A method for desalination and carbon sequestration enhancement in saline-alkali sandy land based on space-induced mutation of Reed ferox

Abstract

This application relates to a method for desalination and carbon sequestration enhancement in saline-alkali sandy land based on space-induced mutation of Reed phloxeria. The method includes the following steps: pre-treating the saline-alkali land by tilling to obtain pre-treated saline-alkali land; selecting saline-alkali tolerant Reed phloxeria varieties to improve saline-alkali adaptability, and planting them in the pre-treated saline-alkali land; wherein, from 0 to 3 months after planting, the soil moisture content in the 0-30cm layer is 65%-80% of field capacity; from 4 months after planting to the end of the first growing season, the soil moisture content in the 0-30cm layer is 42%-60% of field capacity. This method can achieve synergistic effects in desalination, soil improvement, and carbon sequestration enhancement in saline-alkali land.

Description

Technical Field

[0001] This application relates to the field of saline-alkali land planting technology, and in particular to a method for reducing salinity and alkali and enhancing carbon sequestration in saline-alkali sandy land based on space-induced mutation of Reed sphagnum moss. Background Technology

[0002] Saline-alkali land resources are widely distributed. Saline-alkali land refers to soil where the salt content affects the normal growth of crops. This type of land generally suffers from poor physical and chemical properties, accompanied by defects such as soil compaction and extremely low organic matter content (usually less than 0.5%). The poor physical and chemical properties of the soil not only inhibit the normal growth of regional vegetation and severely restrict the potential for agricultural production, but also lead to weak regional ecological stability, continuous degradation of the ecological barrier function, and prominent risks of desertification and secondary salinization.

[0003] Currently, the main technologies for improving and restoring saline-alkali land include three categories: chemical improvement, engineering improvement, and phytoremediation. Chemical improvement often uses agents such as gypsum, which shows significant short-term effects in reducing alkali content, but long-term application can easily lead to secondary soil pollution and has high costs. Engineering methods such as salt removal and irrigation / leaching improve soil quickly, but they have drawbacks such as high water consumption, high construction and maintenance costs, and are not suitable for promotion in remote, cold, and arid areas. Compared to the first two methods, phytoremediation, with its advantages of being green and pollution-free, having low maintenance costs, providing long-term soil improvement, and possessing carbon sequestration potential, has become a research hotspot for the ecological governance of saline-alkali land. However, current phytoremediation technologies for saline-alkali land still have significant technical shortcomings, and the industry generally faces the problem of limited carbon sequestration efficiency.

[0004] Therefore, there is an urgent need for a method that can effectively improve the carbon sequestration capacity of saline-alkali land and achieve the industrial application effect of short-cycle soil improvement and continuous carbon fixation. Summary of the Invention

[0005] Based on this, this application provides an efficient and sustainable method for desalination and carbon sequestration enhancement, which can achieve significant improvement in soil physicochemical properties and stable carbon fixation benefits in a short period of time.

[0006] The technical solution to the above-mentioned technical problems in this application is as follows:

[0007] A method for desalination and carbon sequestration enhancement in saline-alkali sandy land based on space-induced mutation of Reed ferox includes the following steps:

[0008] Pre-treatment of saline-alkali land by plowing and tilling is carried out to obtain pre-treated saline-alkali land;

[0009] Select salt-tolerant Reed cultivars to improve their adaptability to saline-alkali soil, and plant them in the pretreated saline-alkali land; wherein, from 0 to 3 months after planting, the soil moisture content of the 0-30cm layer is 65%-80% of the field capacity; from 4 months after planting to the end of the first growing season, the soil moisture content of the 0-30cm layer is 42%-60% of the field capacity.

[0010] In some embodiments, the salt-tolerant Arundo donax varieties have a survival rate of ≥85% under conditions where the conductivity of the soil saturated extract is ≥8dS / m, and the aboveground biomass dry weight in the third year is ≥150t / ha under conditions where the average annual precipitation is 120mm~250mm, and the maximum root depth of mature Arundo donax plants is ≥1.8m.

[0011] In some of these embodiments, the salt-tolerant Reed cultivar includes Hangyu No. 1 Reed.

[0012] And / or, the total salt content of the soil in the saline-alkali land is 0.3% to 1.5%, and the pH value is 8.5 to 10.5.

[0013] In some embodiments, the row spacing is 1.2m to 1.8m, the plant spacing is 0.6m to 1.0m, and the planting depth is 8cm to 12cm.

[0014] In some of these embodiments, from 0 to 3 months after transplanting, the irrigation frequency is 1 to 2 times per month, and the amount of water per irrigation is 12 mm to 18 mm.

[0015] And / or, from the fourth month after transplanting to the end of the first growing season, the irrigation frequency is 0 to 1 time per month, and the amount of water for each irrigation is 15mm to 25mm.

[0016] And / or, irrigation methods include drip irrigation.

[0017] In some embodiments, the tillage depth of the tillage pretreatment is 25cm to 35cm.

[0018] In some embodiments, the method further includes no-till management starting from the second year after planting, retaining fallen leaves on the ground to form an organic cover layer with a thickness of 3cm to 8cm.

[0019] In some embodiments, after the step of tilling the saline-alkali land for pretreatment and before the step of obtaining the pretreated saline-alkali land, the saline-alkali land is further subjected to initial salt leaching, and then allowed to stand and drain for 3 to 5 days before subsequent planting.

[0020] Optionally, if the initial total salinity of the saline-alkali land is 0.3% to 0.6%, the irrigation amount is 15 mm to 20 mm; or, if the initial total salinity of the saline-alkali land is 0.61% to 1.0%, the irrigation amount is 21 mm to 30 mm; or, if the initial total salinity of the saline-alkali land is >1.0%, the irrigation amount is 30 mm to 40 mm.

[0021] In some embodiments, the method further includes applying 2t / ha to 4t / ha of biochar before planting in severely saline-alkali land with a total soil salinity of >1.0% and a pH value of >9.0, and / or treating the roots of Arundo donax with a salt-tolerant microbial agent at the time of planting.

[0022] In some of these embodiments, after 3 years of planting, the total salt content of the soil in the 0-30cm soil layer decreased by ≥60%, and the soil organic matter content increased by ≥200%.

[0023] The aforementioned method for enhancing the carbon sequestration capacity of saline-alkali land first involves pre-treating the land by tilling to break up the plow pan and increase soil porosity. Then, salt-tolerant Reed cultivars are selected to improve their adaptability. By controlling soil moisture management during the early growth stage of Reed saplings, rapid root recovery and above-ground growth are ensured. Furthermore, controlling soil moisture management during the mid-growth stage allows for drought in the upper soil layer, driving deep root development and creating a soil water potential gradient from the surface to deeper layers. This promotes the migration of soluble salts to soil layers below 40cm via infiltration water, significantly reducing the salt content of the cultivated soil layer. This method is characterized by its ease of operation, short improvement cycle, and significant carbon sequestration benefits. It is suitable for large-scale ecological restoration and carbon sequestration of saline-alkali land, ultimately achieving a synergistic effect of saline-alkali land desalination, soil improvement, and carbon sequestration enhancement. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of the method for desalination and carbon sequestration enhancement in cold, arid, saline-alkali sandy land based on space-induced mutation of Reed hyacinth in Embodiment 1 of this application. Detailed Implementation

[0026] Reference will now be made to detailed embodiments of this application, one or more of which are described below. Each example is provided for explanation and not for limitation of this application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0027] Therefore, this application is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of this application are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0029] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0030] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the weights mentioned in the embodiments of this application can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0031] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0032] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0033] As shown in the background section, current phytoremediation technologies for saline-alkali land still have significant technical shortcomings, and the industry generally faces the problem of limited carbon sequestration efficiency. Through long-term research, the researchers of this application have found that *Arundo donax*, a perennial tall grass (C3 species), has high biomass yield potential, strong root penetration, and a certain degree of salt tolerance. However, common *Arundo donax* germplasm exhibits a winter survival rate of <60% and an annual aboveground biomass dry weight of ≤8 t / mu in cold, arid, saline-alkali sandy land with soil electrical conductivity (EC) ≥8 dS / m or annual average temperature ≤8℃, indicating limited carbon sequestration efficiency.

[0034] Further research by the technical personnel involved in this application revealed that new varieties of Phragmites australis bred using space mutation breeding technology, through genetic variation induced by the high vacuum, microgravity, and strong radiation environment of space, followed by multiple generations of directional screening on the ground, yielded germplasm materials with significantly enhanced cold resistance, drought resistance, and salt tolerance. However, there is currently a lack of quantifiable and replicable field operation procedures for systematically translating the biological advantages of these new varieties into technical solutions for saline-alkali land remediation and carbon sequestration enhancement.

[0035] Based on this, one embodiment of this application provides a method for desalination and carbon sequestration enhancement in saline-alkali sandy land based on space-induced mutation of Reed hyacinth, including the following steps S100 to S200.

[0036] Step S100: Pre-treat the saline-alkali land by tilling to obtain pre-treated saline-alkali land.

[0037] Step S200: Select salt-tolerant Reed cultivars to improve their salt-alkali adaptability and plant them in the pretreated saline-alkali land. The soil moisture content in the 0-30cm layer should be 65%-80% of the field capacity from 0 to 3 months after planting; the soil moisture content in the 0-30cm layer should be 42%-60% of the field capacity from 4 months after planting to the end of the first growing season.

[0038] The aforementioned method for enhancing the carbon sequestration capacity of saline-alkali land first involves pre-treating the land by tilling to break up the plow pan and increase soil porosity. Then, salt-tolerant Reed cultivars are selected to improve their adaptability. By controlling soil moisture management during the early growth stage of Reed saplings, rapid root recovery and above-ground growth are ensured. Furthermore, controlling soil moisture management during the mid-growth stage allows for drought in the upper soil layer, driving deep root development and creating a soil water potential gradient from the surface to deeper layers. This promotes the migration of soluble salts to soil layers below 40cm via infiltration water, significantly reducing the salt content of the cultivated soil layer. This method is characterized by its ease of operation, short improvement cycle, and significant carbon sequestration benefits. It is suitable for large-scale ecological restoration and carbon sequestration of saline-alkali land, ultimately achieving a synergistic effect of saline-alkali land desalination, soil improvement, and carbon sequestration enhancement.

[0039] It should be noted that the percentage of soil moisture content in the 0-30cm layer relative to field capacity during the first three months after transplanting is considered to be between 65% and 80%. This range includes the minimum and maximum values ​​within this range, as well as every value between them. Specific examples include, but are not limited to, the point values ​​in the examples and the following point values: 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, or 80%. Alternatively, any range consisting of any two of these values, for example, includes 65% to 75%.

[0040] The percentage of soil moisture content in the 0-30cm layer relative to field capacity, from the 4th month after transplanting to the end of the first growing season, should be within the range of 42% to 60%. This range includes the minimum and maximum values, as well as every value between these values. Specific examples include, but are not limited to, the point values ​​in the examples and the following point values: 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%. Alternatively, any range consisting of any two of these values, for example, includes 45% to 55%.

[0041] In some of these embodiments, the above-mentioned salt-tolerant Arundo donax varieties have a survival rate of ≥85% under conditions where the conductivity of the soil saturated extract is ≥8dS / m, and the aboveground biomass dry weight in the third year is ≥150t / ha under conditions where the average annual precipitation is 120mm~250mm, and the maximum root depth of mature Arundo donax plants is ≥1.8m.

[0042] In some of the embodiments, the above-mentioned salt-tolerant Reed cultivars had a survival rate of 85% to 100% under the condition that the conductivity of the soil saturated extract was ≥8dS / m, and the aboveground biomass dry weight in the third year was 150t / ha to 220t / ha under the condition of an average annual precipitation of 120mm to 250mm. The maximum root depth of mature Reed cultivars was 1.8m to 3.5m.

[0043] In some of these embodiments, the salt-tolerant Reed cultivar mentioned above includes Hangyu No. 1 Reed.

[0044] In some of these embodiments, the salt-tolerant Reed truncata variety was approved by the National Grass Variety Approval Committee in 2023, with variety number: S-BV-AD-005-2023. It was granted a Plant Variety Rights Certificate in January 2025, with variety rights number: 20240753.

[0045] In some embodiments, the total salinity of the soil in the aforementioned saline-alkali land is 0.3%–1.5%, and the pH value is 8.5–10.5. For example, the total salinity can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%, and the pH can be 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, or 10.5. In some examples, the range can be any two of these point values ​​as endpoints, and the same applies below.

[0046] In some embodiments, the row spacing is 1.2m to 1.8m, the plant spacing is 0.6m to 1.0m, and the planting depth is 8cm to 12cm. For example, the row spacing can be 1.2m, 1.3m, 1.4m, 1.5m, 1.6m, 1.7m, or 1.8m, the plant spacing can be 0.6m, 0.7m, 0.8m, 0.9m, or 1.0m, and the planting depth can be 8cm, 9cm, 10cm, 11cm, or 12cm.

[0047] Understandably, controlling the row and plant spacing within the aforementioned range optimizes ventilation and light penetration within the plant community, reduces capillary salt return between rows, lowers the probability of pests and diseases, and facilitates mechanized field management. Reasonable planting density avoids competition for water and fertilizer among plants, allows for interwoven root distribution, expands the soil improvement area, and enhances vegetation community stability and biomass accumulation. Limiting the planting depth to 8-12 cm avoids high-salt stress in the topsoil layer, ensures close contact between roots and rhizomes, promotes adventitious root development, and improves heat and moisture retention under low-temperature conditions, significantly increasing seedling survival rate and overwintering stability.

[0048] In some embodiments, the planting density is 5,500 plants / ha to 11,000 plants / ha. For example, the density can be 5,500 plants / ha, 6,000 plants / ha, 6,500 plants / ha, 7,000 plants / ha, 7,500 plants / ha, 8,000 plants / ha, 8,500 plants / ha, 9,000 plants / ha, 9,500 plants / ha, 10,000 plants / ha, 10,500 plants / ha, or 11,000 plants / ha.

[0049] In some embodiments, from 0 to 3 months after transplanting, the irrigation frequency is 1 to 2 times per month, and the amount of water per irrigation is 12mm to 18mm.

[0050] In some embodiments, from the fourth month after planting to the end of the first growing season, the irrigation frequency is 0 to 1 times per month, and the amount of water per irrigation is 15 mm to 25 mm.

[0051] In some of these embodiments, irrigation methods include drip irrigation.

[0052] In some embodiments, the tillage depth of the pre-tillage treatment is 25cm to 35cm. For example, the tillage depth can be 25cm, 26cm, 27cm, 28cm, 29cm, 30cm, 31cm, 32cm, 33cm, 34cm, or 35cm.

[0053] This depth can effectively break up the dense crust on the surface and the shallow plow pan, reduce soil bulk density, improve soil pore structure, enhance soil permeability and aeration, and facilitate irrigation water and rainwater to wash away surface salts, thus inhibiting salt accumulation and return.

[0054] In some of these embodiments, the materials used for planting include rhizome segments and tissue culture seedlings.

[0055] In some embodiments, the preparation method of planting materials includes: selecting rhizomes with plump buds and no diseases, cutting them into stem segments with a length of 15cm to 20cm and containing 2 to 3 internodes, making the cut surface flat, and disinfecting them by soaking in wood ash or 800 times dilution of 50% carbendazim wettable powder.

[0056] In some embodiments, the method for preparing planting materials includes: using aseptic tissue culture rooted seedlings with a height of ≥15 cm and well-developed root systems, and transplanting them after hardening off for 7 to 10 days.

[0057] In some embodiments, the method further includes no-till management starting from the second year after planting, retaining the fallen leaves on the ground to form an organic cover layer with a thickness of 3cm to 8cm.

[0058] Understandably, except in years of extreme drought (more than 60 consecutive days without effective precipitation), artificial irrigation is stopped, relying entirely on natural rainfall and deep soil water storage to maintain surface litter cover and reduce evaporation and salt return. From the second year onwards, no-till management is implemented, utilizing the extensive root system of reeds to stabilize the soil. The above-ground parts naturally wither each winter without being harvested or removed, forming an organic mulch layer 3-8 cm thick to reduce surface evaporation, inhibit salt accumulation, and increase soil organic matter input.

[0059] In some embodiments, after the step of tilling and pre-treating the saline-alkali land and before the step of obtaining the pre-treated saline-alkali land, the process includes initial salt leaching of the saline-alkali land, followed by allowing it to stand and drain for 3 to 5 days before subsequent planting.

[0060] In some embodiments, if the initial total salinity of the saline-alkali land is 0.3% to 0.6%, the irrigation amount is 15 mm to 20 mm; or, if the initial total salinity of the saline-alkali land is 0.61% to 1.0%, the irrigation amount is 21 mm to 30 mm; or, if the initial total salinity of the saline-alkali land is >1.0%, the irrigation amount is 30 mm to 40 mm.

[0061] In some embodiments, the above method further includes applying 2t / ha to 4t / ha of biochar before planting in severely saline-alkali land with a total soil salinity of 1.0% to 1.5% and a pH of 9.0 to 10.5, and / or soaking the roots of Arundo donax in a salt-tolerant microbial agent at the time of planting.

[0062] Understandably, applying rice husk charcoal or straw charcoal once before transplanting, combined with tilling, at a rate of 2-4 t / ha, can increase soil cation exchange capacity and buffer against salt damage. At transplanting, using a salt-tolerant growth-promoting microbial agent (containing ≥2×10⁻⁶ live Bacillus subtilis bacteria) is recommended.8 Soak roots in a 50-fold diluted solution (CFU / mL, arbuscular mycorrhizal fungal spore density ≥50 spores / g) for 5-10 minutes.

[0063] In some of these embodiments, after 3 years of planting, the total salt content of the soil in the 0-30cm soil layer decreased by ≥60%, and the soil organic matter content increased by ≥200%.

[0064] The aforementioned method for enhancing the carbon sequestration capacity of saline-alkali land utilizes the combined resistance of cold, drought, and salinity to *Arundinaria lobata* induced by space mutation, increasing the vegetation establishment success rate in cold, arid, and saline-alkali sandy land from less than 60% to over 85%. It avoids reliance on large-scale salt drainage engineering facilities and chemical amendments, achieving a reduction of over 60% in soil salinity through only three years of water gradient regulation and biological processes, with the average cost per acre decreasing by over 70% compared to engineering measures. In the third year, biomass reaches over 12 tons per acre, and carbon sequestration reaches 4.5 to 8.0 tons of CO2 per acre. These data are based on accurate calculations using a dry basis and carbon coefficient, providing a verifiable methodological foundation for carbon trading. The planting density, irrigation threshold, and soil moisture indicators in the above scheme are all quantitatively constrained, facilitating replication and implementation in plots with varying degrees of salinization.

[0065] The present application will be described below with reference to specific embodiments, but the present application is not limited to the following embodiments. It should be understood that the appended claims summarize the scope of the present application. Under the guidance of the concept of the present application, those skilled in the art should realize that certain changes made to the various embodiments of the present application will be covered by the spirit and scope of the claims of the present application.

[0066] An experiment was conducted in the arid, saline-alkali sandy land of the Tarim Basin in Xinjiang: a randomized block design was adopted, with each treatment group replicated three times, and the plot area was 200m². 2 (20 m × 10 m), with 1.5 m isolation rows between sections. Initial saline-alkali soil: Total salt content (0–30 cm) 0.62 ± 0.05% (determined by gravimetric method); Soil organic matter (0–30 cm) 0.48 ± 0.03% (potassium dichromate oxidation method); Soil texture: sandy loam, bulk density 1.48 g / cm³. 3 Average annual precipitation: 162 mm; Average annual temperature: 6.5℃, extreme minimum temperature: -27.3℃.

[0067] Example 1

[0068] 1. Site preparation and pretreatment

[0069] (1) Tillage and land preparation: On April 10, deep tillage was carried out on the target saline-alkali sandy land to a depth of 28cm to break up the plow pan and increase soil porosity; after tillage, the land was leveled and large gravel and invasive weed roots were removed.

[0070] (2) Initial salt leaching: When the plot has an irrigation water source (including slightly saline water with a mineralization of <3 g / L), an initial leaching is carried out after tilling, with a specific irrigation amount of 25 mm. After standing and draining for 3 to 5 days, subsequent planting can be carried out.

[0071] 2. Seedling preparation

[0072] The selected variety, "Hangyu No. 1," was a Reed cultivar obtained through space mutation breeding technology and validated in the field for at least three growing seasons. Specifically, it originated from Reed ferns from southern China carried aboard the Shenzhou-10 manned spacecraft in June 2013, which underwent space mutation followed by several rounds of screening and identification on the ground over several years. It was bred by Aerospace Green Peng Biotechnology (Beijing) Co., Ltd. The quantitative characteristics exhibited by this variety in controlled trials include: a survival rate of 88% in the first year after planting under conditions of soil saturated mud extract conductivity ECe ≥ 8 dS / m; a aboveground biomass dry weight of 170 t / ha in the third year under conditions of an average annual rainfall of 120–250 mm without supplemental irrigation; and a maximum root depth of 2.2 m for mature plants.

[0073] The planting material uses rhizome segments: select rhizomes of Hangyu No. 1 Reed with plump buds and free from disease, cut them into segments 18cm long with 2-3 internodes, keep the cut surface flat and disinfect with wood ash.

[0074] 3. Planting methods

[0075] Place the stem segments flat in the holes, cover them with 5-8 cm of soil, and compact the soil slightly to ensure close contact between the roots and the soil. Plant them as follows: row spacing is 1.5 m; plant spacing is 0.8 m; planting hole diameter is 20 cm, depth is 10 cm, and planting density is 8333 effective plants per hectare.

[0076] 4. Phased water regulation

[0077] Water management adopts a three-stage soil moisture gradient-driven strategy of "promoting vitality in the early stage, promoting root growth in the middle stage, and controlling salt in the later stage".

[0078] (1) From April 20 to July 20 (seedling stage): Irrigate twice a month (April 25, May 15, June 10, and July 5), with each irrigation volume being 15 mm (precisely measured by a water meter, drip irrigation method). During this period, the relative soil moisture content (i.e., the percentage of soil moisture content to field capacity) in the 0-30 cm soil layer was maintained between 68% and 78%.

[0079] (2) From July 21 to the end of October: only on August 20 when rainfall is insufficient (monthly precipitation <5 mm), supplemental irrigation of 20 mm is given once. At other times, the relative soil moisture content is controlled within the range of 42% to 55%.

[0080] 5. Growth Management: No chemical amendments are applied. From the second winter onwards, all withered stems and fallen leaves are retained, and the ground cover thickness reaches approximately 4 cm by the end of the third year.

[0081] Example 2

[0082] The method for improving the carbon sequestration capacity of saline-alkali land in Example 2 is basically the same as that in Example 1. The only difference is that the planting method in step (3) is different. Specifically, the stem segments are placed flat in the hole, covered with soil with a thickness of 5cm to 8cm, and slightly compacted to make the roots and stems in close contact with the soil. The planting is carried out in the following manner: the row spacing is 1.2m; the plant spacing is 0.6m; the diameter of the planting hole is 20cm, the depth is 8cm, and the planting density is 13,888 effective plants per hectare.

[0083] The remaining steps and parameters are the same as in Example 1.

[0084] Example 3

[0085] The method for improving the carbon sequestration capacity of saline-alkali land in Example 3 is basically the same as that in Example 1. The only difference is that the planting method in step (3) is different. Specifically, the stem segments are placed flat in the hole, covered with soil with a thickness of 5cm to 8cm, and slightly compacted to make the roots and stems in close contact with the soil. The planting is carried out in the following manner: the row spacing is 1.8m; the plant spacing is 1.0m; the diameter of the planting hole is 20cm, the depth is 12cm, and the planting density is 5556 effective plants per hectare.

[0086] The remaining steps and parameters are the same as in Example 1.

[0087] Comparative Example 1

[0088] The method for improving the carbon sequestration capacity of saline-alkali land in Comparative Example 1 is basically the same as that in Example 1. The only difference is that in step (2), common reed (specifically, wild reed (Arundo donax L.) rhizomes collected locally in Zhanhua District, Binzhou City, Shandong Province, China, without spatial mutagenesis or salt-tolerant directional breeding, collected and propagated in March 2020 and preserved at the experimental base of Tarim University in Xinjiang) are planted. In step (3), 15 mm of root-setting water is irrigated on the day of planting. The artificial water replenishment and water control measures in step (4) are omitted. In step (5), dead materials are removed and removed from the plot every spring.

[0089] The remaining steps and parameters are the same as in Example 1.

[0090] Comparative Example 2

[0091] The method for improving the carbon sequestration capacity of saline-alkali land in Comparative Example 2 is basically the same as that in Example 1, except that Reed is not planted in steps (2) and (3), and water management is not carried out in step (4).

[0092] The remaining steps and parameters are the same as in Example 1.

[0093] Comparative Example 3

[0094] The method of improving the carbon sequestration capacity of saline-alkali land in Comparative Example 3 is basically the same as that in Example 1. The only difference is that in step (4), the soil moisture content of the 0-30cm layer is 50% of the field water holding capacity from 0 to 3 months after planting; and the soil moisture content of the 0-30cm layer is 80% of the field water holding capacity from 4 months after planting to the end of the first growing season.

[0095] The remaining steps and parameters are the same as in Example 1.

[0096] test:

[0097] 1. The relative soil moisture content of the saline-alkali land in each embodiment and comparative example was monitored. Specifically, the in-situ measurement method of time domain reflectometer (TDR) was adopted. The field water holding capacity was measured according to NY / T 1121.22-2010 "Soil Testing Part 22: Determination of Soil Field Water Holding Capacity by Ring Method". The relative soil moisture content was calculated by the ratio of volumetric water content to field water holding capacity.

[0098] 2. The total salt content of the saline-alkali land in each embodiment and comparative example was monitored, specifically determined by the gravimetric method. The determination was performed at the end of each growing season (end of October) using the gravimetric method, referring to LY / T 1251-1999 "Analysis of Water-Soluble Salts in Forest Soils".

[0099] 3. The soil organic matter content of the saline-alkali land in each embodiment and comparative example was monitored. Specifically, the potassium dichromate oxidation-external heating method was used for determination, referring to NY / T 1121.6-2006 "Soil Testing Part 6: Determination of Soil Organic Matter".

[0100] 4. The aboveground biomass (dry weight) of the saline-alkali land in each embodiment and comparative example was monitored. Specifically, the quadrat harvesting method was used for determination. The land was dried at 65℃ to constant weight, and the aboveground biomass determination method was performed in accordance with NY / T 2998-2016 "Technical Specification for Grassland Resource Survey".

[0101] 5. The annual carbon sequestration of the saline-alkali land in each embodiment and comparative example was monitored, specifically by cutting 1 m of land at the end of each growing season (October). 2 The fresh weight of aboveground biomass was determined by quadrat sampling, and the dry weight was determined after drying at 65℃ to constant weight. Carbon reserves were calculated using the following formula:

[0102] C = B × CF × 3.67;

[0103] Wherein, B is the aboveground biomass dry weight (t / ha).

[0104] CF—carbon coefficient of dry matter in Reed sibirica, determined by elemental analysis to be 0.45–0.48;

[0105] 3.67 – The coefficient for converting C to CO2 equivalent. The results are shown in Table 1.

[0106] Table 1

[0107]

[0108] Table 2

[0109]

[0110] As shown in Tables 1 and 2, Example 1 significantly reduced the salt content of the topsoil by utilizing the strong root penetration of space-induced *Arundinaria mirifica* and salt leaching driven by water potential gradients, combined with surface mulching to suppress evaporation. Simultaneously, the annual dry matter return of up to 12.8 t / mu was the core driving factor for the rapid increase in soil organic matter. The data indicate that the method described in this application is superior to existing conventional planting methods in terms of quantitative indicators.

[0111] This application selects space-mutated Reed cultivars with a survival rate of ≥85% and an annual biomass of ≥150 t / ha under conditions of electrical conductivity ≥8 dS / m; plants them at specific spacing; and implements a phased soil moisture control strategy of high water potential to promote seedling survival and low water potential to displace salt in the mid-to-late stages, while retaining litter cover. Through three consecutive years of implementation, the total salt content of the 0–30 cm soil can be reduced by ≥60%, organic matter increased by ≥200%, and the annual carbon fixation reaches 4.5–8.0 t CO2 equivalent / acre. This application quantitatively constrains key planting parameters and water thresholds, and is characterized by strong operability, short improvement cycle, and significant carbon sequestration benefits, making it suitable for large-scale ecological restoration and carbon sequestration in saline-alkali sandy lands in cold and arid regions.

[0112] In summary, the method proposed in this application for enhancing the carbon sequestration capacity of saline-alkali land quantitatively constrains key planting parameters and moisture thresholds, and is characterized by strong operability, short improvement cycle, and significant carbon sequestration benefits. It is suitable for large-scale ecological restoration and carbon sequestration enhancement of saline-alkali sandy land in cold and arid regions.

[0113] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for desalination and carbon sequestration enhancement in saline-alkali sandy land based on space-induced mutation of Reed phloxeria, characterized in that, Includes the following steps: Pre-treatment of saline-alkali land by plowing and tilling is carried out to obtain pre-treated saline-alkali land; Select salt-tolerant Reed cultivars to improve their adaptability to saline-alkali soil, and plant them in the pretreated saline-alkali land; wherein, from 0 to 3 months after planting, the soil moisture content of the 0-30cm layer is 65%-80% of the field capacity; from 4 months after planting to the end of the first growing season, the soil moisture content of the 0-30cm layer is 42%-60% of the field capacity.

2. The method as described in claim 1, characterized in that, The saline-alkali tolerant Arundinacea varieties have a planting survival rate of ≥85% under conditions where the electrical conductivity of the soil saturated extract is ≥8dS / m, and the aboveground biomass dry weight in the third year is ≥150t / ha under conditions where the average annual precipitation is 120mm~250mm. The maximum root depth of mature Arundinacea plants is ≥1.8m.

3. The method as described in claim 2, characterized in that, The salt-tolerant Reed variety includes Hangyu No. 1 Reed. And / or, the total salt content of the soil in the saline-alkali land is 0.3% to 1.5%, and the pH value is 8.5 to 10.

5.

4. The method according to any one of claims 1 to 3, characterized in that, The row spacing for planting is 1.2m to 1.8m, the plant spacing is 0.6m to 1.0m, and the planting depth is 8cm to 12cm.

5. The method according to any one of claims 1 to 3, characterized in that, From 0 to 3 months after transplanting, the irrigation frequency is 1 to 2 times per month, and the amount of water per irrigation is 12mm to 18mm. And / or, from the fourth month after transplanting to the end of the first growing season, the irrigation frequency is 0 to 1 time per month, and the amount of water for each irrigation is 15mm to 25mm. And / or, irrigation methods include drip irrigation.

6. The method according to any one of claims 1 to 3, characterized in that, The tillage depth for pre-tillage treatment is 25cm to 35cm.

7. The method according to any one of claims 1 to 3, characterized in that, The method also includes no-till management starting from the second year after planting, retaining fallen leaves on the ground to form an organic cover layer with a thickness of 3cm to 8cm.

8. The method according to any one of claims 1 to 3, characterized in that, After the pre-treatment step of tilling the saline-alkali land and before the step of obtaining the pre-treated saline-alkali land, the process also includes initial salt leaching of the saline-alkali land, followed by subsequent planting after allowing the land to stand and drain for 3 to 5 days. Optionally, if the initial total salinity of the saline-alkali land is 0.3% to 0.6%, the irrigation amount is 15 mm to 20 mm; or, if the initial total salinity of the saline-alkali land is 0.61% to 1.0%, the irrigation amount is 21 mm to 30 mm; or, if the initial total salinity of the saline-alkali land is >1.0%, the irrigation amount is 30 mm to 40 mm.

9. The method according to any one of claims 1 to 3, characterized in that, The method also includes applying 2t / ha to 4t / ha of biochar before planting in severely saline-alkali land with a total soil salinity of 1.0% to 1.5% and a pH of 9.0 to 10.5, and / or soaking the roots of Reed in salt-tolerant microbial agents at the time of planting.

10. The method according to any one of claims 1 to 3, characterized in that, Three years after planting, the total salt content of the soil in the 0-30cm soil layer decreased by ≥60%, and the soil organic matter content increased by ≥200%.

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