Method for improving carbon sequestration and stabilization of tamarix artificial forest in coastal heavy saline-alkali soil

Abstract

The present application belongs to the field of saline-alkali soil improvement and carbon sequestration, and provides a method for improving carbon sequestration and stability of Tamarix chinensis artificial forest in coastal heavy saline-alkali soil. The method is characterized by the following steps: crushing and throwing litter and branches into the field, applying acetic acid to promote decomposition, supplementing soil nutrient and carbon pools, cutting roots and spraying treatment liquid to the cut roots to increase root exudates and secretion capacity, and promoting carbon sequestration and stability in the soil. Through the above measures, the carbon sequestration and stability capacity of Tamarix forest land is improved by more than 32%, and the treatment measures for Tamarix forest land are proposed to increase soil carbon storage and maintain carbon pool, which has multiple effects such as rapid carbon sequestration and soil fertilization, and has important application value for improving the carbon sink function of coastal saline-alkali soil ecosystem.

Description

Technical Field

[0001] This invention belongs to the field of saline-alkali soil improvement and carbon sequestration technology, and specifically relates to a method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal heavily saline-alkali land. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Coastal areas, as the intersection of terrestrial and marine ecosystems, possess unique ecological types. Severe salinization of the soil in these regions, coupled with relatively poor soil quality, limits primary productivity. Furthermore, vegetation degradation and nutrient loss severely impact soil carbon storage. The soil carbon pool is the largest carbon pool in terrestrial ecosystems and is crucial to the global carbon cycle.

[0004] Tamarix ( Tamarix chinensis As a key woody species for establishing communities in saline-alkali areas, tamarisk is a halophyte with strong soil-fertility capabilities. It has become a major ecological restoration tree species in the coastal saline-alkali areas of the Yellow River Delta and inland low-lying saline-alkali areas, demonstrating significant effects in saline-alkali land improvement, climate regulation, windbreak and sand fixation / embankment protection. It is irreplaceable in the severely saline-alkali areas of northern China. Currently, with the maintenance and construction of the regional ecological environment, the area of ​​tamarisk plantations is gradually increasing. However, due to various reasons such as secondary soil salinization, insufficient rainfall, extensive management, and human interference, tamarisk forests in this area are experiencing death and degradation, with some forming low-quality and low-efficiency forests, and a significant reduction in the carbon sequestration capacity of trees and soil. Currently, the effects and functions of tamarisk in improving soil properties, reducing soil salinity, and improving soil fertility in saline-alkali areas have reached a basic consensus (Zhang Libin et al., 2008; He Xiuping et al., 2014; Zhang Tianju et al., 2018). However, there is limited research on the carbon sequestration function of tamarisk, which is limited to studies on the spatial distribution of soil organic carbon (Wang Jianjian et al., 2014; Wang Hao et al., 2022). There are no reports on how to improve the carbon sequestration and carbon stabilization function of existing tamarisk forests.

[0005] As a deciduous plant, tamarisk's litter deposition can convert biological carbon into soil carbon, becoming an important pathway for carbon sequestration in saline-alkali lands (He Junxia et al., 20009). However, the saline-alkali environment has a certain inhibitory effect on tamarisk's ability to increase soil carbon sequestration. Litter decomposition characteristics show that the mass loss rate, decomposition coefficient, and time required for 50% leaf decomposition of tamarisk litter are 12.04%, 0.1283, and 5.4 years, respectively (Ge Liuwei, 2016). Therefore, although there are many methods for carbon sequestration and stabilization, how to improve the carbon sequestration and stabilization capacity of coastal saline-alkali soils remains a research gap. Summary of the Invention

[0006] This invention addresses the prominent problems of high salinity, poor stand quality, and weak soil carbon sequestration and stabilization capacity in coastal saline-alkali lands. For the first time, it proposes a method to significantly improve the carbon sequestration and stabilization effect of *Tamarix chinensis* plantations in heavily saline-alkali coastal areas. This method involves returning pulverized litter and branches to the soil, combined with acetic acid to promote decomposition, thus replenishing the soil's nutrient and carbon pools. Root pruning and spraying treatment solutions at the pruning sites increase root exudates and their capacity, promoting carbon sequestration and stabilization in the soil. Through these measures, the carbon sequestration and stabilization capacity of *Tamarix chinensis* forests is increased by more than 32%. This leads to the proposal of treatment measures for *Tamarix chinensis* forests that increase soil carbon storage and maintain the carbon pool, achieving multiple effects such as rapid carbon enrichment and fertilization. This method has significant application value in enhancing the carbon sink function of coastal saline-alkali land ecosystems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for improving carbon gain and stability in Tamarix chinensis plantations in coastal saline-alkali land, comprising:

[0009] (1) Improve the quality of the forest stand: During the dormant period from November to February of the following year, the trees in the Tamarix plantation are heavily pruned to remove branches below 1.2-1.8 m;

[0010] At the same time, during the growing season, regular sanitation and light penetration pruning should be carried out to remove shaded, diseased, and dead branches of trees, with the lower edge controlled at 1.5-2.0 m;

[0011] After tending, all the pruned diseased and dead branches were removed from the forest and destroyed in a centralized manner, and the remaining branches were shredded using a branch shredder;

[0012] After tending, the canopy closure of young and middle-aged forests was controlled at 0.5-0.7 after the quality of the forest stands was improved.

[0013] (2) Root treatment: Using the trunk as a reference, cut the lateral roots and fibrous roots vertically downwards for 10-30cm at a distance of 8-9 times the diameter at breast height on both sides of the row; at the same time, spray the cut roots with treatment solution.

[0014] (3) Litter treatment: After the litter has fallen, spray a layer of acetic acid solution with a concentration of 6%-8% on the litter layer in the forest every March-April. After 2-3 days, when the solution is absorbed, combine with inter-row cultivation to turn the litter back into the field.

[0015] (4) Soil treatment: After the litter is treated, a layer of microbial fertilizer is evenly spread on the soil surface in conjunction with rainfall or irrigation;

[0016] The ground cover should be centered on the main trunk of the tamarisk tree and extended outward to the drip line of the canopy. The mulch material should be weed control fabric or non-woven fabric.

[0017] From late October to early November, remove the weed control cloth or non-woven fabric when the tamarisk leaves fall; in March or April of the following year, after the fallen leaves have completely fallen, cover the area again with the non-woven fabric using the same method.

[0018] (5) Intercropping of forest and grass: For 1-2 year old seedlings of Tamarix chinensis with a row spacing of 4-5m, salt-tolerant low-stem plants are planted between the rows; field management is carried out in accordance with conventional measures, and the salt-tolerant low-stem plants are directly plowed back into the field when the initial flowering period is reached.

[0019] Soil nutrients and soil carbon pool are closely related and mutually reinforcing. Plant litter, root exudates, and plant and animal residues are the main sources of soil organic matter, and an increase in organic matter correspondingly increases soil nutrient and organic carbon content. Among these, organic matter is the main source of soil nutrients, containing various nutrients required for crop growth, and can directly or indirectly provide crops with N, P, K, Ca, Mg, S, and other trace elements.

[0020] Based on this, the present invention plays an important role in the carbon balance of the saline-alkali land system by increasing the growth rate of tamarisk, increasing the aboveground and underground biomass of the plant, accelerating the decomposition of litter in the forest and improving the soil environment, and giving full play to the potential of saline-alkali land in carbon sequestration and emission control.

[0021] In some implementations, in step (1), the pulverized material is 3-5 mm in size.

[0022] Therefore, in some embodiments, the treatment solution is a mixture of glucose, acetic acid and glycine, with a mass percentage of 45%:15%:40%.

[0023] In some implementations, the depth of returning the soil to the field in step (3) is controlled at 10-20 cm.

[0024] In some implementations, in step (4), 1.5-2 kg per mu is applied.

[0025] In some embodiments, in step (4), the microbial fertilizer is an alcohol-based microbial fertilizer, the components of which include: colloidal fertilizer and soybean meal, wherein organic matter ≥50%, humus ≥20%, N+P2O5+K2O ≥4%, total viable bacteria ≥200 million / g, and effective viable bacteria ≥50 million / g.

[0026] In some implementations, the thickness of the covering in step (4) is 1.5-2 mm.

[0027] In some implementations, in step (5), the planting is carried out by sowing under the forest, either by row sowing or broadcast sowing.

[0028] In some implementations, in step (5), a 1-1.2m clear area is left under the tree during planting, and the seeding rate is 11.5-13.0kg / hm². 2 .

[0029] In some implementations, intercropping between forest and grassland is carried out for two consecutive years.

[0030] Beneficial effects of the present invention

[0031] (1) This invention replenishes the soil nutrient pool and carbon pool by crushing and spreading litter and branches back into the field, along with the application of acetic acid to promote decomposition. Root pruning and spraying the pruned areas with a treatment solution increase root exudates and exudation capacity, promoting carbon sequestration and stabilization in the soil. Through these measures, the carbon sequestration and stabilization capacity of tamarisk forest land is increased by more than 32%. This invention proposes a treatment measure for tamarisk forest land that increases soil carbon storage and maintains the carbon pool, achieving multiple effects such as rapid carbon enrichment and fertilization. It has significant application value for enhancing the carbon sink function of coastal saline-alkali land ecosystems.

[0032] (2) The preparation method of the present invention is simple, practical and easy to promote. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 Diagram showing root pruning combined with spraying of a mixed solution;

[0035] Figure 2 A map showing the use of non-woven fabric for ground cover.

[0036] Figure 3 Diagram showing the treatment of tamarisk trees planted in large-spaced forests and grasslands. Detailed Implementation

[0037] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] As described in the background section, most trees typically contribute to increasing soil carbon pools. However, in severely saline-alkali lands (with a salt content generally above 0.5%), most trees cannot survive, while Tamarix chinensis can grow normally in soils with a salt content of 1%. Therefore, a method for "carbon sequestration and stabilization effects of Tamarix chinensis plantations in coastal severely saline-alkali lands" is proposed.

[0039] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0040] Example 1

[0041] A method for improving carbon gain and stability in Tamarix chinensis plantations in coastal saline-alkali land includes the following steps:

[0042] (1) Improvement of forest stand quality: During the dormant period from November to February of the following year, the trees in the Tamarix plantation (young and middle-aged forest) are heavily pruned, mainly removing branches below 1.2-1.8 m to ensure a larger understory space. At the same time, during the growing season, regular sanitation and light-penetration pruning should be carried out to remove shaded branches, diseased branches, and dead branches, with the lower edge controlled at 1.5-2.0 m. After tending, all pruned diseased and dead branches are removed from the forest land and destroyed. The remaining branches are shredded using a branch shredder, with the shredded size controlled at 3-5 mm to accelerate their decomposition rate. After tending, the stand quality of the young and middle-aged forest is improved, and the stand canopy closure is controlled at 0.5-0.7, thereby enhancing the stability of the forest ecosystem and its carbon sequestration capacity.

[0043] (2) Root treatment: Using the trunk as a reference, cut the lateral roots and fibrous roots vertically downwards for 10-30cm at a distance of 8-9 times the diameter at breast height on both sides of the row. The cut should be smooth to facilitate wound healing and fine root growth. At the same time, spray the cut roots with a treatment solution, which is a mixture of 45% glucose, 15% acetic acid and 40% glycine. By increasing the relative content of some sugars, organic acids and amino acids, the concentration and secretion capacity of root exudates are increased, promoting the increase of root length and dry weight, thereby enhancing the carbon fixation capacity of the roots.

[0044] (3) Litter treatment: After the litter has fallen, spray a layer of acetic acid solution with a concentration of 6%-8% on the litter layer in the forest every March-April. After 2-3 days, when the solution is absorbed, combine with inter-cultivation to turn the litter back into the field. The depth of returning to the field should be controlled at 10-20 cm to improve the decomposition rate of litter and shorten its turnover period.

[0045] (4) Soil treatment: After the litter treatment is completed, apply a layer of microbial fertilizer evenly to the soil surface in conjunction with rainfall or irrigation, at a rate of about 1.5-2 kg per mu. This fertilizer is an alcohol-based microbial fertilizer produced by Qihe Chuangdi Biological Treatment Engineering Co., Ltd., with colloidal fertilizer and soybean meal as the main raw materials. The fertilizer contains ≥50% organic matter, ≥20% humus, ≥4% N+P2O5+K2O, ≥200 million / g total viable bacteria, and ≥50 million / g effective viable bacteria. It can improve soil aggregate structure and nutrient balance, and increase the types and quantities of beneficial bacteria in the soil. Secondly, cover the ground with the main trunk of the tamarisk tree as the center, extending outward to the drip line of the canopy. The covering material can be weed control cloth or non-woven fabric with a thickness of 1.5-2 mm to reduce soil disturbance and appropriately increase soil temperature, further increasing the rate of litter decomposition and carbon return, and enhancing the soil's carbon sequestration and carbon stabilization capabilities. From late October to early November, remove the weed control cloth or non-woven fabric when the tamarisk leaves have fallen. In March or April of the following year, after the fallen leaves have completely settled, re-cover with the non-woven fabric using the same method.

[0046] (5) Intercropping with grassland: This measure is only applicable to afforestation sites of 1-2 year old tamarisk seedlings with a row spacing of 4-5m. Salt-tolerant low-growing plants such as alfalfa can be planted between the rows. Sowing should be done under the trees, either by row sowing or broadcasting. A 1-1.2m clear area should be left under the trees during planting. The sowing rate is 11.5-13.0 kg / hm². 2 Field management follows standard procedures; alfalfa is directly plowed back into the field at the initial flowering stage. Intercropping with forestry and grassland can be carried out for two consecutive years to increase soil organic matter content and enhance soil carbon sequestration.

[0047] Experimental Example 1:

[0048] The experiment was conducted in a tamarisk experimental forest in Kenli District, Dongying City, Shandong Province. The forest was 3 years old and the spacing between trees was 3m×2m. The organic carbon content, carbon pool index (CPI) and carbon pool management index (CMI) of the tamarisk forest were measured and calculated for 1-3 consecutive years using the method of Example 1 of this invention and the untreated method (CK).

[0049] Table 1

[0050]

[0051] Experimental Example 2:

[0052] The experiment was conducted in a tamarisk experimental forest with a forest age of 3 years and a plant spacing of 3m×2m. One or more steps of the method in Example 1 of this invention and the untreated method were used to measure and calculate the organic carbon content, carbon pool index (CPI), and carbon pool management index (CMI) of the tamarisk forest land after 3 years.

[0053] Table 2

[0054]

[0055] Experimental Example 3:

[0056] The experiment was conducted in a tamarisk afforestation area with a forest age of 2 years and a plant spacing of 4m×2m. The organic carbon content, carbon pool index (CPI), and carbon pool management index (CMI) of the tamarisk forest were measured and calculated for 1-2 consecutive years using the intercropping treatment and the untreated method of Example 1 of this invention.

[0057] Table 3

[0058]

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving carbon increase and stabilization in Tamarix chinensis plantations in coastal saline-alkali land, characterized in that, include: (1) Improve the quality of the forest stand: During the dormant period from November to February of the following year, the trees in the Tamarix plantation are heavily pruned to remove branches below 1.2-1.8 m; At the same time, during the growing season, regular sanitation and light penetration pruning should be carried out to remove shaded, diseased, and dead branches of trees, with the lower edge controlled at 1.5-2.0 m; After tending, all the pruned diseased and dead branches were removed from the forest and destroyed in a centralized manner, and the remaining branches were shredded using a branch shredder; After tending, the canopy closure of young and middle-aged forests was controlled at 0.5-0.7 after the quality of the forest stands was improved. (2) Root treatment: Using the trunk as a reference, cut the lateral roots and fibrous roots vertically downwards for 10-30cm at a distance of 8-9 times the diameter at breast height on both sides of the row; at the same time, spray the cut roots with a treatment solution; the treatment solution is a mixture of glucose, acetic acid and glycine, with a mass percentage of 45%:15%:40%; (3) Litter treatment: After the litter has fallen, spray a layer of acetic acid solution with a concentration of 6%-8% on the litter layer in the forest every March-April. After 2-3 days, when the solution is absorbed, combine with inter-row cultivation to turn the litter back into the field. (4) Soil treatment: After the litter is treated, a layer of microbial fertilizer is evenly spread on the soil surface in conjunction with rainfall or irrigation; The ground cover is centered on the main trunk of the tamarisk tree and extends outward to the drip line of the canopy. The cover material is weed control fabric or non-woven fabric. This is to reduce soil disturbance, increase soil temperature, increase the rate of litter decomposition and carbon return, and enhance the soil's ability to fix and stabilize carbon. From late October to early November, remove the weed control cloth or non-woven fabric when the tamarisk leaves fall; in March or April of the following year, after the fallen leaves have completely fallen, cover the area again with the non-woven fabric using the same method. (5) Intercropping of forest and grass: For 1-2 year old seedlings of Tamarix chinensis with a row spacing of 4-5m, salt-tolerant low-stem plants are planted between the rows; field management is carried out in accordance with conventional measures, and the salt-tolerant low-stem plants are directly plowed back into the field when the initial flowering period is reached.

2. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (1), the pulverized material is 3-5mm in size.

3. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (3), the depth of returning the soil to the field is controlled at 10-20 cm.

4. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (4), apply 1.5-2 kg per mu.

5. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (4), the microbial fertilizer is an alcohol-based microbial fertilizer, the components of which include: colloidal fertilizer and soybean meal, wherein organic matter ≥50%, humus ≥20%, N+P2O5+K2O ≥4%, total viable bacteria ≥200 million / g, and effective viable bacteria ≥50 million / g.

6. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (4), the thickness of the covering is 1.5-2 mm.

7. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (5), the understory sowing method is adopted for planting, which is either row sowing or broadcast sowing.

8. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, In step (5), leave a 1-1.2m clear area under the tree during planting, and the sowing rate is 11.5-13.0kg / hm. 2 .

9. The method for improving carbon increase and stabilization of Tamarix chinensis plantations in coastal saline-alkali land as described in claim 1, characterized in that, Agroforestry intercropping was carried out for two consecutive years.

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