Matts-shaped soil preparation and vegetation recovery method suitable for semi-arid region

Abstract

The invention relates to a matts-shaped soil preparation and vegetation recovery method suitable for a semi-arid region, which comprises the following steps of: flattening and compacting the top of a spoil field of the semi-arid region, covering the upper part of the spoil field with a planting soil layer, separating the spoil field by using ridges to form matts, and performing hole-shaped soil preparation in each matts, and a pot-bottom-shaped planting hole is formed in the pot-bottom shape. According to the vegetation recovery method, shrubs are planted in the centers of the pot-bottom-shaped planting holes, and herbaceous plants are planted in the planting holes in a clump planting mode. According to the method, natural rainfall infiltrates in situ through tits-shaped soil preparation, and new water and soil loss caused by sinking holes, gullies and the like formed by runoff collection is avoided; pot-bottom-shaped microenvironment shaping is adopted, so that rainfall in the lattices shaped like the Chinese character'tian 'gathers into the microenvironment where plants grow, a rain culture environment is provided for vegetation recovery in the semi-arid area, natural guarantee can be provided for survival and continuous improvement of vegetation in bare land such as soil taking and spoil areas, and water and soil loss caused by slope runoff scouring can be greatly reduced.

Description

Technical Field

[0001] The invention relates to a method for grid-shaped land preparation and vegetation restoration suitable for semi-arid areas, belonging to the technical field of soil and water conservation. Background Art

[0002] In recent years, with the construction of railways, highways, power transmission and transformation projects, various pipeline projects and mining, a large number of artificial bare lands such as soil dumps and waste dumps have been generated. In terms of the railway industry, Zhang Shuai et al. (Zhang Shuai, Han Lihe. Analysis of the causes of changes in waste dumps in railway construction projects and research on prevention and control measures, Railway Standard Design. 2023. (4) 67.) analyzed the water conservation plans approved and publicized by the Ministry of Water Resources from 2007 to 2021. A total of 2131 waste dumps were set up in 21 railway projects, covering hundreds of thousands of hectares of land, not including the waste dumps specified in the water conservation plans approved by various provinces and cities and the sites formed by the construction of soil dumps, mixing stations, camps, etc. set up along the railway. The waste dumps formed by water conservancy and hydropower projects, mines, etc. have a larger single area. For production and construction projects, the above sites are all temporary occupations and need to be restored and transferred according to the original land use attributes after the project construction is completed.

[0003] The restoration of bare sites caused by engineering construction is mainly restricted by site conditions, plant planting methods, tree and grass species selection, and climatic conditions. my country's climatic conditions vary greatly, spanning tropical, subtropical, warm temperate, mid-temperate, cold temperate, and Qinghai-Tibet Plateau temperature zones. From the perspective of the temporal and spatial distribution of rainfall, the southeast generally has heavy rainfall, while the northwest has less rainfall. The 400 mm precipitation line is roughly along the Greater Khingan Range-Zhangjiakou-Lanzhou-Lhasa-southeast Himalayas line, while the northwest end belongs to the semi-arid zone with less than 400 mm rainfall. As far as vegetation restoration is concerned, the semi-arid zone has little rainfall and high evaporation, and it is extremely difficult for vegetation to grow on bare land caused by production and construction projects. To maintain long-term ecological functions, it is necessary to choose an ecological restoration model suitable for the above site conditions.

[0004] For bare land such as soil dumping and dumping sites caused by production and construction projects, the traditional model is mainly to level the site, then dig tree holes and plant plants, and then build up soil in a ring around the plants to form planting pits. This model can collect rainfall in the range of circular soil building during the vegetation recovery period, which has a certain effect on areas with heavy rainfall, but in semi-arid areas with rainfall of 300 to 400 mm, it blocks ground rainwater from entering the planting pits, causing plants to die due to lack of water, affecting the survival rate of vegetation. According to the investigation, the above reasons are the main reasons for the degradation or death of artificial vegetation in semi-arid areas within three years after planting.

[0005] Temporary land requisitioned for production and construction projects needs to be transferred to the land-owning unit or individual after the vegetation is restored. After the transfer, there is a lack of human maintenance and management, and it is necessary to fully rely on external natural conditions to form "rain-fed forestry" and "rain-fed vegetation". This is the necessary vegetation restoration model for vegetation restoration in semi-arid areas. The National Forestry and Grassland Administration of the People's Government of the Ningxia Hui Autonomous Region issued the "Implementation Plan for the Construction of Scientific Greening Pilot Demonstration Zone in Ningxia Hui Autonomous Region", which fully reflects the technical requirements for vegetation planting in semi-arid areas.

[0006] Some large-scale soil extraction and disposal sites or dumping sites often form a large catchment area after the site is leveled. If it cannot be divided into areas or blocks for local infiltration, surface runoff will quickly form. After the runoff is gathered, it will not only cause new soil and water losses such as gully erosion, but it will also easily form sinkholes in the loess area, triggering geological disasters such as headwater erosion and causing the soil extraction and disposal site to become unstable.

[0007] Traditional step-shaped land preparation requires the formation of an inwardly inclined slope and the installation of a transverse drainage ditch on the inside of each terrace. The above land preparation mode requires a large amount of earthwork, poor continuity in construction such as covering soil, and the installation of an inner drainage ditch increases the cost of the project. At the same time, since the abandoned soil dump and other places are loose earthworks, the filling materials are complex and diverse in type, and the drainage ditch is often broken or damaged due to uneven settlement of the site after construction, causing the collected rainwater to seep along the cracks to form sinkholes. The larger the catchment area in the loess area, the more prominent the problem. If the inward slope of the step-shaped land preparation is insufficient, the rainwater will overflow along the lower slope after collection, forming an erosion ditch hanging slope or slope collapse, causing new and more serious soil and water loss.

[0008] Traditional vegetation restoration techniques in semi-arid areas generally use broadcasting and planting grass in combination with hole-shaped land preparation and circular soil cultivation. However, due to the poor soil quality of the exposed surface formed by artificial filling, it is difficult to provide a stable growth environment for vegetation growth even if the planting soil is replaced. In the loess region, if there is no irrigation facility, the survival rate of grass seeds broadcast on bare land is less than 30% under natural conditions. After one to two growing seasons, almost all of them die and are replaced by foreign annual weeds. The poor vegetation restoration effect has always been a key problem that has troubled all parties. Even if drought-resistant shrubs such as Tamarix, Caragana, Flower Stick, and Seabuckthorn are selected, after two to three replantings, the survival rate in most areas is less than 60%, and the growth is slow. The installation of drip irrigation and other facilities requires the configuration of a reservoir, which is not only expensive, but also difficult to guarantee the water source. Some projects need to transport water over long distances by water trucks, and the facilities are abandoned after the handover, resulting in great waste. Summary of the invention

[0009] 1. Technical issues to be resolved

[0010] To solve the above problems of the prior art, the present invention provides a method suitable for grid-shaped land preparation and vegetation restoration in semi-arid regions, particularly relating to a soil and water conservation technology system for afforestation on the top of spoil banks in semi-arid loess regions. By means of grid-shaped land preparation, regional runoff is collected and preserved, and in combination with the "pot-bottom" micro-topography, a "rain-fed" micro-environment is formed, providing a new model for vegetation restoration and afforestation in spoil banks and borrow pits in semi-arid regions.

[0011] (II) Technical Solution

[0012] To achieve the above object, the main technical solutions adopted by the present invention include:

[0013] A method suitable for grid-shaped land preparation in semi-arid regions, which comprises leveling and compacting the top of the spoil bank in semi-arid regions, covering the upper part with a planting soil layer, separating the spoil bank with soil ridges to form a "grid" shape, and carrying out pit-shaped land preparation in each grid to make the pit-shaped land preparation in a "pot-bottom" shape to form a pot-bottom-shaped planting pit.

[0014] For the method as described above, preferably, the thickness of the planting soil layer is 30 - 50 cm.

[0015] For the method as described above, preferably, a drainage ditch is arranged around the spoil bank to prevent rainwater outside the ditch from entering the inside of the landfill body.

[0016] For the method as described above, preferably, an agricultural access road is reserved in the middle or on one side of the grid, and a low crosswise soil ridge for the agricultural access road is arranged every 5 - 7 m in the agricultural access road. Further, the height of the low soil ridge is 9 - 11 cm.

[0017] For the method as described above, preferably, the bottom width of the soil ridge forming the "grid" shape is 45 - 55 cm, and the height is 25 - 35 cm.

[0018] For the method as described above, preferably, each grid is set with a plot according to the size of the site plane in the specification of 5 - 15 m wide × 7 - 20 m long.

[0019] Further, preferably, each grid is set with a plot according to the size of the site plane in the specification of 6 m × 8 m or 12 m × 16 m.

[0020] For the method as described above, preferably, the radius of the pot-bottom-shaped planting pit is 0.8 - 1.2 m, and the depth is 25 - 35 cm. Further, the radius of the pot-bottom-shaped planting pit is 1 m, and the depth is 30 cm.

[0021] For the method described above, preferably, the replacement filling depth of the planting soil in the pot-bottom-shaped planting hole is not less than 50 cm, and the edge of the pot-bottom-shaped planting hole is connected to the flat ground, avoiding the setting of circumferential soil ridges to ensure that the rainwater on the site can flow smoothly into the pot-bottom-shaped planting hole, continuously providing the guarantee of rainfall irrigation and maintenance for plant growth.

[0022] A method suitable for the grid-shaped land preparation and vegetation restoration in semi-arid areas, which is to plant shrubs in the center of the pot-bottom-shaped planting holes set by the land preparation method described above, and plant herbaceous plants in the planting holes in a cluster planting pattern.

[0023] In a preferred embodiment, the shrubs are Atriplex canescens, Hippohgae rhamnoides and / or Caragana korshinskii, and the herbaceous plants are Achnatherum splendens and / or Agropyron cristatum. After the shrubs are planted, the planting holes are covered with plastic film. Further, 1 - 3 shrubs are planted in each hole, and the shrubs are preferably 2 - 3-year-old seedlings or container seedlings; the herbaceous plants occupy 2 / 3 of the area at the bottom of the hole.

[0024] For the method for grid-shaped land preparation in semi-arid areas described above, the "grid-shaped" can be replaced with "triangle-shaped", and the "grid" shape can be replaced with the "triangle" shape.

[0025] (III) Beneficial effects

[0026] The beneficial effects of the present invention are as follows:

[0027] The present invention provides a method for grid-shaped land preparation and vegetation restoration, which can effectively solve the deficiencies of traditional land preparation and vegetation restoration measures, and can provide an effective new ecological governance model for semi-arid areas.

[0028] The method for grid-shaped land preparation and vegetation restoration provided by the present invention is applicable to large-scale land preparation and vegetation restoration in spoil grounds and waste slag yards in semi-arid areas, can replace the terrace-shaped land preparation and the construction of transverse drainage ditches in the site, and can create a good microenvironment for the vegetation restoration of artificial bare land.

[0029] The method for grid-shaped land preparation and vegetation restoration provided by the present invention enables natural precipitation to infiltrate locally through grid-shaped land preparation, avoiding the formation of new soil erosion caused by the concentration of runoff to form sinkholes, gullies, etc.

[0030] Based on the "grid" - shaped land preparation, the present invention proposes the shaping of a "pot-bottom" - shaped microenvironment, enabling the rainfall separated in the grids to converge into the microenvironment for plant growth, providing a "rain-fed" environment for vegetation restoration in semi-arid areas, and being able to provide a natural guarantee for the survival and continuous improvement of vegetation on bare lands such as spoil grounds and waste slag yards.

[0031] The invention provides a method for grid-shaped land preparation and vegetation restoration, which can use local materials, can be mechanically formed, and can also be constructed by workers. After land preparation, the site is neat and orderly, which can greatly reduce serious soil and water loss phenomena such as "channel hanging slope" caused by slope runoff scouring, and avoid secondary soil and water loss disasters such as sinkholes caused by excessive concentration and infiltration of rainwater inside the site in the collapsible loess area.

[0032] The invention provides a method for land preparation and vegetation restoration in a grid pattern. On the basis of land preparation in a grid pattern combined with a pot bottom pattern, vegetation is selected such as drought-resistant, salt-alkali-resistant and barren-resistant shrubs as Atriplex canescens (Pursh) Nutt., Hippophae rhamnoides L., Caragana korshinskii Kom., etc., and grass species are Neotrinia splendens (Trin.) Nevski. and Agropyron cristatum (L.) Gaertn. as pioneer vegetation. Under the natural condition of "rain feeding", a new model can be provided for the restoration of vegetation of temporary land for construction projects in semi-arid areas, especially in semi-arid loess areas, and the survival rate and preservation rate of vegetation are further improved on the basis of reducing the engineering cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a technical layout diagram of grid-shaped land preparation and vegetation restoration;

[0034] Figure 2 This is a cross-sectional diagram of shrub planting using the grid-like land preparation and vegetation restoration techniques;

[0035] Figure 3 This is a cross-section diagram of herbaceous planting using grid-like land preparation and vegetation restoration techniques.

[0036] [Description of Reference Numerals]

[0037] 1: Low earth ridges across the mechanized farming road;

[0038] 2: Mechanized farming roads;

[0039] 3: Vertical field grid earth ridge;

[0040] 4: Horizontal field grid earth ridge;

[0041] 5: Pot-shaped planting hole;

[0042] 6: Vegetation;

[0043] 7: Fill the earth ridge;

[0044] 8: Landfill;

[0045] 9: shrubs;

[0046] 10: Clustered herbs. DETAILED DESCRIPTION

[0047] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0048] Example 1

[0049] A "field"-shaped land preparation and vegetation restoration technology is to set up drainage ditches around the temporary landfills such as soil and waste after the landfills are filled to the designed elevation to prevent external rainwater from entering the ditches. On this basis, the top of the soil and waste is leveled and compacted, and a 30-50 cm thick planting soil layer is covered on the top. The fields are set up in the size of the site in the size of 6 meters (width) × 8 meters (length), or 12 meters (width) × 16 meters (length). Figure 1 As shown, adjacent fields are separated by earth ridges with a bottom width of 50 cm and a height of 30 cm, and the fields separated by the longitudinal earth ridge 3 and the transverse earth ridge 4 are connected to form a "field" grid. According to the size of the site plane, a lane for farming vehicles and the like can be set in the middle or one side of the field grid as a reserved mechanized farming road 2. A 10 cm low earth ridge, i.e., a transverse low earth ridge 1 of the mechanized farming road, is set horizontally at about 6 meters intervals between the lanes, which can prevent rainwater from gathering into runoff and causing soil and water loss problems such as gully erosion while ensuring the passage of vehicles.

[0050] "Tianzi grid" is a figurative description. During the land preparation process, the above-mentioned fields can also be separated into "pin" shapes by earthen ridges, but in general, "Tianzi grid"-shaped land preparation is more convenient. "Tianzi grid" uses local materials and can be constructed manually or mechanically using backfilled planting soil. During manual construction, attention should be paid to compacting to avoid human disturbance during the planting process of surrounding vegetation, which may cause earthen ridges to collapse. "Tianzi grid"-shaped land preparation can be set up on the top of a fully leveled soil and waste dump, or it can be implemented after step-shaped land preparation on the top of the soil and waste dump. It mainly plays the role of separating rainfall runoff and promoting local rainwater infiltration.

[0051] After the "field" shape land preparation, hole-shaped land preparation is carried out at a spacing of 2 meters (width) × 2 meters (length). The planting holes are filled with planting soil, and the filling depth is not less than 50 cm. The radius of the planting hole is controlled at 1 meter. The hole-shaped land preparation is in the shape of a "pot bottom". A depth of 30 cm is appropriate to form a pot bottom planting hole 5. Vegetation 6 is planted in the pot bottom planting hole 5. The edge of the pot bottom planting hole 5 is connected with the flat site to avoid setting up a circular earth ridge to ensure that rainwater on the site can flow smoothly into the "pot bottom" shaped planting hole, providing continuous rainfall irrigation and maintenance for plant growth. The center of the pot bottom planting hole 5 is 1 meter away from the "field" separation earth ridge to ensure the uniformity of the hole-shaped land preparation space and seedling planting.

[0052] On the basis of the above-mentioned "field grid" combined with the "pot bottom" shape land preparation, shrubs such as Atriplex, Hippophae rhamnoides, and Caragana korshinskii are planted in the center of the pot bottom shaped planting hole. Herbaceous vegetation should be planted in clumps in the planting hole, occupying 2 / 3 of the area of ​​the hole bottom. Select Achnatherum splendens and Ice grass as pioneer vegetation. Grass seeds can be mixed planted. One shrub is planted in each planting hole, 1 to 3 plants per hole. Shrubs should be selected from 2 to 3 year old seedlings or container seedlings.

[0053] Shrubs and grass seeds should be planted in spring or autumn. After shrubs are planted, the planting holes should be covered with mulch. Attention should be paid to watering in the early stage of planting to increase the survival rate.

[0054] The present invention collects and preserves regional runoff through "grid-shaped" land preparation, and cooperates with the "bottom of a pot"-shaped micro-topography to form a "rain-fed" micro-environment, providing a new model for vegetation restoration and afforestation in soil borrowing sites and abandoned soil slag sites in semi-arid areas.

[0055] The present invention provides an easy-to-implement "grid"-shaped land preparation model for semi-arid areas. After the backfill or excavation surface is covered with soil, mechanical or manual soil shaping can be adopted on site. Compared with step-shaped land preparation, the land preparation earthwork volume is reduced by 98%. At the same time, the arrangement of the lateral drainage ditch inside the step-shaped land preparation is reduced, and the construction period and cost are greatly reduced.

[0056] The present invention provides a "field grid" combined with a "pot bottom" shaped land preparation mode for bare land such as soil dumping and waste dumping sites in semi-arid areas. Compared with traditional land preparation modes such as steps, the "field grid" earth ridge separation can make 100% of the rainfall in the top projection range of the soil dumping and waste dumping site be intercepted in the "field grid". At the same time, the "pot bottom" hole-shaped land preparation reduces the setting of circumferential soil ridges around the planting holes, and the rainfall runoff accumulated in the surrounding range of the "field grid" can all enter the "pot bottom" and gather at the roots of plants, providing a good microenvironment and continuous soil moisture conditions for plant growth.

[0057] Tests at the abandoned soil dump of the Gansu section of the Zhonglan Railway found that the "grid-shaped" combined with the "pot bottom" land preparation pattern, under the same rainfall conditions, increased the plant root wetting depth by 25 to 30 centimeters and the soil moisture content by 20% compared with the ordinary planting hole combined with the circular earth ridge land preparation pattern.

[0058] Example 2

[0059] A method of "grid-shaped" land preparation and vegetation restoration, in which the top of the excavated and abandoned soil residues is leveled and compacted in semi-arid areas, such as Figure 2 and Figure 3After the backfill soil 8 is leveled, a planting soil layer 30 cm to 50 cm thick is covered on the top to form a soil ridge 7. The field plots are set according to the size of the site plane with a specification of 6 meters (width) × 8 meters (length). Adjacent fields are separated by a soil ridge with a bottom width of 50 cm and a height of 30 cm. The fields separated by the longitudinal field grid soil ridge 3 and the transverse field grid soil ridge are connected to form a "field" grid shape. In the field, a "pot-shaped" hole preparation is carried out at a spacing of 2 meters × 2 meters. The planting hole is replaced with planting soil. The replacement depth is not less than 50 cm. The planting hole radius is 1 meter, and the depth is 30 cm to form a pot-shaped planting hole 5.

[0060] A shrub 9 is planted in the center of the pot-bottom-shaped planting hole. By comparing the planting conditions of several suitable shrubs such as Atriplex, Hippophae rhamnoides and Caragana korshinskii, it is found that after planting in spring without irrigation, the survival rate of Caragana korshinskii planted in ordinary holes is less than 35% for the first planting, and the survival rate is less than 70% in autumn of the same year after two replantings; while the survival rate in autumn of the same year can generally reach about 85% under the "field grid" combined with the "pot-bottom" shaped land preparation mode provided by the present invention, and the seedling height and growth momentum are significantly higher than those of ordinary land preparation. Under the land preparation conditions of the present invention, the growth height of Atriplex caneskinensis in the same year is about 30 cm higher on average than that of the ordinary land preparation mode.

[0061] Planting 10 clumps of herbs in a pot-bottom-shaped planting hole, experimental research found that the survival rate of Achnatherum splendens and Ice Grass after sowing in the ordinary land preparation mode is less than 30%. In the hot and dry climate in summer, the survival rate and preservation rate in the autumn of the same year are less than 10%, and they are scattered in small pieces in low-lying areas. The above two kinds of herbaceous vegetation planted in the "pot bottom" shaped hole of the present invention have a survival rate of up to 75% under the same conditions, and the effect is obvious. Experiments in the Ningxia area of ​​the Zhonglan Railway found that the ordinary land preparation mode combined with drip irrigation maintenance for one growing season can achieve a shrub survival rate of about 75%, and the survival rate of sowing grass seeds is about 40%. In contrast, the "field grid" of the present invention combined with the "pot bottom" shaped land preparation mode can irrigate the shrubs once a day in the early stage of planting for one week, and the survival rate of shrubs and herbaceous vegetation can reach 90% in the same year.

[0062] After the same plot was leveled, serious ditch "hanging slope" phenomenon and other serious soil and water loss occurred on the front slope before the "field grid" combined with "pot bottom" shaped micro-topography land preparation was adopted. After the "field grid" combined with "pot bottom" shaped land preparation mode provided by the present invention was rectified, the "hanging slope" phenomenon of the front slope ditch was reduced by 98%, and only a small number of erosion gullies were formed by confluence scouring after the destruction of a small number of earth ridges around the field grid, and the soil and water conservation effect was extremely significant.

[0063] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any person skilled in the art can use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for grid-shaped land preparation in semi-arid areas, characterized in that: It is to level and compact the top of the waste soil yard in the semi-arid area, cover the upper part with a planting soil layer, use earth dikes to separate the waste soil yard into a "field" grid shape, and carry out hole-shaped land preparation in each "field" grid so that the hole-shaped land preparation is in a "pot bottom shape" to form a pot-bottom-shaped planting hole.

2. The method according to claim 1, characterized in that The thickness of the said planting soil layer is 30 - 50 cm.

3. The method according to claim 1, characterized in that A drainage ditch is set around the waste soil yard to prevent rainwater outside the ditch from entering the inside of the landfill body.

4. The method according to claim 1, characterized in that An agricultural tractor road is reserved in the middle or on one side of the "field" grid, and a low horizontal earth dike for the agricultural tractor road is set every 5 - 7 m in the agricultural tractor road.

5. The method according to claim 1, characterized in that The bottom width of the earth dike forming the "field" grid shape is 45 - 55 cm, and the height is 25 - 35 cm.

6. The method according to any one of claims 1 to 5, characterized in that Each "field" grid is set with a field block according to the size of the site plane in the specification of 5 - 15 m wide × 7 - 20 m long; the radius of the pot-bottom-shaped planting hole is 0.8 - 1.2 m, and the depth is 25 - 35 cm.

7. The method according to claim 1, characterized in that The planting soil with a replacement depth of not less than 50 cm is backfilled in the pot-bottom-shaped planting hole, and the edge of the pot-bottom-shaped planting hole is connected with the flat site, avoiding setting a circumferential earth dike to ensure that the site rainwater can flow smoothly into the pot-bottom-shaped planting hole, and continuously provide the guarantee of rainfall irrigation and maintenance for plant growth.

8. A method for grid-like land preparation and vegetation restoration in semi-arid areas, characterized in that: Shrubs are planted in the center of the pot-bottom-shaped planting hole set by the land preparation method described in any one of claims 1 - 7, and herbaceous plants are planted in the planting holes in a clump planting manner.

9. The method according to claim 8, characterized in that The said shrubs are Atriplex canescens, Hippohgae rhamnoides, and / or Caragana korshinskii, and the herbaceous plants are Achnatherum splendens and / or Agropyron cristatum. After the shrubs are planted, the planting holes are covered with plastic film.

10. The method for preparing a field grid shape applicable to the semi-arid area described in any one of claims 1 - 7, wherein the "field" grid shape can be replaced by a "product" grid shape, and the "field" grid shape can be replaced by a "product" grid shape.

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