Vegetation ecological restoration method for salinized land

Abstract

The invention relates to the technical field of soil remediation, in particular to a saline land vegetation ecological remediation method. The method comprises the following steps: S101, reducing salinity in the salinized land, selecting native dominant halophyte in the salinized land, planting the halophyte in the salinized land, replanting halophyte with the same variety after the first season of halophyte is mature, and repeating the process for 1-4 times; s102, microbial flora establishment: after replanting halophyte for 2-3 times, applying an organic fertilizer mixed with the microbial flora during replanting, and repeating the process for 1-2 times; and S103, vegetation ecology restoration: planting salt-tolerant plants on the salinized land after the microbial flora is established, and restoring vegetation ecology. The invention has the advantages of no pollution and low cost. The method is simple and feasible. The vegetation survival rate is high. The application range is wide, and the universality is high.

Description

Technical Field

[0001] The invention relates to the technical field of soil restoration, and in particular to a method for ecological restoration of vegetation in salinized land. Background Art

[0002] 25% of the world's land is salinized, about 8×10 8 hm 2 of land is affected by salinization, and the salinized land area in my country has reached 33 million hm2 2 The above are mainly distributed in 17 provinces including coastal areas, northeastern China, northwest China, the upper and middle reaches of the Yellow River and the Huang-Huai-Hai Plain. Among them, the saline-alkali wasteland and saline-alkali barrier cultivated land with agricultural utilization potential are about 13 million hm2. 2 , and the potential for utilization is huge. However, to date, about 80% of saline land has not been developed and utilized.

[0003] Land salinization seriously restricts my country's ecological environment construction and economic development. The increase in the concentration of saline-alkali soil solution and the increase in osmotic pressure will cause the seed coat cells, embryo cells, endosperm cells, etc. of the plant to be directly poisoned by the soil saline-alkali solution, resulting in the inability of plant seeds to obtain the water and nutrients required for development, making it impossible for the plants to germinate normally or even unable to germinate. Therefore, salt has greatly reduced the production of non-halophytes, especially some important economic crops. Non-halophytes show a significant decrease in yield in soils with a salt concentration of 50mmol / LNaCl. However, for halophytes, appropriate saline-alkali habitats will promote the growth and development of halophytes.

[0004] Therefore, developing methods for ecological restoration of vegetation on salinized land is an important way to improve saline land and also an important way to enhance the use value of saline land in my country. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical problems and provide a method for ecological restoration of vegetation in salinized land which is simple, easy to operate, low in cost, high in vegetation survival rate and highly versatile.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows.

[0007] A method for ecological restoration of vegetation on salinized land, the method comprising the following steps:

[0008] S101: Reduce salt in salinized land. Select the native dominant halophytes in salinized land and plant them in the salinized land. After the first season of halophytes mature, replant the same halophytes. Repeat the process 1 to 4 times.

[0009] S102 microbial flora is established, and after replanting halophytes 2 to 3 times, organic fertilizer mixed with microbial flora is applied when replanting again, and the process is repeated 1 to 2 times;

[0010] S103 vegetation ecological restoration, planting salt-tolerant plants on salinized land after the establishment of microbial flora to restore vegetation ecology.

[0011] The step S101 also includes collecting the native dominant halophyte root soil before planting, isolating, identifying and purifying the microorganisms therein, and then expanding the culture and collecting the mixed culture.

[0012] The mixed culture is acclimated to a salt gradient concentration before use, and the final salt content is ≥0.33MPa.

[0013] The step S101 also includes, after the planted halophytes mature and the seeds are collected, the above-ground parts are cut off and the roots are retained.

[0014] The step S101 also includes performing field management after planting the native dominant halophytes.

[0015] The salinized land in step S101 includes, but is not limited to, salt marshes, saline-alkali land, saline-alkali desert, salinized soil, residual salinized soil and potential salinized soil.

[0016] The native dominant halophytes selected in step S102 are planted singly or in combination;

[0017] The native dominant halophytes include but are not limited to Nitraria tangutorum, Tamarix chinensis, Salicornia herba, Phragmites australis, Suaeda salsa and Lycium barbarum.

[0018] The microbial flora in step S102 is microorganisms collected from the root soil of native dominant halophytes;

[0019] The microorganisms in the root soil include but are not limited to bacteria, actinomycetes and fungi.

[0020] In the step S102, the application amount of organic fertilizer is 100-500 kg / mu; the addition amount of microbial flora is 1-5% of the weight of the organic fertilizer.

[0021] The salt-tolerant plant in step S103 is alfalfa.

[0022] The method for ecological restoration of vegetation in salinized land provided by the present invention utilizes the native dominant halophytes in salinized land and can be planted in the target soil without domestication, which is low-cost and simple and reliable. The planted halophytes can effectively absorb the salt in the soil, and then the above-ground part thereof is harvested to prevent the salt absorbed by the halophytes from returning to the soil. After multiple rounds of planting and harvesting, the salt in the soil after planting can be effectively reduced.

[0023] The method for ecological restoration of vegetation in salinized land provided by the present invention applies and adds microorganisms separated and purified from the root soil of the halophytes while adding native dominant halophytes to increase the number of microorganisms in the soil, thereby improving the microecological environment in the salinized soil, and improving the biochemical activity of the soil and the composition and conversion of soil nutrients. Because the added microbial flora is separated from the root soil of the native dominant halophytes and applied after simple domestication / undomestication, it has excellent adaptability.

[0024] The method for ecological restoration of salinized land vegetation provided by the present invention can significantly reduce the salinity of salinized land after multiple rounds of planting-microbial flora establishment-harvesting-planting cycles, while effectively improving the biochemical activity of the soil and the composition and conversion capacity of soil nutrients, laying a foundation for ecological restoration of salinized land vegetation. After the salinity of salinized land is reduced, salt-tolerant plants, such as perennial plants such as alfalfa, can be planted to restore the vegetation ecology of salinized land.

[0025] Compared with physical and chemical restoration methods, the method for ecological restoration of salinized land vegetation provided by the present invention is not only low-cost and pollution-free, but also does not affect the mechanical composition and moisture content of the soil.

[0026] Compared with the prior art, the method for ecological restoration of vegetation on salinized land provided by the present invention has the following advantages:

[0027] (1) No pollution and low cost.

[0028] (2) The method is simple and easy to implement.

[0029] (3) High vegetation survival rate.

[0030] (4) Wide range of applications and strong versatility. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail in the following examples. The following examples are only used to illustrate the invention but are not used to limit the scope of the present invention.

[0032] A method for ecological restoration of vegetation on salinized land, the method comprising the following steps:

[0033] S101: Reduce salt in salinized land. Select the native dominant halophytes in salinized land and plant them in the salinized land. After the first season of halophytes mature, replant the same halophytes. Repeat the process 1 to 4 times.

[0034] S102 microbial flora is established, and after replanting halophytes 2 to 3 times, organic fertilizer mixed with microbial flora is applied when replanting again, and the process is repeated 1 to 2 times;

[0035] S103 vegetation ecological restoration, planting salt-tolerant plants on salinized land after the establishment of microbial flora to restore vegetation ecology.

[0036] The step S101 also includes collecting the native dominant halophyte root soil before planting, isolating, identifying and purifying the microorganisms therein, and then expanding the culture and collecting the mixed culture.

[0037] The mixed culture is acclimated to a salt gradient concentration before use, and the final salt content is ≥0.33MPa.

[0038] The step S101 also includes, after the planted halophytes mature and the seeds are collected, the above-ground parts are cut off and the roots are retained.

[0039] The step S101 also includes performing field management after planting the native dominant halophytes.

[0040] The salinized land in step S101 includes, but is not limited to, salt marshes, saline-alkali land, saline-alkali desert, salinized soil, residual salinized soil and potential salinized soil.

[0041] The native dominant halophytes selected in step S102 are planted singly or in combination;

[0042] The native dominant halophytes include but are not limited to Nitraria tangutorum, Tamarix chinensis, Salicornia herba, Phragmites australis, Suaeda salsa and Lycium barbarum.

[0043] The microbial flora in step S102 is microorganisms collected from the root soil of native dominant halophytes;

[0044] The microorganisms in the root soil include but are not limited to bacteria, actinomycetes and fungi.

[0045] In the step S102, the application amount of organic fertilizer is 100-500 kg / mu; the addition amount of microbial flora is 1-5% of the weight of the organic fertilizer.

[0046] The salt-tolerant plant in step S103 is alfalfa. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of a specific embodiment of the present invention.

[0048] Example 1

[0049] Isolation and culture of microbial flora

[0050] Gahai Lake is located in Delingha City, Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Province, on the northeastern edge of the Qaidam Basin. From June to September, the roots and root soil of the native dominant halophytes were collected, separated and purified, and then expanded and cultured respectively, and the cultures were collected for later use.

[0051] The specific method is as follows:

[0052] 1. Sampling

[0053] Determine the sampling area and sampling point distribution, and use the cross sampling method to collect samples at five points (such as Figure 1 As shown). All tools, sampling bags or other items used for sampling must be sterile. Use a shovel to remove fallen leaves and other impurities on the surface, use a small hoe to gently dig up the soil, and use a soil drill to obtain a mixed sample of soil and roots (sampling depth 30cm). The collected root samples are divided into sterile sampling bags, marked, and sealed for storage. The sterile sampling bags are immediately placed in a biological sample sampling box for low-temperature storage (ice bags or dry ice are placed in the sampling box in advance). Transport to the laboratory at low temperature for root soil collection. Shake off the root soil, collect and mark.

[0054] 2. Isolation and purification of soil microorganisms

[0055] Weigh 10 g of fresh soil sample and add it into a 250 mL conical flask containing 90 mL of sterile water. Place it in a constant temperature oscillator for enrichment culture at 16 °C and 160 rpm for 60 min. After shaking, take out the soil suspension, let it stand for 10 min, and then take 1 mL into a 1.5 mL sterile centrifuge tube. According to the 10-fold dilution method, dilute it in sequence to prepare dilutions of 10 and 10. -2 , 10 -3 , 10 -4 Take 0.15 mL of bacterial suspension and spread it on LB plates. Set 3 replicates for each dilution. After spreading, place the plates upside down in a 30°C constant temperature biochemical incubator for 36 hours. Select a dilution with 15 to 150 colonies per dish to count the number of colonies and calculate the number of bacteria. Observe the growth of the colonies, further separate and purify according to the characteristics of the colony morphology, size, color, etc., pick a single colony and transfer it to a fresh LB solid medium for pure culture.

[0056] 3. Soil bacteria preservation

[0057] Transfer the pure strain to sterile LB liquid medium and culture at 30℃ and 180r / min for 36h. Pipette 500μL of culture solution into a 2.0mL cryotube, add an equal volume of 50% sterile glycerol solution, mix well, number and record the time, and store in a -80℃ refrigerator.

[0058] 4. Preliminary identification of soil bacteria

[0059] The colony morphology of pure microorganisms was observed and described with reference to the Manual of Identification of Common Bacteria Systems, mainly including colonies, shapes, colors, surface conditions, edge conditions and heights, and Gram staining was performed at the same time. The microscopic morphology of each strain was observed under an optical microscope, and it was determined whether each strain was a Gram-positive strain or a Gram-negative strain. On this basis, the physiological and biochemical characteristics of each pure bacteria, such as sugar fermentation, vos, urea, citrate, indole, and methyl red, were studied according to the Common Identification Methods for General Bacteria.

[0060] 5. Isolation, purification and identification of soil bacteria

[0061] Results of culturable bacteria count: The dilution plate count method was used to count the bacteria in the soil samples. The results showed that the total number of culturable bacteria in the rhizosphere soil was 1.46×10 7 cfu·g -1 .

[0062] Colony characteristics, cell morphology and Gram staining results: The rhizosphere soil bacteria were isolated and purified by the 10-fold dilution method. A total of 17 bacteria were isolated from the rhizosphere soil, of which 16 were rod-shaped bacteria and 11 were Gram-positive bacteria.

[0063] Soil bacteria expansion culture: After the isolated soil microorganisms are expanded through three levels of culture, the fermentation liquid containing the bacteria is reduced in pressure and concentrated or freeze-dried and then used directly as a microbial flora additive.

[0064] Example 2

[0065] Vegetation ecological restoration of salinized land in the northeastern margin of the Qaidam Basin

[0066] 1. Reducing salt levels in salinized land

[0067] The salinized land in the Gahai National Wetland Park in Delingha, Qinghai Province, is planted with the native dominant halophyte, the salt claw (the first planting). After the salt claw matures and the seeds are collected, the above-ground part is cut off and the roots are retained, and reeds are planted (the second planting). Field management is carried out after the first and second plantings.

[0068] 2. Salt reduction and establishment of microbial flora

[0069] Plant twice, after the reeds mature and the seeds are collected, cut off the above-ground parts and keep the roots, and replant with salt claws (third planting). After the salt claws mature and the seeds are collected, cut off the above-ground parts and keep the roots, and replant with reeds (fourth planting). Apply organic fertilizer mixed with microbial flora during the third and fourth plantings, and repeat this process twice;

[0070] The added microbial flora is the microorganisms collected from the root soil of native dominant halophytes;

[0071] The application amount of organic fertilizer is 100kg / mu; the addition amount of microbial flora is 2.5% of the weight of organic fertilizer.

[0072] After cutting off the above-ground part of each planting, the soil at the root of the plant was sampled and the salt content of the soil at the root was measured according to the method of Example 1. The results are shown in Table 1.

[0073] When sampling for the first time, the sampling points were marked as A0, A1, A2, A3 and A4, and sampling was carried out at the marked points each time after planting.

[0074] Table 1 Changes in soil salinity at the roots of plants at different planting times (soil salt content / %)

[0075] Sample number A0 A1 A2 A3 A4 Undisturbed soil 2.15 1.85 2.39 2.40 1.96 First planting 1.78 1.54 1.97 2.01 1.61 Second planting 1.42 1.25 1.58 1.61 1.28 The third planting 0.96 0.87 1.10 1.02 0.86 The fourth planting 0.46 0.50 0.59 0.59 0.47

[0076] The decrease in soil salinity at the roots of plants after each planting was calculated and the results are shown in Table 2.

[0077] Table 2 Reduction of soil salt at plant roots at different planting times

[0078] Sample number A0 A1 A2 A3 A4 Mean First planting 17.09％ 16.98％ 17.66％ 16.36％ 17.68％ 17.15％ Second planting 20.56％ 18.82％ 19.97％ 19.96％ 20.67％ 20.00％ The third planting 32.26％ 30.33％ 29.92％ 36.30％ 32.45％ 32.25％ The fourth planting 52.00％ 42.12％ 46.84％ 42.58％ 45.69％ 45.85％

[0079] As shown in Table 1, the method provided by the present invention significantly reduces the soil salinity at the roots of plants after each planting, and the soil salinity at the roots of plants is reduced to about 0.5% after four plantings. The method provided by the present invention can effectively reduce the soil salinity of salinized land. As shown in Table 2, the average reduction in soil salinity after the first, second, third and fourth plantings is 17.15%, 20.00%, 32.25% and 45.85%, respectively.

[0080] 3. Vegetation ecological restoration

[0081] After salt reduction and establishment of microbial flora (four plantings), alfalfa was planted on the salinized land to restore the vegetation ecology.

[0082] Example 3

[0083] Vegetation ecological restoration of salinized land in the northeastern margin of the Qaidam Basin

[0084] 1. Reducing salt levels in salinized land

[0085] In the salinized land of the Gahai National Wetland Park in Delingha, Qinghai, native dominant halophytes Nitraria tangutorum and Tamarix chinensis were transplanted (intercropping, first year). After the fruits of Nitraria tangutorum matured and were harvested, 15 to 20 cm above the roots were retained and the remaining branches were cut off. Field management was carried out after intercropping.

[0086] 2. Salt reduction and establishment of microbial flora

[0087] Two years after planting, organic fertilizer mixed with microbial flora was applied, and the process was repeated twice; the added microbial flora were microorganisms collected from the root soil of native dominant halophytes; the application rate of organic fertilizer was 100 kg / mu; the amount of microbial flora added was 2.5% of the weight of organic fertilizer.

[0088] After the fruits of Nitraria tangutorum matured and were harvested each year, 15 to 20 cm above the roots were retained, and the remaining branches were cut off. The soil at the roots of the plants was sampled and the salt content of the soil at the roots was measured according to Example 1. The results are shown in Table 3.

[0089] When sampling for the first time, mark the sampling points as B0, B1, B2, B3 and B4 respectively, and sample at the marked points each time.

[0090] Table 3 Changes in soil salinity at the roots of plants in different planting years (soil salt content / %)

[0091] Sample number B0 B1 B2 B3 B4 Undisturbed soil 2.22 2.48 1.98 1.89 2.22 First year of planting 1.90 2.06 1.73 1.62 1.92 Second year of planting 1.55 1.72 1.38 1.36 1.52 The third year of planting 1.22 1.33 1.00 0.86 1.03 Fourth year of planting 0.62 0.64 0.53 0.50 0.56

[0092] The reduction in soil salinity at the roots of plants after transplantation was calculated and the results are shown in Table 4.

[0093] Table 4 Reduction of soil salt content at plant roots in different years after transplantation

[0094] Sample number B0 B1 B2 B3 B4 Mean First year of planting 14.35％ 16.81％ 12.94％ 14.53％ 13.61％ 14.45％ Second year of planting 18.38％ 16.71％ 19.79％ 16.19％ 20.67％ 18.35％ The third year of planting 21.21％ 22.20％ 28.03％ 36.30％ 32.45％ 28.04％ Fourth year of planting 49.61％ 52.03％ 46.84％ 42.58％ 45.69％ 47.35％

[0095] As shown in Table 3, the method provided by the present invention significantly reduces the soil salinity at the roots of plants after each planting. After 4 years of transplanting (interplanting) Nitraria tangutorum and Tamarix chinensis, the soil salinity at the roots has dropped to about 0.6%. The method provided by the present invention can effectively reduce the soil salinity in salinized land. As shown in Table 4, after the first, second, third and fourth years of transplanting, the average reduction in soil salinity was 14.45%, 18.35%, 28.04% and 47.35%, respectively.

[0096] 3. Vegetation ecological restoration

[0097] After salt reduction and the establishment of microbial flora (four years after transplanting white thorn and tamarisk, the entire plant is dug out), alfalfa is planted on the salinized land to restore the vegetation ecology.

[0098] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various changes can be made to the technical scheme of the present invention. These simple variations all belong to the protection scope of the present invention.

[0099] It should also be noted that the various specific technical features and steps described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0100] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for ecological restoration of vegetation on salinized land, characterized in that: The method comprises the following steps: S101: Reduce salt in salinized land. Select the native dominant halophytes in salinized land and plant them in the salinized land. After the first season of halophytes mature, replant the same halophytes. Repeat the process 1 to 4 times. S102 microbial flora is established, and after replanting halophytes 2 to 3 times, organic fertilizer mixed with microbial flora is applied when replanting again, and the process is repeated 1 to 2 times; S103 vegetation ecological restoration, planting salt-tolerant plants on salinized land after the establishment of microbial flora to restore vegetation ecology.

2. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The step S101 also includes collecting the native dominant halophyte root soil before planting, isolating, identifying and purifying the microorganisms therein, and then expanding the culture and collecting the mixed culture.

3. The method for ecological restoration of vegetation in salinized land according to claim 2, characterized in that: The mixed culture is acclimated to a salt gradient concentration before use, and the final salt content is ≥0.33MPa.

4. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The step S101 also includes, after the planted halophytes mature and the seeds are collected, the above-ground parts are cut off and the roots are retained.

5. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The step S101 also includes performing field management after planting the native dominant halophytes.

6. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The salinized land in step S101 includes, but is not limited to, salt marshes, saline-alkali land, saline-alkali desert, salinized soil, residual salinized soil and potential salinized soil.

7. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The native dominant halophytes selected in step S102 are planted singly or in combination; The native dominant halophytes include but are not limited to Nitraria tangutorum, Tamarix chinensis, Salicornia herba, Phragmites australis, Suaeda salsa and Lycium barbarum.

8. The method for ecological restoration of vegetation in salinized land according to claim 2, characterized in that: The microbial flora in step S102 is microorganisms collected from the root soil of native dominant halophytes; The microorganisms in the root soil include but are not limited to bacteria, actinomycetes and fungi.

9. The method for ecological restoration of vegetation in salinized land according to claim 2, characterized in that: In the step S102, the application amount of organic fertilizer is 100-500 kg / mu; the addition amount of microbial flora is 1-5% of the weight of the organic fertilizer.

10. The method for ecological restoration of vegetation in salinized land according to claim 1, characterized in that: The salt-tolerant plant in step S103 is alfalfa.

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