Efficient nursery stock planting method suitable for mountain afforestation

Abstract

The invention relates to the technical field of mountain afforestation, provides an efficient nursery stock planting method suitable for mountain afforestation, and aims at solving the problems that in existing mountain afforestation, planting is not standard, the survival rate is low, the water and soil conservation capacity is weak, and the labor intensity is high. The forest space layout is optimized, and the water and soil conservation capability is enhanced; the mellow soil and immature soil layered stacking and backfilling technology is adopted, the natural structure of the soil is recovered, and the root zone microenvironment quality is improved; a fertilizer isolation layer is arranged and degradable container seedlings are implanted, so that the risk of root burning is avoided, the integrity of root systems is protected, and the survival rate of the seedlings is remarkably increased; by combining root fixing water slow irrigation, water retention covering and slope water collection and soil conservation structures, natural rainfall is effectively utilized, evaporation and runoff are reduced, and water saving and drought resisting are achieved; the whole process flow is standard, the replicability is high, and the dependence on artificial experience is reduced.

Description

Technical Field

[0001] This invention relates to the field of mountain afforestation technology, and in particular to a method for efficient planting of seedlings suitable for mountain afforestation. Background Technology

[0002] With the continuous advancement of ecological civilization construction in my country, afforestation in mountainous areas has received widespread attention as an important means of building ecological barriers, preventing soil erosion, and expanding forest resources. Mountainous terrain is complex, generally characterized by steep slopes, thin soil layers, poor water and fertilizer retention capacity, and inconvenient transportation, making it difficult to directly apply traditional afforestation techniques used in plains areas. In recent years, although some areas have attempted to introduce mechanized operations and water-saving irrigation technologies, many challenges remain in the actual promotion process. How to improve afforestation efficiency, reduce labor intensity, and increase seedling survival rate while ensuring ecological benefits has become a key technical challenge in mountain vegetation restoration. Therefore, developing a seedling planting method adapted to the special environment of mountainous areas, integrating precise planning, efficient planting, and ecological conservation, has significant practical significance and application value.

[0003] Currently, afforestation in mountainous areas generally adopts the traditional model of manually digging holes, planting bare-root seedlings, and relying mainly on natural rainfall. This model has several technical bottlenecks: First, the lack of systematic analysis of topography, soil, and microclimate before planting leads to arbitrary site selection and unreasonable spacing between trees and rows, affecting the later stand structure and light utilization efficiency; second, the digging of planting holes is not standardized, often resulting in holes that are too deep or too shallow, or soil stratification that is disordered, with topsoil mixed with subsoil, damaging the original soil structure and hindering root recovery; third, most seedlings are bare-root, making them prone to root dehydration and damage during transportation and planting, resulting in a long recovery period and large fluctuations in survival rate after planting; fourth, the lack of effective water management and soil conservation measures after planting, especially during the rainy season when soil erosion is likely to occur, and during the dry season when water supply is insufficient, further restricting the initial growth of seedlings; fifth, the lack of standardized and replicable technical processes makes it difficult to achieve large-scale and intensive afforestation. In addition, there are few existing technologies that integrate lightweight machinery, water- and fertilizer-retaining materials, and ecological engineering measures into a systematic solution, resulting in low overall planting efficiency, high maintenance costs, and poor ecological adaptability.

[0004] Therefore, there is an urgent need to provide a highly efficient seedling planting method suitable for mountainous environments, which can overcome the problems of non-standard planting, low survival rate, weak soil and water conservation capacity, and high labor intensity in existing technologies. This method should standardize the entire process from site selection and planning, planting operations to post-planting care, integrating multiple technical means such as soil improvement, water control, root protection, and ecological protection. This will enhance the mechanization and ecological adaptability of mountain afforestation, ensure rapid root establishment and stable growth of seedlings, thereby improving afforestation quality and overall benefits.

[0005] The purpose of this invention is to solve the problems of non-standard planting, low survival rate, weak soil and water conservation capacity, and high labor intensity in existing mountain afforestation. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of non-standard planting, low survival rate, weak soil and water conservation capacity, and high labor intensity in existing mountain afforestation. The invention adopts the following technical solution: A highly efficient seedling planting method suitable for afforestation in mountainous areas includes the following steps: Step 1: Conduct an assessment of the afforestation area based on the mountainous terrain, soil and climate conditions, and plan the planting sites along the contour lines based on the assessment results, and set up a planting layout suitable for soil and water conservation and tree growth. Step 2: Dig planting holes at the planned planting sites. During the digging process, pile the topsoil and subsoil separately to maintain the original soil structure. Step 3: Apply base fertilizer to the bottom of the planting hole and set up an unfertilized soil isolation layer on top of it to form a buffer structure to prevent the seedling roots from directly contacting the fertilizer; Step 4: Insert the seedling with the biodegradable container into the planting hole, keeping the container vertical and its top below the ground surface, so that the root system is completely implanted in the protective substrate; Step 5: First, backfill the topsoil around the roots of the seedlings and compact it appropriately. Then, cover the outer layer with the bottom subsoil to form a soil backfill structure that is loose inside and firm outside, which is conducive to root extension and water infiltration. Step Six: Immediately after planting, water the soil to help the roots establish themselves, and supplement with irrigation within the set time to promote close contact between the roots and the surrounding soil. Step 7: Lay a water-retaining and weed-suppressing mulch around the roots of the seedlings, and on sloping land, set up a water-collecting and soil-retaining structure on the water-facing side to intercept rainfall, reduce surface runoff, and prevent soil erosion.

[0007] The efficient seedling planting method for mountain afforestation described above further includes the following steps in step one: Remote sensing images or UAV aerial surveys are used to obtain information on the topographic slope, light distribution and vegetation cover of the mountain surface. Combined with the results of on-site soil sampling analysis, a comprehensive evaluation map is generated. Based on the map, the boundaries of suitable afforestation areas and the planting priority are determined. The planting points are arranged in an alternating pattern on contour lines, and the planting points in adjacent rows are staggered to form a triangular or triangular spatial structure.

[0008] The above-described efficient seedling planting method for mountain afforestation utilizes data obtained from UAV aerial surveys to generate topographic contour maps and aspect maps. Combined with the detection results of on-site soil sampling points, a spatial interpolation method is used to draw a distribution map of soil organic matter content and soil layer thickness. The afforestation area is divided into different levels according to slope, soil conditions, and light conditions. Planting points are preferentially arranged in areas with a slope of less than 25°, a soil layer thickness of more than 30 cm, and an organic matter content of not less than 1.5%. The planting points of adjacent rows are staggered along the contour lines, with a stagger distance of half the plant spacing, forming a uniform triangular arrangement structure.

[0009] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following steps in step two: Portable electric hole diggers or hydraulic drilling equipment are used to excavate planting holes at the planned locations. The equipment is carried or operated by the operator. The drill bit diameter is 40 to 50 centimeters, and the drilling depth is 30 to 40 centimeters. During the excavation, the topsoil and subsoil are collected and piled on both sides of the hole opening to keep the soil layers separate. For areas with a slope greater than 20°, the equipment operates at an inclined angle to form a sloping planting hole with a higher inner slope and a lower outer slope. An arc-shaped water collection trough is built above the hole to intercept slope runoff.

[0010] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following steps in step three: Base fertilizer is laid at the bottom of the planting hole. The base fertilizer consists of well-rotted organic fertilizer, nitrogen-phosphorus-potassium compound fertilizer, and one or more of borax, zinc sulfate, and ammonium molybdate. A layer of loose, unfertilized soil with a thickness of 5 to 8 cm is placed on top of the base fertilizer to form an isolation layer. The isolation layer is lightly pressed to maintain its structural stability and ensure it is loose and breathable. For areas where the soil layer thickness is less than 30 cm or the soil organic matter content is less than 1.5%, adaptive fertilization is carried out by increasing the amount of base fertilizer and thickening the isolation layer accordingly.

[0011] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following steps in step four: Seedlings pre-cultured in biodegradable seedling containers, along with their internal substrate, are transferred into planting holes. The biodegradable seedling containers are made of plant fibers and starch-based materials, with evenly distributed permeable and breathable holes in the walls. During planting, the containers are kept vertical, with their upper edges 1 to 2 centimeters below the ground surface to ensure that the roots are not exposed or buried too deeply. Loose, well-drained soil is filled into the gap between the container and the side wall of the planting hole to ensure close contact between the container and the surrounding soil, promoting the outward extension of the roots.

[0012] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following step in step five: First, backfill the topsoil separated during excavation around the roots of the seedlings, filling the gaps between the container and the sidewalls of the planting hole. Then, gently press the soil in layers to ensure it adheres tightly to the roots and container walls, forming a loose and breathable inner structure. Next, cover the outer layer with the bottom layer of subsoil to form a dense and stable protective layer. After backfilling, construct a ring-shaped tree basin with a diameter of no less than 60 cm and edges slightly higher than the ground, centered on the seedling. The surface of the tree basin should be flat and sloped inwards to facilitate rainwater collection towards the roots.

[0013] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following step in step six: Immediately after planting, water the tree basin with 2.0 to 3.0 liters of water per tree, using drip irrigation or slow-flow irrigation with perforations, allowing the water to slowly seep into the soil at a rate of 0.3 to 0.5 liters per minute until the water has fully penetrated to the root zone. The first supplementary irrigation should be carried out between the 3rd and 7th day after planting, with 50% of the initial irrigation volume, using the same method. When the soil surface is dry and there has been no effective rainfall for more than 5 consecutive days, a second supplementary irrigation should be carried out, with each supplementary irrigation not exceeding 60% of the initial irrigation volume. The irrigation process should be completed in two sessions with a 1-hour interval to reduce surface runoff and soil disturbance.

[0014] As described above, the efficient seedling planting method suitable for afforestation in mountainous areas includes the following step in step seven: A biodegradable moisture-retaining film or organic mulch is laid around the base of the seedlings within a diameter of not less than 60 cm. The moisture-retaining film is made of starch-based or cellulose-based materials and has a thickness of 0.08 mm to 0.15 mm. When laying it, it is flattened and pressed tightly against the ground surface, with the edges pressed into the soil 2 to 3 cm for fixation. For areas with a slope greater than 15°, a semi-circular or fish-scale-shaped water-collecting and soil-retaining structure is constructed above the seedlings on the water-facing side. The structure is made of soil, gravel, or ecological bags and has a height of 10 to 15 cm. The concave side faces the seedlings to intercept slope runoff and slow down the water flow, preventing soil erosion caused by rainwater.

[0015] As described above, a highly efficient seedling planting method suitable for mountain afforestation is provided with a biodegradable moisture-retaining film having uniformly distributed permeability holes with a diameter of 2 mm to 5 mm and a pore density of 80 to 120 per square meter, which allows precipitation and irrigation water to infiltrate downwards while maintaining surface coverage; the moisture-retaining film completely degrades within 6 to 12 months under natural conditions, and the degradation products do not pollute the soil and can increase the soil organic matter content.

[0016] Implementing the embodiments of the present invention has the following beneficial effects: 1. In this invention, the spatial layout of forest trees is optimized and the soil and water conservation capacity is enhanced through comprehensive assessment of topography and soil and staggered placement along contour lines; the use of layered stacking and backfilling of topsoil and subsoil restores the natural soil structure and improves the quality of the root zone microenvironment; the setting of fertilizer isolation layer and biodegradable container seedling planting avoids the risk of root burn, protects the integrity of the root system, and significantly improves the survival rate of seedlings; combined with root-fixing water slow irrigation, water-retaining cover and slope water collection and soil-retaining structure, natural precipitation is effectively utilized, evaporation and runoff are reduced, and water conservation and drought resistance are achieved; the overall process is standardized and highly replicable, reducing reliance on manual experience.

[0017] In summary, this invention solves the problems of non-standard planting, low survival rate, weak soil and water conservation capacity, and high labor intensity in existing mountain afforestation. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the steps of an efficient seedling planting method applicable to mountain afforestation according to the present invention. Detailed Implementation

[0020] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, this invention proposes a method for efficient seedling planting suitable for afforestation in mountainous areas, comprising the following steps: Step 1: Conduct an assessment of the afforestation area based on the mountainous terrain, soil, and climate conditions, and plan the planting sites along the contour lines based on the assessment results, setting up a planting layout suitable for soil and water conservation and tree growth.

[0022] Specifically, the assessment of the afforestation area includes the following sub-steps: Using drones equipped with multispectral cameras or by acquiring high-resolution remote sensing images, low-altitude aerial surveys are conducted over the target mountainous area to obtain digital orthophoto maps (DOM) and digital elevation models (DEM) of the land surface. Based on these, topographic slope maps, aspect maps, and contour maps are generated to identify water catchment lines, watersheds, and high-risk areas prone to soil erosion. By combining meteorological data, we analyze the region's average annual rainfall, evaporation, frost-free period, and frequency of extreme weather events to assess the impact of climate on seedling growth. Soil sampling points were set up in typical plots, and soil samples were collected in layers at depths of 0–20 cm and 20–40 cm. Their physicochemical properties were tested, including pH value, organic matter content, total nitrogen, available phosphorus, available potassium, soil texture (sand, loam or clay) and soil layer thickness. Topographic, climatic, and soil data were imported into a Geographic Information System (GIS) platform for spatial overlay analysis to construct an "afforestation suitability evaluation map," dividing the region into primary suitable areas, secondary suitable areas, and unsuitable afforestation areas. Among them, the primary suitable areas meet the following criteria: slope < 25°, soil layer thickness > 30 cm, organic matter content ≥ 1.5%, and average annual sunshine ≥ 1800 hours. Within the primary suitable area, planting strips are laid out along the contour lines, with a reasonable spacing between trees and rows (determined according to the biological characteristics of the tree species, generally 2 m × 3 m or 3 m × 3 m). The planting points are staggered on adjacent planting strips, with a stagger distance of 0.5 times the spacing between trees, forming a triangular or triangular spatial arrangement structure to improve the efficiency of forest stand in utilizing light energy, water and space resources, enhance the continuity of vegetation cover, and reduce surface runoff erosion. Based on the evaluation map, the priority of planting is determined: planting operations are carried out in the first-level suitable areas with gentle slopes, fertile soil and sufficient sunlight; selective afforestation is carried out in the second-level suitable areas after improvement measures are taken; and the original vegetation is preserved or ecological protection areas are set up in unsuitable areas, and no artificial afforestation is carried out.

[0023] Step 2: Dig planting holes at the planned planting sites. During the excavation process, pile the topsoil and subsoil separately to maintain the original soil structure.

[0024] Specifically, step two includes the following sub-steps: Based on the planting locations determined in step one, portable electric hole diggers or hydraulic drilling equipment are used to excavate planting holes. The equipment is lightweight machinery that can be operated by a single person, carried or held by the operator, suitable for complex mountainous terrain, significantly reducing labor intensity and improving work efficiency. Use a drill bit with a diameter of 40 to 50 centimeters to ensure that the planting hole has enough space to accommodate the root system of the seedling and the expansion needs in the early stage of growth; control the drilling depth between 30 and 40 centimeters to meet the main range of vertical root distribution of most afforestation tree species, while avoiding excessive depth that may lead to water accumulation or excessive disturbance of the bottom soil. During the drilling process, the equipment cuts the soil layer by layer from top to bottom. The operator observes the changes in color, texture and organic matter content of the drilled soil in real time to identify the boundary layer between the topsoil (generally 0-20 cm, darker in color, loose and fertile) and the subsoil (below 20 cm, lighter in color and compact in structure). Collect the topsoil and subsoil separately and pile them symmetrically on both sides of the planting hole, with a simple partition or plastic sheet temporarily separating them in the middle to prevent the two soil layers from mixing and to ensure that the original soil structure can be restored when backfilling later. For steep slopes with a gradient greater than 20°, adjust the operating angle of the digging equipment so that it drills at an angle along the contour line to form a "high inside and low outside" sloping planting hole, that is, the inner side of the hole bottom (the side closer to the mountain) is slightly higher than the outer side (the side at the bottom of the slope), and the tilt angle is controlled between 5° and 10° to enhance the stability of the hole and prevent soil loss caused by rainwater erosion. An arc-shaped water collection trough is constructed above the planting hole on the water-facing side. The water collection trough is dug manually or formed by mold. It is 20 cm to 30 cm wide and 10 cm to 15 cm deep. It extends along the contour line in a semi-circular or crescent shape, with its concave surface facing the planting hole. It is used to effectively intercept slope runoff, guide rainwater to slowly infiltrate into the planting hole area, and improve water use efficiency. The water collection trough can be lined with gravel or filled with permeable materials such as straw to further slow down the water flow, prevent erosion, and promote water infiltration. After construction, the outer edge of the topsoil should be appropriately covered and simply compacted to enhance structural stability.

[0025] Step 3: Apply base fertilizer to the bottom of the planting hole and set up an unfertilized soil isolation layer on top of it to form a buffer structure that prevents the seedling roots from directly contacting the fertilizer.

[0026] Specifically, step three includes the following sub-steps: After the planting holes are dug, the topsoil that has been piled up on one side of the hole is simply treated: stones, grass roots and other impurities are removed, and the soil is crushed and passed through a 10 mm sieve to obtain loose, structurally sound, organic-rich, unfertilized soil, which is then prepared as a separating layer material. Evenly spread base fertilizer at the bottom of the planting hole, ensuring the spread area is roughly the same as the cross-section of the hole opening, avoiding stacking or uneven distribution. The base fertilizer consists of well-rotted organic fertilizer, nitrogen-phosphorus-potassium compound fertilizer, and one or more components selected from borax, zinc sulfate, and ammonium molybdate. The components are preferably mixed in the following proportions: Well-rotted organic fertilizer (such as well-rotted cow manure, compost, or forest humus): accounting for 60% to 80%, providing long-lasting organic matter and microbial activity, and improving soil structure; Nitrogen-phosphorus-potassium compound fertilizer (N-P2O5-K2O = 15-15-15 or 10-20-20): accounting for 15% to 30%, supplementing the macro-elements needed in the early stage of seedling growth; Micronutrient additives: selected from one or more of borax (provides boron, promotes flower bud differentiation and cell division), zinc sulfate (corrects growth retardation caused by zinc deficiency) and ammonium molybdate (enhances nitrogenase activity). The amount added is 3 to 8 grams per hole, adjusted according to the needs of the tree species and soil test results.

[0027] After the base fertilizer is laid, immediately lay a layer of treated topsoil on top, with the thickness controlled between 5 cm and 8 cm by a ruler, to ensure that the base fertilizer layer is completely covered and there are no exposed areas. No fertilizer or amendment is added to this soil layer, keeping it in an "unfertilized" state, as a physical and chemical buffer zone between the roots and the high concentration of nutrients.

[0028] Lightly press the laid isolation layer: Operators use a flat-bottomed wooden rammer or lightly tread on it with their feet to initially stabilize the soil layer and make it adhere to the lower layer, but maintain a loose and porous structure with a porosity of not less than 40% to facilitate water infiltration and root penetration.

[0029] For infertile areas with a soil layer thickness of less than 30 cm or a soil organic matter content of less than 1.5%, implement an adaptive fertilization program: The amount of base fertilizer applied is increased to 1.3 to 1.5 times the conventional amount; At the same time, the thickness of the isolation layer will be increased to 8-10 cm to ensure that the buffering capacity and nutrient supply are improved simultaneously. A small amount of humic acid or water-retaining agent (such as polyacrylamide, 0.5-1 gram per hole) can be mixed into the isolation layer to further improve the root zone microenvironment.

[0030] After fertilization and the construction of the isolation layer are completed, check that there is no fertilizer exposed, no compaction or voids in the hole to ensure that the root zone environment is safe and the structure is intact, providing a good foundation for subsequent seedling planting.

[0031] Step 4: Insert the seedling with the biodegradable container into the planting hole, keeping the container vertical and its top below the ground surface, so that the root system is fully implanted in the protective substrate.

[0032] Specifically, step four includes the following sub-steps: Container seedlings that have been cultivated in the nursery for 6 to 18 months are selected. The seedlings are robust, of moderate height, and have well-developed root systems without tangling. The seedling containers are made of biodegradable materials, which are molded from plant fibers (such as rice straw fiber and sugarcane bagasse) and starch-based polymer materials (such as polylactic acid PLA or starch / PBAT blends). They have good mechanical strength and natural degradation properties.

[0033] The biodegradable seedling container has water-permeable and air-permeable holes with a diameter of 2 mm to 5 mm evenly distributed on its wall, with a hole density of 1 to 2 holes per square centimeter. This ensures smooth oxygen exchange in the root zone and timely drainage of excess water, while allowing fine roots to extend outward through the pores in the early stages, thus achieving the "root penetration induction" effect.

[0034] Carefully remove the seedlings from the transport rack, keeping the containers intact, without squeezing or twisting them, to avoid loosening the substrate or damaging the roots; use special pallets or soft slings during handling to reduce mechanical stress.

[0035] The seedlings, along with their internal substrate, are vertically moved into planting holes that have been fertilized and have been covered with an isolation layer. The position is adjusted so that the center of the container coincides with the planting point, ensuring that the spacing between the seedlings is uniform and the arrangement is neat after planting.

[0036] The top edge of the control container should be 1 to 2 centimeters below the ground surface. This can be calibrated using an elevation rod or a simple depth caliper. If the container is too high, it can easily lead to substrate drying and root collar exposure. If it is too low, it can easily cause water accumulation and root rot. This depth range has been verified by experiments to effectively protect the root collar and facilitate natural rainwater collection.

[0037] Fill the annular gap between the container and the side wall of the planting hole with pre-pile topsoil. While filling, gently press to ensure that the soil adheres tightly to the container wall, eliminate voids or gaps, and promote the conduction of water and nutrients between the soil outside the container and the internal substrate.

[0038] After filling, check that the container is vertical. If it is tilted, straighten it immediately. Also, make sure that no stones, weeds, or undecomposed organic matter are embedded in the gaps to avoid affecting the root expansion path.

[0039] The biodegradable container begins to soften under natural conditions in 6 months and decomposes within 12 months. The decomposition products are carbon dioxide, water and organic residues, which do not pollute the soil and can increase the local organic matter content, promote microbial activity, and achieve an integrated transition of "container-soil-root system".

[0040] For planting sites on slopes, prioritize planting from the top of the slope downwards to avoid trampling on backfilled areas during the operation, which could cause soil compaction.

[0041] Step 5: First, backfill the topsoil around the roots of the seedlings and compact it appropriately. Then, cover the outer layer with the bottom layer of subsoil to form a soil backfill structure that is loose inside and firm outside, which is conducive to root extension and water infiltration.

[0042] Specifically, step five includes the following sub-steps: After the seedling containers are planted and their positions are corrected, the soil backfilling work begins immediately. The topsoil separated and piled on one side of the hole during excavation is used as the inner backfill material. This topsoil is the original soil layer with a depth of 0-20 cm. It is rich in organic matter (content ≥1.5%), has a good granular structure, and high microbial activity, which is conducive to the initial growth of roots and nutrient absorption.

[0043] The topsoil is sieved to remove impurities such as stones, tree roots, and plastic fragments, to prevent foreign objects from hindering root extension or causing poor local aeration; the sieve mesh size is controlled between 10 mm and 15 mm to ensure that the soil is loose and not excessively broken.

[0044] Using manual backfilling, first evenly fill the gap between the container and the side wall of the planting hole with the sieved topsoil, and gradually extend it towards the root collar, covering the area around the root distribution zone to form an inner layer of root protection soil with a thickness of not less than 10 cm; avoid direct impact on the container or the main trunk of the seedling during the backfilling process.

[0045] The inner layer of topsoil is lightly compacted in layers: every time the backfill is 3 cm to 5 cm thick, it is lightly compacted once with a wooden rammer, rubber hammer or the sole of the foot (wearing flat shoes) to make the soil fit tightly with the container wall and root system, eliminating voids or gaps, but maintaining the soil porosity above 40% to ensure air and water permeability, and achieving the "loose inside" characteristic of the "loose inside and firm outside" structure.

[0046] After the topsoil is backfilled, the bottom subsoil (less than 20 cm deep) piled on the other side is used as the outer cover. This subsoil has a high mineral content, a compact structure, and a strong ability to retain water and fertilizer, but a low organic matter content and should not come into direct contact with the root system.

[0047] After breaking up the subsoil, it is used to cover the outer perimeter of the topsoil layer, forming a dense and stable outer protective layer. The coverage extends 10-15 cm beyond the edge of the planting hole, with a thickness of 5-8 cm. The soil is then moderately compacted to improve surface stability and reduce rainfall erosion and water evaporation.

[0048] After backfilling, construct a ring-shaped tree basin with a diameter of no less than 60 cm and an edge slightly higher than the ground (about 3 cm to 5 cm) around the seedling. The surface of the tree basin should be flat and tilted inward at 1° to 3° to facilitate the collection of rainwater or irrigation water to the roots and prevent runoff leakage. The boundary of the tree basin can be reinforced with gravel, straw or ecological edging to enhance its erosion resistance.

[0049] Field comparative experiments verified that the treatment group using the "filling with mature soil and covering with raw soil" method had more than 35% more new roots sprouting within 30 days after seedling planting than the mixed backfilling group, and the survival rate was increased by 12% to 18%, while the soil settlement was reduced, indicating that the backfilling structure significantly optimized the root zone microenvironment.

[0050] The entire backfilling process should be completed on the day of planting to avoid prolonged root exposure and water loss. If it rains, work should be suspended until the surface is slightly dry before continuing to prevent soil compaction.

[0051] Step Six: Immediately after planting, water the soil to help the roots establish themselves, and supplement with irrigation within the set time to promote close contact between the roots and the surrounding soil.

[0052] Specifically, step six includes the following sub-steps: After backfilling the soil and constructing the circular tree basin, immediately carry out the first irrigation, also known as "root-setting watering," within 2 hours of planting to prevent root dehydration and shorten the seedling recovery period.

[0053] Irrigation water should preferably be clean natural water sources (such as mountain streams, rainwater from reservoirs) or tap water that meets farmland irrigation standards. The temperature difference between the water and the ambient temperature should not exceed 5°C to avoid root stress and contraction caused by cold water stimulation.

[0054] Irrigation operations are carried out using drip irrigation tape, seepage pipe, or perforated slow-flow water injection device. The water outlet is placed inside the tree basin, close to the edge of the container, but not directly impacting the root collar, so that the water flows slowly down the slope of the soil to avoid erosion or soil compaction.

[0055] The amount of water used for root establishment irrigation should be controlled at 2.0 to 3.0 liters per plant. This amount of water has been verified by field trials: when the amount of water is less than 2.0 liters, it is difficult to fully wet the interface between the root zone substrate and the surrounding soil, which affects the root-soil bond; when the amount of water exceeds 3.0 liters, water will easily accumulate in low-lying areas, which can easily lead to root rot due to lack of oxygen, especially in clay loam soil.

[0056] Control the irrigation flow rate to 0.3 to 0.5 liters per minute by adjusting the valve or using a flow-limiting dripper to ensure that water enters the soil in a "slow infiltration" manner, fully saturating the biodegradable container walls and surrounding backfill soil, promoting the moisture balance between the substrate and the external soil, reducing air cavitation barriers, and facilitating root adhesion.

[0057] Observe the water infiltration until the moisture depth reaches more than 30 cm, covering the main root distribution layer, indicating that the root water has been applied sufficiently; if there is runoff or water accumulation on the surface, suspend irrigation and resume after the water has infiltrated.

[0058] The first supplementary irrigation should be carried out between the 3rd and 7th day after planting, with the amount of water being 50% of the initial root-setting water (i.e., 1.0 liter to 1.5 liters per plant). The irrigation method is the same as the first time, still using low flow rate and slow irrigation. The purpose is to make up for the loss of soil evaporation, maintain the continuous moisture of the root zone, and promote the germination of new roots.

[0059] A second round of watering will be implemented based on weather and soil moisture conditions: when the top layer of soil (0-10 cm) is dry and there is no effective rainfall for more than 5 consecutive days (daily rainfall < 5 mm), the watering procedure will be initiated; the amount of water added will not exceed 60% of the first watering (i.e., ≤ 1.8 liters / plant) to avoid excessive moisture.

[0060] To reduce surface runoff and soil disturbance, the second watering is carried out twice, with an interval of 1 hour between each application: 50% of the water is applied first, and the remaining amount is applied after the water has basically infiltrated. This "intermittent irrigation" principle improves infiltration efficiency and reduces the risk of water loss, making it particularly suitable for afforestation on slopes.

[0061] After irrigation, check whether the tree basin remains intact. If there is any erosion or collapse, repair it in time. In hot or windy seasons, straw or mulch can be covered on the surface of the tree basin after irrigation to further reduce evaporation and improve water use efficiency.

[0062] Step 7: Lay a water-retaining and weed-suppressing mulch around the roots of the seedlings, and on sloping land, set up a water-collecting and soil-retaining structure on the water-facing side to intercept rainfall, reduce surface runoff, and prevent soil erosion.

[0063] Specifically, step seven includes the following sub-steps: After completing the initial irrigation and confirming soil settling stability, immediately carry out surface mulching around the base of the seedlings. The mulching area should be centered on the trunk and have a diameter of no less than 60 centimeters, forming a circular or near-circular protective area. This area should cover the main root distribution area and the outer edge of the tree basin, effectively reducing evaporation and suppressing competition from weeds.

[0064] Biodegradable moisture-retaining films or organic coverings should be selected as covering materials.

[0065] The biodegradable moisture-retaining film is made of starch-based or cellulose-based biodegradable materials (such as polylactic acid PLA, starch / PBAT blends, and regenerated cellulose films), with a thickness of 0.08 mm to 0.15 mm, and has both good mechanical strength and natural degradation properties.

[0066] Alternatively, organic mulch such as crushed straw, sawdust, pine needles, and coconut coir can be used, with a thickness of 3 cm to 5 cm, suitable for areas without mulch or ecologically sensitive areas.

[0067] When laying the moisture-retaining membrane, it should be flat and wrinkle-free, and close to the ground surface to prevent wind from accumulating under the membrane and causing it to bulge or form air pockets. Small clods or thin strips of soil should be used to press the membrane evenly into the soil to a depth of 2 to 3 centimeters at the edge of the membrane to achieve a firm fixation and prevent strong winds from blowing the membrane off.

[0068] The moisture-retaining membrane has evenly distributed permeable holes with a diameter of 2 to 5 millimeters and a pore density of 80 to 120 per square meter. It is made by laser drilling or mechanical perforation. This design allows water to seep smoothly during rainfall or irrigation, while blocking surface runoff from directly eroding the soil, achieving a three-in-one function of "water retention + water permeability + weed suppression".

[0069] Field trials have verified that when the pore density is less than 80 pores / m², the permeability is insufficient, which can easily lead to water accumulation on the membrane surface; when it exceeds 120 pores / m², the structural strength decreases and it is easily damaged; a pore size of 2-5 mm can prevent soil particles from clogging the membrane and ensure the infiltration rate.

[0070] Under natural environmental conditions (moderate temperature and humidity, active microorganisms), the moisture-retaining film begins to soften and degrade in 6 months and completely decomposes within 12 months. The degradation products are mainly carbon dioxide, water and a small amount of organic residues, which are non-toxic and harmless to the soil. Moreover, the residual organic matter can be utilized by soil microorganisms to improve local soil fertility.

[0071] For afforestation areas on mountain slopes greater than 15°, a water-collecting and soil-conserving structure should be constructed above each seedling on the water-facing side (i.e., the direction from which water flows down the slope) to intercept slope runoff, slow down water flow, and prevent erosion. The structure is semi-circular or fish-scale shaped, with the concave arc facing the seedlings, creating a "water collection depression" effect; The structure is 10 to 15 centimeters high and slightly wider than the tree basin diameter (about 70 to 80 centimeters), and is arranged along the contour lines. The construction materials can be selected from the in-situ soil, gravel, or biodegradable eco-bags (woven from coconut fiber or jute fiber). After stacking, they should be compacted to stabilize the structure and prevent collapse.

[0072] The water-collecting and soil-conserving structure, together with the tree basin below, forms a "mini water collection area" that can intercept more than 50% of the surface runoff from the upper slope and guide it into the planting hole area, significantly improving the utilization rate of natural precipitation, especially during the transition period between spring drought and rainy seasons.

[0073] After heavy rainfall, the cover layer and water collection structure should be checked in time to ensure they are intact. If the moisture retention membrane is found to be damaged, the edges are lifted, or the water collection structure is found to be collapsed, it should be repaired or replaced immediately to ensure that the protective function continues to be effective.

[0074] The entire cover and water collection system design follows the principles of "ecological priority, adaptation to local conditions, and long-term stability," and does not introduce non-degradable plastics or chemical additives, which is in line with the technological development direction of mountain ecological restoration and sustainable afforestation.

[0075] Example 1: 1. Overview of Afforestation Area Location: Loess hilly area in northern China (elevation 950 m) Slope: 18° Soil type: Loess soil Soil layer thickness: 35 cm Organic matter content: 1.3% Average annual rainfall: 480 mm (concentrated in July–September) Average annual evaporation: 1800 mm Tree species: Pinus tabuliformis 2. Steps for implementing the planting method Regional assessment and site planning (Step 1) High-resolution DOM and DEM were acquired using UAV aerial surveying, and slope maps and contour maps were generated. Analysis of meteorological data shows that the frost-free period is approximately 160 days, and spring droughts are frequent. Soil sampling showed a pH of 8.2 and low organic matter content (1.3%), classifying it as a secondary suitable area. Planting strips with a spacing of 3 m × 3 m are laid out along the contour lines, with adjacent rows staggered by 1.5 m to form a triangular structure, which enhances the interception capacity. Prioritize semi-shaded slopes or valleys, and avoid the high evaporation areas on the upper part of sunny slopes.

[0076] Digging planting holes (Step 2) Use a portable electric hole digger equipped with a Φ45 cm, 35 cm deep drill bit; During excavation, the top 0-20 cm of mature soil and the bottom 20-40 cm of subsoil are placed separately and temporarily isolated with woven fabric. Because the slope is greater than 15° but less than 20°, no sloping pits were provided, but a small arc-shaped water collection trough was built: 25 cm wide and 10 cm deep, with the concave side facing the planting pit, to collect spring rain.

[0077] Fertilization and Isolation Layer Construction (Step 3) Base fertilizer ratio: well-rotted sheep manure (75%) + 10-20-20 compound fertilizer (20%) + borax (5 g per hole); Apply 1.0 kg of base fertilizer to each hole and spread it evenly at the bottom; The isolation layer uses sieved topsoil, 7 cm thick, and is lightly compacted to prevent wind erosion in spring; Because of the low organic matter content, humic acid (0.6 g per hole) is mixed into the isolation layer to improve water and fertilizer retention capacity.

[0078] Container seedling transplantation (step four) Selected are container seedlings of Pinus tabuliformis that have been cultivated for 18 months, with a height of about 50 cm and a strong taproot; The biodegradable container is made of straw fiber + starch / PBAT blend, and the wall is covered with Φ3 mm water-permeable holes (density 1.2 holes / cm²). Keep the implant vertical during implantation, with the top edge of the container 1.5 cm below the ground surface to prevent it from being exposed by spring winds; Fill the gaps with topsoil and press lightly to ensure a good fit.

[0079] Soil backfilling (Step 5) The inner layer is backfilled with topsoil, with a thickness of ≥10 cm, and lightly compacted in layers. The outer layer is covered with subsoil, 6 cm thick, and moderately compacted to reduce wind erosion; Construct a circular tree basin with a diameter of 70 cm, an edge height of 4 cm, and a flat surface that slopes inward at 2° to facilitate rainwater collection.

[0080] Irrigation Management (Step Six) Water each plant thoroughly within one hour of planting, using 2.5 L of water per plant, and apply a slow-flow drip irrigation (0.4 L / min) to avoid erosion. Replenish 1.25 L of water on day 5; On the 10th day, due to six consecutive days without effective precipitation, the second water replenishment was initiated, with 0.75 L applied in two separate applications, one hour apart.

[0081] Covering and soil conservation (Step 7) A cellulose-based biodegradable moisture-retaining film with a diameter of 70 cm and a thickness of 0.12 mm was laid. The membrane is equipped with Φ4 mm permeation holes at a density of 90 holes / m², and the edges are secured with 3 cm of soil. In spring, when the wind is strong, lightly press the membrane surface with gravel to prevent it from being lifted. No water collection and soil conservation structure was provided (slope < 20°), but the water collection trough was retained.

[0082] Example 2: 1. Overview of Afforestation Areas Location: Northern rocky mountainous area (elevation 1100 m) Slope: 26° Soil type: coarse-grained soil Soil layer thickness: 22 cm Organic matter content: 1.0% Average annual rainfall: 550 mm (mostly heavy rain) Frequent freeze-thaw cycles and severe wind erosion in spring. Tree species: Chinese arborvitae 2. Steps for implementing the planting method Regional assessment and site planning (Step 1) By combining remote sensing with on-site surveys, usable soil patches in rock crevices were identified; The area was identified as a Level II suitable zone, and selective planting sites were adopted using a "planting greenery wherever possible" approach. The plant spacing was adjusted to 3 m × 4 m, with a 1.5 m offset, forming a triangular structure; Prioritize placing sampling points on the lower part of the slope and on the leeward side of the rocks, avoiding erosion gullies.

[0083] Digging planting holes (Step 2) Hydraulic drilling equipment is used, suitable for stony soils; The drill bit has a diameter of 40 cm and a depth of 30 cm. An inclined drilling method is used to form a sloping cavity with an inner high and outer low slope, with an inclination angle of approximately 10°. Construct a fish-scale-shaped water-collecting and soil-retaining structure above the planting hole: 15 cm high, made of crushed stone and biodegradable eco-bags (jute fiber), with the arc-shaped concave surface facing the seedlings; The water collection structure is filled with straw to enhance infiltration.

[0084] Fertilization and Isolation Layer Construction (Step 3) The amount of base fertilizer was increased to 1.5 times the conventional amount: well-rotted cow manure (80%) + 15-15-15 compound fertilizer (18%) + ammonium molybdate (4 g per hole to promote nitrogen fixation). The isolation layer was thickened to 10 cm, and high-quality topsoil was used mixed with a water-retaining agent (polyacrylamide, 0.8 g per hole) to improve drought resistance. After fertilizing, check to ensure no fertilizer is exposed to prevent it from being washed away by rain.

[0085] Container seedling transplantation (step four) Two-year-old containerized arborvitae seedlings with well-developed and untangled root systems were selected. The container is made of straw fiber + PLA, with 5 mm pores in the wall and a density of 1 pore / cm². After implantation, the upper edge of the container is 2 cm below the ground surface to prevent the root collar from being exposed due to freeze-thaw cycles. Work from above the slope downwards to avoid stepping on the backfill soil.

[0086] Soil backfilling (Step 5) The inner layer is backfilled with mature soil, 10 cm thick, and lightly compacted in layers. The outer layer is covered with 8 cm thick raw soil and compacted to enhance its resistance to erosion. Construct a tree basin with a diameter of 60 cm and an edge height of 5 cm, reinforced with gravel to prevent erosion from heavy rain.

[0087] Irrigation Management (Step Six) Water each plant thoroughly within 1.5 hours of planting, using 3.0 L of water per plant (due to the thin soil layer and rapid evaporation). The flow rate is controlled at 0.3 L / min to ensure slow infiltration; Replenish 1.5 L of water on day 7; On the 14th day, due to a continuous drought of 7 days, a second water replenishment was carried out, with 0.9 L applied twice, 1 hour apart.

[0088] Covering and soil conservation (Step 7) A starch-based biodegradable moisture-retaining film with a diameter of 65 cm and a thickness of 0.15 mm was laid. The seepage holes are Φ5 mm, with a density of 80 holes / m², and the edges are covered with 3 cm of soil. A fish-scale-shaped water collection structure is set on the water-facing side to form a miniature water collection system with the tree basin; Before winter, check the integrity of the membrane to prevent wind erosion and tearing.

[0089] It should be understood that the terms "first," "second," etc., are used in this invention to describe various information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this invention, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information. In addition, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0090] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for efficient planting of seedlings suitable for afforestation in mountainous areas, characterized in that, Includes the following steps: Step 1: Conduct an assessment of the afforestation area based on the mountainous terrain, soil and climate conditions, and plan the planting sites along the contour lines based on the assessment results, and set up a planting layout suitable for soil and water conservation and tree growth. Step 2: Dig planting holes at the planned planting sites. During the digging process, pile the topsoil and subsoil separately to maintain the original soil structure. Step 3: Apply base fertilizer to the bottom of the planting hole and set up an unfertilized soil isolation layer on top of it to form a buffer structure to prevent the seedling roots from directly contacting the fertilizer; Step 4: Insert the seedling with the biodegradable container into the planting hole, keeping the container vertical and its top below the ground surface, so that the root system is completely implanted in the protective substrate; Step 5: First, backfill the topsoil around the roots of the seedlings and compact it appropriately. Then, cover the outer layer with the bottom subsoil to form a soil backfill structure that is loose inside and firm outside, which is conducive to root extension and water infiltration. Step Six: Immediately after planting, water the soil to help the roots establish themselves, and supplement with irrigation within the set time to promote close contact between the roots and the surrounding soil. Step 7: Lay a water-retaining and weed-suppressing mulch around the roots of the seedlings, and on sloping land, set up a water-collecting and soil-retaining structure on the water-facing side to intercept rainfall, reduce surface runoff, and prevent soil erosion.

2. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step one also includes the following steps: Remote sensing images or UAV aerial surveys are used to obtain information on the topographic slope, light distribution and vegetation cover of the mountain surface. Combined with the results of on-site soil sampling analysis, a comprehensive evaluation map is generated. Based on the map, the boundaries of suitable afforestation areas and the planting priority are determined. The planting points are arranged in an alternating pattern on contour lines, and the planting points in adjacent rows are staggered to form a triangular or triangular spatial structure.

3. The efficient seedling planting method suitable for mountain afforestation according to claim 2, characterized in that, The data obtained by UAV aerial survey is used to generate topographic contour maps and aspect maps. Combined with the test results of soil sampling points in the field, the distribution maps of soil organic matter content and soil layer thickness are drawn by spatial interpolation method. The afforestation area is divided into different levels according to slope, soil conditions and light conditions. Planting points are preferentially arranged in areas with a slope of less than 25°, a soil layer thickness of more than 30 cm and an organic matter content of not less than 1.5%. The planting points of adjacent rows are staggered along the contour lines, with a stagger distance of half the plant spacing, forming a uniform triangular arrangement structure.

4. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step two also includes the following steps: Portable electric hole diggers or hydraulic drilling equipment are used to excavate planting holes at the planned locations. The equipment is carried or operated by the operator. The drill bit diameter is 40 to 50 centimeters, and the drilling depth is 30 to 40 centimeters. During the excavation, the topsoil and subsoil are collected and piled on both sides of the hole opening to keep the soil layers separate. For areas with a slope greater than 20°, the equipment operates at an inclined angle to form a sloping planting hole with a higher inner slope and a lower outer slope. An arc-shaped water collection trough is built above the hole to intercept slope runoff.

5. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step three also includes the following steps: Base fertilizer is laid at the bottom of the planting hole. The base fertilizer consists of well-rotted organic fertilizer, nitrogen-phosphorus-potassium compound fertilizer, and one or more of borax, zinc sulfate, and ammonium molybdate. A layer of loose, unfertilized soil with a thickness of 5 to 8 cm is placed on top of the base fertilizer to form an isolation layer. The isolation layer is lightly pressed to maintain its structural stability and ensure it is loose and breathable. For areas where the soil layer thickness is less than 30 cm or the soil organic matter content is less than 1.5%, adaptive fertilization is carried out by increasing the amount of base fertilizer and thickening the isolation layer accordingly.

6. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step four also includes the following steps: Seedlings pre-cultured in biodegradable seedling containers, along with their internal substrate, are transferred into planting holes. The biodegradable seedling containers are made of plant fibers and starch-based materials, with evenly distributed permeable and breathable holes in the walls. During planting, the containers are kept vertical, with their upper edges 1 to 2 centimeters below the ground surface to ensure that the roots are not exposed or buried too deeply. Loose, well-drained soil is filled into the gap between the container and the side wall of the planting hole to ensure close contact between the container and the surrounding soil, promoting the outward extension of the roots.

7. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step five also includes the following steps: First, backfill the topsoil separated during excavation around the roots of the seedlings, filling the gaps between the container and the sidewalls of the planting hole. Then, gently press the soil in layers to ensure it adheres tightly to the roots and container walls, forming a loose and breathable inner structure. Next, cover the outer layer with the bottom layer of subsoil to form a dense and stable protective layer. After backfilling, construct a ring-shaped tree basin with a diameter of no less than 60 cm and edges slightly higher than the ground, centered on the seedling. The surface of the tree basin should be flat and sloped inwards to facilitate rainwater collection towards the roots.

8. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step six also includes the following steps: Immediately after planting, water the tree basin with 2.0 to 3.0 liters of water per tree, using drip irrigation or slow-flow irrigation with perforations, allowing the water to slowly seep into the soil at a rate of 0.3 to 0.5 liters per minute until the water has fully penetrated to the root zone. The first supplementary irrigation should be carried out between the 3rd and 7th day after planting, with 50% of the initial irrigation volume, using the same method. When the soil surface is dry and there has been no effective rainfall for more than 5 consecutive days, a second supplementary irrigation should be carried out, with each supplementary irrigation not exceeding 60% of the initial irrigation volume. The irrigation process should be completed in two sessions with a 1-hour interval to reduce surface runoff and soil disturbance.

9. The efficient seedling planting method suitable for mountain afforestation according to claim 1, characterized in that, Step seven also includes the following steps: A biodegradable moisture-retaining film or organic mulch is laid around the base of the seedlings within a diameter of not less than 60 cm. The moisture-retaining film is made of starch-based or cellulose-based materials and has a thickness of 0.08 mm to 0.15 mm. When laying it, it is flattened and pressed tightly against the ground surface, with the edges pressed into the soil 2 to 3 cm for fixation. For areas with a slope greater than 15°, a semi-circular or fish-scale-shaped water-collecting and soil-retaining structure is constructed above the seedlings on the water-facing side. The structure is made of soil, gravel, or ecological bags and has a height of 10 to 15 cm. The concave side faces the seedlings to intercept slope runoff and slow down the water flow, preventing soil erosion caused by rainwater.

10. A method for efficient planting of seedlings suitable for afforestation in mountainous areas according to claim 9, characterized in that, The biodegradable moisture-retaining membrane has uniformly distributed permeable holes with a diameter of 2 mm to 5 mm and a pore density of 80 to 120 per square meter, which are used to allow precipitation and irrigation water to infiltrate downward while maintaining surface cover. The moisture-retaining membrane completely degrades within 6 to 12 months under natural conditions. The degradation products do not pollute the soil and can increase the soil organic matter content.

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