A planting structure suitable for reservoir drawdown zone in karst area

Abstract

This utility model relates to the field of ecological restoration technology for drawdown zones, specifically to a planting pit structure suitable for karst reservoir drawdown zones. In this structure, a first water-retaining layer is provided on the inner wall of the planting pit, and a second water-retaining layer is provided at the bottom. Several root expansion holes extending downwards are drilled from the inside out at the bottom of the planting pit. Planting soil and a surface cover layer are sequentially filled above the root expansion holes. Moisture-retaining units are distributed within the planting soil, with small holes in the moisture-retaining units for threading long water-draining strips. In this utility model, the water-retaining layer effectively delays lateral and bottom water infiltration and inhibits water evaporation, enhancing the drought resistance of trees and shrubs within the planting pit. The root expansion holes create space for the later growth of tree and shrub roots, while the gravel structure at the bottom of the expansion holes allows for the rapid drainage of excess water from the planting pit after the drawdown zone recedes. The bermudagrass in the surface cover layer forms a water-retaining buffer zone, reducing soil loss and water evaporation within the planting pit.

Description

Technical Field

[0001] This utility model relates to the field of ecological restoration technology for drawdown zones, specifically to a planting pit suitable for the drawdown zones of reservoirs in karst areas, belonging to the field of ecological restoration technology. Background Technology

[0002] Vegetation is a crucial component of the reservoir drawdown zone ecosystem. Strengthening vegetation management and restoring degraded vegetation in the drawdown zone are considered essential for restoring its ecological functions. In southwestern my country, the unique karst topography makes the ecosystem extremely sensitive to changes in the external environment. When karst topography is coupled with the reservoir drawdown zone, factors such as poor soil quality, low water and fertilizer retention capacity, alternating wet and dry periods, and complex topography can hinder the reconstruction and restoration of vegetation in the drawdown zone.

[0003] Currently, vegetation restoration in drawdown zones typically employs a three-dimensional configuration of trees, shrubs, and herbaceous plants, arranged from top to bottom based on elevation. Herbaceous plants are highly environmentally tolerant, grow rapidly, and have strong seed dispersal capabilities, quickly covering the ground surface. However, trees and shrubs usually require a thicker soil layer, while the thin and infertile soil in karst regions hinders root development. Furthermore, in the early stages of vegetation restoration, although placing trees and shrubs in the upper and middle parts of the drawdown zone can reduce mortality due to prolonged submersion, the poor water retention capacity of karst soils means that the drawdown zone will experience water deficits and drought as reservoir levels drop. This drought directly impacts plant growth and can even lead to death. These combined factors result in the initial restoration of trees and shrubs in the drawdown zone being more difficult than that of herbaceous plants, leading to a lower success rate.

[0004] Currently, a common practice to increase soil water retention capacity is to directly mix water-retaining agents into the soil. However, because these agents are dispersed after mixing with the soil, the amount of water that plant roots can effectively utilize in the early stages of planting may be insufficient. Increasing the amount of water-retaining agent may affect soil aeration and is also costly. Furthermore, some researchers have proposed constructing separate water-retaining structures to improve soil water retention capacity. However, in karst regions, due to the thin soil layer and numerous fissures in the bedrock, constructing water-retaining pits under tree and shrub planting structures is difficult and unsuitable. Therefore, it is necessary to provide a tree and shrub planting structure suitable for the drawdown zone of reservoirs in karst regions, combining ecological engineering and adaptive management to improve the success rate of tree and shrub restoration in karst drawdown zones. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a tree and shrub planting structure suitable for the drawdown zone of reservoirs in karst areas, thereby solving the problem of poor water retention in the drawdown zone of karst areas, which is not conducive to the initial recovery of trees and shrubs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A planting structure for trees and shrubs suitable for the drawdown zone of reservoirs in karst areas is characterized by comprising planting pits, a first water-retaining layer on the inner wall of the planting pits, a second water-retaining layer at the bottom of the planting pits, and several root expansion holes extending downwards drilled from the inside to the outside of the bottom of the planting pits. The planting pits above the root expansion holes are filled with planting soil, and moisture-retaining units are distributed in the planting soil. Each moisture-retaining unit has 3-5 small holes of about 1 cm in diameter evenly opened from top to bottom on one side. A 30 cm long water-guiding tape adapted to the hole diameter is threaded through each small hole. The water-guiding tape is knotted at one end inside the moisture-retaining unit and the other end extends out of the moisture-retaining unit. A surface covering layer is laid on top of the planting soil.

[0007] Furthermore, the ratio of the planting hole surface diameter: bottom diameter: depth is 1.15-1.3:1:1.

[0008] Furthermore, the water-retaining layer has a strength of 200-300 g / m³. 2 The non-woven or woven geotextile is used, and the water-retaining layer at the bottom of the planting hole has an opening at the corresponding position at the top of the root expansion hole.

[0009] Furthermore, the root expansion hole is cylindrical with a diameter of 15-20cm and a length of 40-60cm.

[0010] Furthermore, the root expansion holes are filled with 10cm zeolite and 1-2cm particle size zeolite and planting soil from bottom to top.

[0011] Furthermore, the number of root expansion holes is determined according to the size of the planting hole. When the diameter D of the planting hole is 30-50cm, dig an expansion hole in the center of the planting hole; When the diameter D of the planting hole is 50-90cm, dig three expansion holes at the bottom of the planting hole in a triangular arrangement. When the diameter D of the planting hole is greater than 90cm, five expansion holes are dug at the bottom of the planting hole in a plum blossom shape.

[0012] Furthermore, the main body of the moisturizing unit is a cylindrical bamboo basket with a lid, 8cm in diameter and 15cm in height, filled with water-retaining material.

[0013] Furthermore, the material of the water-guiding belt is coconut fiber or cotton and linen woven belt.

[0014] Furthermore, the number of moisture-retaining units should be determined based on the size of the planted trees and shrubs and their root balls. Specifically, the number of units should be the number of root expansion holes + 2, and they should be evenly distributed around the root ball.

[0015] Furthermore, the surface cover is bermudagrass turf.

[0016] Beneficial Effects: Compared with existing technologies, the advantages of this invention are as follows: Laying a water-retaining layer inside the planting hole effectively slows down lateral and bottom water infiltration and inhibits water evaporation, enhancing the drought resistance of trees and shrubs within the planting hole; the root expansion holes dug at the bottom of the planting hole create space for the later growth of tree and shrub roots, while the gravel structure at the bottom of the expansion holes allows for the rapid drainage of excess water from the planting hole after the drawdown zone recedes. The water-retaining material filled inside the moisture-retaining unit continues to release water slowly after the water recedes, and the bamboo basket confines the water-retaining material near the plant roots, delivering water to the roots via a water pipe. The moisture-retaining unit is also easy to remove after the trees and shrubs have stabilized. The bermudagrass covering the ground forms a water-retaining buffer zone, reducing soil loss and vertical water evaporation within the planting hole. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the planting structure.

[0018] Figure 2 A top view showing the arrangement of root extension holes.

[0019] The markings in the diagram are as follows: 1. Planting hole; 2. First water-retaining layer; 3. Second water-retaining layer; 4. Root expansion hole; 5. Planting soil; 6. Moisture-retaining unit; 7. Covering layer; 8. Water-draining strip. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0021] Example: like Figure 1 As shown, this utility model includes a planting hole 1 excavated in the upper part of the drawdown zone, a first water-retaining layer 2 set on the inner side wall of the planting hole, a second water-retaining layer 3 set at the bottom of the planting hole, a number of root expansion holes 4 extending downward from the inside to the outside of the bottom of the planting hole, planting soil 5 filled in the planting hole above the root expansion holes, moisture-retaining units 6 distributed in the planting soil, and a surface covering layer 7 laid on top of the planting soil.

[0022] The size of the planting hole 1 needs to be determined based on the size of the tree or shrub plant and its root ball. The ratio of the planting hole surface diameter: bottom diameter: depth is 1.15-1.3:1:1.

[0023] The main materials of the first and second water-retaining layers are 200-300 g / m². 2 Non-woven or woven geotextiles, by fully covering the sidewalls and bottom of the planting structure with a water-retaining layer, can effectively delay the lateral and bottom water infiltration and loss, and enhance the drought resistance of trees and shrubs in the planting hole.

[0024] Several root expansion holes 4 are drilled at the bottom of the planting hole, and the second water-retaining layer at the bottom of the planting hole has openings at corresponding positions at the top of the root expansion holes. The root expansion holes are cylindrical, 15-20cm in diameter and 40-60cm in length, to create space for the later growth of tree and shrub roots. The number of root expansion holes is determined according to the size of the planting hole. When the bottom diameter D of the planting hole is 30-50cm, one expansion hole is dug in the center of the planting hole; when the bottom diameter of the planting hole is 50-90cm, three expansion holes are dug at the bottom of the planting hole, arranged in a triangular pattern; when the bottom diameter of the planting hole is greater than 90cm, five expansion holes are dug at the bottom of the planting hole, arranged in a quincunx pattern.

[0025] Fill the bottom of the root expansion hole with 10cm of zeolite with a particle size of 1-2cm. This can promote the rapid drainage of supersaturated water in the planting hole after the drawdown zone recedes. The remaining part of the expansion hole is filled with planting soil up to the bottom elevation of the planting hole.

[0026] Planting soil 5 is an improved backfill soil. Its composition and proportions are as follows: 100 parts by weight of the broken and cleaned backfill soil from the excavation of planting holes, 3-5 parts by weight of biochar, 0.5 parts by weight of potassium humate, 0.5 parts by weight of sodium alginate, and 0.3-0.5 parts by weight of EM bacteria, mixed evenly. Biochar can improve the aeration and aggregate structure of the soil in the drawdown zone after water recedes, and reduce soil compaction. The addition of potassium humate and sodium alginate can not only increase soil fertility, but also adjust the pH of the original high-pH soil in the karst region.

[0027] When planting, first backfill the bottom of the planting hole with planting soil to a depth of one-third, then place the root ball of the tree or shrub, and arrange several moisture-retaining units 6 around the root ball. The main body of the moisture-retaining unit is a cylindrical bamboo basket with a lid, 8cm in diameter and 15cm in height. On one side of the moisture-retaining unit, there are 3-5 small holes with a diameter of about 1cm evenly distributed from top to bottom. Each small hole has a 30cm long water-draining tape 8 that is adapted to the hole diameter. The water-draining tape is made of coconut fiber or cotton and linen woven tape. The water-draining tape is tied into a small knot at the inside end of the moisture-retaining unit to ensure that it does not fall out of the moisture-retaining unit, and the other end extends out of the moisture-retaining unit.

[0028] The moisture-retaining unit 6 is filled with one or more of the following as water-retaining materials: highly absorbent resin, expanded vermiculite, and expanded perlite, filling approximately 80% of its volume. The number of moisture-retaining units 6 should be determined based on the size of the planted shrub or tree and its root ball; the specific number is the number of root expansion holes + 2. When placing the unit, align the opening side of the moisture-retaining unit 6 with the plant root ball, and ensure the extended water-guiding tape is horizontally aligned with the root ball, then promptly cover it with soil to secure it.

[0029] As the water level in the drawdown zone decreases, the water-retaining material in the moisture-retaining unit 6 can slowly release moisture, which is then transported to the area around the plant roots via the water-guiding belt 8, thus ensuring that the area around the plant roots remains moist. The moisture-retaining unit 6 should be thoroughly watered during its initial placement to prevent it from competing with the plant roots for water.

[0030] After the moisture-retaining unit 6 is arranged, the planting soil is backfilled to the original ground level, and bermudagrass turf is planted on the top of the planting hole as a surface cover layer 7. Bermudagrass has a very strong survival ability, is tolerant of flooding, drought and barrenness, and can form a water-retaining buffer zone on the surface of the planting hole to reduce soil loss and water evaporation in the planting hole.

[0031] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.

Claims

1. A tree and shrub planting structure suitable for the drawdown zone of reservoirs in karst areas, characterized in that, The device includes a planting hole, with a first water-retaining layer on the inner wall of the planting hole and a second water-retaining layer at the bottom of the planting hole. Several root expansion holes extending downwards are drilled from the inside to the outside of the bottom of the planting hole. The planting hole above the root expansion holes is filled with planting soil, and moisture-retaining units are distributed in the planting soil. On one side of the moisture-retaining unit, 3-5 small holes are evenly opened from top to bottom, and a long water-draining tape with an appropriate diameter is threaded through each small hole. A surface covering layer is laid on top of the planting soil.

2. The tree and shrub planting structure suitable for the drawdown zone of reservoirs in karst areas according to claim 1, characterized in that, The ratio of the planting hole diameter to the bottom diameter to the depth is 1.15-1.3:1:

1.

3. The tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region according to claim 1, characterized in that, Both the first and second water-retaining layers have a strength of 200-300 g / m². 2 The non-woven or woven geotextile is used, and the second water-retaining layer at the bottom of the planting hole has an opening at the corresponding position at the top of the root expansion hole.

4. The tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region according to claim 1, characterized in that, The root expansion hole is cylindrical with a diameter of 15-20cm and a length of 40-60cm.

5. The tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region according to claim 1, characterized in that, The root expansion holes are filled from bottom to top with 10cm zeolite and 1-2cm particle size soil.

6. The tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region according to claim 1, characterized in that, The number of root expansion holes is determined according to the size of the planting hole. When the diameter D of the planting hole is 30-50cm, dig an expansion hole in the center of the planting hole; When the diameter D of the planting hole is 50-90cm, dig three expansion holes at the bottom of the planting hole in a triangular arrangement. When the diameter D of the planting hole is greater than 90cm, five expansion holes are dug at the bottom of the planting hole in a plum blossom shape.

7. A tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region, as described in claim 1, is characterized in that... The main body of the moisturizing unit is a cylindrical bamboo basket with a lid, 8cm in diameter and 15cm in height, filled with water-retaining material. The moisturizing units are vertically and evenly distributed around the root ball of the plant.

8. A tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region, as described in claim 7, is characterized in that... The amount of water-retaining material is 80% of the volume of the moisture-retaining unit.

9. A tree and shrub planting structure suitable for the drawdown zone of a reservoir in a karst region, as described in claim 1, is characterized in that... The surface cover is bermudagrass.

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