A terraced structure for improving coastal saline soil and a terraced planting method utilizing organic solid waste humus in conjunction with coastal saline soil.

Abstract

This invention relates to a terraced structure for improving coastal saline soil and a terraced planting method utilizing easily decomposable organic solid waste in conjunction with coastal saline soil. The terraced structure for improving coastal saline soil comprises at least three planting zones constructed along the seaward direction towards the coast. These planting zones are arranged in a terraced pattern and include at least one of the following: herbaceous plant planting zone, shrub planting zone, and tree planting zone. All three zones are constructed from coastal saline soil. This invention utilizes humic organic solid waste, derived from the decomposition of kitchen waste, domestic sewage sludge, and livestock manure, to provide the nutrients and foundation required by coastal plants. Simultaneously, the humic acid contained in the humic organic solid waste adjusts the pH of the coastal saline soil, improving its plantability while simultaneously preventing erosion of the coastal sand.

Description

Technical Field

[0001] This invention relates to the field of coastal ecological environmental management technology, and in particular to a terraced structure for improving coastal saline soil and a terraced planting method that utilizes organic solid waste humus in conjunction with coastal saline soil. Background Technology

[0002] Topography is one of the conditions for soil salinization. The undulation of topography directly affects the movement of surface and underground runoff, and also the movement of salts in the soil. From a macro- to micro-topographical perspective, soil salt accumulation gradually increases from higher to lower elevations. In coastal areas, the terrain is low and flat; due to the influence of seawater, the parent material of the soil and groundwater contains a large amount of salt, and the salt composition is consistent with seawater, with NaCl being the dominant component. In the coastal areas of Northeast and North China, the closer to the coast, the closer the marine deposits are to the surface. Because groundwater is connected to seawater and is subject to periodic tidal infiltration, a large amount of salt accumulates in the parent material. The parent material of coastal saline soils is recent marine or lacustrine sediments, originating from large amounts of silt carried by rivers flowing into the sea. Under the action of waves and tides, this silt is continuously deposited at the estuary. While still in the underwater deposition stage, it is infiltrated by seawater and becomes saline silt. The original salt content of saline silt is mostly between 1.0% and 3.0% (conditions for the formation of coastal saline soils).

[0003] Meanwhile, marine soil with low organic matter content is also generated near the coastline. Due to its high salt content, marine soil is not suitable for planting herbaceous plants, shrubs and trees. At the same time, the ecological environment management of the coastline has put forward new requirements for the ecological greening of the coastline. Marine soil is mainly silt and silty soil. Its characteristics are high natural water content, large porosity, high compressibility coefficient, low strength, and special engineering properties such as creep and thixotropy. Most of them contain a certain amount of organic matter, but the organic matter content is low and the engineering geological conditions are poor.

[0004] The following methods can be used to improve this type of soil:

[0005] I. Site Preparation Engineering. Site preparation engineering is the foundation of landscaping, mainly including raising the ground and leveling the land.

[0006] 1. Raising the ground level by adding topsoil. In landscaping, most plants are deep-rooted with vigorous root systems. They generally thrive in loose, fertile soil. However, in coastal saline-alkali soils, the water table and groundwater mineralization are very high, far from meeting the needs of plant growth. Therefore, raising the ground level is necessary to lower the water table and control the rise in groundwater mineralization. Other measures to regulate salinity and reduce alkalinity can then be implemented to create a suitable environment for plant growth.

[0007] The standard for raising the ground level with topsoil should generally not be less than 3.5 meters, and a layer of planting soil at least 0.6-0.8 meters thick should be laid on top. The soil used should be well-developed, fertile, and rich in organic matter. It should also be loose, breathable, and have good water and fertilizer retention capacity.

[0008] 2. Site leveling and topsoil preparation. In coastal saline-alkali land improvement, site leveling is a crucial step after raising the soil level with imported topsoil and is a necessary step before planting garden plants. Soil salinity is often closely related to subtle changes in topography. When there are low-lying areas with water accumulation, these areas can easily become difficult to desalinate. Therefore, it is essential to level the site and ensure it is flat.

[0009] II. Traditional Coastal Saline Soil Drainage and Salt Removal Projects. Traditional coastal saline soil drainage and salt removal projects aim to reduce salinity by laying underground drainage and salt removal pipes. The following methods are typically used.

[0010] 1. Underground drainage. This involves laying a certain number of pipes at a suitable depth underground. Salt is then flushed out through the pipes by irrigation or rainwater runoff. The advantage of this method is that it requires a one-time investment and can continuously remove salt and alkali. However, this method involves a large amount of engineering work and has high investment costs. For lawns and flowering plants, the pipes are typically buried at a depth of 0.5-0.6 meters, while for trees, it's about 0.8 meters deep. This method can generally reduce the salt content within 1 meter to below 0.3%, essentially solving the problem of salt and alkali damage to garden plants. It also provides some flood prevention.

[0011] 2. Open ditch drainage. This method is easy to construct and has a large drainage capacity, but the salt discharge is uneven. Generally, a drainage ditch is required every 100-200 meters. For areas with less severe salinity, the distance can be increased appropriately.

[0012] 3. Laying an isolation layer. This method is generally used in moderately saline-alkali areas, and the isolation layer is typically laid to a depth of 1.0-1.2 meters. The isolation layer usually uses materials such as pebbles, slag, furnace ash, and broken bark, and a thickness of 20-30 cm is recommended. This method is often used in small green spaces, courtyards, or tree pits.

[0013] 4. Irrigation for salt leaching. This method involves using fresh water for irrigation to wash away salt and alkali, and to drain it from the soil. It is often implemented in severely saline-alkali areas.

[0014] III. Fertilizing and Hilling

[0015] This method typically uses organic fertilizers and bio-fertilizers to adjust soil aggregate structure and soil organic matter content, and regulates soil salinity through organic matter fermentation and microbial activity, thereby achieving the goal of saline-alkali improvement.

[0016] IV. Chemical Improvement

[0017] Chemical soil amendment is a method to reduce the harmful effects of salinity and alkali by using soil amendments to neutralize saline-alkali soil through chemical reactions. Commonly used soil amendments include calcareous amendments (gypsum, phosphogypsum, desulfurized gypsum), acidic amendments (sulfuric acid, sulfur, aluminum sulfate, coal gangue, etc.), organic amendments (peat, weathered coal, furfural residue, etc.), organic-inorganic composite amendments (mostly processed from industrial waste), and soil structure amendments (polyacrylamide, polyvinyl alcohol, etc.).

[0018] V. Utilization of Salt-Tolerant Plants

[0019] Common salt-tolerant plants include Salicornia glutinosa and Tamarix chinensis. The appropriate salt-tolerant plant should be selected based on the specific type of saline-alkali soil.

[0020] All of the above methods have specific limitations. How to solidify coastal saline soil, improve the coastal ecological environment, effectively prevent excessive soil salinization by gradually blocking saltwater intrusion, and how to utilize vegetation to achieve salt drainage are current challenges in coastal ecological governance. Summary of the Invention

[0021] To address the above technical problems, this invention provides a terraced structure for improving coastal saline soil and a method for terraced planting using organic solid waste humus in conjunction with coastal saline soil. This invention utilizes organic solid waste humus, derived from the decomposition of kitchen waste, domestic sewage sludge, and livestock manure, to provide the nutrients and foundation required by coastal plants. Simultaneously, the humic acid contained in the organic solid waste humus adjusts the pH of the coastal saline soil, improving its plantability while simultaneously preventing erosion of coastal beaches.

[0022] The first objective of this invention is to provide a terraced structure for improving coastal saline soil, which includes at least three planting areas constructed along the seaward direction towards the coast. The planting areas are arranged in a terraced manner and include at least one of herbaceous plant planting areas, shrub planting areas, and tree planting areas.

[0023] The herbaceous plant planting area and shrub planting area include a first base layer, a first frame and a first nutrient soil layer laid sequentially from the bottom of the beach upwards. Multiple planting holes are excavated at intervals in the first nutrient soil layer, and organic solid waste humus is buried in the planting holes.

[0024] The tree planting area is divided into multiple holes at intervals. Each hole is laid with a second base layer, a second frame, and a second nutrient soil layer in sequence. The second base layer is arranged to be laid along the inner wall of the hole. Each hole is constructed to form a tree pit.

[0025] Preferably, the diameter of the implantation hole is not less than 0.1m and the depth is not less than 0.3m;

[0026] Preferably, the diameter of the tree pit is not less than 0.8m and the depth is not less than 1.2m;

[0027] Preferably, the first matrix layer and the second matrix layer are constructed by mixing coastal saline soil and sand, and the mass ratio of coastal saline soil to sand in the first matrix layer and the second matrix layer is (1-2):(1-3).

[0028] Preferably, the distance between two adjacent tree holes is ≥2 meters, and the distance between two adjacent planting holes is ≥1 meter;

[0029] Preferably, the first nutrient soil layer and the second nutrient soil layer are constructed by mixing and piling up coastal saline soil, kitchen waste and sludge, and the mass ratio of coastal saline soil, kitchen waste and sludge in the first nutrient soil layer and the second nutrient soil layer is (4-7):(3~2):1, preferably 6:3:1.

[0030] Preferably, the first frame includes a first permeable brick frame layer and a first skeleton frame layer arranged sequentially;

[0031] The first permeable brick frame layer is disposed above the first substrate layer, and the first permeable brick frame layer is formed by sponge city permeable bricks;

[0032] The first skeleton frame layer is a lightweight brick skeleton structure layer filled with cellulose hydrogel.

[0033] Preferably, the second frame includes a second skeleton frame layer and a second permeable brick frame layer and a third permeable brick frame layer respectively disposed on the inner and outer sides of the second skeleton frame layer;

[0034] The second permeable brick frame layer and the third permeable brick frame layer are constructed from permeable bricks used in sponge cities. The second permeable brick frame layer is laid inside the second skeleton frame layer, and the third permeable brick frame layer is laid outside the second skeleton frame layer.

[0035] The second skeleton frame layer is a lightweight brick skeleton structure layer filled with cellulose hydrogel.

[0036] Preferably, the second permeable brick frame layer is arranged to form a dovetail groove structure that is wider at the top and narrower at the bottom.

[0037] Preferably, a plurality of nutrient supply holes are provided around the tree pit, and organic solid waste humus is buried in the nutrient supply holes;

[0038] The diameter of the nutrient supply hole is 50-70cm, and the depth is 2 / 3-3 / 4 of the second nutrient soil layer.

[0039] Preferably, the organic solid waste humus is formed by the decomposition of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure.

[0040] Preferably, a second objective of the present invention is to provide a method for terraced planting using easily degradable organic solid waste in conjunction with coastal saline soil, comprising the following steps:

[0041] S1. Construct at least one of the following in a stepped arrangement along the direction away from the coast: herbaceous plant planting area, shrub planting area, and tree planting area;

[0042] S1-1 Construction of shrub and herb planting areas: In the herb planting area and / or shrub planting area, a first substrate layer is formed by laying a mixture of coastal saline soil and sand at the bottom of the beach; then, permeable bricks for sponge city are laid on the surface of the first substrate layer to obtain the first permeable brick frame layer; next, lightweight bricks filled with cellulose hydrogel are laid to form the first skeleton frame layer; then, the first nutrient soil layer is laid on the first skeleton frame layer, which is composed of a mixture of coastal saline soil, kitchen waste and sludge; finally, the shrub and herb planting areas are obtained.

[0043] S1-2. Construction of tree pits in the tree planting area: Multiple pits are excavated from the original soil layer of the tree planting area; a second matrix layer is laid on the inner wall of each pit using a mixture of coastal saline soil and sand; then, permeable bricks for sponge city construction are laid on the surface of the second matrix layer to form a third permeable brick frame layer; next, lightweight bricks filled with cellulose hydrogel are laid to form a second skeleton frame layer; then, permeable bricks for sponge city construction are laid to form a second permeable brick frame layer; finally, a second nutrient soil layer is laid on the second permeable brick frame layer, which is composed of a mixture of coastal saline soil, kitchen waste, and sludge; ultimately, a tree planting area with multiple tree pits is obtained.

[0044] S2. Excavate planting holes in the first nutrient soil layer, fill the planting holes with organic solid waste humus and compact it, and set up a protective fence around the planting holes and leave them to stand for 24-48 hours.

[0045] S3. Excavate multiple nutrient supply holes around each tree pit, fill the nutrient supply holes with organic solid waste humus and compact it, and set up a protective fence around the tree pit and leave it to stand for 24h-48h.

[0046] S4. After the plant has settled, plant herbaceous plants in the planting holes of the herbaceous plant planting area, plant shrubs in the planting holes of the shrub planting area, and plant trees in the tree holes.

[0047] Preferably, the diameter of the implantation hole is not less than 0.1m and the depth is not less than 0.3m;

[0048] The diameter of the pit for the tree shall not be less than 0.8m and the depth shall not be less than 1.2m;

[0049] The organic solid waste humus is formed by the decomposition of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure.

[0050] Preferably, the mass ratio of coastal saline soil, kitchen waste and sludge in the first nutrient soil layer and the second nutrient soil layer is (4-7):(3-2):1.

[0051] The technical solution of the present invention has the following advantages compared with the prior art:

[0052] This invention provides a terraced structure for improving coastal saline soil and a terraced planting method utilizing easily decomposable organic solid waste in conjunction with coastal saline soil. It utilizes humus from well-rotted kitchen waste, domestic sewage sludge, and livestock manure to provide the nutrients and foundation needed by coastal plants. Simultaneously, the humic acid contained in the humus adjusts the pH of the coastal saline soil. Furthermore, the terraced structure of this invention ensures that saltwater can be washed away from the sand next to the tree planting holes, thus preventing it from damaging the plants and avoiding excessive salinization of the sand. Ultimately, this improves the plantability of coastal saline soil while simultaneously preventing erosion of the coastal beach.

[0053] This invention provides a terraced structure for improving coastal saline soil and a terraced planting method that utilizes easily decomposable organic solid waste in conjunction with coastal saline soil. After the organic solid waste humus in the planting holes, tree pits, and nutrient supply holes is compacted, on the one hand, the gaps are smaller and the fertility is higher, allowing the roots of herbaceous plants, shrubs, and trees to firmly hold on, providing nutrients for the planted plants for a long time. On the other hand, after being wrapped by the plant roots, it can strengthen the coastal saline soil, improve the erosion resistance of the coastal saline soil, and solidify the coastline.

[0054] The main principle of this invention is to utilize the salinity of coastal saline soil. After being washed by rainwater, the saline solution permeates through permeable bricks into the framework layer. The lightweight brick framework (which is honeycomb-shaped and is the most common type of lightweight brick on the market, made primarily of blown lime or perlite and fired at high temperatures) in the framework layer turns into powder or deforms upon contact with the saline solution. From the initial bonding of the lightweight bricks with the cellulose hydrogel to the later powdery bonding, both processes effectively isolate the salt and reduce soil gaps. After a period of maintenance, a mixture of uncomposted coastal saline soil, kitchen waste, and sludge can be added to increase organic acids, further draining salt from the tree pits while ensuring the pits are enclosed by lightweight bricks filled with cellulose gel, thus reducing salt intrusion. After planting, the lightweight bricks and cellulose hydrogel deform and decompose, affecting plant growth. Continuously adding semi-organic solid waste to the oxygen supply holes increases the organic acid content and fertility, promoting salt removal.

[0055] This invention utilizes cellulose hydrogel, which is not corroded by salt water. Salt accumulates on the surface of the cellulose hydrogel, making the tree layer, located at higher elevations, virtually immune to seawater intrusion. Even if seawater does reach the top tree layer, it can drain away through the surrounding soil around the trees, preventing permanent salt pollution and acting as a protective sheath for the tree roots. Simultaneously, the high porosity of coastal saline soil and sand promotes salt drainage, avoiding plants. Organic acids are produced above, while the lower layer has high porosity and small gaps around the plants. Over time, this process allows for the growth of plants in the planting area, creating an interactive planting technique between the fresh and salty soil layers of coastal saline soil. Attached Figure Description

[0056] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0057] Figure 1 This is a schematic diagram of a stepped structure for improving coastal saline soil according to the present invention.

[0058] Figure 2 This is a schematic diagram of the herbaceous plant planting area of ​​the present invention;

[0059] Figure 3 This is a schematic diagram of the shrub planting area of ​​the present invention;

[0060] Figure 4 This is a schematic diagram of the structure of the tree planting area in front of the tree pit constructed according to the present invention;

[0061] Figure 5 This is a schematic diagram of the tree planting area after constructing the tree pit according to the present invention;

[0062] In the attached diagram: 1. Herbaceous plant planting area; 2. Shrub planting area; 3. Tree planting area; 4. Planting hole; 5. Tree pit; 6. Nutrient supply hole; A. Ocean; B. Beach; 001. First substrate layer; 002. First permeable brick frame layer; 003. First skeleton frame layer; 004. First nutrient soil layer; 100. Original soil layer; 200. Cave; 300. Second nutrient soil layer; 400. Second substrate layer; 500. Third permeable brick frame layer; 600. Second skeleton frame layer; 700. Second permeable brick frame layer. Detailed Implementation

[0063] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0064] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the referred to element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0065] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0066] Open sandy beaches face significant challenges in ecological planting due to the strong effects of waves, tides, and typhoons, as well as fluctuations in sand surface elevation and lack of nutrients. Furthermore, the high salt content of coastal saline soil limits the range of suitable planting options, resulting in numerous technical obstacles to coastal ecological restoration.

[0067] Based on this, as a preferred embodiment of the present invention, this embodiment provides a stepped structure for improving coastal saline soil, see reference. Figure 1 In the diagram, A represents the ocean, and B represents the beach. Along the direction from the sea to the coast, at least three planting areas are constructed, arranged in a stepped pattern. These stepped planting areas include at least one of the following: herbaceous plant planting area 1, shrub planting area 2, and tree planting area 3. That is, any one of these three types can be sequentially set up along the direction from the sea to the coast. Herbaceous plant planting area 1 and shrub planting area 2 include a first substrate layer 001, a first frame, and a first nutrient soil layer 004, laid sequentially upwards from the bottom of the beach. Multiple planting holes 4 are excavated at intervals in the first nutrient soil layer 004, and organic solid waste humus is filled into the planting holes 4. In other words, the first substrate layer 001, the first frame, and the first nutrient soil layer 004 are laid upwards from the original beach bottom to construct herbaceous plant planting area 1 and shrub planting area 2. The first substrate layer 001 is connected to the bottom of the beach and serves as the base for the herbaceous plant planting area 1 and / or shrub planting area 2 to support the first frame and the first nutrient soil layer 004, as well as the herbaceous plants and / or shrubs. By setting the first frame, the loss of nutrients from the first nutrient soil layer 004 can be avoided. Planting holes 4 are spaced apart in the first nutrient soil layer 004. Organic solid waste humus is buried in the first nutrient soil layer 004 to provide nutrients to the planted herbaceous plants and shrubs.

[0068] In the tree planting area 3, multiple caves 200 are excavated at intervals. In each cave 200, a second substrate layer 400, a second frame, and a second nutrient soil layer 300 are sequentially laid inwards. The second substrate layer 400 is arranged along the inner wall of the cave 200, forming a tree planting hole 5 in each cave. In other words, the tree planting area 3 is located at the furthest point from the sea surface, and multiple caves 200 are excavated at intervals within it for planting trees. Considering the high requirements of trees for soil structure, the second substrate layer 400, the second frame, and the second nutrient soil layer 300 are sequentially laid inwards from the perimeter of the cave 200. The second substrate layer 400 connects to the bottom of the sandy beach, serving as the base of the tree planting area 3 to support the second frame, the second nutrient soil layer 300, and the trees. The second frame helps prevent nutrient loss from the second nutrient soil layer 300, which is filled with organic solid waste humus to provide nutrients to the planted trees.

[0069] Specifically, the diameter of planting hole 4 should be no less than 0.1m and the depth no less than 0.3m. Properly setting the diameter and depth of planting hole 4 allows herbaceous plants and shrubs to take root in the soil, which is beneficial for their growth.

[0070] Preferably, the diameter of the tree pit 5 is not less than 0.8m and the depth is not less than 1.2m. By reasonably setting the diameter and depth of the tree pit 5, the tree can take root in the soil, which is beneficial to the growth of the tree.

[0071] Preferably, the first substrate layer 001 and the second substrate layer 400 are constructed by mixing coastal saline soil and sand, with a mass ratio of coastal saline soil to sand of 1-2:1-3. By using a mixture of coastal saline soil and sand to form the first substrate layer 001 and the second substrate layer 400, a higher bonding strength is ensured between the herbaceous plant planting area 1, the shrub planting area 2, and the bottom of the sand.

[0072] Preferably, the distance between two adjacent tree holes 5 is ≥2 meters, and the distance between two adjacent planting holes 4 is ≥1 meter. That is to say, by reasonably setting the distance between two adjacent tree holes 5 and two adjacent planting holes 4, trees, herbaceous plants, and shrubs can take root in the soil, which is beneficial to their growth.

[0073] Preferably, the first nutrient soil layer 004 and the second nutrient soil layer 300 are constructed by mixing and piling up coastal saline soil, kitchen waste, and sludge, with a mass ratio of 6:3:1 between the coastal saline soil, kitchen waste, and sludge in the first nutrient soil layer 004 and the second nutrient soil layer 300. In other words, by rationally setting the ratio of coastal saline soil, kitchen waste, and sludge to form the first nutrient soil layer 004 and the second nutrient soil layer 300, the growth of herbaceous plants and shrubs is facilitated.

[0074] Preferably, the first frame includes a first permeable brick frame layer 002 and a first skeleton frame layer 003 arranged sequentially; the first permeable brick frame layer 002 is located above the first substrate layer 001, and is formed by constructing permeable bricks for sponge cities; the first skeleton frame layer 003 is a lightweight brick skeleton structure layer filled with cellulose hydrogel. That is, by setting the first skeleton frame layer 003 filled with cellulose hydrogel, the lightweight brick material used in this invention is formed by high-temperature firing using blown lime or perlite as the main production material. When it encounters salt water, it will turn into powder or deform. From the initial bonding with cellulose hydrogel to the later powdery bonding, the lightweight bricks effectively isolate salt and reduce soil gaps. After a period of maintenance, some uncomposted organic solid waste can be added to increase organic acids, further draining salt from the tree pit and ensuring that the pit is encased by the lightweight brick skeleton structure layer, reducing salt intrusion. After planting, the lightweight bricks and cellulose hydrogel deform and decompose, affecting plant growth. However, continuously adding organic solid waste semi-attachments into the oxygen supply holes increases organic acid production and fertility, promoting salt removal. Furthermore, the cellulose hydrogel is not corroded by saltwater; salt accumulates on its surface, effectively protecting the overlying tree layer from seawater intrusion. Even if seawater reaches the top layer (tree planting area), it can drain away around the tree holes, preventing permanent salt pollution. This acts as a protective sheath for the tree roots. Simultaneously, the large porosity of the S4 structure facilitates salt removal, avoiding contact with plants. The upper layer produces organic acids, while the lower layer has high porosity and small gaps around the plants. Over time, this process fosters plant growth in the planting layer, creating an interactive planting technique that transforms the coastal saline soil into a slightly saline soil layer.

[0075] Preferably, the second frame includes a second skeleton frame layer 600 and a second permeable brick frame layer 700 and a third permeable brick frame layer 500 respectively disposed on the inner and outer sides of the second skeleton frame layer 600; the second permeable brick frame layer 700 and the third permeable brick frame layer 500 are formed by constructing permeable bricks for sponge cities, with the second permeable brick frame layer 700 laid inside the second skeleton frame layer 600 and the third permeable brick frame layer 500 laid outside the second skeleton frame layer 600; the second skeleton frame layer 600 is a lightweight brick skeleton structure layer filled with cellulose hydrogel. That is, by setting a second skeleton frame layer 600 filled with a lightweight brick skeleton structure layer of cellulose hydrogel; the lightweight brick material used in this invention is mainly produced by blowing lime or perlite, and is formed by high-temperature firing. When it encounters salt water, it will turn into powder or deform. When the lightweight brick goes from "initial bonding with cellulose hydrogel" to "later powdery bonding", it plays the role of isolating salt and reducing soil gaps. After a period of maintenance, some uncomposted organic solid waste can be added to increase organic acids, further draining salt from the tree pits while ensuring the pits are encased in a lightweight brick framework structure, reducing salt intrusion. After planting, the lightweight bricks and cellulose hydrogel will deform and decompose, affecting plant growth. Continuously adding semi-appendage organic solid waste into the oxygen supply holes increases organic acid production and fertility, promoting salt drainage. Furthermore, the cellulose hydrogel is not corroded by salt water; salt will accumulate on its surface, leaving the tree layer above largely unaffected by seawater. If seawater does reach the top layer (tree planting area), it can drain away around the tree pits, preventing permanent salt pollution. This acts as a protective sheath for tree roots. Simultaneously, the large porosity of the S4 structure promotes salt drainage, avoiding contact with plants. The upper layer produces organic acids, while the lower layer has high porosity and small gaps around the plants. After long-term restoration, this allows for the growth of plants in the planting layer, creating an interactive planting technique between the saline and brine layers of coastal saline soil.

[0076] Preferably, the second permeable brick frame layer 700 is configured to form a dovetail groove structure that is wider at the top and narrower at the bottom. That is, by setting the second permeable brick frame layer 700 into a dovetail groove structure, the tree pit 5 becomes narrower from top to bottom, thereby preventing the materials inside the second permeable brick frame layer 700, including organic solid waste humus and lightweight bricks filled with cellulose hydrogel, from being washed away.

[0077] Preferably, multiple nutrient supply holes 6 are also provided around the tree pit 5, and organic solid waste humus is buried in the nutrient supply holes 6; the diameter of the nutrient supply holes 6 is 50-70cm, and the depth is 2 / 3-3 / 4 of the second nutrient soil layer 300. That is to say, by reasonably setting the position and size of the nutrient supply holes 6, nutrients are further supplied to the tree, which is beneficial to the growth of the tree.

[0078] Preferably, the organic solid waste humus is derived from the decomposition of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure. The purpose of using kitchen waste, domestic sewage sludge, and livestock and poultry manure is that, after decomposition, these organic solid wastes produce trace amounts of organic acids, increasing soil porosity and nutrients such as organic matter, preventing salt accumulation in the upper soil layer, thus making it more conducive to plant growth and survival along the coastline. Simultaneously, the humic acid contained in the organic solid waste humus adjusts the pH of coastal saline soil, improving its plantability while also preventing erosion of coastal beaches.

[0079] In this invention, after the organic solid waste humus in the planting holes, tree pits and nutrient supply holes is compacted, on the one hand, the gaps are smaller and the fertility is higher, so that the roots of herbaceous plants, shrubs and trees can be firmly held, providing nutrients for the planted plants for a long time. On the other hand, after being wrapped by the growth of plant roots, it can strengthen the coastal saline soil, improve the erosion resistance of the coastal saline soil and solidify the coastline.

[0080] A stepped structure for improving coastal saline soil based on the present invention, such as Figure 1 As shown, a terraced planting method utilizing easily degradable organic solid waste in conjunction with coastal saline soil is proposed, including the following steps:

[0081] S1. Construct at least one of the following in a stepped arrangement: a herbaceous plant planting area 1, a shrub planting area 2, and a tree planting area 3, arranged sequentially along the coastline. That is, on the outer side of the ocean beach, at least one planting area is constructed using coastal saline soil. This planting area may include, for example, herbaceous plant planting area 1, shrub planting area 2, and tree planting area 3. The planting areas are arranged along the coastline in a stepped arrangement, with tree planting area 3 further away from the ocean, herbaceous plant planting area 1 closer to the ocean, and shrub planting area 2 located between herbaceous plant planting area 1 and tree planting area 3.

[0082] Specifically, the construction of S1-1, shrub planting area 2, and herb planting area 1 is as follows: In herb planting area 1 and / or shrub planting area 2, a first substrate layer 001 is formed by laying a mixture of coastal saline soil and sand at the bottom of the beach; then, permeable bricks for sponge city construction are laid on the surface of the first substrate layer 001 to obtain the first permeable brick frame layer 002; next, lightweight bricks filled with cellulose hydrogel are laid to form the first skeleton frame layer 003; then, a first nutrient soil layer 004 is laid on the first skeleton frame layer 003, which is composed of a mixture of coastal saline soil, kitchen waste, and sludge; finally, shrub planting area 2 and herb planting area 1 are obtained.

[0083] Construction of tree pits 5 in tree planting area 3 (S1-2): Multiple pits 200 are excavated in the original soil layer 100 of tree planting area 3; a second base layer 400 is laid on the inner wall of each pit 200 using a mixture of coastal saline soil and sand; then, permeable bricks for sponge city are laid on the surface of the second base layer 400 to form a third permeable brick frame layer 500; next, lightweight bricks filled with cellulose hydrogel are laid to form a second skeleton frame layer 600; then, permeable bricks for sponge city are laid to form a second permeable brick frame layer 700; finally, a second nutrient soil layer 300 is laid on the second permeable brick frame layer 700, which is made of a mixture of coastal saline soil, kitchen waste and sludge; finally, tree planting area 3 with multiple tree pits 5 is obtained.

[0084] S2. Planting holes 4 are excavated in the first nutrient soil layer 004. Organic solid waste humus is filled into the planting holes 4 and compacted. A protective fence is then erected around the planting holes 4, and the soil is left to stand for 24-48 hours. More specifically, planting holes 4 with a diameter of not less than 0.1m and a depth of not less than 0.3m are excavated in the herbaceous plant planting area 1 and the shrub planting area 2. Organic solid waste humus is filled into the planting holes 4 and compacted. A protective fence is then erected around the planting holes 4, and the soil is left to stand for 24-48 hours. It is worth noting that the organic solid waste humus is composed of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure. The mass ratio of coastal saline soil, kitchen waste, and sludge in the first nutrient soil layer 004 and the second nutrient soil layer 300 is 6:3:1.

[0085] S3. Excavate multiple nutrient supply holes 6 around each tree pit 5, fill the nutrient supply holes 6 with organic solid waste humus and compact it, and set up a protective fence around the tree pit 5 and let it stand for 24h-48h. More specifically, excavate tree pits 5 with a diameter of not less than 0.8m and a depth of not less than 1.2m in the tree planting area 3; fill the tree pits 5 with organic solid waste humus and compact it, and set up a protective fence around the planting holes 4 and tree pits 5 and let it stand for 24h-48h. It is worth noting that the organic solid waste humus is composed of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure; the mass ratio of coastal saline soil, kitchen waste, and sludge in the first nutrient soil layer 004 and the second nutrient soil layer 300 is 6:3:1.

[0086] S4. After the plant has settled, plant herbaceous plants in the planting holes of herbaceous plant planting area 1, plant shrubs in the planting holes of shrub planting area 2, and plant trees in tree holes 5.

[0087] In this method, organic solid waste humus is filled and compacted in the planting holes, nutrient supply holes, and tree pits. The compaction strength is preferably 0.3-0.8 MPa. This provides the necessary nutrients for plant growth in a long-term and stable manner. At the same time, it can prevent seawater erosion during high tide. This is because the density of organic solid waste humus is much higher than that of coastal saline soil. When seawater erodes, it quickly permeates through the coastal saline soil and cannot penetrate into the organic solid waste humus in large quantities. Therefore, the growth environment required by the plants can be stably maintained. At the same time, it can solve the problem of urban kitchen waste and domestic sewage sludge disposal.

[0088] After a certain growth cycle, the plant roots bind the coastal saline soil and organic solid waste humus together, thus forming a solid waterproof embankment below the water surface. Above the water surface, the layered arrangement of herbaceous plants, shrubs, and trees resists and intercepts the challenges posed by waves and sea winds to the coastal ecological environment. In time, this can significantly improve the ecological planting environment of the coastal saline soil and the ecological environment of the coastline. Planting greenery by the sea can also firmly lock in the soil and prevent soil erosion.

[0089] In a preferred embodiment, in step S3, a nutrient supply hole 6 is also excavated in the tree planting area. The nutrient supply hole 6 is located around the tree pit 5, and the organic solid waste humus is buried in the nutrient supply hole 6.

[0090] In a preferred embodiment, the organic solid waste humus is produced by fermentation and decomposition of at least two of the following: kitchen waste, domestic sewage sludge, and livestock and poultry manure.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A coastal saline soil amelioration terracing structure characterised in that, Along the sea surface to the coast, at least three planting areas are built, the planting areas are arranged in a stepped manner, and the planting areas include at least one of a herb planting area (1), a shrub planting area (2) and a tree planting area (3); The herb planting area (1) and the shrub planting area (2) include a first base layer (001), a first frame and a first nutrient soil layer (004) which are sequentially laid from the bottom of the beach upwards, the first nutrient soil layer (004) is spaced to dig a plurality of planting holes (4), and the planting holes (4) are filled with organic solid waste humus; The tree planting area (3) is spaced to dig a plurality of caves (200), each cave (200) sequentially lays a second base layer (400), a second frame and a second nutrient soil layer (300) inwards, and the second base layer (400) is arranged along the inner wall of the cave (200); The second frame includes a second skeleton frame layer (600) and a second water permeable brick frame layer (700) and a third water permeable brick frame layer (500) arranged on the inner and outer sides of the second skeleton frame layer (600) respectively; The second water permeable brick frame layer (700) and the third water permeable brick frame layer (500) are built by sponge city water permeable bricks, the second water permeable brick frame layer (700) is laid in the inside of the second skeleton frame layer (600), and the third water permeable brick frame layer (500) is laid in the outside of the second skeleton frame layer (600); The second skeleton frame layer (600) is a light brick skeleton structure layer filled with cellulose hydrogel; The diameter of the planting hole (4) is not less than 0.1 m, and the depth is not less than 0.3 m; The diameter of the tree hole (5) is not less than 0.8 m, and the depth is not less than 1.2 m; The first base layer (001) and the second base layer (400) are built by mixing coastal saline soil and sandy soil, and the mass ratio of the coastal saline soil and the sandy soil in the first base layer (001) and the second base layer (400) is (1-2):(1-3); The distance between adjacent two tree holes (5) is greater than or equal to 2 meters, and the distance between adjacent two planting holes (4) is greater than or equal to 1 meter; The first nutrient soil layer (004) and the second nutrient soil layer (300) are built by mixing coastal saline soil, kitchen garbage and sludge, and the mass ratio of the coastal saline soil, the kitchen garbage and the sludge in the first nutrient soil layer (004) and the second nutrient soil layer (300) is (4-7):(3-2):1; The first frame includes a first water permeable brick frame layer (002) and a first skeleton frame layer (003) which are sequentially arranged; The first water permeable brick frame layer (002) is arranged above the first base layer (001), and the first water permeable brick frame layer (002) is built by sponge city water permeable bricks; The first skeleton frame layer (003) is a light brick skeleton structure layer filled with cellulose hydrogel; The second water permeable brick frame layer (700) is arranged to form a swallow tail groove structure which is wide at the top and narrow at the bottom. A plurality of feeding holes (6) are further arranged around the arbor hole (5), and organic solid waste humus is embedded in the feeding holes (6); The diameter of the feeding hole (6) is 50-70 cm, and the depth is at 2 / 3-3 / 4 of the second nutrient soil layer (300).

2. A coastal saline soil amelioration terracing structure according to claim 1, characterised in that, The organic solid waste humus is formed by at least two of kitchen garbage, domestic sewage sludge and livestock and poultry manure.

3. A step planting method using perishable organic solid waste in cooperation with coastal saline soil, characterized by, The step of planting on the coastal saline soil improvement ladder structure of claim 1 comprises the following steps: S1, at least one of the herbaceous plant planting area (1), the shrub planting area (2) and the arbor planting area (3) arranged in a ladder shape is constructed in sequence along the direction away from the coast; S1-1, construction of the shrub planting area (2) and the herbaceous plant planting area (1): in the herbaceous plant planting area (1) and / or the shrub planting area (2), the first base layer (001) is formed by laying the mixed coastal saline soil and sand on the bottom of the beach; then the first water permeable brick frame layer (002) is obtained by laying the sponge city water permeable brick on the surface of the first base layer (001); then the first skeleton frame layer (003) is formed by laying the light brick filled with cellulose hydrogel; then the first nutrient soil layer (004) is laid on the first skeleton frame layer (003), and the first nutrient soil layer (004) is formed by mixing and stacking the coastal saline soil, kitchen garbage and sludge; finally, the shrub planting area (2) and the herbaceous plant planting area (1) are obtained; S1-2, construction of the arbor hole (5) in the arbor planting area (3): a plurality of holes (200) are formed by excavating the original soil layer (100) of the arbor planting area (3); the second base layer (400) is laid on the inner wall of each hole (200) by mixing the coastal saline soil and sand; then the third water permeable brick frame layer (500) is formed by laying the sponge city water permeable brick on the surface of the second base layer (400); then the second skeleton frame layer (600) is formed by laying the light brick filled with cellulose hydrogel; then the second water permeable brick frame layer (700) is formed by laying the sponge city water permeable brick; finally, the second nutrient soil layer (300) is laid on the second water permeable brick frame layer (700), and the second nutrient soil layer (300) is formed by mixing and stacking the coastal saline soil, kitchen garbage and sludge; finally, the arbor planting area (3) with a plurality of arbor holes (5) is obtained; S2, a planting hole (4) is excavated in the first nutrient soil layer (004), organic solid waste humus is filled and compacted in the planting hole (4), and a protective fence is arranged around the planting hole (4) and left for 24-48 hours; S3, a plurality of feeding holes (6) are excavated around each arbor hole (5), organic solid waste humus is filled and compacted in the feeding holes (6), and a protective fence is arranged around the arbor hole (5) and left for 24-48 hours; S4, after the standing is completed, herbaceous plants are planted in the planting holes (4) of the herbaceous plant planting area (1), shrubs are planted in the planting holes (4) of the shrub planting area (2), and arbor plants are planted in the arbor holes (5).

4. The step planting method according to claim 3, wherein The diameter of the planting hole (4) is not less than 0.1 m, and the depth is not less than 0.3 m. The diameter of the arbor hole (5) is not less than 0.8 m, and the depth is not less than 1.2 m; The organic solid waste humus is formed by at least two of kitchen garbage, domestic sewage sludge and livestock and poultry manure.

5. The step-planting method according to claim 3, wherein The mass ratio of the first nutrient soil layer (004), the second nutrient soil layer (300), coastal saline soil, kitchen garbage and sludge is (4-7):(3~2):1.

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