided into two-stage, wherein one-level drain dyke surface laying grass-planting brick, along domatic low-lying place perpendicular to slope Face contour is laid, and two level drain dyke is laid along domatic contour, and the one-level drain dyke passes through with two level drain dyke The setting pot connection that centre is laid, ecological grass ditch is formed after hygrophyte is planted in one-level gutter；

   Domatic upper setting step water storage system, the step water storage system by domatic where sloping upland from high to low, on to Multiple cisterns of lower distribution are formed by connecting, and the cistern upper end is provided with the spillway being connected with gutter, the water storage Pond entrance is connected with ecological grass ditch, and exit is connected with lower section arable land Irrigation Ditch；

   Terminal purifying system is set to include pretreatment to entering river, storage water quality progress ecological intercepting and purification, terminal purifying system Unit and main body processing unit, the pretreatment unit are mainly sedimentation pond, anaerobic digester, and the main unit includes Artificial swamp and biological floating bed.
10. 10. sloping upland agricultural non-point source pollution method for integrated control as claimed in claim 9, it is characterised in that：The plant hedge Based on eurytopicity herbaceos perennial, species include day lily, honeysuckle and false indigo.