CN102603071A - Construction method for nitrogen and phosphorus loss system of greenhouse soil of intercept river network area - Google Patents

Abstract

The invention relates to a construction method for a nitrogen and phosphorus loss system of greenhouse soil of an intercept river network area, which comprises the following steps that: an ecological canal is constructed on the earth surface of greenhouse soil, the ecological canal is formed by splicing pipes with U-shaped cross sections, the bottoms of the U-shaped pipes are poured with concrete, a side wall joint between every two U-shaped pipes is provided with a gap, and plants are planted in the gap; the bottom of the ecological canal is provided with a growth box, a growth medium is arranged in the growth box, plants are planted in the growth box, and the growth medium is coal cinder, detritus or ceramsite; the ecological canal is communicated with a water collecting tank, the water collecting tank is connected with a wetland rice field, two ends of the wetland rice field are provided with buffer zones, rice is planted in the middle zone between the buffer zones, and stored water flowing out from the water collecting tank flows into the wetland rice field through the buffer zone, and then flows out from the buffer zone at the other end of the wetland rice field. According to the invention, the load of nitrogen, phosphorus nutrient and other nutrient substances can be effectively reduced, the runoff load of the greenhouse soil is effectively reduced, and the problem of eutrophication of river network water near the greenhouse soil can be solved.

Description

Construction method of nitrogen and phosphorus loss system for intercepting water network area facility vegetable field

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technical field

The technology of the present invention belongs to the technical field of water supply and drainage of facility vegetable fields. It can carry out ecological ditch interception treatment for the runoff pollution of facility vegetable fields, and at the same time use the wetland paddy field system to absorb and reuse the surplus nutrients in the vegetable field drainage that has been intercepted by ecological ditch. In particular, it has a strong reduction effect on pollutants such as nitrogen and phosphorus.

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Background technique

Non-point source (also known as non-point source) pollution is a serious environmental problem that exists in the world today. Studies in developed countries such as the United States and the European Union have shown that agricultural activities are the largest source of non-point source pollution. In 1985, the United States conducted the most extensive survey of non-point source pollution so far. The survey results showed that among the rivers and lakes polluted by non-point sources, the contribution rates of agricultural non-point source pollution were 64% and 57%, respectively. The loss of N and P in farmland surface runoff is the main cause of eutrophication in surface water bodies. In the process of agricultural production, nutrient loss due to factors such as rainfall is inevitable, and surface runoff formed by rainfall is the main way for rivers and lakes to collect pollutants. one. Therefore, the bioabsorption, immobilization and recycling of nutrients lost in farmland has become an important content in the study of ecological environment.

In my country, there are mainly two types of drainage ditches for facility vegetable fields: soil ditches and concrete ditches. Due to the problems of soil erosion and overgrown weeds, soil ditches will pollute the receiving water body; the main problems of concrete ditches are that the water velocity is fast and it is difficult to settle the sediment in the drainage completely; the second is the lack of plants and Microorganisms cannot absorb, adsorb and degrade nitrogen and phosphorus in wastewater. For farmland runoff, there is currently an ecological ditch interception technology that can effectively intercept nitrogen and phosphorus in farmland drainage, but there is no such technology for the control of runoff pollution from facility vegetable fields. Surface runoff is one of the main ways for non-point source pollution to export nitrogen and phosphorus to water bodies. The existing control technology for vegetable runoff mainly includes ecological grass belt interception technology, which can effectively absorb and intercept the nitrogen and phosphorus from vegetable surface runoff and underground runoff. Nitrogen and phosphorus nutrients (Li Guodong, 2006), but the ecological grass belt is difficult to promote on a large scale because it occupies a certain area of cultivated land. At the same time, there are disadvantages such as poor interception effect and low nutrient reuse rate under the condition of moderate rainfall and above. Seasonal differences in growth, vegetation withers and rots in its withering season, and the release of nutrients contained in itself increases the load of lost nutrients.

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Contents of the invention

Technical problem to be solved: The purpose of this invention is to provide a construction method for intercepting the loss of nitrogen and phosphorus in the vegetable field in the water network area, which mainly solves the runoff pollution of the vegetable field in the water network area.

Technical solutions:

A method for constructing a system for intercepting nitrogen and phosphorus loss in a facility vegetable field in a water network area. The steps include: constructing an ecological ditch on the surface of the facility vegetable field. Concrete pouring, there is a gap at the side wall connection between every two "U"-shaped pipes, and plants are planted in the gap; a growth box is set at the bottom of the ecological ditch, and the growth medium is installed in the growth box and plants are planted. The growth medium is cinder, crushed stone or ceramsite; the ecological ditch is connected to the sump, and the sump is connected to the wetland paddy field. The stored water flowing out of the pool flows into the wetland paddy field through the buffer zone, and then flows out from the buffer zone at the other end of the wetland paddy field.

The middle junction of the above-mentioned "U"-shaped pipe is left open with a width of 30 cm.

The plant planted on the side wall of the ecological ditch is Bermudagrass, and the plant planted in the growth box is the nitrogen-efficient rice Guidan No. 4.

The arrangement pitch of the above-mentioned growth boxes is 80 cm.

The above-mentioned "U" shaped pipeline is formed by pouring cement.

A lifting pump is arranged in the above sump, and the stored water flows into the wetland paddy field through the lifting pump.

The outer wall of the growth box is covered with holes.

Beneficial effects: the invention can effectively reduce the load of nutrients such as nitrogen and phosphorus, effectively reduce the runoff load of the facility vegetable field, and can solve the eutrophication problem of the river network water body near the facility vegetable field. Utilize the method for intercepting the nitrogen and phosphorus loss ecological ditch in the facility vegetable field provided by the present invention and the wetland paddy field coupling interception method, one can effectively intercept the nitrogen and phosphorus in the runoff of the facility vegetable field, and the interception rate reaches more than 80% and 85% respectively; First, it can reduce 20%~30% nitrogen fertilizer input in wetland rice fields, and has no effect on yield; third, it can make full use of the original farmland drainage ditches, which solves the problem of ecological engineering occupying more cultivated land; fourth, planting plants on both walls of ecological ditches is easier It is convenient and has a high survival rate; fifthly, the construction cost and maintenance cost are low, the operation and maintenance are simple, and it is convenient for large-scale promotion and application.

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Description of drawings

Figure 1 is a schematic diagram of the overall structure and water flow direction of the ecological ditch for nitrogen and phosphorus loss in the facility vegetable field and the wetland rice field coupling interception system in the water network area;

Figure 2 is a schematic diagram of the cross-section of the ecological ditch;

Figure 3 is a schematic diagram of the ecological ditch structure

Fig. 4 is the schematic diagram of the side wall and bottom structure of ecological ditch;

Fig. 5 is a schematic diagram of an ecological ditch growth box and its arrangement at the bottom of the ditch;

Fig. 6 is a schematic diagram of the structure of the sump;

Figure 7 is a schematic diagram of the wetland paddy field structure.

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Detailed ways

In order to describe the technology of the present invention in more detail, it is illustrated below in conjunction with the implementation examples:

Embodiment 1 :

The Taihu Lake Basin covers an area of 36 900 square kilometers, mainly plains, accounting for 4/6 of the total area, water surface accounts for 1/6, and the rest is hills and mountains. The project demonstration area is located in Binhu District, Wuxi City. With the adjustment of the agricultural structure, facility cultivation, especially greenhouse vegetable cultivation area has been expanding, and greenhouse vegetable production has become one of the important components of local agricultural production. For the Taihu Lake area, most of the protected vegetables are replanted from rice fields, and the coexistence of rice fields and vegetable fields in the same area is common. The Taihu Lake area is densely covered with river networks, and many facility vegetable fields are adjacent to water bodies. Fertilizers easily enter the water bodies through runoff under the erosion of rainwater. Therefore, nitrogen and phosphorus runoff from vegetable fields is an important source of pollution. Rainfall in the Taihu Lake area is mainly concentrated in spring and summer, which are also the periods of frequent fertilization of vegetables, and the protected vegetable fields are in the period of uncovering the sheds in summer, so the runoff of the protected vegetable fields in summer is the main part of the annual runoff.

The implementation of the project is carried out in Longyan Village, Hudai Town, Binhu District, Wuxi City. Design description of the coupling interception technology of ecological ditches and wetland paddy fields for nitrogen and phosphorus loss in the water network area:

Referring to Figure 1, it is a schematic diagram of the overall structure and water flow direction of the ecological ditch for the loss of nitrogen and phosphorus in the vegetable field of the water network area and the coupling interception system of the wetland paddy field. The runoff from the original facility vegetable field is transformed into the river after being intercepted and treated by the ecological ditch, and then the water stored in the sump is pumped into the wetland paddy field through the lift pump, and then discharged into the river after being absorbed and reused by the paddy field.

Referring to Fig. 2, it is a schematic diagram of a cross-section of an ecological interception ditch. Place a U-shaped cement pipe with length × width × height = 40 × 50 × 60 (cm) every 30 cm in the original farmland soil drainage ditch, and transform it into a U-shaped concrete ditch in cross section.

Referring to Fig. 3, it is a schematic diagram of the structure of an ecological interception ditch. The bottom 3 of every two U-shaped pipe joints is connected by pouring cement, and a plurality of 30 cm wide empty intermediate joints 4 are distributed on the two side walls 1 of the ditch.

Referring to FIG. 4 , it is a schematic diagram of the side wall and bottom structure of an ecological interception ditch. It can be seen from FIG. 4 that a number of empty intermediate joints 4 are provided on the side wall 1 . Bermudagrass 5 with strong absorption capacity for nitrogen and phosphorus is planted in the empty middle joint part 4 of the side wall 1 .

With reference to Fig. 5, it is the schematic diagram of the growth box and its arrangement at the bottom of the ditch, the growth box 6 placed every 80 cm is arranged at the bottom 2 of the ditch with intervals, the outer wall of the growth box 6 is covered with holes 7, and the growth box 6 is full of holes 7. The box 6 is filled with an adsorption material with strong adsorption capacity for nitrogen and phosphorus, and nitrogen-efficient rice Guidan No. 4 No. 8 is planted in the growth box.

Referring to FIG. 6 , it is a schematic diagram of a sump. After being intercepted by an ecological ditch, the vegetable field drains into the sump 9 , and the water stored in the sump is pumped into the wetland paddy field through a lift pump 10 .

Referring to Figure 7, it is a schematic diagram of a wetland paddy field. The water storage in the sump is pumped into the buffer zone 11 of the wetland paddy field through the lift pump 10, and evenly flows into the paddy field 12 through the buffer zone, and the surplus nutrients are absorbed and utilized by the rice and pass through the buffer zone 13 into the river.

This project was constructed in May 2010 and started operation in June 2010. Using the ecological ditch for the loss of nitrogen and phosphorus in the water network area facilities and vegetable fields provided by the present invention and the wetland paddy field coupling interception method, the whole rice growing season (June 2010) 20th to November 5th, 2010) can effectively intercept the discharge of nitrogen and phosphorus from the vegetable field runoff in the project demonstration area. The present invention reduces 15 kg/hm ² of nitrate nitrogen, 16.81 kg/hm ² of total nitrogen, and 0.16 kg/hm ² of total phosphorus in runoff discharge from facility vegetable fields in the demonstration area, and reduces TN and TP by 87% and 89% respectively. %. In addition, the average concentration of TN and TP in the runoff discharge from vegetable fields during rainfall (30 min) can be reduced from 11.31 mg/L and 0.05 mg/L to 2.59 mg/L and 0.04 mg/L respectively, and the average resistance control rate reaches After the rainfall, the average concentration of TN and TP decreased from 12.38 mg/L and 0.06 mg/L to 2.9 mg/L and 0.03 mg/L respectively, and the average resistance and control rate reached 81% and 64%. Compared with the local recommended fertilization rate, wetland paddy field can reduce nitrogen fertilizer input by 20%, and has no effect on yield. The invention can effectively improve the nutrient reutilization rate, make full use of the original soil drainage ditches, and solve the problem that more cultivated land is occupied by ecological projects. Compared with the prefabricated slab in the ecological ditch, the use of U-shaped cement pipe has the advantages of low cost, convenient planting of ditch wall plants and high survival rate. The invention has the characteristics of good pollution control effect, low engineering cost and maintenance cost, simple operation and maintenance, and easy popularization and application in a large area.

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Example 2

The construction method of intercepting the nitrogen and phosphorus loss system of the facility vegetable field in the water network area: introduce the runoff of the facility vegetable field into the ecological ditch, absorb the nitrogen and phosphorus in the runoff through the ecological ditch, reduce the water speed, and settle the sediment; the cross section of the ditch is U-shaped , The ditch is composed of a plurality of U-shaped cement pipes arranged in length × width × height = 40 × 50 × 60 (cm), and the bottom of the middle junction of every two U-shaped pipes is connected by cement pouring, and the side wall is left with a 30cm wide soil At the bottom of the ditch, a growth box filled with adsorption materials with strong adsorption capacity for nitrogen and phosphorus is placed at a distance of 80 cm. Bermudagrass and nitrogen-efficient rice Guidan No. 4; the drainage of the treated vegetable field is intercepted by the ecological ditch and then poured into the sump, and the water in the sump is pumped into the wetland paddy field for absorption and reuse through pump lifting. Absorb and reuse surplus nutrients to improve nutrient reutilization rate. Its flow direction is referring to accompanying drawing 1. The growth box is a box whose outer wall is covered with holes and is filled with adsorption materials with strong adsorption capacity for nitrogen and phosphorus, and nitrogen-efficient rice Guidan 4 with strong absorption capacity for nitrogen and phosphorus is planted in the growth box. Number.

The basic technology and working principle of the nitrogen and phosphorus loss ecological ditch and wetland paddy field coupling interception system in the water network area: the process route is as follows: runoff from the facility vegetable field - ecological ditch - catchment pond - wetland paddy field - river. Working principle: plants that absorb nitrogen and phosphorus efficiently are planted in the ditch wall and ditch bottom growth box in the ecological ditch, and the growth medium in the growth box is cinder, gravel, ceramsite, etc.; the collection pool collects the vegetable field intercepted by the ecological ditch Drainage: reduce the input of nitrogen fertilizer in wetland paddy fields, and replenish nutrients through the water storage in the irrigation sump.

Claims (7)

1. The construction method of intercepting the nitrogen and phosphorus loss system of the facility vegetable field in the water network area is characterized in that the steps are: constructing an ecological ditch on the surface of the facility vegetable field, and the ecological ditch is spliced by "U"-shaped pipelines in cross section, The bottom between every two "U"-shaped pipes is connected by cement pouring, and there are gaps at the joints of the side walls on both sides, and plants are planted in the gaps; a growth box is installed at the bottom of the ecological ditch, and the growth box is filled with growth media and planted. Plants, the growth medium is cinder, gravel or ceramsite; the ecological ditch is connected to the sump, and the sump is connected to the wetland paddy field. The two ends of the wetland paddy field are buffer zones, and the middle zone between the buffer zone is planted For rice, the water storage flowing out from the sump flows into the wetland paddy field through the buffer zone, and then flows out from the buffer zone at the other end of the wetland paddy field. 2. The construction method of the nitrogen and phosphorus loss system for intercepting water network area facilities and vegetable fields according to claim 1, characterized in that the middle junction of the "U"-shaped pipe has a width of 30 cm. 3. The construction method of the nitrogen and phosphorus loss system of intercepting water network area facility vegetable field according to claim 1, it is characterized in that the plant planted on the side wall of the ecological ditch is Bermudagrass, and the plant planted in the growth box is nitrogen efficient rice Guidan No. 4. 4. The construction method of the nitrogen and phosphorus loss system of intercepting water network area facility vegetable field according to claim 1, characterized in that the arrangement spacing of the growth boxes is 80 cm. 5. The construction method of the nitrogen and phosphorus loss system for intercepting water network area facilities and vegetable fields according to claim 1, characterized in that the bottom of the "U"-shaped pipeline is made of cement. 6. The construction method of the system for intercepting the loss of nitrogen and phosphorus in vegetable fields in the water network area according to claim 1, characterized in that a lift pump is installed in the sump, and the stored water flows into the wetland paddy field through the lift pump. 7. The construction method of the nitrogen and phosphorus loss system for intercepting water network area facility vegetable fields according to claim 1, characterized in that the outer wall of the growth box is covered with holes.

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