Method for rapidly recovering waste land and abandoned land carbon sequestration through root tiller fast-growing trees

Abstract

The invention discloses a method for rapidly recovering waste land and abandoned land carbon sequestration through root tiller fast-growing trees. The method comprises the following steps that 1, proper tree species are selected; 2, root section treatment; 3, land parcel treatment and root section cuttage; 4, harvesting the overground part; 5, treating the overground part into a carbon-rich solid and an organic liquid; 6, performing innocent treatment on the organic liquid to obtain improved organic liquid; 7, treating carbon-rich solids and filling the carbon-rich solids into the land parcels; and 8, adding the improved organic liquid into the land parcels. By utilizing a root tiller fast-growing tree and a root segment propagation technology thereof and combining with application of producing carbon-rich solid and organic liquid, not only can the fertility, the structure and the microbial activity of soil be improved, but also the loss of a carbon element is effectively reduced, and meanwhile, by adding arbuscular mycorrhizal fungi, the growth and nutrition absorption capacities of plants can be enhanced, and the yield of the plants is increased. Therefore, solid storage of soil carbon and long-term stability of mining area carbon sink are promoted.

Description

Technical Field

[0001] The invention relates to the field of ecological restoration of wasteland in mining areas, and in particular to a method for rapidly restoring carbon sinks of abandoned land and wasteland by using fast-growing root suckers. Background Art

[0002] In recent years, with the rapid advancement of industrialization, urbanization and agricultural modernization, natural resources and ecological environment constraints have become increasingly prominent. In the same space, rural farmland fragmentation, disordered spatial layout, inefficient land resource utilization, ecological quality degradation and other multi-dimensional problems coexist. The land consolidation model with a single factor and a single means is no longer able to completely solve the comprehensive problems. In particular, the degraded ecosystem in cities and towns has not only destroyed the ecological function of the land, but also posed a huge threat to the surrounding environment and residents' lives, forming a typical ecological environment "black hole" that is extremely difficult to manage.

[0003] As an important means to address climate change and achieve carbon neutrality, the role of carbon sinks is becoming increasingly prominent. Abandoned and abandoned lands have long been neglected for their potential contribution to carbon sinks due to the extremely low organic matter content and lack of vegetation in the soil. However, once abandoned and abandoned lands are effectively restored, they can not only restore ecosystem functions, but also fix atmospheric carbon dioxide into stable soil organic carbon through vegetation growth and soil improvement, providing important support for achieving the "dual carbon" goals. Therefore, the combination of restoration of abandoned and abandoned lands and the enhancement of carbon sink functions has significant ecological value and social significance.

[0004] At present, the management methods of abandoned and wasteland mainly include mechanical land preparation, planting artificial grassland, applying chemical fertilizers and soil conditioners, etc. However, these methods generally have disadvantages such as high cost, complex operation, and limited long-term effect, especially for the restoration of severely degraded soil. As pioneer plants, root sucker species such as paper mulberry, willow, and paulownia show significant advantages in the restoration of abandoned and wasteland. Its root system is deep and well-developed, which can fix the soil and accumulate a large amount of carbon underground; it has strong vitality and can grow in poor environments; at the same time, it has extremely high biomass and adaptability, and also plays a certain role in absorbing heavy metals and improving soil structure. These characteristics make fast-growing tree species ideal plants for the restoration of abandoned and wasteland.

[0005] Based on the ecological characteristics of fast-growing root-sucking trees, it is very possible and innovative to develop a carbon sink technology for the rapid restoration of abandoned and wasteland with fast-growing root-sucking trees as the core. This can not only significantly improve the carbon sink capacity of abandoned and wasteland, but also provide new ideas for the restoration of barren wasteland, and provide a feasible path for achieving a win-win situation of ecological restoration and carbon neutrality. Summary of the invention

[0006] To address the deficiencies in the above-mentioned existing technologies, the present invention provides a method for rapidly restoring the carbon sinks of abandoned lands and fallow lands using root-suckering fast-growing trees. By utilizing root-suckering fast-growing trees and their root segment propagation techniques, combined with the application of producing carbon-rich solids and organic liquids, it not only improves the soil fertility, structure, and microbial activity, but also effectively reduces the loss of carbon elements. At the same time, by adding arbuscular mycorrhizal fungi, it can enhance the plant growth and nutrient absorption ability, thereby promoting the soil carbon sequestration and the long-term stability of the carbon sink in the mining area.

[0007] To achieve the above-mentioned invention objectives, the present invention provides the following technical solutions:

[0008] A method for rapidly restoring the carbon sinks of abandoned lands and fallow lands using root-suckering fast-growing trees, the method comprising the following steps:

[0009] Step 1: Select the corresponding root-suckering fast-growing tree species according to the type of the plot to be restored;

[0010] Step 2: After selecting the root-suckering fast-growing tree species, in March or April, screen out the healthy mother plants without diseases and pests, and process the main roots or rhizomes of the mother plants into root segments to be planted;

[0011] Step 3: Arrange the plot to be restored: Dig planting trenches on the plot to be restored, insert the processed root segments into the planting trenches, ensure that the root segments are in a vertical state and compact the soil around the root segments to ensure sufficient water for the growth of the root segments without waterlogging;

[0012] Step 4: Harvest the above-ground parts of the root-suckering fast-growing trees in October or November every year;

[0013] Step 5: Dry the harvested above-ground parts, then crush them into particles and mix them with water. The mixture is subjected to a heating reaction in a closed container, and after the reaction is complete, carbon-rich solids and organic liquids are separated;

[0014] Step 6: Treat the organic liquid harmlessly, and use the organic liquid with a phenol degradation rate of more than 80% after treatment as the improved organic liquid for standby;

[0015] Step 7: Process the carbon-rich solids, dig landfill trenches between the planting trenches, mix the processed carbon-rich solids with soil and bury them in the landfill trenches, and then cover with soil;

[0016] Step 8: Add the improved organic liquid to the root-suckering fast-growing trees in February or March every year starting from the second year of planting the root-suckering fast-growing trees.

[0017] Furthermore, in the above-mentioned Step 1: The method for selecting the corresponding root-suckering fast-growing tree species according to the type of the plot to be restored is carried out in the following manner:

[0018]

[0019]

[0020] Further, in the second step, the method of processing the main root or rhizome of the mother plant into root segments to be planted is as follows: select a thick and mature main root or rhizome of the mother plant, cut the selected root into segments 10-20 cm long, and each root segment should have at least one bud point. Then soak the root segments in a rooting hormone, which includes indolebutyric acid solution with a concentration of 0.2%-0.5%, for 30-60 minutes. After soaking, take out the root segments and dry them in the dark for 20-30 minutes before planting.

[0021] Further, in the third step, the width of the planting groove is 30-50 cm, the depth is 30-40 cm, and the spacing between planting grooves is 2-3 m; the insertion depth of the root segments is 5-10 cm, and the spacing in the groove is 2-3 m; after the root segments are cut and inserted, it is necessary to ensure that the soil is moist within the first 1-2 months. If there is no natural precipitation for more than 2-3 weeks during the remaining time, artificial irrigation can be carried out; for fast-growing root-sprouting trees, 15-40 kg of nitrogen and potassium fertilizers need to be applied per hectare every 2-3 months in the first year of planting and growth. If the fast-growing root-sprouting tree is Broussonetia papyrifera, only potassium fertilizer is applied.

[0022] Further, in the fourth step, the stubble height after harvesting the above-ground part is 10-30 cm.

[0023] Further, in the fifth step, the drying time of the harvested above-ground part is 10-30 days, the particle size of the crushed particles is 3-5 cm, and the volume ratio of the particles to water is 3:1-5:1; the temperature for the heating reaction in a closed container is 180-250 °C, the pressure is 10-30 MPa, the reaction time is 4-6 h, and after the reaction is completed, after cooling and depressurizing, the carbon-rich solid and organic liquid are separated.

[0024] Further, for fast-growing root-sprouting trees on heavy metal-polluted land and fast-growing root-sprouting trees on organic-polluted land, 1 / 3-1 / 4 of the harvested part is selected every year and processed according to the fifth step.

[0025] Further, in the sixth step, the method for harmless treatment of the organic liquid is as follows: Dilute the organic liquid with water by 10 - 20 times, then inoculate white rot fungi into the culture tank of the organic liquid, and the inoculation amount is 5 - 10% of the volume of the diluted liquid. Add 5 - 10 g / L of glucose or maltose, 1 - 2 g / L of amino acid or ammonium nitrate, 0.5 - 1 g / L of potassium dihydrogen phosphate, and 10 - 20 mL / L of 0.1 M phosphate buffer solution to the diluted liquid. Adjust the pH of the diluted liquid to 5.5 - 6.5 with sodium hydroxide or sodium carbonate. During the cultivation period, the temperature is 20 - 30 °C, stir 2 - 3 times a day, 10 - 15 minutes each time, and control the linear velocity of the stirrer paddle at 0.2 m / s. Ventilate during the cultivation period, and the ventilation volume is 0.1 - 0.2 vvm. The cultivation period is about 10 - 20 days to obtain an organic liquid with a phenol degradation rate of more than 80% as the improved organic liquid for standby.

[0026] Further, in the seventh step, for the treatment of the carbon-rich solid, the method of excavating a landfill trench between the planting trenches and mixing the treated carbon-rich solid with soil and then burying it in the landfill trench and then covering the soil is as follows: Crush the carbon-rich solid to a particle size less than 1 cm and sieve out impurities, then soak the carbon-rich solid in a bentonite gel-like suspension, and the weight ratio of bentonite to water is 1:3 - 1:5, and the soaking time is 10 - 30 min, and then air-dry naturally; the depth of the landfill trench is 30 - 60 cm; Mix the carbon-rich solid soaked in the bentonite gel-like suspension and the soil at a ratio of 1:5 - 1:10, and then add 0.5 - 1 kg of arbuscular mycorrhizal fungal dry powder to every 1000 kg of the mixed soil and mix evenly. Uniformly bury the mixture in the trench, cover the soil, and water once after gently compacting.

[0027] Further, in the eighth step, when adding, dilute the improved organic liquid with water by 2 - 5 times; if there is salinization in the plot to be repaired, directly add the diluted improved organic liquid. If there is no salinization in the plot to be repaired, adjust the pH of the diluted improved organic liquid to 6 - 7 with lime.

[0028] Based on the above technical solutions, compared with the prior art, the present invention has the following advantages:

[0029] 1. This technology rapidly restores the carbon sinks of abandoned lands and fallow lands through root-suckering fast-growing trees, with strong biological advantages and technological innovation. As pioneer plants, root-suckering fast-growing trees have deep and developed roots, strong vitality, are tolerant of barrenness and drought, and are extremely suitable for ecological restoration of abandoned lands and fallow lands. Through root segment propagation, not only is the technical threshold for propagation reduced, but the survival rate and growth rate of plants are significantly increased compared with seed propagation and stem cutting. Combined with a reasonable planting groove design, it ensures that root-suckering fast-growing trees can take root smoothly in barren soil and reduces competition among plants, enabling them to obtain sufficient water. Root-suckering fast-growing trees have strong nitrogen-fixing ability, and adding potassium dihydrogen phosphate in the harmless treatment of organic liquid ensures the survival of white rot fungi while ensuring the nutritional requirements of root-suckering fast-growing trees throughout their growth process. These technologies provide a basis for subsequent restoration work.

[0030] 2. In this technology, producing carbon-rich solids and improving organic liquid by harvesting the above-ground parts of root-suckering fast-growing trees provides an effective way for resource utilization in mine area restoration, realizing a positive cycle of soil improvement and carbon sink increase. The carbon-rich solids can significantly improve their stability and reduce carbon element loss through stabilization treatment with bentonite gel-like suspension. After being mixed with soil and buried deeply, it not only increases the carbon content of the soil, improves the physical and chemical properties of the soil, but also delays the decomposition and consumption of soil carbon, promoting the restoration of soil fertility and structure in abandoned lands and fallow lands. The application of arbuscular mycorrhizal fungi (AM fungi) further enhances the nutrient absorption ability of plants, improves the stress resistance of plants, and promotes the improvement of soil carbon sink function. AM fungi can combine with minerals and organic matter in the soil through hyphae, more stably holding the carbon-rich solids produced by root-suckering fast-growing trees in the soil. And AM fungi can accelerate the decomposition of biodegradable organic matter in carbon-rich solids, promoting its transformation into stable soil organic matter and storing it in the soil for a long time. AM fungi accelerate the fixation of plant carbon and enhance the soil carbon sink capacity by enhancing the absorption of water and nutrients by plant roots, enabling plants to grow more vigorously in the soil.

[0031] 3. The use of improved organic liquid provides another important means for soil restoration. The white rot fungi in it can degrade lignin and phenolic compounds, have strong tolerance to high-concentration phenols, and are facultative aerobic fungi, with relatively easy oxygen demand, suitable for large-scale industrial production. Under the degradation of white rot fungi, harmful phenolic substances in the liquid are effectively removed, and the remaining organic acids and sugars can regulate the soil pH, improve the salinization problem, and enhance soil fertility. This organic liquid can be widely applied in abandoned lands and fallow lands. Through precise formulation adjustment, it not only realizes the supplement of soil organic matter but also promotes the gradual restoration of the mine area ecosystem.

[0032] 4. The whole set of technologies utilizes the biological characteristics of root-suckering fast-growing trees and resource treatment means to form a closed-loop ecological restoration system. By harvesting Broussonetia papyrifera every year and recycling its biomass, it not only reduces the carbon decomposition in the mining area soil but also promotes the accumulation of carbon in the soil. The implementation cost of this technology is relatively low, and the required materials are easily available, making it suitable for large-scale popularization and application. Through this technology, the ecological restoration of abandoned land and fallow land can be completed in a relatively short time, and it can significantly enhance the carbon sink capacity, providing a practical path for the global response to climate change and achieving the carbon neutrality goal. Specific implementation manners

[0033] To make the purpose, technical solutions, and advantages of this application clearer, the following describes this application through specific embodiments. However, it should be understood that these descriptions are only exemplary and do not intend to limit the scope of this application. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of this application.

[0034] The terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit this disclosure. The singular forms "a", "the", and "said" used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0035] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0036] In the description of this application, unless otherwise specified and limited, it should be noted that the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a mechanical connection, or it may be the communication inside two components. It may be directly connected, or it may be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-suckering fast-growing trees, the method comprising the following steps:

[0038] Step 1: According to the type of the plot to be repaired, select the corresponding root-sprouting fast-growing tree species. The method for selecting the corresponding root-sprouting fast-growing tree species is as follows:

[0039]

[0040]

[0041] Step 2: After selecting the root-sprouting fast-growing tree species, in March or April, screen out the mother plants that are growing vigorously and have no pests or diseases, and process the main roots or rhizomes of the mother plants into root segments to be planted: Usually, select 1-2-year-old plants as mother plants with relatively developed roots. In March or April, gently dig the roots of the mother plants with a shovel, select thick and mature main roots or rhizomes, and avoid overly aged or too thin roots. Cut the selected roots into segments 10-20 cm long, and each root segment should have at least one bud point (or bud eye). Immerse the root segments in a rooting hormone (such as indolebutyric acid (IBA) solution with a concentration of 0.2%-0.5%) for 30-60 minutes. Take out the root segments and dry them in the dark for 20-30 minutes before planting;

[0042] Step 3: Rearrange the plot to be repaired: Dig planting trenches on the plot to be repaired, and insert the processed root segments into the planting trenches, ensuring that the root segments are in a vertical state and compact the soil around the root segments to ensure that the root segments have sufficient water for growth without waterlogging: The width of the planting trenches is usually 30-50 cm, the depth is 30-40 cm, and the spacing between the planting trenches is 2-3 m. In poor soil, it can reduce the competition between plants, ensure that the roots can take root better, obtain sufficient water and nutrients, reduce underground carbon decomposition, and facilitate mechanized operation and later management. For the first planting, organic fertilizers or soil improvers can be added to the soil in the planting trenches to improve soil fertility. Insert the processed root segments into the soft soil, with an insertion depth of about 5-10 cm and a spacing of 2-3 m in the trench. Keep the root segments vertical or slightly inclined, and ensure that the soil around the root segments is compacted to avoid rapid water loss. Water immediately after planting to keep the soil moist, but avoid waterlogging. A thin layer of organic matter (such as withered leaves or grass seedlings) can be covered around the root segments to help maintain soil moisture and protect the root segments. Root-sprouting fast-growing trees are tolerant of barrenness and drought. There may be a lack of water sources in industrial wasteland and abandoned land. Therefore, it is only necessary to ensure that the soil is moist within 1-2 months before cutting. If there is no natural precipitation for more than 2-3 weeks at other times, artificial irrigation can be carried out. Apply 15-40 kg of nitrogen and potassium fertilizers per hectare every 2-3 months in the first year of growth. For example, when planting Broussonetia papyrifera, because it has strong nitrogen-fixing ability, only potassium fertilizer needs to be applied;

[0043] Step 4: Harvest the above-ground parts of the root-sprouting fast-growing trees in October or November every year, and the stubble height after harvesting the above-ground parts is 10-30 cm;

[0044] Step Five: Dry the harvested above-ground parts, then crush them into particles and mix with water. The mixture is subjected to a heating reaction in a closed container, and after the reaction is complete, the carbon-rich solid and organic liquid are separated: Dry the harvested above-ground parts sufficiently for 10 - 30 days, then crush them into particles with a particle size of 3 - 5 cm, and mix with water at a volume ratio of 3:1 - 5:1. Then carry out a heating reaction in a closed container at a temperature of 180 - 250 °C, a pressure of 10 - 30 MPa, and a reaction time of 4 - 6 h. After cooling and depressurizing, separate the carbon-rich solid and organic liquid. Among them, for heavy metal pollution (soil remediation) tree species and organic pollution remediation (oil, pesticides) tree species, 1 / 3 - 1 / 4 of the annually harvested parts are processed in this step, and the rest are subjected to harmless centralized treatment;

[0045] Step Six: Treat the organic liquid harmlessly, and use the organic liquid with a phenol degradation rate of more than 80% after treatment as the improved organic liquid for standby: The organic liquid is rich in organic substances such as organic acids, sugars, and phenolic compounds. Among them, organic substances such as organic acids and sugars can effectively increase soil fertility, regulate plant growth and the pH of saline-alkali soil, and increase soil aggregate structure. However, some of the phenolic compounds can inhibit plants. Therefore, it is necessary to treat the organic liquid harmlessly. Dilute the organic liquid with water to 10 - 20 times, inoculate white rot fungi into the culture tank of the organic liquid, and the inoculation amount is 5 - 10% of the volume ratio of the diluted liquid. Add 5 - 10 g / L of glucose or maltose, 1 - 2 g / L of amino acid or ammonium nitrate, 0.5 - 1 g / L of potassium dihydrogen phosphate, and 10 - 20 mL / L of 0.1 M phosphate buffer solution to the liquid. Use sodium hydroxide or sodium carbonate to adjust the pH of the liquid to 5.5 - 6.5. During the cultivation period, the temperature is 20 - 30 °C, stir 2 - 3 times a day, each time for 10 - 15 minutes, and control the linear velocity of the stirring paddle at 0.2 m / s. Aerate during the cultivation period, and the aeration rate is 0.1 - 0.2 vvm. The cultivation period is about 10 - 20 days. After the cultivation is completed, detect that the phenol degradation rate in the liquid is more than 80% as the qualified improved organic liquid;

[0046] Step 7: Process the carbon-rich solid. Excavate a landfill trench between the planting trenches, mix the processed carbon-rich solid with soil, bury it in the landfill trench, and then cover it with soil: Crush the carbon-rich solid to a particle size less than 1 cm, screen out impurities to ensure pure organic carbon substances, then soak the carbon-rich solid in a bentonite gel-like suspension (the weight ratio of bentonite to water is 1:3 - 1:5), soak for 10 - 30 minutes, and then air-dry naturally. From December to February of the following year, excavate a landfill trench with a depth between 30 - 60 cm between the planting trenches, mix the carbon-rich solid soaked in the bentonite gel-like suspension and soil at a ratio of 1:5 - 1:10, then add 0.5 - 1 kg of arbuscular mycorrhizal fungi (AM fungi) dry powder per 1000 kg of the mixed soil and mix evenly. Bury the mixture evenly in the trench, cover it with soil, and gently compact it to avoid excessive air pores and prevent settlement. After completion, water once;

[0047] Step 8: From February to March every year starting from the second year of the root-suckering fast-growing tree planting, add the improved organic liquid to the root-suckering fast-growing tree. When adding, dilute the improved organic liquid with water by 2 - 5 times. Most of the abandoned lands and wastelands are accompanied by serious salinization. The diluted improved organic liquid can be directly added. If there is no salinization phenomenon in the improved plot, use lime to adjust the pH of the diluted improved organic liquid to 6 - 7.

[0048] Example 1

[0049] Set up 3 one-hectare plots (100×100 m) in the saline-alkali land. The tree species for planting and restoration is Broussonetia papyrifera. Set up 1 control group and 4 experimental groups in each plot according to Table 1

[0050] Table 1

[0051]

[0052]

[0053] The experiment was carried out for three years. Every year, the total soil carbon sequestration, nitrogen, phosphorus, potassium contents, and soil bulk density were detected. The results are shown in Table 2.

[0054] Table 2

[0055]

[0056] Control Group 1: No treatment was applied. Therefore, the changes in carbon sequestration, soil nutrients, and physical properties were relatively slow. As time passed, the carbon sequestration gradually increased to 0.34 t / ha (in the third year), but the growth rate was limited. The physical and chemical properties such as the nitrogen, phosphorus, potassium contents and bulk density of the soil also changed little.

[0057] Experimental Group 1: The planting treatment of root sucker fast-growing trees was carried out. Over time, the carbon sequestration amount increased year by year to 1.95 t / ha (in the third year). Due to the well-developed underground roots of root sucker fast-growing trees, it showed a strong carbon sequestration effect. And root sucker fast-growing trees have a strong nitrogen fixation effect, with a significant increase in nitrogen content and a slight increase in the contents of phosphorus and potassium. The bulk density decreased year by year, and the soil structure was improved.

[0058] Experimental Group 2: Since the above-ground part of Broussonetia papyrifera was harvested. The underground part of root sucker fast-growing trees grew more vigorously, and the carbon sequestration amount further increased to 2.85 t / ha (in the third year). The soil nutrients were improved, indicating that the harvesting treatment contributed to nutrient cycling and the improvement of soil fertility. The bulk density also decreased year by year, and the physical properties of the soil were improved.

[0059] Experimental Group 3: On the basis of the planting and harvesting of root sucker fast-growing trees, the application of improved organic liquid was increased. The carbon sequestration amount further increased to 3.45 t / ha (in the third year). The contents of phosphorus and potassium were significantly higher than those of the control group and Experimental Groups 1 and 2, indicating that the improved organic liquid could significantly improve soil fertility and promote plant growth. The bulk density decreased year by year, and the soil structure was improved, showing a strong soil improvement effect.

[0060] Experimental Group 4: Experimental Group 4 combined the planting, harvesting, application of improved organic liquid and deep burial of carbon-rich solids of root sucker fast-growing trees. This group showed the most significant effect. The carbon sequestration amount in the third year was 7.74 t / ha, the nitrogen content increased to 3.21 g / kg, and the contents of phosphorus and potassium were 29.34 mg / kg and 176.33 mg / kg respectively. The bulk density further decreased to 1.07 g / cm 3 , showing the best soil improvement effect. The deep burial treatment of carbon-rich solids significantly promoted carbon sequestration and the improvement of soil fertility, and at the same time improved the physical properties of the soil.

[0061] 2. Heavy metal contaminated land remediation experiment

[0062] Three 1-hectare plots (100×100 m) were set up in the heavy metal contaminated land. A control group and three experimental groups were established. The experimental groups planted Salix matsudana var. pseudomatsudana, Salix × aureo-pendula, and Populus deltoides cv. 'Wugong' according to the method of this patent respectively. The results of soil heavy metal contents are shown in Table 3 every year

[0063]

[0064] It can be seen from Table 2 that with the extension of the planting time of the three tree species, the heavy metal content in the soil gradually decreases. By using the method described in the present invention, the average contents of Cu, Pb, and Zn in the soil in the sixth year are all lower than the screening values of agricultural land soil pollution risks. Among them, in the experimental groups 1 and 2, the average contents of Cu and Pb in the soil in the fourth year have already been lower than the screening values of agricultural land soil pollution risks, indicating that this method can effectively repair heavy metal contaminated soil in a relatively short period of time.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that; it is still possible to modify the specific implementation manners of the application or perform equivalent replacements on some technical features; without departing from the spirit of the technical solutions of the present application, they should all be covered within the scope of the technical solutions claimed in the present application.

Claims

1. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root sucker fast-growing trees, characterized in that, The method includes the following steps: Step 1: Select the corresponding root-suckering fast-growing tree species according to the type of the plot to be repaired; Step 2: After selecting the root-suckering fast-growing tree species, in March or April, screen out the mother plants that are strong in growth and free of pests and diseases, and process the main roots or rhizomes of the mother plants into root segments to be planted; Step 3: Prepare the plot to be repaired: Dig planting trenches on the plot to be repaired, insert the processed root segments into the planting trenches, ensure that the root segments are in a vertical state, and compact the soil around the root segments to ensure sufficient water for the growth of the root segments without waterlogging; Step 4: Harvest the above-ground parts of the root-suckering fast-growing trees in October or November every year; Step 5: Dry the harvested above-ground parts, then crush them into particles and mix them with water. The mixture is subjected to a heating reaction in a closed container, and after the reaction is complete, the carbon-rich solid and the organic liquid are separated; Step 6: Perform harmless treatment on the organic liquid, and use the organic liquid with a phenol degradation rate of more than 80% after treatment as the improved organic liquid for standby; Step 7: Process the carbon-rich solid, dig a landfill trench between the planting trenches, mix the processed carbon-rich solid with soil and bury it in the landfill trench, and then cover the soil; Step 8: Add the improved organic liquid to the root-suckering fast-growing trees in February or March every year starting from the second year of planting the root-suckering fast-growing trees.

2. The method for rapidly restoring the carbon sink of abandoned lands and fallow lands by using root-suckering fast-growing trees according to claim 1, characterized in that, In the above-mentioned Step 1: The method of selecting the corresponding root-suckering fast-growing tree species according to the type of the plot to be repaired is carried out in the following manner:

3. A method for rapidly restoring the carbon sink of abandoned lands and fallow lands by using root sucker fast-growing trees according to claim 1, characterized in that, In the above-mentioned Step 2, the method of processing the main roots or rhizomes of the mother plants into root segments to be planted is as follows: Select the thick and mature main roots or rhizomes of the mother plants, cut the selected roots into segments 10-20 cm long, and each root segment should have at least one bud point. Then soak the root segments in a rooting hormone, and the rooting hormone includes indolebutyric acid solution with a concentration of 0.2%-0.5%. The soaking time is 30-60 minutes. After soaking, take out the root segments and dry them in the dark for 20-30 minutes before planting.

4. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-suckering fast-growing trees according to claim 1, characterized in that, In the above-mentioned Step 3, the width of the planting trench is 30-50 cm, the depth is 30-40 cm, and the spacing between the planting trenches is 2-3 m; the insertion depth of the root segments is 5-10 cm, and the spacing in the trench is 2-3 m; it is necessary to ensure that the soil is moist within the first 1-2 months after the root segments are cut, and if there is no natural precipitation for more than 2-3 weeks during the remaining time, artificial irrigation can be carried out; the root-suckering fast-growing trees need to be applied with 15-40 kg of nitrogen and potassium fertilizers per hectare every 2-3 months in the first year of planting and growing. If the root-suckering fast-growing tree is Broussonetia papyrifera, only potassium fertilizer is applied.

5. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-suckering fast-growing trees according to claim 1, characterized in that, In the above-mentioned Step 4, the stubble height after harvesting the above-ground parts is 10-30 cm.

6. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-suckering fast-growing trees according to claim 1, characterized in that, In the above-mentioned Step 5, the drying time of the harvested above-ground parts is 10-30 days, the particle size of the crushed particles is 3-5 cm, and the volume ratio of the particles to water is 3:1-5:1; the temperature of the heating reaction in the closed container is 180-250 °C, the pressure is 10-30 MPa, the reaction time is 4-6 h, and after the reaction is complete, the pressure is released after cooling to separate the carbon-rich solid and the organic liquid.

7. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-suckering fast-growing trees according to claim 1 or 6, characterized in that For the root-sprouting fast-growing trees on heavy metal contaminated land and the root-sprouting fast-growing trees on organic contaminated land, 1 / 3 - 1 / 4 of the part selected for annual harvest is processed according to Step Five.

8. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root sucker fast-growing trees according to claim 1, characterized in that, In Step Six, the method for harmless treatment of the organic liquid is as follows: Dilute the organic liquid with water by 10 - 20 times, then inoculate white rot fungi into the culture tank of the organic liquid, with the inoculation amount being 5 - 10% of the volume of the diluted liquid. Add 5 - 10 g / L of glucose or maltose, 1 - 2 g / L of amino acid or ammonium nitrate, 0.5 - 1 g / L of potassium dihydrogen phosphate, and 10 - 20 mL / L of 0.1 M phosphate buffer solution to the diluted liquid. Adjust the pH of the diluted liquid to 5.5 - 6.5 using sodium hydroxide or sodium carbonate. During the cultivation period, the temperature is 20 - 30 °C, stir 2 - 3 times a day, each time for 10 - 15 minutes, control the linear velocity of the stirring paddle at 0.2 m / s, conduct aeration during the cultivation period, with the aeration rate being 0.1 - 0.2 vvm, and the cultivation cycle is about 10 - 20 days to obtain an organic liquid with a phenol degradation rate of over 80% as the standby improved organic liquid.

9. A method for rapidly restoring the carbon sink of abandoned land and fallow land by using root-sprouting fast-growing trees according to claim 1, characterized in that, In Step Seven, for the treatment of the carbon-rich solid, the method of excavating a landfill trench between the planting trenches and mixing the treated carbon-rich solid with soil and then burying it in the landfill trench and then covering the soil is as follows: Crush the carbon-rich solid to a particle size less than 1 cm and screen out impurities, then soak the carbon-rich solid in a bentonite gel-like suspension, with the weight ratio of bentonite to water being 1:3 - 1:5, and the soaking time being 10 - 30 min, then air-dry naturally; the depth of the landfill trench is 30 - 60 cm; Mix the carbon-rich solid soaked in the bentonite gel-like suspension and soil in a ratio of 1:5 - 1:10, then add 0.5 - 1 kg of arbuscular mycorrhizal fungal dry powder per 1000 kg of the mixed soil and mix evenly, evenly bury the mixture in the trench, cover the soil, gently compact it and water once.

10. A method for rapidly restoring the carbon sink of abandoned lands and fallow lands by using root-suckering fast-growing trees according to claim 1, characterized in that, In Step Eight, when adding, dilute the improved organic liquid with water by 2 - 5 times; if there is salinization in the plot to be repaired, directly add the diluted improved organic liquid, if there is no salinization in the plot to be repaired, adjust the pH of the diluted improved organic liquid to 6 - 7 with lime.

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