Method for constructing riparian buffer zone in cold region for controlling agricultural non-point source pollution

Abstract

The present disclosure is applicable to the technical field of ecological engineering and provides a method for constructing a riparian buffer zone in a cold region for controlling agricultural non-po

Description

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[0001] The present disclosure belongs to the technical field of ecological engineering, and in particular to a method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution. BACKGROUND

[0002] Agricultural area in North China belongs to arid and semi-arid climate, with less precipitation, long freezing and thawing period in winter and poor self-purification ability of water bodies. In addition, serious rural non-point source pollution, high development and utilization intensity of riparian zone, short route of pollutants entering the river, intensified ecological damage and water and soil loss, seriously damaged natural vegetation in riparian zone and poor pollution interception ability lead to outstanding water environment pollution problem. Ecological buffer zone, as a special land-water ecotone, has ecological functions such as revetment, non-point source pollution filtering, corridor and habitat, material production and landscape entertainment. Vegetation of riparian zone can effectively remove agricultural non-point source pollutants, and can intercept pollutants carried by surface runoff through the filtration, infiltration, absorption, retention and deposition of composite system of the water, soil and plant in the riparian zone, so as to remove non-point source nutrients.

[0003] In recent years, riparian ecological governance methods of constructing buffer zones on the river bank have appeared one after another. These methods can be roughly divided into three categories: the first type is to construct a riparian zone combined with plant cultivation through an engineering method to prevent water and soil loss, and stabilize and protect shore, such as providing a partition in a riparian area and filling the riparian area with gravel, shale and ceramsite, and planting herbaceous plants such as Phragmites australis and Typha orientalis on the upper layer in a mixed manner, for another example, protecting dike using dry masonry and stone piling, stabilizing riverbed by measures such as using woodpiles, stones and woven fabrics filled with concrete, and then planting herbaceous plants or planting woody and herbaceous plants on the riverbed in a mixed manner. All the above schemes will greatly change the original soil layer structure of the riparian zone, destroy the riparian zone structure, break the balance of the original soil microbial community and take a long time to restore the ecosystem. In serious 17 04 24 cases, the riparian ecosystem will be destroyed, greatly affecting the pollution interception effect. The second type is to purify pollutants entering the river by applying certain materials and substances, thus preventing water pollution, such as controlling non-point source pollution using biochar materials. The third type is to construct a near-natural riparian buffer zone. Through the collocation of trees, shrubs and herbaceous plants, the biodiversity and biomass of the riparian zone are improved, the ability of water and soil loss control is enhanced, and the landscape of the riparian zone is improved. In the prior art, there are many researches on the pollutant purification function of aquatic plants, but there are relatively few researches on terrestrial plants. The construction of buffer zone mostly aims at landscape construction and biomass enhancement, but less at agricultural non-point source pollution control. The North China is long and cold in winter, and a large number of non-point source pollutants on both sides of the river bank enter the river with melting snow in spring. The existing technology does not take into account the influence of freezing and thawing on pollutant interception effect in the cold region in North China, and lacks the technology of applying cold-resistant and cold-tolerant plants to achieve buffer zone interception. In the prior art, microbial inoculum technology is seldom used to improve the effect of pollutant interception and control. In conclusion, there is still a lack of a riparian buffer zone construction technology which is suitable for the cold region in North China and has good agricultural non-point source pollutant control effect. SUMMARY

[0004] An objective of the present disclosure is to provide a method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution, aiming at solving the problem in the background art.

[0005] To achieve the objective above, the present disclosure employs the following technical solution:

[0006] A method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution includes the following steps:

[0007] Step one: trimming a river riparian zone;

[0008] Step two: planting trees, shrubs and herbaceous plants in the river riparian zone in sequence;

[0009] Step three: applying AMF (Arbuscular mycorrhizal fungi) inoculant at a gradual freezing period and a spring thawing period; and

[0010] Step four: carrying out daily maintenance and management on an ecological buffer zone.

[0011] Further, in Step one, an area in the range of 15-30 m from a normal water line of a river 17 04 24 reach in an agricultural region in North China faces to a land area is selected as a construction area of the riparian ecological buffer zone.

[0012] Further, a smooth slope of the construction area is adjusted into a flat slope with a slope of 15-25°.

[0013] Further, in Step two, the tree species is selected from one or more of Salix matsudana and Primus padus. The shrub is selected from one or more of Amorpha fruticosa, Spiraea salicifolia, Primus triloba, and Cornus alba, and the herbaceous plant is selected from one or more of Medicago sativa, Trifolium repens, and Festuca elata.

[0014] Further, in Step two, according to a distance from far to near of the river normal water level, a tree area, a shrub area and a herbaceous plant area are arranged in turn from far to near. The distance from the tree area to the river normal water level is 10-15 m, the distance from the shrub area to the river normal water level is 5-10 m, and the distance from the herbaceous plant area to the river normal water level is 0-5 m. The height of tree species gradually increases from near to far of the river normal water level, the herbaceous plants are planted by sowing, and woody plants employ measures of planting purchased seedings.

[0015] Further, in Step three, an application amount of the AMF inoculant is 100-200 g / m2.

[0016] Further, in Step four, watering, weeds removal and pest control are carried out in due time according to a growth status of plants in the buffer zone.

[0017] Compared with the prior art, the present disclosure has beneficial effects as follows:

[0018] According to the method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution, a vegetation coverage of the constructed riparian ecological zone is increased to 95% and more. The water and soil loss in the riparian zone area is effectively prevented, the soil and water conservation capacity of the riparian zone is improved, and the soil erosion is effectively prevented. The interception effect of the non-point source pollution is good, and the load of pollutants such as TN (total nitrogen) and TP (total phosphorous) is reduced by more than 50%. The eutrophication of water bodies is effectively prevented, and the landscape ornamental appreciation is achieved. The biodiversity in the riparian zone is significantly improved, which is beneficial to form a stable plant community. The riparian buffer zone has good stress resistance, is suitable for the prevention and control of river basin pollution in northern cold regions, and significantly improves the pollutant interception capacity during freezing and thawing period. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a plan view of a riparian ecological buffer zone after construction according to 17 04 24 the present disclosure;

[0020] FIG. 2 is a sectional view of a riparian ecological buffer zone after construction according to the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly, the present disclosure is further described in detail below with reference to the drawing and embodiments. It should be understood that specific embodiments described here are only used to illustrate rather than limiting the present disclosure.

[0022] The specific implementation of the present disclosure is further described below with reference to specific embodiments.

[0023] As shown in FIG. 1 and FIG. 2, a method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution includes the following steps:

[0024] Step one: trimming a river riparian zone;

[0025] Step two: planting trees, shrubs and herbaceous plants in the river riparian zone in sequence;

[0026] Step three: applying AMF inoculant at a gradual freezing period and a spring thawing period; and

[0027] Step four: carrying out daily maintenance and management on an ecological buffer zone.

[0028] In this embodiment, after the riparian buffer zone is constructed, a vegetation coverage of the riparian zone is increased to 95% and more. The interception effect of the non-point source pollution is good, and the load of pollutants such as TN and TP is reduced by more than 50%. The biodiversity in the riparian zone is significantly improved, and the soil erosion and eutrophication of water bodies are effectively prevented.

[0029] As a preferred embodiment of the present disclosure, in Step one, an area in the range of 15-30 m from a normal water line of a river reach in an agricultural region in North China faces to a land area is selected as a construction area of the riparian ecological buffer zone.

[0030] In the embodiment of the present disclosure, preferably, a width of the construction area is at least 15 m. If the width of the construction area is less than 15 m, the interception rate of runoff particles and pollutants is low. Meanwhile, the width of the construction area should not exceed 30 m, so as to not waste funds and land.

[0031] As a preferred embodiment of the present disclosure, a smooth slope of the construction area is adjusted into a flat slope with a slope of 15-25°.

[0032] In this embodiment of the present disclosure, preferably, the bank slope of the selected 17 04 24 area is adjusted into a flat slope with a slope of 15-25°, thus facilitating the control of surface runoffs. During the adjustment of the slope of the construction area, it is best not to change the internal environment of the soil layer, and the adjusted terrain and slope should be as close as possible to the original to increase economy. Mechanical comprehensive soil preparation method is adopted to remove stones, roots and other sundries in the bank slope. Soil preparation should be carried out at early April in spring.

[0033] As a preferred embodiment of the present disclosure, in Step two, the tree species is selected from one or more of Salix matsudana and Primus padus. The shrub is selected from one or more of Amorpha fruticosa, Spiraea salicifolia, Prunus triloba, and Cornus alba. The herbaceous plant is selected from one or more of Medicago saliva, Trifolium repens, and Festuca elata.

[0034] In the embodiment of the present disclosure, it is preferable to select the common perennial trees, shrubs and herbaceous plants in the cold region in North China to carry out simulation experiments, thus screening out the species with strong stress resistance and high nitrogen and phosphorus pollutant purification ability, and the species with cold resistance, cold tolerance and good pollutant purification effect are further screened base on the above. Through the combination experiments of different species, species combination for the plant community construction is determined. The screened tree species include Salix matsudana and Prunuspadus, the screened shrubs include Amorpha fruticosa, Spiraea salicifolia, Prunus triloba, and Cornus alba, and the selected herbaceous plants include Medicago sativa, Trifolium repens, and Festuca elata. From these species, the plants with better TN and TP interception effect are selected for random combined planting, thus determining that the combined plants of the trees, the shrubs and the herbaceous plants have the strongest pollutant interception ability. One or more of the screened trees, the shrubs and the herbaceous plants can be selected respectively.

[0035] Willow has strong purification function due to its strong physiological activity and rapid biochemical reaction and metabolism in vivo. There are many varieties of Spiraea salicifolia, which not only have strong cold tolerance and stress resistance, but also can increase the landscape effect because of its long flowering period, bright colors and beautiful shape. The rhizosphere environment of Spiraea salicifolia is more suitable for the propagation and development of arbuscular mycorrhizal fungi (AMF), thus having a good purification effect on all pollutants. Amorpha fruticosa is cold-resistant, wind-resistant, fast-growing, long-growing, not prone to pests and diseases, with beautiful tree shape and strong soil-fixing and water-retaining ability, and is also a honey source and feed plant. The Amorpha fruticosa is a nitrogen-fixing plant with high demand for nitrogen and strong ability to purify TN. Poa annua 17 04 24 and Trifolium repens have better purification rate on the TN in runoffs than other plants. The herbaceous plants have the best creeping property, which can slow down the velocity of surface runoffs and promote the surface runoffs to infiltrate into soil.

[0036] As a preferred embodiment of the present disclosure, in Step two, according to a distance from far to near of the river normal water level, a tree area, a shrub area and a herbaceous plant area are arranged in turn from far to near. The distance from the tree area to the river normal water level is 10-15 m, the distance from the shrub area to the river normal water level is 5-10 m, and the distance from the herbaceous plant area to the river normal water level is 0-5 m. The height of tree species gradually increases from near to far of the river normal water level, the herbaceous plants are planted by sowing, and woody plants employ measures of planting purchased seedings.

[0037] In this embodiment of the present disclosure, preferably, the trees are planted regularly, the shrubs and the herbaceous plant can be planted regularly or naturally according to specific requirements. In order to prevent the root system from losing water, it should be avoided to lift seedling in windy and dry weather. The seedlings should be watered once 3-4 days before seedling lifting if the soil is too dry. In this way, the soil is moist, which is easy to lift the seedlings without damaging the roots. The trees may be single species or mixture of Salix matsudana and Prunus padus, and a distance between trees in a horizontal direction is 3-4 m. The shrubs may be single species or mixture of Amorpha fruticosa, Spiraea salicifolia, Prunus triloba, and Cornus alba, the height of the shrub is greater than 0.5 m, a configuration mode of 0.5 mx0.5 m is adopted, and a planting mode of one plant per pit is adopted, with a density of 4 plants / m2. The herbaceous plants may be single species or mixture of Medicago saliva. Trifolium repens, and Festuca elata, and grass seeds should be sown evenly. The sowing density of the seeds is 50 m2 / lkg, and plant seeds can be purchased from markets or nurseries. The paved soil layer mixed with plant seeds comes from nearby farmland with good soil quality, and a thickness of the soil layer mixed with the seeds is 20 cm. After the soil layer is paved, the soil layer is watered until the soil layer is completely wet.

[0038] Before planting, all afforestation seedlings shall be soaked with rooting powder. When planting the seedlings, the bottom water shall be poured once, the seedlings are righted, the roots are stretched, hilling is carried out in layers, the soil is compacted in layers, and the buried depth shall be 2-4 cm higher than the root of the seedlings. After the seedling is planted on a plot with poor soil moisture, it is necessary to water the seedling permeable once, strengthen the seedling and compact the soil, then make a water storage tray for rainwater storage.

[0039] As a preferred embodiment in the present disclosure, in Step three, an application 17 04 24 amount of the AMF inoculant is 100-200 g / m2.

[0040] In the embodiment of the present disclosure, preferably, the Arbuscular mycorrhizal fungi (AMF) can inhibit pathogenic bacteria, promote plant growth, and remove non-point source pollutants effectively. The AMF inoculant can still play a good role in the gradual freezing period and the spring thawing period, and has a remarkable strengthening effect on the pollutant purification of the shrubs and herbaceous plant. This artificial strengthening method can improve the performance of the buffer zone in purifying non-point source pollution, and the inoculants can be appropriately applied every spring, which can promote growth and improve pollution interception ability.

[0041] As a preferred embodiment in the present disclosure, in Step four, watering, weeds removal and pest control are carried out in due time according to a growth status of plants in the buffer zone.

[0042] In the embodiment of the present disclosure, the watering of the trees and shrubs is as follows: the survival rate of plants should be ensured in the first year, and the plants should be watered irregularly according to the situation, generally 5-7 days after heavy rain, 3-5 days after moderate rain and 1-3 days after light rain, depending on the soil moisture. Weed removal should be combined with soil scarifying, the weeds should be eradicated, and meanwhile, the tree pits are sorted, the soil should be scarified in time after each soaking rain or watering, so as to keep moisture and prevent soil hardening. The tree pit area should be kept as follows: 1.2 m2 for the tree and 0.8 m2 for the shrub, and the depth of soil scarifying and pit sorting is 5-15 cm. Prevention should be carried out according to the different onset periods of different plants, and plants with pests and diseases should be isolated. The diseased branches and leaves of the plant with mild incidence should be removed and burned with fire, so as to reduce the spread of diseases and insect pests.

[0043] The watering of lawns and herbaceous flowers is as follows: the lawns and herbaceous flowers are generally watered 5-7 days after heavy rain, 3-5 days after moderate rain and 1-3 days after light rain, depending on the soil moisture. Water should be thoroughly poured every time, and the water should permeate below 10 cm of the soil surface. After pruning or fertilization, the lawns and herbaceous flowers should be watered once, so as to benefit greening and nutrient absorption. In order to reduce irrigation cost and improve efficiency, potassium fertilizer should be applied appropriately to increase root system growth and enhance drought resistance, and organic fertilizer should be used appropriately to improve the soil structure. Weeds should be eradicated in early spring and 3-6 times in spring and summer, thus preventing the weeds from seed setting and large number of breeding. In maintenance, the prevention and 17 04 24 control of Cynodon dactylon, Chrysopogon aciculatus and other Malignant weeds with extremely strong spread and extremely easy to cause devastating damage to lawns are particularly important, and these Malignant weeds must be eradicated to avoid re-germination.

[0044] Example:

[0045] The method provided by the present disclosure is applied in the integrated pollution renovation project of the whole basin of Xiaohongzui River in Siping City, and an ecological buffer zone is constructed on the bank of the Xiaohongzui River, a tributary of Tiaozi River in Liaohe River Basin of Jilin Province.

[0046] By monitoring the water quality of upstream and downstream cross sections of the river before and after the implementation of the project, the average removal rates of three pollutants of NH3-N, TN and TP reached 52.67%, 71.89% and 69.39%, indicating that the construction of a vegetation buffer zone has a prominent effect on nutrient interception. Compared with the river bank before the demonstration project is constructed, after the demonstration project is constructed, the biomass is significantly improved, the biodiversity is more significant, the fresh and dry weight of biomass are increased by 49.05% and 68.94%, respectively, and the river bank zone is rich in species and beautiful in landscape.

[0047] Example:

[0048] The method provided by the present disclosure is applied in the project of "Comprehensive Governance of Black-odorous Water in Dongxinkaihe River Basin of Changchun City". In a landscape construction planning area where the downstream of Dongxin Kaihe River intersect with Xinkai Street, the south bank of a demonstration section has a length of 450 m, and a width of 62 m, and the north bank has a length of 300 m and a width of 46 m.

[0049] The foregoing description is merely preferred embodiments of the present disclosure. It should be noted that, for those of skilled in the art, various deformations and improvements can be made without departing from the concept of the present disclosure. Such deformations and improvements shall be regarded as falling into the scope of protection of the present disclosure, and will not affect the implementation effect of the present disclosure and the practicability of the patent.

Claims

17 04 241. A method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution, comprising the following steps:Step one: trimming a river riparian zone;Step two: planting trees, shrubs and herbaceous plants in the river riparian zone according to a distance from far to near of the river normal water level to form an ecological buffer zone;Step three: applying AMF (Arbuscular mycorrhizal fungi) inoculant at a gradual freezing period and a spring thawing period; andStep four: carrying out daily maintenance and management on the ecological buffer zone.

2. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 1, wherein in Step one, an area in the range of 15-30 m from a normal water line of a river reach in an agricultural region in North China faces to a land area is selected as a construction area of the ecological buffer zone.

3. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 2, wherein a bank slope of the construction area is adjusted into a flat slope with a slope of 15-25°.

4. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 1, wherein in Step two, the tree species is selected from one or more of Salix matsudana and Primus padus, the shrub is selected from one or more of Amorpha fruticosa, Spiraea salicifolia, Prunus triloba, and Cornus alba, and the herbaceous plant is selected from one or more of Medicago sativa, Trifolium repens, and Festuca elata.

5. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 4, wherein in Step two, according to a distance from far to near of the river normal water level, a tree area, a shrub area and a herbaceous plant area are arranged in turn from far to near, the distance from the tree area to the river normal water level is 10-15 m, the distance from the shrub area to the river normal water level is 5-10 m, and the distance from the herbaceous plant area to the river normal water level is 0-5 m; the height of tree species gradually increases from near to far of the river normal waterlevel, the herbaceous plants are planted by sowing, and woody plants employ measures of planting purchased seedings.

6. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 1, wherein in Step three, an application amount of the AMF inoculant is 100-200 g / m2.

7. The method for constructing a riparian buffer zone in a cold region for controlling agricultural non-point source pollution according to claim 1, wherein in Step four, watering, weeds removal and pest control are carried out in due time according to a growth status of plants in the ecological buffer zone.17 04 24

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