Seedling afforestation method for abrupt slope mountain land

Abstract

The invention discloses an abrupt slope mountain nursery stock afforestation method, which belongs to the technical field of forestry afforestation, and comprises the following steps: S1, constructing a normalized and structurally stable microtopography reconstruction unit on a slope surface; s2, performing root pruning, root dipping and leaf cutting pretreatment on the target nursery stock; s3, planting the target nursery stock at a specific point position in the microtopography transformation unit, and cooperatively using a degradable basal disc container; s4, performing accurate water and fertilizer supply based on a soil moisture threshold value through an integrated water and fertilizer management module (a porous infiltrating irrigation pipe and a water collection cellar); and S5, performing survival period monitoring and maintenance. According to the method, engineering and management measures are integrated, the technical problems of low seedling survival rate, difficult water and soil conservation and high maintenance cost in abrupt slope mountainous region afforestation are effectively solved, and the afforestation effect and ecological benefits under the difficult site condition are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of forestry afforestation technology, and in particular to a method for afforestation of seedlings on steep mountain slopes. Background Technology

[0002] Steep slopes and mountainous areas are key areas for soil and water conservation and ecological restoration, and also present challenges in traditional afforestation techniques. These areas typically feature steep slopes (25°–60°), thin soil layers, high gravel content, poor water and fertilizer retention capacity, and susceptibility to soil erosion, making them typical difficult site conditions. Afforestation in these areas faces the following long-standing and unresolved technical bottlenecks: (1) Low survival rate of seedlings: Conventional pit size and structure are easily destroyed by rainstorms and have insufficient water storage capacity during drought, making it difficult to meet the root growth and water needs of seedlings; (2) Limited soil and water conservation effect: Traditional methods do not modify the micro-topography enough, have weak water collection, water storage and soil conservation capabilities, and fail to effectively overcome the adverse conditions of steep slopes. In the early stage of afforestation, the project is prone to failure due to soil erosion. (3) Difficulty in maintenance and management: The steep slope is inconvenient to access, and the cost of manual watering and fertilization is high and inefficient. Seedlings lack a continuous and precise supply of water and fertilizer during the critical survival period. (4) Low integration of technology: Existing technologies focus on a single land preparation or planting process, and fail to systematically integrate micro-topography modification, seedling pretreatment, precision water and fertilizer management and monitoring and maintenance to form an integrated solution for the special habitat of steep slopes.

[0003] Currently, although there are some afforestation techniques for difficult sites, such as using horizontal trenching, setting up drainage ditches, or using wooden piles to stabilize slopes, they still have limitations in practice. For example, some techniques fail to systematically integrate land preparation, soil improvement, seedling treatment, stabilization, and post-planting maintenance; some methods are costly or limited by terrain (e.g., large machinery cannot access steep slopes); and some methods are ineffective when dealing with extremely steep (e.g., slopes > 45°) or severely stony sites. Summary of the Invention

[0004] The purpose of this invention is to propose a method for afforestation of seedlings on steep slopes to solve the problems mentioned in the background art. This method aims to significantly improve the survival rate and early growth vigor of seedlings under difficult site conditions on steep slopes by integrating micro-topography modification, seedling pretreatment, positioning planting and integrated water and fertilizer management, while enhancing the water and soil conservation function in the early stage of afforestation and reducing the later maintenance cost.

[0005] To achieve the above objectives, the present invention provides a method for afforestation of seedlings on steep mountain slopes, comprising the following steps: Step S1: Construction of micro-topography modification units: On the slope of the afforestation area in the steep mountain, construct several micro-topography modification units for planting target seedlings. The micro-topography modification units are equipped with water and fertilizer management modules for supplying water and fertilizer to the target seedlings. Step S2: Pretreatment of target seedlings: Select target seedlings that are suitable for the conditions of steep mountain slopes and perform pretreatment; Step S3: Positioning and planting: Plant the pretreated target seedlings at the designated planting points in the micro-topography modification unit; Step S4: Integrated water and fertilizer management: After planting, the target seedlings are initially supplied with water and fertilizer through the water and fertilizer management module integrated into the micro-topography modification unit. Step S5: Survival period monitoring and maintenance: During the survival period after afforestation, monitor and maintain the growth status of the target seedlings and the stability of the micro-topography modification unit.

[0006] Preferably, in step S1, steep mountainous terrain refers to mountainous terrain with a slope greater than 25 degrees and less than 60 degrees, a soil layer thickness of no more than 50 cm, and varying degrees of risk of soil erosion. The structure of the micro-topography modification unit is as follows: a semi-circular or approximately crescent-shaped pit is dug on the slope along the contour line direction. The pit surface is inclined inward to form a water catchment area. The outside of the pit is built with excavated soil or stones to form a dam.

[0007] Preferably, in step S1, the construction of the micro-topography modification unit is determined based on the specifications of the target seedlings and the slope soil conditions. The target seedlings are classified into Grade I and Grade II seedlings based on their diameter at ground level (D) and height (H): Grade I seedlings have a diameter at ground level of not less than 0.5 cm and a height at ground level of not less than 50 cm; Grade II seedlings have a diameter at ground level of not less than 0.3 cm and a height at ground level of not less than 0.5 cm and a height at ground level of not less than 30 cm and a height at ground level of not less than 50 cm. For Grade I seedlings, construct large-scale micro-topography modification units with a pit opening length greater than 80cm and less than 100cm, a pit width greater than 60cm and less than 80cm, and a pit depth greater than 40cm and less than 50cm; for Grade II seedlings, construct small-scale micro-topography modification units with a pit opening length greater than 60cm and less than 80cm, a pit width greater than 40cm and less than 60cm, and a pit depth greater than 30cm and less than 40cm.

[0008] Preferably, in step S2, the target seedlings refer to native tree species that are adapted to the climate of the afforestation site and have strong drought resistance and tolerance to poor soil conditions, or seedlings of superior tree species that have been successfully introduced through trials. The drought resistance and tolerance to poor soil characteristics are as follows: drought resistance: after 30 consecutive days of drought, the wilting rate of the target seedlings is no more than 30%; tolerance to poor soil: the target seedlings sprout new shoots normally under the condition of no external fertilization. Excellent tree species seedlings that have successfully undergone introduction trials are characterized by: completing an introduction and domestication trial of no less than 3 years, with a seedling survival rate of no less than 85%, an annual growth of no less than 20 cm, and no major outbreaks of diseases and pests during the trial period.

[0009] Preferably, in step S2, the preprocessing process includes: Root pruning involves trimming excessively long or damaged roots in the target seedlings, retaining roots longer than 20cm and shorter than 30cm. Root dipping involves coating the roots of the target seedling with a mud slurry containing a water-retaining agent and rooting powder. Pruning: For broadleaf target seedlings, remove one-third to one-half of the leaves to reduce transpiration.

[0010] Preferably, in step S3, the designated planting point is the bottom center point of the micro-topography modification unit; during planting, the base container is first placed at the designated planting point, then the target seedling is placed in the base container, and then fine topsoil is backfilled and gently compacted so that the soil surface at the root collar of the seedling is 3cm lower than the surface of the pit opening; the base container is a cylindrical container made of biodegradable material, containing nutrient soil and slow-release fertilizer, with a bottom diameter greater than 12cm and less than 18cm and a height greater than 15cm and less than 25cm.

[0011] Preferably, in step S4, the water and fertilizer management module includes: a porous drip irrigation pipe buried near the root system of the target seedling and a detachable water collection cellar located above the micro-topography modification unit; Initial water and fertilizer supply refers to: immediately after planting, watering is carried out through porous drip irrigation pipes to allow water to penetrate into the main distribution layer of the root system; in the event of continuous drought, rainwater collected in water collection pits or artificial irrigation is used to supplement the irrigation water, and water-soluble compound fertilizer with a predetermined concentration ratio is added to the irrigation water.

[0012] Preferably, the predetermined concentration refers to a water-soluble compound fertilizer concentration of greater than 0.1% and less than 0.3% by mass volume percentage. The trigger condition for supplemental irrigation is when the soil volumetric water content is monitored to be lower than the critical water and fertilizer threshold. The critical water and fertilizer threshold is defined as: the minimum soil moisture content required to maintain the normal physiological activities of the root system for the target seedlings, which is greater than 50% or 60% of the field capacity.

[0013] Therefore, the above-mentioned method for afforestation of seedlings on steep mountain slopes has the following advantages: (1) System integration and strong targeting: This invention integrates engineering measures (micro-topography modification unit), biological measures (seedling pretreatment), material measures (base tray container) and management measures (water and fertilizer integration) into a complete technical system specifically for the characteristics of steep mountain habitats, solving the problem of limited effect of single technical measures; (2) Improve survival rate and growth potential: Differentiated micro-topography modification units provide stable growth space for seedlings of different specifications; seedling pretreatment reduces transplant stress; base tray containers provide an excellent rhizosphere environment; integrated water and fertilizer management ensures water and nutrient supply during critical periods, thereby comprehensively guaranteeing the survival and early rapid growth of seedlings. (3) High-efficiency soil and water conservation and resource utilization: The micro-topographical modification unit with reinforced structure can effectively intercept surface runoff and prevent soil erosion. The combination of water collection cellar and seepage irrigation pipe realizes the collection and efficient utilization of natural precipitation, reduces dependence on external water sources, and is particularly suitable for water-scarce mountainous areas; (4) Reduce long-term maintenance costs: Through precise water and fertilizer management and solid engineering measures in the early stage, the frequency and workload of manual patrol, irrigation and replanting in the later stage are reduced, thus reducing the overall afforestation cost from the perspective of the whole life cycle. (5) Standardization and scalability: The method quantifies key aspects (such as pit specifications, seedling grading, and water and fertilizer thresholds), forming a standardized operating procedure that is easy to promote and apply in afforestation projects on steep slopes in different regions.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the steps of a method for afforestation of seedlings on steep mountain slopes mentioned in an embodiment of the present invention; Figure 2 This is a schematic diagram of a micro-topography modification unit in a method for afforestation of seedlings on steep slopes mentioned in an embodiment of the present invention.

[0016] Figure label: 1. Steep slopes and mountains; 2. Target seedlings; 3. Embankments and weirs; 4. Base containers; 5. Porous drip irrigation pipes; 6. Water collection pits. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0019] Example like Figure 1-2 As shown in the figure, this embodiment provides a method for afforestation of seedlings on steep mountain slopes, including the following steps: Step S1: Construction of Micro-topography Modification Units: On the slope of the afforestation area in the steep mountain area 1 (steep mountain area 1 refers to mountainous terrain with a slope of not less than 25 degrees, relatively thin soil layer, and varying degrees of risk of soil erosion), several micro-topography modification units for the target seedlings 2 are constructed. A micro-topography modification unit is an independent soil structure that is artificially or semi-artificially shaped on the slope of the steep mountain area 1, which can locally improve soil moisture and nutrient conditions and provide a stable space for the root growth of seedlings. The specific structure of the micro-topography modification unit is as follows: a semi-circular or approximately crescent-shaped pit is dug along the contour line on the slope. The pit surface is slightly inclined inward to form a water catchment area. The outer side is built with excavated subsoil or stones to form a dam 3. The micro-topography modification unit is equipped with a water and fertilizer management module for supplying water and fertilizer to the target seedlings 2.

[0020] The construction of the micro-topography modification unit is determined based on the specifications of the target seedling 2 and the slope soil conditions. The specifications of the target seedling 2 are divided into Grade I seedlings and Grade II seedlings according to the diameter at ground level (D) and seedling height (H). The D of Grade I seedlings is not less than 0.5 cm and the H is not less than 50 cm. The D of Grade II seedlings is not less than 0.3 cm and less than 0.5 cm, and the H is not less than 30 cm and less than 50 cm.

[0021] For Grade I seedlings, construct large-scale micro-topography modification units with a pit opening length greater than 80cm and less than 100cm, a pit width greater than 60cm and less than 80cm, and a pit depth greater than 40cm and less than 50cm; for Grade II seedlings, construct small-scale micro-topography modification units with a pit opening length greater than 60cm and less than 80cm, a pit width greater than 40cm and less than 60cm, and a pit depth greater than 30cm and less than 40cm.

[0022] Step S2: Seedling Pretreatment: Select target seedlings 2 that are adapted to the conditions of the steep slope mountain 1 and pretreat them; target seedlings 2 refer to native tree species that are adapted to the climate of the afforestation site and have strong drought resistance and barren soil tolerance, or excellent tree species seedlings that have been successfully introduced and tested. Target seedlings 2 have well-developed root systems and are free from diseases and pests; the pretreatment process specifically includes: root pruning, appropriately pruning excessively long or damaged roots, retaining root lengths greater than 20cm and less than 30cm; root dipping, using mud containing water-retaining agents and rooting powder to dip and coat the roots; leaf pruning, for broad-leaved target seedlings 2, pruning one-third to one-half of the leaves to reduce transpiration.

[0023] Step S3: Positioning and planting: Plant the pretreated target seedling 2 at the designated planting point in the micro-topography transformation unit; the designated planting point is approximately one-third of the way from the bottom center point of the micro-topography transformation unit towards the inner side of the slope body; during planting, first place the base plate container 4 at the planting point, then place the target seedling 2 into the base plate container 4, and then backfill with fine surface soil and gently compact it so that the soil surface at the root collar of the seedling is slightly lower than the surface of the pit mouth; the base plate container 4 is a cylindrical container made of biodegradable material and contains nutrient soil and slow-release fertilizer.

[0024] Step S4: Integrated water and fertilizer management: After planting, through the water and fertilizer management module integrated in the micro-topography transformation unit, provide initial water and fertilizer supply to the target seedling 2; the water and fertilizer management module includes: a porous infiltration irrigation pipe 5 buried near the rhizosphere of the target seedling 2 and a detachable water collection cellar 6 located above the micro-topography transformation unit; the initial water and fertilizer supply means: immediately after planting, irrigate the root-fixing water through the porous infiltration irrigation pipe 5 so that the water penetrates to the main root distribution layer; in case of continuous drought, collect rainwater or supplement irrigation manually through the water collection cellar 6, and add water-soluble compound fertilizer in the irrigation water according to a predetermined concentration ratio. The predetermined concentration refers to the mass-volume percentage concentration of the water-soluble compound fertilizer being greater than 0.1% and less than 0.3%; the trigger condition for supplementary irrigation is that the volumetric water content of the soil is monitored to be lower than the water and fertilizer critical threshold, and the water and fertilizer critical threshold is defined as: for the target seedling 2, the minimum soil water content required to maintain the normal physiological activities of its roots, usually greater than 50% or 60% of the field capacity.

[0025] Step S5: Monitoring and maintenance during the survival period: During the survival period after afforestation, monitor and maintain the growth status of the target seedling 2 and the stability of the micro-topography transformation unit.

[0026] A specific implementation process is as follows: Using this embodiment, in a red soil hilly area in the south, select an erosion slope with a slope of about 28° and a soil layer thickness of about 30 cm for implementation. The specific steps are as follows: S1. Construction of micro-topography transformation unit: Along the contour line of the slope, adopt a "pin" layout and manually excavate the micro-topography transformation unit. Select Schima superba as the target tree species and use its first-class seedlings (ground diameter D = 0.6 cm, seedling height H = 55 cm). Therefore, construct a large-sized micro-topography transformation unit with a long diameter of about 90 cm, a short diameter of about 70 cm, and a pit depth of about 45 cm at the pit mouth. Separate the excavated surface soil and subsoil and stack them separately. Use some subsoil and slope stones to build a firm retaining dam 3 with a height of about 20 cm and a top width of about 15 cm outside the pit.

[0027] S2. Seedling pretreatment: Pretreatment of Grade I seedlings of *Symplocos edulis*: Trim excessively long and damaged roots with pruning shears, leaving roots about 25cm in length; Dip the roots into a thick mud mixture of water, clay, water-retaining agent (polyacrylamide) and rooting powder (ABT-1); Remove about 1 / 3 of the leaves to reduce water transpiration.

[0028] S3. Positioning and Planting: At the center of the pit bottom of the micro-topography modification unit, about 1 / 3 of the way in from the inside of the slope, place a cylindrical biodegradable non-woven fabric base container 4 with a diameter of about 15cm and a height of about 20cm. The container is pre-filled with nutrient soil composed of loam, humus, and slow-release compound fertilizer. Place the pre-treated *Symplocos edulis* seedling vertically in the center of the base container 4, straighten it, and then backfill the gap between the pit and the container with fine topsoil, compacting it in layers to ensure that the soil surface at the root collar of the seedling is slightly lower than the pit opening.

[0029] S4. Integrated water and fertilizer management: While planting seedlings, a porous drip irrigation pipe 5 about 30cm long is horizontally buried near the root zone, with the pipe opening leading to the pit surface. At a solid location on the embankment 3 of the micro-topography modification unit, a detachable plastic water collection cellar 6 of about 20 liters is installed and connected to a diversion channel.

[0030] Immediately after planting, thoroughly water the plants using the porous drip irrigation pipe 5 (approximately 10 liters per plant). In subsequent management, rainwater is collected in the water collection pit 6. Using a portable soil moisture meter, when the soil volumetric water content in the pit is below 18% (approximately 55% of the field capacity, i.e., the set water and fertilizer critical threshold) and no rain is forecast for the next few days, the stored water in the pit or water is manually transported for irrigation, with 0.2% (by weight) of water-soluble compound fertilizer added to the irrigation water.

[0031] S5. Survival Monitoring and Maintenance: The first growing season after planting (approximately 6 months) is the critical survival monitoring period. Monthly inspections should be conducted to check for new buds, wilting leaves, and the integrity of the micro-topography modification unit's embankment 3. Dead plants should be promptly replanted with pre-treated seedlings of the same specifications; damaged embankments 3 should be repaired with soil and stones; and the water and fertilizer management module should be activated as needed based on monitored soil moisture for supplemental irrigation.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for afforestation of seedlings on steep mountain slopes, characterized in that, Includes the following steps: Step S1: Construction of micro-topography modification units: On the slope of the afforestation area in the steep mountain, construct several micro-topography modification units for planting target seedlings. The micro-topography modification units are equipped with water and fertilizer management modules for supplying water and fertilizer to the target seedlings. Step S2: Pretreatment of target seedlings: Select target seedlings that are suitable for the conditions of steep mountain slopes and perform pretreatment; Step S3: Positioning and planting: Plant the pretreated target seedlings at the designated planting points in the micro-topography modification unit; Step S4: Integrated water and fertilizer management: After planting, the target seedlings are initially supplied with water and fertilizer through the water and fertilizer management module integrated into the micro-topography modification unit. Step S5: Survival period monitoring and maintenance: During the survival period after afforestation, monitor and maintain the growth status of the target seedlings and the stability of the micro-topography modification unit.

2. The method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S1, steep mountainous terrain refers to mountainous terrain with a slope greater than 25 degrees and less than 60 degrees, a soil layer thickness of no more than 50 cm, and varying degrees of risk of soil erosion. The structure of the micro-topography modification unit is as follows: a semi-circular or approximately crescent-shaped pit is dug on the slope along the contour line direction. The pit surface is inclined inward to form a water catchment area. The outside of the pit is built with excavated raw soil or stones to form a dam.

3. The method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S1, the construction of the micro-topography modification unit is determined based on the specifications of the target seedlings and the slope soil conditions. The target seedlings are classified into Grade I and Grade II seedlings based on their diameter at ground level (D) and height (H): Grade I seedlings have a diameter at ground level of not less than 0.5 cm and a height at ground level of not less than 50 cm; Grade II seedlings have a diameter at ground level of not less than 0.3 cm and a height at ground level of not less than 0.5 cm and a height at ground level of not less than 30 cm and a height at ground level of not less than 50 cm. For Grade I seedlings, construct large-scale micro-topography modification units with a pit opening length greater than 80cm and less than 100cm, a pit width greater than 60cm and less than 80cm, and a pit depth greater than 40cm and less than 50cm; for Grade II seedlings, construct small-scale micro-topography modification units with a pit opening length greater than 60cm and less than 80cm, a pit width greater than 40cm and less than 60cm, and a pit depth greater than 30cm and less than 40cm.

4. The method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S2, the target seedlings refer to native tree species that are adapted to the climate of the afforestation site and have strong drought resistance and tolerance to poor soil conditions, or seedlings of superior tree species that have been successfully introduced through trials. The drought resistance and tolerance to poor soil characteristics are as follows: drought resistance: after 30 consecutive days of drought, the wilting rate of the target seedlings is no more than 30%; tolerance to poor soil: the target seedlings sprout new shoots normally under the condition of no external fertilization. Excellent tree species seedlings that have successfully undergone introduction trials are characterized by: completing an introduction and domestication trial of no less than 3 years, with a seedling survival rate of no less than 85%, an annual growth of no less than 20 cm, and no major outbreaks of diseases and pests during the trial period.

5. A method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S2, the preprocessing process includes: Root pruning involves trimming excessively long or damaged roots in the target seedlings, retaining roots longer than 20cm and shorter than 30cm. Root dipping involves coating the roots of the target seedling with a mud slurry containing a water-retaining agent and rooting powder. Pruning: For broad-leaved seedlings, remove one-third to one-half of the leaves to reduce transpiration.

6. The method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S3, the designated planting point is the bottom center point of the micro-topography modification unit. When planting, first place the base container at the designated planting point, then place the target seedling in the base container, and then backfill with fine topsoil and gently compact it so that the soil surface at the root collar of the seedling is 3cm lower than the surface of the pit opening. The base container is a cylindrical container made of biodegradable material, containing nutrient soil and slow-release fertilizer. The bottom diameter of the cylindrical container is greater than 12cm and less than 18cm, and the height is greater than 15cm and less than 25cm.

7. The method for afforestation of seedlings on steep slopes according to claim 1, characterized in that: In step S4, the water and fertilizer management module includes: a porous drip irrigation pipe buried near the root system of the target seedling and a detachable water collection cellar located above the micro-topography modification unit. Initial water and fertilizer supply refers to: immediately after planting, watering is carried out through porous drip irrigation pipes to allow water to penetrate into the main distribution layer of the root system; in the event of continuous drought, rainwater collected in water collection pits or artificial irrigation is used to supplement the irrigation water, and water-soluble compound fertilizer with a predetermined concentration ratio is added to the irrigation water.

8. A method for afforestation of seedlings on steep slopes according to claim 7, characterized in that: The predetermined concentration refers to a water-soluble compound fertilizer concentration of greater than 0.1% and less than 0.3% by mass volume percentage. The trigger condition for supplemental irrigation is when the soil volumetric water content is monitored to be lower than the critical water and fertilizer threshold. The critical water and fertilizer threshold is defined as: the minimum soil moisture content required to maintain the normal physiological activities of the root system for the target seedlings, which is greater than 50% or 60% of the field capacity.

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