Method for river and lake spray-seeding slope protection through dredged sediment

Abstract

The invention provides a method for river and lake spray-seeding slope protection through dredged sediment. A mixed planting base material is prepared from dredged soil and leaf mold and is used for spray-seeding river and lake ecological slope banks. The method provided by the invention effectively solves the problem that water and fertilizer loss is easy to generate after dredged soil serves as the slope protection and is scoured by rainfall, and cement with relatively strong alkalinity is not used as an adhesive, so that the ecological rapid restoration of the slope protection is facilitated, and the water and fertilizer retention capability of the spray-seeding matrix is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of ecological restoration, and in particular to a method for spraying and protecting river and lake slopes by utilizing dredged bottom mud. Background Art

[0002] At present, the main method of utilizing dredged mud resources is to use dredged mud as fill material in low-lying areas at sea or on land. After blowing dredged mud into a certain area, vacuum or pile consolidation methods are used to improve the foundation strength. In this process, a large amount of cement, lime and other curing agents are required to reinforce the foundation to achieve the ideal strength. However, the foundation of land reclamation and foundation pit backfilling with dredged mud is relatively weak and has low bearing capacity. In addition, since most of the dredged soil is composed of fine-grained soil, it has poor permeability and a long consolidation time, which often requires a relatively generous construction period. At the same time, after applying chemical curing agents such as cement and lime, the pH value of the soil will be too high, which will damage the surrounding environment and is no longer suitable for the growth of vegetation and organisms.

[0003] Silt has the characteristics of high water content, low strength, high compressibility, and high pollution, and its engineering properties are poor. Existing methods cannot quickly and environmentally friendly treat silt, so a large amount of silt is landfilled or thrown into the sea every year, causing great waste and pollution. How to efficiently utilize river silt while taking into account economic efficiency and green environmental protection is an urgent issue.

[0004] The solidification treatment method is a new method proposed in recent years. It is mainly based on soil solidifiers. An appropriate amount of solidifying material is added to the silt. After stirring and mixing, the pore water of the silt and the solidifying material undergo hydrolysis and hydration reactions, and gelling substances are produced on the surface of the silt particles to improve the overall stability of the silt. The generated hydration products use their gelling substances to further react with the silt particles to form a silt skeleton with a network structure, so that the silt with high water content but no high mechanical properties becomes a solidified soil with a certain strength.

[0005] The existing spraying greening technology often consumes a large amount of local high-quality soil to prepare the spraying greening matrix during implementation, which will undoubtedly cause new excavation surfaces and damage the natural environment. Therefore, if dredged soil is used to replace the high-quality loam in the spraying greening matrix, a new way to reduce dredged soil resources can be opened up, environmental damage can be avoided, and the shortage of high-quality soil resources can be alleviated. At the same time, the production of spraying substrates should be developed towards the diversification of raw materials and high efficiency, such as establishing a pre-mixed spraying matrix factory to save on-site material transportation and labor costs. Summary of the invention

[0006] In view of this, the present invention aims to propose a method for utilizing dredged sediment to spray seeding for river and lake slope protection. The method adopts in-situ treatment of sediment without the need for ex-situ disposal. The slope protection matrix with compost products, silt, water retaining agent, adhesive, and vegetation seeds as raw materials provides an outlet for source recycling, realizes the transformation of waste into treasure, does not damage the surrounding environment, and is suitable for the growth of vegetation and organisms.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A method for spraying and protecting river and lake slopes by using dredged sediment, the method comprising the following steps:

[0009] 1) leaf humus, silt, common soil, water retaining agent, adhesive and vegetation seeds are mixed and stirred to obtain a spraying matrix for standby use, wherein the leaf humus is obtained by crushing garden waste and then composting and fermenting, the mass ratio of water, soil and wood fiber in the spraying matrix is ​​1:1.5-2.5:1, the wood fiber content in the spraying matrix is ​​10%-30%, and the water content is 20%-30%;

[0010] Among them, the minimum content of wood fiber is 4%, but the reduction of wood fiber content corresponds to the need to increase the content of water retaining agent and compound fertilizer, so the economic minimum content of wood fiber is considered to be 10%, and it is recommended that the difference of all components should not exceed 5%; the proportion of soil is determined based on sandy soil, and other soils need to be appropriately reduced according to specific conditions.

[0011] 2) For river and lake slopes with a slope angle of no more than 45°, direct spraying and covering with soil are carried out, and the thickness of the covering soil layer is 10-30cm; the seeds to be sprayed are a combination of grass, shrubs and flowers. After spraying, it is necessary to cover with a sunshade net in time for protection, and then water and maintain;

[0012] 3) For river and lake slopes with a slope angle greater than 45°, first use a wood fiber base material to weave a filamentary network as a cushion layer and then spray-seed it. The spray-seeding method is the same as step 2).

[0013] Water and fertilizers in the spraying matrix are easily lost during the scouring process on steep slopes, and water retainers can retain water and nutrients in them. In the application of spraying matrix, water retainers can promote the water demand of ryegrass, increase the water and fertilizer absorption of grass, and thus promote the effect of planting plants in the spraying matrix. At the same time, water retainers are conducive to the activity of rhizosphere microorganisms, promote microbial degradation of organic matter and subsequent nutrient supply. The wood fiber in the spraying matrix can enhance the effect of water retainers to a certain extent, because the wood fiber itself can reinforce the soil, stretch the soil when cracks appear in the soil, enhance the cohesion of the soil, prevent cracks from occurring, and thus improve the water and fertilizer retention of the spraying matrix.

[0014] The leaf mold used in the present invention can take into account the functions of garden soil, peat soil, cellulose and water retaining agent, thereby greatly reducing the raw materials and preparation steps.

[0015] Silt is rich in nutrients, and most plants cannot survive directly using it, so it needs to be neutralized by other poor soils. Silt has a high water content, so in order to ensure that the final substrate moisture content is 20-30%, the silt needs to be neutralized or dehydrated. When the spraying area is large, there is not enough silt in the river channel, and the cost of leaf mold is high, ordinary soil can be added to supplement the soil quality.

[0016] Furthermore, the garden waste includes algae, water plants, small branches and leaves, and withered flowers and grass clippings. The carbon-nitrogen ratio of the garden waste is 20:1-30:1, and the water content is 40-60%.

[0017] The carbon-nitrogen ratio refers to the ratio of the total carbon content to the total nitrogen content in organic matter. Generally, for every 25g of organic carbon consumed by microorganisms, 1g of nitrogen needs to be absorbed. The most suitable carbon-nitrogen ratio for microorganisms to decompose organic matter is 25.

[0018] The carbon-nitrogen ratio of algae and water grass is 10-12, the carbon-nitrogen ratio of small branches and leaves and dead flowers is 40-45, and the carbon-nitrogen ratio after neutralization is 20-30. The moisture content of fresh water grass is 80%, the moisture content of dry grass and dry branches is 0%, and the moisture content of water grass that has been exposed for two days is 20-30%. The compost raw materials are roughly calculated before composting and then replenished with water. The general moisture content is about 50%.

[0019] Furthermore, the particle size of the leaf mold compost is ≤45mm.

[0020] Furthermore, the wood fiber substrate is prepared by composting and fermenting large branches and small branches with high lignin and cellulose content, and the compost particle size is greater than 45 mm.

[0021] Furthermore, the composting method is: after mixing the crushed garden waste with the fermentation agent, first use primary high-temperature aerobic composting, the entire high-temperature fermentation time is controlled within 8-24 hours, the fermentation temperature is 60-80°C, the stirring speed is 30-45r / min, and the oxygen concentration is 3-4mg / kg; then use secondary composting technology to continue aerobic fermentation, the fermentation temperature is room temperature without additional heating, and the fermentation time is 1-2 weeks.

[0022] In addition, secondary fermentation is not necessary during the actual operation.

[0023] Furthermore, the fermentation agent is a thermophilic composite bacteria, including Potssteine ​​Brevibacillus, Bacillus, Geobacillus, extreme thermophilic bacteria and Saccharomyces cerevisiae in a mass ratio of (0.1-0.2):(0.1-0.5):(0.3-0.4):(0.2-0.5):(0.2-0.5), wherein the highest thermophilic temperature of the composite bacteria is >80°C, and a stabilized, decomposed and harmless organic fertilizer product can be produced through high-temperature fermentation within 10 hours.

[0024] Furthermore, each kilogram of the spraying matrix includes 500-750g of leaf mold, 100-250g of silt, 0-330g of common soil, 0-12g of water retaining agent, 0.1-10g of adhesive and 2kg-6kg / mu of vegetation seeds.

[0025] Among them, the number of vegetation seeds is only related to the spraying area.

[0026] Furthermore, the lignin content of the leaf humus is 20%-50%, and the moisture content is 25%-50%;

[0027] The silt is river dredging silt, and the moisture content of the silt is 65%-97%;

[0028] Each kilogram of spraying substrate also includes 0-15g of slow-release compound fertilizer.

[0029] Furthermore, the water retaining agent is a potassium salt type polymer water-absorbing resin, and the binder is one or more of anionic polyacrylamide, seaweed polysaccharide, and sodium carboxymethyl cellulose.

[0030] Water retaining agent is small in size and can absorb water. High molecular weight water absorbent resin can absorb 6000 times more water. Polyacrylic acid accounts for more than 75% of the highly absorbent resins on the market. It has a strong water retention effect and can promote plant rooting. During the seedling development, it can enhance the disease resistance of seedlings, increase the water storage capacity of the soil, and improve the water retention and drought resistance. It can also be used as a soil conditioner to improve the soil and increase the survival rate of transplanted seedlings. In addition, it can quickly absorb fertilizers, organic matter and other nutrients in the soil, and gradually release them during the growth of plants, prolonging the fertilization effect. It can also react with some ions (Ca 2+ Mg 2+ Therefore, super absorbent resin can be mixed with other substances to comprehensively improve soil fertility.

[0031] The adhesive sodium carboxymethyl cellulose can increase the stability of the fiber matrix, improve the adhesion of the fiber to the ground, make the matrix firmly attached to the surface, reduce splash erosion and protect the germination and growth of plants. Seaweed polysaccharide is an extracellular polysaccharide extracted from plants, which has a good cementing effect, can be automatically degraded in the natural environment, and has little impact on the ecological environment. Polyacrylamide is effective in preventing rain from entering the river, is the most commonly used in sludge dehydration, is inexpensive, and is easy to purchase.

[0032] Preferably, each kilogram of spraying substrate includes 750g of leaf humus (30% moisture content, 33% cellulose content), 105g of silt, 135g of ordinary soil, 10g of adhesive and 2kg / mu of vegetation seeds, 20cm thick, and the number of seeds is only related to the spraying area. The adhesive is seaweed polysaccharide, and the leaf humus has a high content, so no water retaining agent is added.

[0033] Preferably, each kilogram of spraying matrix includes 500g of leaf humus (30% moisture content, 50% cellulose content), 188g of dehydrated sludge (80% moisture content), 298g of ordinary soil, 10g of slow-release compound fertilizer, 3g of water retaining agent, 1g of adhesive and 3kg / mu of vegetation seeds, 10cm thick, and the number of seeds is only related to the spraying area. The adhesive is polyacrylamide. The dehydrated sludge contains a large amount of PAM, so the water retaining agent and adhesive content are low. The leaf humus has a high cellulose content, so the fertilizer in the early stage is insufficient. The sludge can be dehydrated or not according to the on-site conditions. The moisture content of some dried-up river sludge is low or even lower than that of soil.

[0034] Furthermore, vegetation seeds include woody seeds and herbaceous seeds. The spraying density of woody seeds is 4000g / 667m 2 The spraying density of herbal seeds is 1500g / 667m 2 The woody seeds are one or more of Cassia tora, Lespedeza, Horsethorn, Sophora japonica, and Cajanus ovata; the herbaceous seeds are one or more of Tall Fescue, Setaria viridis, White Clover, Medicago sativa, Cosmos, Poa annua, rye, and Ophiopogon japonicus.

[0035] Compared with the prior art, the method of using dredged sediment for river and lake spraying slope protection described in the present invention has the following advantages:

[0036] This method uses in-situ treatment of bottom mud without ex-situ disposal. The slope protection matrix with compost products, sludge, water retaining agent, adhesive, and vegetation seeds as raw materials provides an outlet for source reuse, realizes the transformation of waste into treasure, does not damage the surrounding environment, and is suitable for the growth of vegetation and organisms. This method is simple to operate, low in cost, and does not require drying. It is suitable for the actual situation of rural ditches and urban ecological slope protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 Comparison of the number of germinated seeds between Example 1 and Comparative Examples T1 and T2. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] A method for using dredged sediment to spray and protect river and lake slopes comprises the following steps:

[0043] 1) Leaf mold is made from garden waste after crushing and composting:

[0044] Garden waste includes 60% algae and water plants, 40% small branches and leaves, and flower and grass clippings. The carbon-nitrogen ratio of algae and water plants is 10-12, and the carbon-nitrogen ratio of small branches and leaves and flower and grass clippings is 40-45. The carbon-nitrogen ratio after neutralization is 20-30. The moisture content of fresh water plants is 80%, the moisture content of dry grass and dry branches is 0%, and the moisture content of water plants that have been exposed for two days is 20-30%. The compost raw materials are roughly calculated before composting and then replenished with water. The general moisture content is about 50%.

[0045] The crushed garden waste was mixed with 0.3g / kg fermentation agent and firstly subjected to primary high-temperature aerobic composting. The entire high-temperature fermentation time was controlled within 24 hours, the fermentation temperature was 70°C, the stirring speed was 40r / min, and the oxygen concentration was 4mg / kg. After that, secondary composting technology was used to continue aerobic fermentation. The fermentation temperature was room temperature without additional heating, the stirring speed was 40r / min, and the oxygen concentration was 4mg / kg. The fermentation time was 2 weeks.

[0046] The particle size of leaf mold compost is ≤45mm.

[0047] The fermentation agent is a thermophilic composite bacteria, including Potssteine ​​Brevibacillus, Bacillus, Geobacillus, extreme thermophilic bacteria and Saccharomyces cerevisiae in a mass ratio of 0.1:0.1:0.3:0.3:0.2. The highest thermophilic temperature of the composite bacteria is >80°C, and a stabilized, decomposed and harmless organic fertilizer product can be produced through high-temperature fermentation within 10 hours.

[0048] 2) The leaf mold prepared above is mixed with silt, common soil (garden soil), adhesive and plant seeds to obtain a spraying medium for standby use.

[0049] Each kilogram of spraying matrix includes 750g of leaf humus (30% moisture content, 33% cellulose content), 105g of silt (97% moisture content), 135g of ordinary soil, 10g of adhesive and 2kg / mu of vegetation seeds, 20cm thick, and the number of seeds is only related to the spraying area. The adhesive is seaweed polysaccharide, and the leaf humus has a high content, so no water retaining agent is added.

[0050] The vegetation seeds are Amorpha fruticosa and mixed herb seeds in a ratio of 1:1, and the herbs are preferably from the Poaceae family, such as tall fescue, bluegrass, rye, cosmos, etc. The seed sowing amount is suitable for the sowing of Tianjin's barren-resistant, cold-resistant, and seasonal river grass and shrub vegetation in rural areas.

[0051] 3) For river and lake slopes with a slope angle of no more than 45°, direct spraying and covering with soil are carried out, and the thickness of the covering soil layer is 20 cm; the seeds sprayed are a combination of grass, shrubs and flowers. After spraying, they need to be covered with a shade net for protection in time, and then watered and maintained.

[0052] Sowing in spring, the vegetation will be lush in summer and can last for many years. In the early stage, it will be dominated by herbs, and in the later stage, it will be dominated by shrubs. There will be no silt entering the rivers and lakes again, and it can effectively resist erosion in the rainy season.

[0053] Example 2

[0054] A method for using dredged sediment to spray and protect river and lake slopes comprises the following steps:

[0055] 1) Leaf mold is made from garden waste after crushing and composting:

[0056] Garden waste includes algae, water plants, small branches and leaves, and flower and grass clippings. The carbon-nitrogen ratio of garden waste is 20:1-30:1, and the water content is 50%;

[0057] The crushed garden waste was mixed with 0.3g / kg fermentation agent and firstly subjected to primary high-temperature aerobic composting. The entire high-temperature fermentation time was controlled within 24 hours, the fermentation temperature was 80°C, the stirring speed was 40r / min, and the oxygen concentration was 4mg / kg. After that, secondary composting technology was used to continue aerobic fermentation. The fermentation temperature was room temperature without additional heating, and the fermentation time was 2 weeks.

[0058] The particle size of leaf mold compost is ≤45mm.

[0059] The fermentation agent is a thermophilic composite bacteria, including Potssteine ​​Brevibacillus, Bacillus, Geobacillus, extreme thermophilic bacteria and Saccharomyces cerevisiae in a mass ratio of 0.1:0.1:0.3:0.3:0.5. The highest thermophilic temperature of the composite bacteria is >80°C, and a stabilized, decomposed and harmless organic fertilizer product can be produced through high-temperature fermentation within 10 hours.

[0060] 2) The leaf mold prepared above is mixed with silt, ordinary soil (garden soil), slow-release compound fertilizer, water-retaining agent, adhesive and vegetation seeds to obtain a spraying matrix for standby use.

[0061] Each kilogram of spraying matrix includes 500g of leaf humus (30% moisture content, 50% cellulose content), 188g of silt (80% moisture content), 298g of ordinary soil, 10g of slow-release compound fertilizer, 3g of water retaining agent, 1g of adhesive and 3kg / mu of vegetation seeds, 10cm thick, and the number of seeds is only related to the spraying area. The adhesive is polyacrylamide. After dehydration, the silt contains a lot of PAM, so the water retaining agent and adhesive content are low. The leaf humus has a high cellulose content, so the fertilizer is insufficient in the early stage.

[0062] Vegetation seeds use woody seeds such as Cassia obtusifolia and Lespedeza and herbaceous seeds in a ratio of 2:1. The herbaceous plants are preferably Gramineae, Setaria viridis, Trifolium repens, Medicago sativa, Cosmos chrysanthemum, etc. The seed sowing amount is suitable for the sowing of barren-resistant, cold-resistant, and seasonal river grass and shrub vegetation in rural areas in Tangshan.

[0063] 3) For river and lake slopes with a slope angle greater than 45°, first use a wood fiber base material to weave a filamentary network as a cushion layer and then spray seeding. The thickness of the soil layer covering the spray seeding is 20 cm; the sprayed seeds are a combination of grass, shrubs and flowers. After spraying, they need to be covered with a shade net for protection in time, and then watered and maintained.

[0064] The wood fiber base material is prepared by composting and fermenting large and small branches with high lignin and cellulose content, and the compost particle size is greater than 45 mm.

[0065] Sowing in spring, the vegetation will be lush in summer and can last for many years. In the early stage, it will be dominated by herbs, and in the later stage, it will be dominated by shrubs. There will be no silt entering the rivers and lakes again, and it can effectively resist erosion in the rainy season, and there will be no slope collapse.

[0066] Example 3

[0067] A method for using dredged sediment to spray and protect river and lake slopes comprises the following steps:

[0068] 1) Leaf mold is made from garden waste after crushing and composting:

[0069] Garden waste includes algae, water plants, small branches and leaves, and flower and grass clippings. The carbon-nitrogen ratio of garden waste is 20:1-30:1, and the water content is 50%;

[0070] The crushed garden waste was mixed with 0.3g / kg fermentation agent and firstly subjected to primary high-temperature aerobic composting. The entire high-temperature fermentation time was controlled within 24 hours, the fermentation temperature was 80°C, the stirring speed was 40r / min, and the oxygen concentration was 4mg / kg. After that, secondary composting technology was used to continue aerobic fermentation. The fermentation temperature was room temperature without additional heating, and the fermentation time was 2 weeks.

[0071] The particle size of leaf mold compost is ≤45mm.

[0072] The fermentation agent is a thermophilic composite bacteria, including Potssteine ​​Brevibacillus, Bacillus, Geobacillus, extreme thermophilic bacteria and Saccharomyces cerevisiae in a mass ratio of 0.2:0.1:0.4:0.2:0.4. The highest thermophilic temperature of the composite bacteria is >80°C, and a stabilized, decomposed and harmless organic fertilizer product can be produced through high-temperature fermentation within 10 hours.

[0073] 2) The leaf mold prepared above is mixed with silt, ordinary soil, water retaining agent, adhesive and vegetation seeds to obtain a spraying matrix for standby use.

[0074] Each kilogram of spraying matrix includes 625g of leaf humus (33% moisture content, 40% cellulose content), 170g of silt (65% moisture content), 200g of ordinary soil, 3g of water retaining agent, 2g of adhesive and 4kg / mu of vegetation seeds, 20cm thick, and the number of seeds is only related to the spraying area. The adhesive is seaweed polysaccharide, and the leaf humus has a high content, so no water retaining agent is added.

[0075] Vegetation seeds use woody seeds and herbaceous seeds in a ratio of 1:1. Woody seeds use horsethorn and yellow locust, and herbaceous seeds are preferably from the Poaceae family, such as Medicago sativa, Cosmos, and Poa annua. The seed sowing amount is suitable for sowing barren-resistant, cold-resistant, and seasonal river grass and shrub vegetation in rural areas in Tianjin.

[0076] 3) For river and lake slopes with a slope angle of no more than 45°, direct spraying and covering with soil are carried out, and the thickness of the covering soil layer is 20 cm; the seeds sprayed are a combination of grass, shrubs and flowers. After spraying, they need to be covered with a shade net for protection in time, and then watered and maintained.

[0077] Sowing in spring, the vegetation will be lush in summer and can last for many years. In the early stage, it will be dominated by herbs, and in the later stage, it will be dominated by shrubs. There will be no silt entering the rivers and lakes again, and it can effectively resist erosion in the rainy season, and there will be no slope collapse.

[0078] Comparative Example

[0079] T1: Each kilogram of spraying matrix includes 350g of leaf mold (30% moisture content, 50% cellulose content), 525g of silt dry soil, 119g of water, 4.5g of water retaining agent, and 1.5g of adhesive.

[0080] T2: Each kilogram of spraying matrix includes 693g of dry silt soil, 278g of peat, 19g of perlite, 8.5g of water-retaining agent and 1.5g of adhesive.

[0081] Example 1, T1 and T2 were sprayed and maintained for 7-15 days to form a soil slope, and the soil of the soil slope was tested.

[0082] Table 1 Soil testing

[0083] Example 1 T1 T2 <![CDATA[Unit weight g / cm 3 > 1.36 1.4 1.37 Total porosity% 40.25 40.3 40.29 Moisture content% 34.9 33.5 39.6 Steady seepage rate mm / h 15.1 9.55 14 Surface hardness mm 19.56 19.88 19.32 Organic matter content% 79.5 78.9 77.1 Total nitrogen content% 1.9 1.5 1.7 <![CDATA[Shearing strength N / m 2 > 21 20 20

[0084] From the table above, we can see that the three solutions have roughly the same physical properties, with no significant differences, but the effects after curing are completely different. Figure 1 It can be seen that the soil of Example 1 is superior to the other two schemes in terms of steady infiltration rate, organic matter content, total nitrogen content, and number of seedlings per square meter, and has the best overall performance; the formula of T1 exceeds the preferred ratio range given in this application, T3 does not use leaf mold, and the T1 substrate is superior to the T3 peat substrate in terms of organic matter content and the number of seedlings on the 36th day. The total nitrogen content is at the same level as the other two substrates, but the performance is slightly worse in terms of infiltration rate index.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for spraying and protecting river and lake slopes by using dredged sediment, characterized in that: The method comprises the following steps: 1) leaf humus, silt, common soil, water retaining agent, adhesive and vegetation seeds are mixed and stirred to obtain a spraying matrix for standby use, wherein the leaf humus is obtained by crushing garden waste and then composting and fermenting, the mass ratio of water, soil and wood fiber in the spraying matrix is ​​1: (1.5-2.5): 1, the wood fiber content in the spraying matrix is ​​10%-30%, and the water content is 20%-30%; 2) For river and lake slopes with a slope angle of no more than 45°, direct spraying and covering with soil are carried out, and the thickness of the covering soil layer is 10-30cm; the seeds to be sprayed are a combination of grass, shrubs and flowers. After spraying, it is necessary to cover with a sunshade net in time for protection, and then water and maintain; 3) For river and lake slopes with a slope angle greater than 45°, first use a wood fiber base material to weave a filamentary network as a cushion layer and then spray-seed. The spray-seeding method is the same as step 2).

2. The method for using dredged sediment for river and lake spraying slope protection according to claim 1 is characterized in that: Garden waste includes algae, water plants, small branches and leaves, and withered flowers and grass clippings. The carbon-nitrogen ratio of garden waste is 20:1-30:1, and the water content is 40-60%.

3. The method for using dredged sediment for river and lake spraying slope protection according to claim 1 is characterized in that: The particle size of leaf mold compost is ≤45mm.

4. The method for using dredged sediment for river and lake spraying slope protection according to claim 1 is characterized in that: The wood fiber substrate is prepared by composting and fermenting large and small branches with high lignin and cellulose content, and the compost particle size is greater than 45 mm.

5. The method for using dredged sediment for river and lake spraying slope protection according to claim 1 is characterized in that: The composting method is: after mixing the crushed garden waste with the fermentation agent, first use the first-level high-temperature aerobic composting, the whole high-temperature fermentation time is controlled within 8-24 hours, the fermentation temperature is 60-80℃, the stirring speed is 30-45r / min, and the oxygen concentration is 3-4mg / kg; then use the secondary composting technology to continue the aerobic fermentation, the fermentation temperature is room temperature without additional heating, and the fermentation time is 1-2 weeks.

6. The method for using dredged sediment for river and lake spraying slope protection according to claim 5 is characterized in that: The fermentation agent is a thermophilic composite bacteria, including Potssteine ​​Brevibacillus, Bacillus, Geobacillus, extreme thermophilic bacteria and Saccharomyces cerevisiae in a mass ratio of (0.1-0.2):(0.1-0.5):(0.3-0.4):(0.2-0.5):(0.2-0.5), wherein the highest thermophilic temperature of the composite bacteria is >80°C, and a stabilized, decomposed and harmless organic fertilizer product can be produced through high-temperature fermentation within 10 hours.

7. The method for using dredged sediment for river and lake spraying slope protection according to claim 1 is characterized in that: Each kilogram of spraying matrix includes 500-750g of leaf mold, 100-250g of silt, 0-330g of ordinary soil, 0-12g of water retaining agent, 0.1-10g of adhesive and 2kg to 6kg / mu of vegetation seeds.

8. The method for using dredged sediment for river and lake spraying slope protection according to claim 7 is characterized in that: The lignin content of leaf humus is 20%-50%, and the moisture content is 25-50%; The silt is river dredging silt, and the moisture content of the silt is 65%-97%; Each kilogram of spraying substrate also includes 0-15g of slow-release compound fertilizer.

9. The method for using dredged sediment for river and lake spraying slope protection according to claim 1, characterized in that: The water retaining agent is a potassium salt type high molecular water-absorbing resin, and the binder is one or more of polyacrylamide, seaweed polysaccharide and sodium carboxymethyl cellulose.

10. The method for river and lake slope protection using dredged sediment according to claim 1, characterized in that: Vegetation seeds include woody seeds and herbaceous seeds. The spraying density of woody seeds is 4000g / 667m 2 The spraying density of herbal seeds is 1500g / 667m 2 The woody seeds are one or more of Amorpha fruticosa, Cassia tora, Lespedeza, Eryngium truncatum, Amorpha fruticosa, and Cajanus cajan. The herbaceous seeds are one or more of Tall Fescue, Setaria viridis, White Clover, Medicago sativa, Cosmos, Poa annua, rye, and Ophiopogon japonicus.

Images