Method for improving survival rate of direct cutting afforestation of tamarix chinensis in arid and semi-arid regions

Abstract

The invention relates to the technical field of ecological restoration and forestry afforestation, and discloses a method for improving the survival rate of direct insertion afforestation of tamarix chinensis in arid and semi-arid regions, which comprises the following steps: selecting fresh and compact crop fleshy roots or tubers as biological matrix raw materials, and drilling blind holes which are 8-12cm deep and do not penetrate through the bottom in the longitudinal direction; inserting the lower ends of the tamarix chinensis cuttings after soaking and imbibition into the bottoms of the holes, and tightly wrapping the bases of the cuttings with a matrix meat layer to form a combination; vertically implanting the combination into an afforestation hole, backfilling soil and compacting to ensure that the biological matrix is completely positioned below the earth surface. According to the method, the moisture of the matrix is slowly released to the cutting slips and rhizosphere soil through the permeation effect, a rhizosphere micro-ecological buffer system is constructed, drought stress is blocked through physical wrapping and moisture slow release in the early stage of afforestation to guarantee survival of the cutting slips, the rhizosphere soil fertility is improved through matrix decomposition in the later stage, and root development is induced; and the method has the characteristics of low cost and no pollution.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration and forestry afforestation technology, specifically a method for improving the survival rate of Tamarix chinensis direct-insertion afforestation in arid and semi-arid regions. Background Technology

[0002] Tamarix chinensis, an excellent tree species for windbreak, sand fixation, and soil and water conservation in arid and semi-arid regions, possesses biological characteristics such as drought resistance, salt tolerance, and strong sprouting ability. In ecological restoration projects, direct planting using tamarisk branches is widely used due to its ease of operation and low cost. However, the harsh habitat conditions of arid and semi-arid regions—sparse rainfall, high evaporation, and extremely low soil moisture content—pose a major obstacle to the survival rate of direct planting of tamarisk.

[0003] In existing direct-insertion afforestation practices, cuttings come into direct contact with arid and infertile sandy or saline-alkali soils, and the cut ends of the cuttings face the dual stresses of soil drought and drastic temperature fluctuations. Because the cuttings themselves have limited water storage, they are highly susceptible to physiological dehydration and death due to water deficit in the rhizosphere before adventitious roots form. Although flood irrigation or multiple artificial waterings are commonly used to maintain soil moisture, this not only significantly increases afforestation costs but is also difficult to implement on a large scale in water-scarce desertified areas, failing to meet the low-maintenance requirements for large-scale ecological restoration.

[0004] To alleviate water stress, existing technologies often introduce chemical water-retaining agents or water-absorbing resins to improve rhizosphere moisture conditions. While these chemical materials have a certain water absorption and retention capacity in the short term, their water release characteristics are often difficult to precisely match with the water absorption dynamics of plant roots. Furthermore, chemically synthesized materials degrade slowly in the natural environment, and long-term use can easily lead to soil compaction or microplastic residues, posing a secondary risk of damaging the soil's physical and chemical properties. In addition, simple water management fails to address the nutrient supply problem in the early stages of cutting rooting. Soils in arid areas are typically lacking in organic matter, have poor aggregate structure, severe soil compaction, and high mechanical resistance. This makes it difficult for cuttings to form a well-developed root network even in the early stages of survival, leading to false survival or later death due to insufficient growth momentum.

[0005] In summary, existing technologies lack a comprehensive solution for addressing the problem of direct planting of Tamarix chinensis in arid regions. This solution should provide a stable and continuous micro-water environment in the early stages, improve the physical structure and nutritional status of the rhizosphere, and be environmentally friendly and cost-effective. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for improving the survival rate of Tamarix chinensis direct-planting afforestation in arid and semi-arid regions. This method solves the problems of early death of cuttings due to water deficiency and high temperature stress, limited root development in rhizosphere soil due to poor soil compaction, and high environmental residue risks and high water resource dependence of existing chemical water-retention technologies, which lead to high cultivation costs.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for improving the survival rate of Tamarix chinensis direct-planting afforestation in arid and semi-arid regions, comprising the following steps: Fresh and densely packed fleshy roots or tubers of crops are selected as biological substrate materials. Cutting holes with a depth of 8cm to 12cm are drilled longitudinally on the biological substrate materials. The drilling is controlled to prevent the holes from penetrating the bottom and sidewalls of the biological substrate materials to create a blind hole structure. Select tamarisk branches to prepare cuttings and soak the base in water to allow them to swell; Insert the lower end of the cutting into the cutting hole until it touches the bottom of the hole, and use the fleshy layer of the substrate to form a tight physical wrap around the base of the cutting to obtain a cutting-substrate assembly; Planting holes are dug in the afforestation area, the cutting substrate assembly is planted upright and backfilled with soil and compacted to ensure that the biological substrate is completely below the ground surface, so that the water in the biological substrate can penetrate into the cuttings and the rhizosphere soil.

[0008] By adopting the above technical solution, the rhizosphere microecological buffer system constructed using a biological matrix in this invention significantly improves the survival rate of afforestation through the following physical and biochemical processes: Utilizing an impermeable blind-hole structure, the fleshy tissue of the bio-matrix forms a complete physical wrapping layer at the deepest root base of the cutting. This wrapping layer prevents direct contact between the cutting base and hot, dry soil particles, avoiding heat damage caused by the high temperature at the soil-cutting contact surface, while also reducing the rapid diffusion of moisture from the cutting into the dry soil.

[0009] Fresh bio-based substrates contain abundant cell sap, with a water potential significantly higher than the surrounding dry soil and dehydrated cuttings. In the early stages of planting, driven by both soil substrate potential and plant transpiration pull, water from the bio-based substrate slowly migrates through intercellular spaces to the cutting cut and surrounding rhizosphere soil. This passive, slow-release mechanism based on water potential difference maintains a locally high-humidity microzone around the cutting for over 30 days, providing the necessary physiological window for callus induction and adventitious root development.

[0010] Over time, the bio-based substrate gradually degrades under the action of soil microorganisms. The mineralization and decomposition of starch and sugars rich in the substrate provide a carbon source for rhizosphere microorganisms, promoting their proliferation and the formation of stable soil aggregates, thus improving rhizosphere aeration. At the same time, the endogenous hormones and mineral elements released by the substrate directly act on the newly formed roots, promoting root elongation and thickening, achieving a functional succession from simple water retention to growth promotion.

[0011] Preferably, the bio-based substrate material is selected from white radish (Radish genus) of the Brassicaceae family or potato (Solanaceae family); the bio-based substrate material is in a freshly harvested state.

[0012] By adopting the above technical solutions, the selected white radishes or potatoes have the characteristics of large water storage capacity, dense tissue, and easy accessibility. Fresh harvesting ensures the turgor pressure and activity of thin-walled cells, ensuring sufficient water supply and mechanical support in the early stages of afforestation, and preventing the cuttings from loosening due to rapid water loss and wilting of the substrate.

[0013] Preferably, when the biological substrate material is white radish, individuals with a fleshy root length greater than 15cm are selected; the cutting hole is drilled vertically downward from the center of the cut surface at the top of the radish fleshy root using a drilling tool with a diameter of 0.5cm.

[0014] By adopting the above technical solution, limiting the length of the fleshy root to more than 15cm is to match the drilling depth of 8cm to 12cm, ensuring that a sufficiently thick fleshy layer remains at the bottom after drilling to prevent penetration and rapid water loss. Vertical downward drilling ensures that the direction of gravity of the cutting is consistent with the axis of the substrate, which is beneficial for planting and subsequent downward root growth.

[0015] Preferably, when the biological substrate material is potato, individuals with a long axis length greater than 12cm are selected; the cutting holes are drilled from one end inward along the long axis of the tuber, avoiding areas with dense buds.

[0016] By employing the above technical solution, drilling along the long axis leverages the anatomical advantages of potato tubers, maximizing the contact area between the cuttings and the tuber pith. Avoiding areas with dense buds reduces the probability of the substrate itself germinating lateral buds that consume water and nutrients, allowing more resources to flow to the cuttings and the rhizosphere environment.

[0017] Preferably, the cuttings are selected from tamarisk branches that meet the raw material requirements, and the length of the cut cuttings is 20cm to 24cm, with the diameter of the cuttings matching the diameter of the cutting holes; the soaking involves immersing the base of the cuttings in clean water for 2 to 4 hours.

[0018] By adopting the above technical solution, the cuttings are pre-saturated with water, reducing competition for substrate moisture in the early stages of planting. The appropriate diameter ensures close contact between the cuttings and the substrate pore walls, eliminating air gaps and facilitating the interfacial transport of water and nutrients.

[0019] Preferably, the diameter of the cutting hole is interference-fitted or tight-fitted with the diameter of the cutting, and the fleshy tissue of the biological substrate clamps and fixes the cutting.

[0020] By employing the above-mentioned technical solution, the radial pressure generated by the natural elasticity of fresh fleshy roots or tuber tissues is used to physically secure the cuttings without the need for additional binding materials. This self-locking structure prevents the cuttings from detaching from the substrate during transportation and backfilling, ensuring the continuity of the water transport channels.

[0021] Preferably, the afforestation pit is a fish-scale pit with a size of 50cm to 70cm; the backfilling operation controls the burial depth so that the top of the biological substrate is 5cm to 10cm away from the ground surface, so that the upper end of the cutting is exposed above the ground surface.

[0022] By adopting the above technical solutions, the fish-scale pit structure is conducive to collecting natural rainfall. Controlling the burial depth of the top layer of substrate to 5cm to 10cm avoids drastic water and heat changes in the surface soil that could cause the substrate to dry out, while ensuring that the substrate is in a soil layer with vigorous soil microbial activity, which is beneficial for later decomposition and transformation. Exposing the upper part of the cuttings to the surface ensures photosynthesis and sustains the plant's carbohydrate synthesis.

[0023] Preferably, the depth of the insertion hole is 10 cm.

[0024] By adopting the above technical solution, a depth of 10cm is a proven balance point, which provides sufficient contact area and physical wrapping length, while avoiding instability of the matrix structure or increased operational difficulty caused by excessive hole depth.

[0025] Preferably, the post-planting management also includes: immediately watering the soil layer containing the biological substrate with a single watering to thoroughly irrigate it, and then not artificially watering it unless there is extreme drought.

[0026] By adopting the above technical solution, the purpose of the one-time root-setting water is to establish a hydraulic connection between the substrate and the backfill soil, eliminating large soil pores. Subsequent artificial watering is stopped, forcing the cuttings to utilize the substrate moisture and inducing the roots to grow deeper, forming a drought-resistant root system.

[0027] Preferably, the bio-matrix decomposes in the soil, releasing carbohydrates and endogenous hormones.

[0028] By adopting the above technical solution, the decomposition process of the matrix constitutes the core mechanism of the later stage of this invention: Substrate softening and release: 30 days after transplanting, the matrix cell walls rupture, and the intracellular contents are released into the rhizosphere microdomain.

[0029] Microbial enrichment: The released sugars induce the enrichment of beneficial microorganisms such as rhizosphere nitrogen-fixing bacteria and phosphate-solubilizing bacteria.

[0030] Soil improvement: Microbial metabolites promote soil aggregate formation, reduce soil bulk density, and improve water and fertilizer retention capacity.

[0031] Root development: The released auxin-like substances stimulate the callus tissue at the base of the cutting to differentiate into more secondary roots. The new roots penetrate the already decomposed and loose substrate, extend to the surrounding soil, and eventually establish an independent root absorption system.

[0032] This invention provides a method for improving the survival rate of Tamarix chinensis direct-planting afforestation in arid and semi-arid regions. It has the following beneficial effects: 1. This invention utilizes the fleshy tissue of a fresh biological substrate to construct a rhizosphere microecological buffer system, which improves the survival rate of afforestation. By drilling blind holes inside the substrate that do not penetrate the bottom, the base of the cutting is tightly wrapped by water-rich plant tissue, which physically isolates the cutting from the heat stress and direct water depletion caused by the dry soil. At the same time, by utilizing the water potential difference between the substrate cell sap and the surrounding dry environment, water is slowly released to the cutting and rhizosphere micro-domain through osmosis. Under the condition of no continuous irrigation in the early stage of afforestation, the cuttings are maintained with effective physiological humidity for more than 30 days, which solves the problem of death caused by dehydration in the early stage of direct planting in arid areas.

[0033] 2. This invention promotes the development of seedling roots and the accumulation of aboveground biomass through the decomposition and transformation mechanism of biological substrate. As the afforestation time progresses, the biological substrate buried underground undergoes in-situ degradation under the action of microorganisms. The starch, sugars and endogenous hormones stored in the substrate are gradually mineralized and released, increasing the organic matter content of the rhizosphere soil. In addition, after the substrate decomposes, a loose porous structure is formed around the roots, which effectively improves the soil aggregate structure and aeration, reduces the mechanical resistance to root elongation, and induces the rapid penetration and growth of new roots, realizing the functional succession from single water supply to synergistic regulation of water and fertilizer.

[0034] 3. This invention uses crop tubers or fleshy roots as afforestation auxiliary materials, which has the advantages of low cost, environmental friendliness and simple operation. Compared with traditional chemical water-retaining agents, the biological substrate is completely biodegradable after completing the functions of water storage and fertilizer supply, without producing microplastic residues, avoiding the risk of soil compaction. At the same time, it simplifies the tending and management process after afforestation. Only one-time root-setting water is needed at the time of planting, and growth can be maintained by the slow release of the substrate. This reduces the dependence of vegetation restoration projects in arid areas on water resources and the cost of artificial maintenance in the later stage. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to embodiments, comparative examples, and test examples. 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.

[0036] Preparation Examples 1-4: Preparation Example 1: This preparation example provides a method for preparing a radish substrate for direct planting of Tamarix chinensis in arid and semi-arid regions, including the following steps: Select fresh white radishes that meet the raw material requirements, remove the soil attached to the surface, and check and remove individuals with mechanical damage or pests and diseases; use a woodworking drill bit with a diameter of 0.5cm to drill a cutting hole vertically downward from the center of the cut surface at the top of the radish fleshy root, and precisely control the drilling depth to 8cm. Keep the drill bit stable during the drilling process to prevent the hole wall from breaking. After drilling, clean the residual debris in the hole to obtain radish afforestation substrate with a hole depth of 8cm, and use it immediately after preparation.

[0037] Preparation Example 2: This preparation example provides a method for preparing a radish substrate for direct planting of Tamarix chinensis in arid and semi-arid regions, including the following steps: Select fresh white radishes that meet the raw material requirements, and select individuals with a fleshy root length greater than 15cm. Use a special hole drill with a diameter of 0.5cm to drill cutting holes along the longitudinal axis on the upper part of the radish fleshy root, control the drilling depth to 10cm, ensure that the hole diameter is uniform and the hole wall is smooth, and do not penetrate the bottom and side wall of the radish, retain enough fleshy tissue to cover the cutting hole, clean the debris in the hole, and obtain radish afforestation substrate with a hole depth of 10cm.

[0038] Preparation Example 3: This preparation example provides a method for preparing a radish substrate for direct planting of Tamarix chinensis in arid and semi-arid regions, including the following steps: Fresh white radishes that meet the raw material requirements are selected, and individuals with a fleshy root length greater than 18cm are selected to meet the deep hole requirements. Using a drilling tool with a diameter of 0.5cm, a cutting hole with a depth of 12cm is drilled at the center of the top of the radish fleshy root. During the operation, the drilling angle is strictly controlled to prevent drilling through the side wall, so as to obtain radish afforestation substrate with a hole depth of 12cm.

[0039] Preparation Example 4: This preparation example provides a method for preparing potato substrate for direct planting of Tamarix chinensis in arid and semi-arid regions, including the following steps: Select fresh potato tubers that meet the raw material requirements, screen individuals with a long axis length greater than 12cm, and clean surface impurities; identify the distribution of tuber buds, avoid areas with dense buds, and drill cutting holes from one end inward along the long axis of the tuber. Use a 0.5cm diameter drill bit and control the drilling depth to 10cm to ensure that the overall structure of the tuber is intact and not penetrated. After cleaning the debris in the hole, a potato afforestation substrate with a hole depth of 10cm is obtained.

[0040] Examples 1-4: Example 1: This embodiment provides a method for improving the survival rate of Tamarix chinensis direct planting in arid and semi-arid regions, including the following steps: Cuttings preparation: Select tamarisk branches that meet the raw material requirements, cut them into cuttings with a length of 20cm to 24cm, cut the top end horizontally and the bottom end obliquely, soak the base of the cut cuttings in clean water for 2 hours, and then take them out for use. Direct insertion combination: Select the radish afforestation substrate with a hole depth of 8cm prepared in Preparation Example 1, insert the lower end of the scion after the scion preparation step into the cutting hole of the substrate, and insert it to the depth until the bottom of the scion touches the bottom of the hole to ensure that the scion and the substrate are in close contact. Afforestation and planting: In the afforestation site, dig fish-scale pits with a long diameter of 70cm and a short diameter of 50cm in advance. Dig planting holes in the pits, and place the combination of cuttings and substrate upright in the holes. Backfill the soil and compact it to ensure that the substrate is completely buried underground and that the cuttings are in close contact with the soil. The planting depth is to insert the lower end of the cutting into the cutting hole in the substrate until the bottom (or insert to the same depth as the hole), ensuring that the cuttings are in close contact with the substrate. Post-planting management: Immediately after planting, water thoroughly to help the roots establish. After that, no further artificial watering is required. Rely on natural rainfall to maintain growth until the plants survive.

[0041] Example 2: This embodiment provides a method for improving the survival rate of Tamarix chinensis direct planting in arid and semi-arid regions, including the following steps: Cutting preparation: Select tamarisk branches that meet the raw material requirements, cut them into cuttings 20cm to 24cm in length, cut the top end horizontally and the bottom end at an angle, soak the base of the cut cuttings in clean water for 3 hours, and take them out after they have fully absorbed water; Direct insertion combination: The radish afforestation substrate with a hole depth of 10cm prepared in Preparation Example 2 was selected. The lower end of the scion after the scion preparation step was vertically inserted into the cutting hole of the substrate. The scion was tightly wrapped by the elasticity of the radish flesh tissue. Afforestation and planting: Dig a fish-scale pit with a size of 50cm×70cm in the afforestation site, and plant the combination of cuttings and radish substrate upright in the center of the pit. Backfill with fine soil and tamp it down in layers. After planting, the top of the substrate should be about 5cm-10cm from the ground surface to ensure that the substrate is in a moist soil layer. Post-planting management: Water thoroughly on the day of planting to help the roots establish, then seal the planting pit to retain moisture, strictly control water input, and manage the soil in a manner that simulates the natural environment of arid and semi-arid regions.

[0042] Example 3: This embodiment provides a method for improving the survival rate of Tamarix chinensis direct planting in arid and semi-arid regions, including the following steps: Cutting preparation: Select tamarisk branches that meet the raw material requirements, cut them into cuttings with a length of 20cm to 24cm, treat the cut ends properly, and soak the base of the cuttings in clean water for 4 hours to make them saturated with water. Direct insertion combination: The radish afforestation substrate with a hole depth of 12cm prepared in Preparation Example 3 was selected. This depth can accommodate more of the rooting area at the bottom of the cutting. The cutting was inserted into the hole and confirmed to be secure. Afforestation and planting: Using the same fish-scale pit preparation specifications as in Example 1, the combined cuttings and substrate are planted into the pits, covered with soil and compacted to ensure that the above-ground part of the cuttings is of appropriate length, and to avoid the substrate being exposed and drying out due to shallow burial depth. Post-planting management: Water thoroughly after planting to help the roots establish, and allow the plant to grow naturally without any other watering or fertilization measures.

[0043] Example 4: This embodiment provides a method for improving the survival rate of Tamarix chinensis direct planting in arid and semi-arid regions, including the following steps: Cutting preparation: Select tamarisk branches that meet the raw material requirements, cut them into cuttings with a length of 20cm to 24cm, and after routine cutting treatment, soak the base of the cuttings in clean water for 3 hours; Direct insertion combination: The potato afforestation substrate with a hole depth of 10cm prepared in Preparation Example 4 was used. The lower end of the cutting was inserted into the cutting hole of the potato tuber, and the cutting was fixed by utilizing the dense tissue structure of the potato tuber. Planting: Plant in fish-scale pits with dimensions of 50cm×70cm. The operation procedure is the same as in Example 2. When backfilling, avoid damaging the connection between the potato substrate and the cuttings, and ensure that the soil covering thickness is sufficient to cover the entire potato substrate. Post-planting management: After planting, water thoroughly once to help the roots establish, and then monitor the natural growth.

[0044] Comparative Examples 1-5: Comparative Example 1: Compared to Example 2, the difference is that no afforestation substrate is used. The specific operation is as follows: the prepared tamarisk cuttings are directly inserted into the soil in the center of the fish-scale pit, at the same depth as in Example 2. After planting, the same amount of water is applied to settle the roots. All other steps are the same.

[0045] Comparative Example 2: Compared to Example 1, the difference lies in the depth of the cutting holes in the radish substrate, which is only 3cm. The specific operation is as follows: a shallow hole with a depth of 3cm is drilled in the fleshy root of the radish, and only the base tip of the cutting is inserted into the substrate, with most of the rooting area exposed in the soil. The remaining steps are the same.

[0046] Comparative Example 3: Compared to Example 2, the difference lies in the disruption of the complete physical structure of the substrate. Specifically, fresh radishes of the same size are chopped into small pieces of 1 cm³. At the time of planting, the chopped pieces are mixed with backfill soil and filled around the roots of the cuttings, instead of using whole fleshy roots as containers. The remaining steps are the same.

[0047] Comparative Example 4: Compared to Example 2, the difference lies in the physiological state of the substrate, which is air-dried and dehydrated. Specifically, wilted radishes that have been stored for too long, have wrinkled skin, and a moisture content of less than 50% are selected as the substrate for drilling and direct insertion; the remaining steps are the same.

[0048] Comparative Example 5: Compared to Example 2, the difference lies in the use of a commercially available polymeric water-retaining agent instead of a biological substrate. Specifically, a water-saturated potassium polyacrylate water-retaining agent (20g dry weight of water-absorbed gel) is applied to the planting hole and mixed with the rhizosphere soil. Radishes or potatoes are not used; all other steps remain the same.

[0049] Test Example 1-3: Test Example 1: Statistics on the Survival Rate of Afforestation The experiment was conducted in the Beishan Afforestation Experimental Area of ​​Yuzhong County, Gansu Province. The experimental site is at an altitude of 1980m, with an average annual precipitation of 310mm. The soil type is a transitional type between loess and desert soil, with low surface cover, which is consistent with the characteristics of a typical arid and semi-arid area.

[0050] A completely randomized block design was adopted, with nine treatment groups set up in Examples 1 to 4 and Comparative Examples 1 to 5. Each treatment group had three replicate plots, and 20 afforestation sites were randomly arranged in each plot. A total of 60 tamarisk cuttings were planted in each group.

[0051] Each treatment group strictly followed the methods described in the corresponding embodiments or comparative examples for planting. The planting time was uniformly set in mid-June. On the day of planting, all plants were uniformly watered to help them establish roots, with a watering volume of 3L per plant. During the subsequent 90-day experimental period, artificial watering was completely blocked, and only natural rainfall was accepted.

[0052] During the experiment, regular inspections were conducted to record the growth status of the plants. The final survival rate was calculated on the 90th day after transplanting. The survival criteria were: the length of the new shoots on the above-ground part of the cuttings was ≥2cm and the leaves were still green, or the base of the underground part had obvious callus tissue or new roots. The number of surviving plants in each plot was counted and the average survival rate of each group was calculated.

[0053] Experimental data: Table 1. Statistical data on the survival rate of Tamarix chinensis planted by direct insertion in each treatment group in conclusion: According to the data in Table 1, the overall survival rate of the afforestation in the example group was significantly higher than that in the comparative groups. Example 2 (10cm deep hole radish substrate) achieved the highest average survival rate of 86.7%, which was nearly double that of the traditional direct soil planting method in Comparative Example 1 (45.0%), indicating that the bio-substrate scheme can effectively maintain the vitality of cuttings under drought stress.

[0054] Data comparison reveals several key dimensions of the mechanism of action of this invention: First, the effectiveness of the physical wrapping depth was confirmed by the difference between Examples 1-3 and Comparative Example 2. The survival rate of Examples 1-3 (hole depth 8-12cm) was all above 78%, while that of Comparative Example 2 (hole depth 3cm) was only 55.0%. This indicates that the presence of substrate alone is insufficient; a sufficient physical wrapping depth (8-12cm) must be formed to construct an effective micro-rhizosphere ecological buffer system at the base of the cutting. This utilizes the fleshy layer of the substrate to isolate the cutting from direct heat damage caused by the dry and hot external soil and to reduce water evaporation along the cutting interface.

[0055] Secondly, the integrity of the substrate's physical structure has a decisive impact on water retention. Comparing Example 2 (whole radish, 86.7%) with Comparative Example 3 (chopped radish, 58.3%), it can be seen that although both provide the same biomass, chopping destroys the cellular structure and epidermal protective layer of the fleshy root, leading to rapid water loss in the soil and failing to achieve continuous osmotic pressure water supply and physical support for the base of the cutting. The intact substrate, like a natural water sac, has a water release rate that is more matched to the water absorption needs of the cutting.

[0056] Furthermore, the physiological activity and nutritional function of the substrate are superior to those of a single chemical water-retaining material. The survival rate of Example 2 was significantly better than that of Comparative Example 5 (polymer water-retaining agent, 66.7%). Although the polymer water-retaining agent can provide water, the radish and potato substrate, in addition to providing water, is also rich in active substances such as sugars, vitamins, and endogenous hormones. These endogenous nutrients provide necessary carbon source support and hormone induction in the early stage of rooting of cuttings, promoting rapid differentiation of callus tissue. At the same time, the decomposition process of the biological substrate improves the porosity of the rhizosphere soil, avoiding the problem of reduced local soil aeration caused by the absorption of water by chemical water-retaining agents. Thus, it synergistically promotes the survival of cuttings in three dimensions: water, nutrients, and aeration.

[0057] Finally, the freshness of the substrate is a necessary condition for implementing this invention. The significant difference between Example 2 and Comparative Example 4 (air-dried substrate, 48.3%) indicates that the substrate must be in a fresh state with abundant cell sap to maintain cell turgor pressure and transport water to the cuttings. Dehydrated substrate not only cannot supply water, but also competes for water from the cuttings themselves due to hygroscopic action, leading to afforestation failure.

[0058] In summary, this invention, by selecting fresh and intact radishes or potatoes and using a drilling process at a specific depth, constructs a rhizosphere microenvironment that integrates physical protection, slow water release, and nutrient supply, effectively overcoming the water-limiting factors in direct-planting afforestation in arid and semi-arid regions and improving the survival rate.

[0059] Test Example 2: Determination of Seedling Growth Quality The experimental site and experimental design were the same as in Test Example 1. After the survival rate statistics were completed on the 90th day after transplanting, 15 surviving plants with representative growth status were randomly selected from the treatment groups of Example 2, Example 4, Comparative Example 1 and Comparative Example 5 as test samples for destructive sampling and determination.

[0060] Samples were collected using the whole-plant excavation method. A soil column with a radius of 30cm and a depth of 40cm was dug with the base of the plant stem as the center, and the roots and the surrounding soil ball were completely removed. The sample was placed in a sieve with a 0.5mm aperture and the soil around the roots was rinsed with low-pressure water until the roots were completely exposed and the structure remained intact. The surface moisture was then allowed to air dry naturally.

[0061] The diameter of the plant at ground level (stem diameter 1cm above ground) was measured using a vernier caliper with an accuracy of 0.02mm; the total length of new shoots (the sum of the lengths of all first-order branches) was measured using a measuring tape with an accuracy of 0.1cm; the number of first-order lateral roots longer than 2cm was counted manually; and the length of the longest adventitious root was measured using a ruler.

[0062] The measurement data is entered into statistical software to calculate the average value and standard deviation of each indicator. The growth index reflects the comprehensive impact of different substrates on the growth and development of the above-ground and underground parts of the seedlings.

[0063] Table 2. Data on growth quality indicators of Tamarix chinensis in each treatment group 90 days after planting in conclusion: According to the data in Table 2, the example group outperformed the control group in all indicators of seedling quality, and its performance was particularly outstanding in the root development indicator.

[0064] In Example 2 (radish substrate), the average diameter at rootstock reached 5.22 mm, and the total length of new shoots reached 45.3 cm, significantly higher than that of Comparative Example 1 (blank control) (2.97 mm and 19.9 cm), and also superior to that of Comparative Example 5 (chemical water-retaining agent) (3.98 mm and 33.1 cm). This indicates that the radish substrate not only maintained the survival of the cuttings, but also allowed the starch, sugars, and other carbohydrates and mineral elements stored within it to be decomposed and absorbed and utilized by the plants, acting as a fertilizer and promoting the accumulation of biomass in the above-ground parts, thus achieving a functional leap from simply ensuring survival to promoting growth.

[0065] In terms of underground root development, Examples 2 and 4 showed significant advantages. Example 2 had an average of 13.7 lateral roots and a longest adventitious root length of 31.7 cm, while Comparative Example 5 had only 7.0 roots and a length of 22.9 cm. These differences reveal the fundamental difference in the mechanisms of action between biological substrates and chemical water-retaining agents: while polymeric water-retaining agents can provide moisture, they swell after absorbing water and become gel-like, filling soil pores and hindering rhizosphere aeration to some extent, and they themselves do not contain nutrients; whereas radish or potato substrates gradually decompose in the later stages of planting, forming a loose physical space and organic-rich micro-zones around the roots of the cuttings, improving rhizosphere soil aeration and aggregate structure, reducing soil mechanical resistance, and facilitating root penetration and elongation.

[0066] In addition, the data for potato substrate (Example 4) were slightly lower than those for radish substrate (Example 2). This is presumably because potato tubers have a high starch content and dense texture, resulting in a slower decomposition rate than radishes. The release rate of water and nutrients is relatively delayed, but it has a more lasting effect in long-term drought environments.

[0067] In summary, the bio-matrix used in this invention promotes the simultaneous and robust growth of both the above-ground and underground parts of Tamarix chinensis by providing continuous nutrient supply and creating a favorable rhizosphere physical environment, thus overcoming the technical limitation of traditional chemical water-retaining materials that only retain water but do not promote root growth.

[0068] Test Example 3: Dynamic Monitoring of Rhizosphere Soil Microenvironment Example 2 (radish substrate with a hole depth of 10cm) and Comparative Example 1 (blank control) were selected as the monitoring objects. In the same test plot as Test Example 1, 5 fixed monitoring points were randomly selected for each treatment group.

[0069] At the time of planting, a TDR soil moisture sensor was pre-embedded at a horizontal distance of 5cm and a vertical depth of 15cm at the junction of the rootstock and the cutting (i.e., the core area of ​​the rhizosphere) to monitor the volumetric water content of the rhizosphere soil in real time. After watering thoroughly on the day of planting, soil moisture data were recorded on the 10th, 20th, 30th, 45th and 60th days, respectively. Natural rainfall was also recorded during this period (there was a small amount of rainfall of less than 5mm between the 30th and 45th days of the experiment, which had a negligible impact on the deep soil).

[0070] At the end of the 90th day of the experiment, soil samples were collected from multiple points in the 0-20cm soil layer around the cuttings at the above monitoring points using a soil auger. Undecomposed plant residues and gravel were removed, and the samples were air-dried, ground, and passed through a 100-mesh sieve. The soil organic matter content was determined by potassium dichromate titration method (external heating method).

[0071] We summarized dynamic water monitoring data and final soil organic matter content data to analyze the regulatory effect of biomatrix on water and fertilizer factors in the rhizosphere microenvironment.

[0072] Table 3. Dynamic changes in rhizosphere soil moisture content and soil organic matter content measured on day 90. in conclusion: According to the data in Table 3, Example 2 is significantly better than Comparative Example 1 in maintaining rhizosphere soil moisture stability and improving soil fertility. The data quantitatively reveals the dual mechanism of water slow release and soil improvement of the present invention.

[0073] Regarding water dynamics, during the critical 30-day period after the cessation of artificial irrigation, the rhizosphere soil moisture content in Comparative Example 1 decreased rapidly, reaching an average of approximately 3.2% by day 30, close to the soil wilting coefficient, causing the cuttings to die due to their inability to absorb water. In contrast, the soil moisture content decline curve in Example 2 was significantly flatter, remaining at a relatively high level of approximately 9.4% by day 30. This difference confirms the regulatory function of the radish substrate as a biological water storage capsule: when the surrounding soil water potential decreases, the intact fleshy root tissue relies on the osmotic pressure difference to slowly release water outward, forming a continuously moist micro-domain around the cuttings. This effectively buffers the direct stress of external drought on the root system, providing valuable physiological time for callus formation.

[0074] Regarding the soil improvement effect, the results measured on day 90 showed that the average organic matter content of the rhizosphere soil in Example 2 was 6.97 g / kg, which was 2.1 times that of Comparative Example 1 (3.26 g / kg). This indicates that as the afforestation time progressed, the radish substrate underwent decomposition and transformation under the action of soil microorganisms. The large amount of carbohydrates originally stored in the substrate were not ineffectively lost, but were transformed into humus and enriched around the roots. This in-situ decomposition process not only increased the soil nutrient capacity, but more importantly, promoted the construction of soil aggregate structure through the formation of organic colloids, improving the original compacted and poorly aerated physical properties of desert soil.

[0075] In summary, the microenvironment constructed by the biological matrix in this invention ensures survival in the early stage of afforestation through physical barriers and slow water release, and ensures growth in the later stage of afforestation through matrix decomposition and nutrient release. This temporal functional succession is the core scientific basis for the superiority of this technical solution over single water conservation measures.

Claims

1. A method for improving survival rate of direct-planting of desert-adapted tree species in arid and semi-arid regions, characterized in that, The method comprises the following steps: Selecting fresh and dense tissue of crop root or tuber as biological substrate raw material, drilling a cutting hole with a depth of 8-12 cm on the biological substrate raw material in the longitudinal direction, and controlling the drilling to not penetrate the bottom and sidewall of the biological substrate raw material to form a blind hole structure; Selecting a branch of Tamarix to prepare a cutting and soaking the base for swelling; Inserting the lower end of the cutting into the cutting hole until the bottom of the hole is touched, and forming a close physical package of the cutting base by the substrate pulp layer to obtain a cutting substrate combination; Digging a planting hole in a forestation site, planting the cutting substrate combination vertically and backfilling the soil to be compacted, ensuring that the biological substrate is completely below the ground surface, and allowing the water in the biological substrate to permeate to the cutting and rhizosphere soil.

2. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 1, characterized in that, The biological substrate raw material is selected from white radish of Raphanus of Cruciferae or potato of Solanum of Solanaceae; and the biological substrate raw material is in a fresh harvesting state.

3. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 2, characterized in that, When the biological substrate raw material is white radish, individuals with a root length greater than 15 cm are selected; and the cutting hole is drilled vertically downward from the center of the top end cutting surface of the radish root with a drilling tool with a diameter of 0.5 cm.

4. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 2, characterized in that, When the biological substrate raw material is potato, individuals with a long axis length greater than 12 cm are selected; and the cutting hole is drilled from one end along the long axis direction of the tuber inward, avoiding the bud eye dense area.

5. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 1, characterized in that, The cutting is selected from a Tamarix branch meeting the raw material requirements, and the length of the cutting after cutting is 20-24 cm; the diameter of the cutting is matched with the hole diameter of the cutting hole; and the soaking is soaking the base of the cutting in water for 2-4 hours.

6. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 1, characterized in that, The hole diameter of the cutting hole and the diameter of the cutting are in an interference fit or a close fit, and the pulp tissue of the biological substrate clamps and fixes the cutting.

7. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 1, characterized in that, The forestation hole is a fish scale pit with a specification of 50-70 cm; and the operation of backfilling the soil controls the buried depth of the soil to make the top end of the biological substrate 5-10 cm away from the ground surface, and the upper end of the cutting is exposed to the ground surface.

8. The method for improving survival rate of direct-planting of Tamarix in arid and semi-arid regions according to claim 3, characterized in that, The depth of the cutting hole is 10 cm.

9. The method for improving survival rate of direct-planting of Callerya nudiveris in arid and semi-arid regions according to claim 1, characterized in that, After the planting is completed, the method further comprises post-management: immediately performing one-time root setting water irrigation, and irrigating the soil layer where the biological substrate is located; and thereafter, no artificial water supplement is performed under non-extreme drought conditions.

10. The method for improving survival rate of direct-planting of Tamarix trees in arid and semi-arid regions according to claim 1, characterized in that, The biological substrate is decomposed in the soil to release carbohydrates and endogenous hormones.

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