Constructed wetland water cycle saline-alkali soil leaching and breeding system and operation method thereof

Abstract

The application provides a kind of artificial wetland water circulation saline-alkali soil leaching and breeding system and its operating method, including the farmland soil leaching unit, leaching liquid processing unit and reed-fish-crab breeding unit connected in turn.The leaching inlet channel of farmland soil leaching unit inputs farmland leaching freshwater, and the soil salinity is reduced by using the circulating water level leaching method, and the high salinity soil leaching liquid is collected and input into the leaching liquid processing unit through the leaching drainage channel, and the salt reduction treatment is carried out by flowing through the salt reduction plant planting area, and the obtained low salinity effluent is used as the breeding water in the reed-fish-crab breeding unit.The final effluent of the breeding unit is used as the source of farmland leaching water or irrigation water, and the sediment is used as farmland fertilizer, realizing the recycling of water resources and the reuse of internal resources of the system, and the plant bodies, fish and crabs finally harvested by the system can be used as economic output, so that the system becomes a new type of ecological agricultural system considering saline-alkali soil treatment and resource recycling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of saline-alkali soil treatment, water and energy saving, and ecological and cyclic agriculture, and particularly relates to a system for leaching saline-alkali soil and aquaculture in artificial wetland water circulation and a running method thereof. BACKGROUND

[0002] Soil salinization is one of the main types of soil and land degradation, which is usually caused by the accumulation of soil soluble salts in the surface layer due to high groundwater level. Saline-alkali soil refers to soil with a salt content of more than 0.3%, which leads to a decrease in organic matter content, poor nutrient conditions, destruction of physical structure, and inhibition of microbial activity, and thus causes poor vegetation growth, especially low crop yield or no growth. As can be seen, soil salinization will cause damage to the ecosystem and resources and huge losses in agricultural production. A large number of studies have been carried out on the treatment methods for saline-alkali soil at home and abroad, and the results mainly focus on biological measures, chemical measures, and physical measures, including afforestation of saline-alkali soil, cultivation of salt-tolerant plants and microorganisms, design of soil conditioners, change of tillage methods, use of guest soil to press alkali, and use of water conservancy projects to drain salt, etc. At present, the treatment of saline-alkali soil mainly follows the principle of "salt comes with water and salt goes with water", and simple water conservancy facilities and irrigation measures are used to treat the problem of soil salinization. The main technologies include building terrace method, fresh water soaking field to press salt alkali method, well irrigation and well drainage method, underground pipe drainage method, agricultural biological method, and chemical method, etc. Although irrigation and salt washing are considered to be a first way and an effective measure for soil improvement and utilization, and an effective means for the improvement of heavy saline-alkali soil, the use of this method to reduce salt is prone to soil salt rebound, which requires long-term and continuous investment of a large amount of fresh water resources. At the same time, the discharge of leaching liquid containing high salinity produced in the process of irrigation and salt washing will cause damage to the water-salt balance of local water system, which is not an ideal method for the treatment of saline-alkali soil in water-deficient saline-alkali areas.

[0003] Therefore, how to collect, process and reduce the salinity of leaching water on the basis of the existing irrigation and salt washing technology, improve the reuse rate of limited fresh water resources, and improve the ecological and environmental performance of the treatment technology to achieve the win-win of saline-alkali land treatment, ecological and economic benefits is the difficulty and breakthrough of the current saline-alkali treatment. SUMMARY

[0004] The present application aims to provide a system for leaching saline-alkali soil and aquaculture in artificial wetland water circulation and a running method thereof, so as to solve the problems of water resource waste, secondary pollution caused by leaching liquid discharge, and secondary salinization in the current irrigation and salt washing method for saline-alkali land treatment, and to improve the resource recycling rate and economic income.

[0005] In order to solve the above-mentioned problems and achieve the above-mentioned intended purposes, the present application adopts the following technical solutions:

[0006] The artificial wetland water circulation saline soil leaching and breeding system comprises a farmland soil leaching unit, a leaching liquid treatment unit and a reed-fish-crab breeding unit connected in sequence.

[0007] The farmland soil leaching unit comprises a leaching water channel and a crop planting area, wherein the leaching water channel surrounds the crop planting area, and the leaching water channel comprises a leaching water inlet channel, a water storage channel and a leaching water outlet channel.

[0008] The leaching liquid treatment unit comprises a leaching liquid water channel and a salt-reducing plant planting area, wherein the leaching liquid water channel comprises a leaching liquid inlet channel and a leaching liquid outlet channel arranged at two ends of the leaching liquid treatment unit.

[0009] The reed-fish-crab breeding unit comprises a breeding system, a reed planting area and an anti-escape facility, wherein the breeding system comprises a ring ditch and a crab channel.

[0010] Further, the farmland soil leaching unit comprises a plurality of crop planting areas, and a plurality of water storage channels are arranged between the leaching water inlet channel and the leaching water outlet channel.

[0011] In the leaching liquid treatment unit, a ditch and a protection wall are arranged around the salt-reducing plant planting area.

[0012] In the reed-fish-crab breeding unit, a ring ditch is arranged around the reed planting area, and the reed planting area is divided into a plurality of pieces by a crab channel. 2The anti-escape facilities include: anti-escape nets composed of wooden stakes, wire mesh and film, specifically, a circle of wooden stakes is punched at 1m to 2m outside the ring ditch, the lower end of the wooden stakes is buried in the soil about 20cm, and the wire mesh and film are pulled between the wooden stakes; all water inlets and drainage outlets are intercepted by polyethylene mesh.

[0013] The operation method of the above-mentioned saline-alkali soil leaching and breeding system of the water cycle of the constructed wetland is arranged between crop planting areas, and comprises the following steps:

[0014] The leaching inlet channel of the farmland soil leaching unit inputs farmland leaching fresh water, the cyclic water level leaching method is used to reduce the soil salinity, the high salinity soil leaching liquid is collected and input into the leaching liquid treatment unit through the leaching drainage channel, flows through the salt reduction plant planting area for salt reduction treatment, and the obtained low salinity effluent is input into the reed-fish-crab breeding unit as breeding water.

[0015] The farmland soil leaching unit drainage enters the leaching liquid treatment unit to enter the salt reduction treatment process. Meanwhile, the low concentration effluent output from the leaching liquid treatment unit is used as breeding water of the reed-fish-crab breeding unit, and the final effluent of the reed-fish-crab breeding unit is used as leaching water or irrigation water of the farmland soil leaching unit, so that the recycling of water resources in the system is realized.

[0016] The farmland soil leaching unit adopts the cyclic leaching water level method to leach the soil, that is, the leaching water level in the water storage ditch is changed within a certain range every certain period of time, the leaching water is the effluent of the reed-fish-crab breeding unit, natural rainfall, local river fresh water or other types of water bodies in the local area can also be used as leaching water, and the leaching time is recommended according to the rainfall and crop planting rules of the application area.

[0017] In the leaching liquid treatment unit, the plants can be appropriately maintained at a certain waterlogging level according to the salt reduction plant life habit and salt reduction load, the salinity of the water body is measured regularly by using a salinity meter, and drainage and water replenishment are timely performed.

[0018] The final effluent of the reed-fish-crab breeding unit represents the effluent after the reed purification treatment for a period of time after the fish and crabs are harvested and the sediment is collected.

[0019] The sediment of the reed-fish-crab breeding unit is returned to the field as fertilizer after collection, so that the resources in the system are repeatedly used.

[0020] The present application has the following benefits:

[0021] (1) reducing the soil salinity of farmland and improving the yield of crops;

[0022] (2) Collecting soil leaching solution to prevent its pollution to local natural water system, using the salt reduction ability of salt reduction plants to carry out preliminary treatment and use as aquaculture water, broadening the use of water resources, and using the treatment ability of reed to make aquaculture wastewater become farmland leaching water or irrigation water source, realizing the recycling of water resources;

[0023] (3) Reed as a food source for fish and crabs in the aquaculture unit, reducing external input during aquaculture, and the sludge produced during aquaculture returning to the farmland unit as fertilizer, realizing the reuse of internal resources in the system;

[0024] (4) The final output of the whole system includes not only crops, but also the aboveground parts of salt reduction plants, reeds and fish and crabs, greatly improving the income of farmers and promoting the development of regional agricultural economy. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a top view of the system model of the application.

[0026] Figure 2 It is a side view of the water storage ditch and channel of the farmland soil leaching unit of the application.

[0027] Figure 3 It is a cross-sectional view of the water storage ditch and channel of the farmland soil leaching unit of the application.

[0028] Figure 4 It is a side view of the leaching solution treatment unit of the application.

[0029] Figure 5 It is a side view of the reed-fish-crab aquaculture unit of the application. DETAILED DESCRIPTION

[0030] In order to make the system construction, unit structure and operation process of the application clearer, the application will be described in more detail in combination with the drawings and examples. It should be clarified that the specific examples given here are only used to better explain the application and do not limit the application.

[0031] Referring to the drawings, one embodiment of the application is:

[0032] A kind of artificial wetland water cycle salt alkali soil leaching and aquaculture system applied to coastal saline-alkali area of Yellow River Delta, as shown in Fig. Figure 1 It includes farmland soil leaching unit 1, leaching solution treatment unit 2 and reed-fish-crab aquaculture unit 3, farmland soil leaching unit 1 includes leaching waterway and crop planting area 11, wherein the leaching waterway is divided into leaching inlet channel 12, water storage ditch 14 and leaching outlet channel 13;

[0033] The leaching solution treatment unit 2 comprises a leaching solution water channel, a salt-reducing plant planting area 21 and a protective wall, wherein the leaching solution water channel is further divided into a leaching solution inlet channel 22 and a leaching solution outlet channel 23.

[0034] The reed-fish-crab breeding unit 3 comprises a breeding system, a reed planting area 31, an anti-escape net 34 and other anti-escape measures, wherein the breeding system further comprises a ring ditch 32 and a crab path 33.

[0035] As shown in Figure 1 The leaching inlet channel 12 and the leaching outlet channel 13 of the farmland soil leaching unit 1 are excavated along the horizontal longitudinal direction of the farmland with a width of 0.5 m and a depth of 0.5 m, and the water storage ditch 14 is excavated along the horizontal transverse direction of the farmland to connect the leaching inlet channel 12 and the leaching outlet channel 13. The water storage ditches 14 are arranged alternately with the crop planting area 11, and adjacent water storage ditches 14 are spaced apart by 1.0 m.

[0036] As shown in Figure 2 The farmland of the farmland soil leaching unit 1 has a certain slope, so that water can flow naturally from the leaching inlet channel 12 to the leaching outlet channel 13 through the water storage ditches 14 by gravity.

[0037] As shown in Figure 3 The water storage ditches 14 of the farmland soil leaching unit 1 have a width of 0.5 m at the top, a width of 0.2 m at the bottom, and a depth of 0.5 m, and each planting area has a width of 1.0 m.

[0038] The farmland soil leaching unit 1 uses the circulating leaching water level method for soil leaching, that is, water level markers are set at a distance of 0.2 m and 0.35 m from the ground of the water storage ditches 14, and the water level is controlled to change regularly between 35-50 cm, 20-35 cm and 0-20 cm during leaching, so as to promote the transfer of soil surface salinity to the deep layer and make the crop root system away from the harm of salinization.

[0039] Further, considering the rainfall and crop planting rules in the Yellow River Delta, the leaching time is determined as the interval time after the harvest of the previous year's crops and before the sowing of the next round of crops (usually in June-September), and the leaching water is natural rainfall, Yellow River water and water from the reed-fish-crab breeding unit 3.

[0040] As shown in Figure 1 The leaching solution treatment unit 2 selects Spartina alterniflora as the salt-reducing plant and plants it at a density of 5-6 plants / m 2 The leaching solution treatment unit 2 selects Spartina alterniflora as the salt-reducing plant and plants it at a density of 5-6 plants / m

[0041] Further, referring to Figure 4As shown, the leaching solution treatment unit 2 has a leaching solution channel 0.8m deep, a cross-section 1.0m wide at the top and 0.3m wide at the bottom, and an outer slope of approximately 63.4° and an inner slope of approximately 59.0°. The water level of the plants in the unit is maintained at approximately 0.2m (<0.3m). Cement is poured on the outer wall of the channel to build a protective wall, using the methods of flooding and cement hardening to prevent Spartina alterniflora from invading the environment outside the system.

[0042] Spartina alterniflora is harvested before August each year to prevent it from entering the sexual reproduction stage and spreading its seeds to invade farmland. The harvested Spartina alterniflora above-ground parts are sold to feed mills as raw materials.

[0043] refer to Figure 1 As shown, the reed-fish-crab farming unit 3, the reed planting area 31, is surrounded by a 2.5m wide ring ditch 32, and consists of several 5m square unit plots separated by crab paths 33, each 2m wide. The initial reed planting density is 10-20 plants / m². 2 .

[0044] refer to Figure 5 As shown, the reed-fish-crab farming unit 3 has a crisscross crab passage 33 with a depth of 0.6m and a ring ditch 32 with a depth of 1.2m. The escape-proof net 34 is set by driving wooden stakes around the ring ditch 32 1m outside the ring ditch 32, with the lower end of the wooden stakes buried in the soil for about 20cm. Wire mesh and film are then strung up. At the same time, polyethylene mesh is used to intercept the water inlet and outlet of the unit.

[0045] Silver carp or bighead carp were selected as the fish species for farming, and river crabs were selected as the crab species for farming. Fish and crab fry were released from late March to early April. The size of the juvenile crabs was 120-200 crabs / kg, and the release rate was 1.5kg / mu. The stocking density of fish fry was 1000-1500 fish / mu. Before the release, the unit needed to be circulated with low salinity effluent from the leaching solution treatment unit 2. The water was further treated with reeds to a salinity suitable for farming. At the same time, 15-20 days before the release of the fry, 100-150kg / mu of quicklime was dissolved in water and sprinkled for disinfection.

[0046] The water level at different times in the unit was determined (see Table 1). Fish and crabs were harvested in September of the year following the stocking. After the harvest, the silt in the unit was cleaned and put into the farmland system for fertilization. The entire aquaculture farm was dried in preparation for the next stocking.

[0047] Table 1. Monthly Water Levels of the Reed-Fish-Crab System

[0048]

[0049] Although the application is described in detail by taking the Yellow River Delta coastal saline-alkali area as an application example, the application can be applied to any other area endangered by salinization, and the person skilled in the art can set or modify the parameters in the application according to the characteristics of the area and the specific conditions of the farmland, which will fall within the scope of the principles disclosed in the application. Further, the parameters, layout and species selection of the components in the system can be changed and improved within the scope of the disclosure, drawings and claims of the application to better play the role of the application in the aspects of saline-alkali soil treatment, water and energy saving and ecological agriculture development.

Claims

1. An artificial wetland water cycle system for saline-alkali soil leaching and aquaculture, characterized by: It includes a farmland soil leaching unit (1), a leaching solution treatment unit (2), and a reed-fish-crab aquaculture unit (3) connected in sequence. The farmland soil leaching unit (1) includes leaching waterways and multiple crop planting areas (11). The leaching waterways surround the crop planting areas (11). The leaching waterways include leaching inlet channels (12), water storage ditches (14), and leaching drainage channels (13). Multiple water storage ditches (14) are provided between the leaching inlet channels (12) and the leaching drainage ditches (13). The water storage ditches (14) and the crop planting areas (11) are arranged alternately. The leaching inlet channels (12) and the leaching drainage ditches (13) are located at both ends of the farmland soil leaching unit (1). The leaching inlet channels (12) and the leaching drainage ditches (13) are connected by water storage ditches (14). The leaching inlet channels (12) serve as the input end of farmland leaching fresh water, while the leaching drainage ditches (13) serve as the collection and discharge end of soil leaching liquid. The leaching solution treatment unit (2) includes a leaching solution channel and a salt-reducing plant planting area (21). The leaching solution channel includes a leaching solution inlet channel (22) and a leaching solution outlet channel (23) located at both ends of the leaching solution treatment unit (2). The leaching solution inlet channel (22) is connected to the leaching drainage channel (13) of the farmland soil leaching unit (1). Ditches and protective walls are set up around the salt-reducing plant planting area (21), and Spartina alterniflora is used as a salt-reducing plant. The reed-fish-crab farming unit (3) includes a farming system, a reed planting area (31), and escape prevention facilities. The farming system includes a ring ditch (32) and a crab passage (33). The farmland soil leaching unit (1) inputs farmland leaching fresh water into the leaching inlet channel (12), and uses a circulating water level leaching method to reduce soil salinity. The high salinity soil leaching liquid is collected and input into the leaching liquid treatment unit (2) through the leaching drainage channel (13), flows through the salt-reducing plant planting area (21) for salt reduction treatment, and the resulting low salinity water is then introduced into the reed-fish-crab aquaculture unit (3) as aquaculture water. The circulating water level rinsing method refers to changing the rinsing water level in the water storage ditch (14) within a certain range at regular intervals during rinsing; the rinsing water includes the effluent from the reed-fish-crab farming unit (3), natural rainfall, and external water sources.

2. The artificial wetland water cycle system for saline-alkali soil leaching and aquaculture according to claim 1, characterized in that: The crop planting area (11) has a slope, the rinsing inlet channel (12) is set at the top of the slope, the rinsing outlet channel (13) is set at the bottom of the slope, and is set horizontally along the crop planting area (11); the water storage ditch (14) has a cross-section that is wider at the top and narrower at the bottom, and is set horizontally along the crop planting area (11).

3. The artificial wetland water cycle system for saline-alkali soil leaching and aquaculture according to claim 1, characterized in that: The salt-reducing plant planting area (21) is surrounded by trapezoidal ditches with a cross-section that is wider at the top and narrower at the bottom.

4. The artificial wetland water cycle system for saline-alkali soil leaching and aquaculture according to claim 1, characterized in that: In the reed-fish-crab farming unit (3), a ring ditch (32) is provided around the reed planting area (31). The reed planting area (31) is divided into multiple sections by the crab passage (33). The crab passage (33) and the reed planting area (31) serve as crab activity areas at the same time. The ring ditch (32) is used for fish farming.

5. The artificial wetland water cycle system for saline-alkali soil leaching and aquaculture according to claim 1 or 4, characterized in that: The initial planting density in the reed planting area (31) is 10-20 plants / m². 2 .

6. The artificial wetland water cycle system for saline-alkali soil leaching and aquaculture according to claim 1 or 4, characterized in that: The crab passage (33) is connected to the ring ditch (32).

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