Microalgae-microorganism compound preparation for improving saline-alkali soil and application

Abstract

The invention belongs to the technical field of soil remediation, and relates to a microalgae-microorganism compound preparation for improving saline-alkali soil and application. The microalgae-microorganism compound preparation is prepared from spirulina, chlorella, nostoc, scenedesmus obliquus, bacillus mucilaginosus, bacillus mucilaginosus and pseudomonas. The microalgae-microorganism compound preparation for improving the saline-alkali soil can improve the available phosphorus content of the soil, increase the available potassium content of the soil and effectively improve the soil; soil bulk density is reduced, and soil hardening is improved; therefore, the fertilizer retention property of the soil is enhanced, the growth and development of crop roots are facilitated, the crop yield is remarkably improved, and the application prospect is wide.

Description

Technical Field

[0001] This invention belongs to the field of soil remediation technology, and relates to a microalgae-microorganism composite preparation for improving saline-alkali soil and its application. Background Technology

[0002] Saline-alkali land is a general term for various types of saline soil, alkaline soil, and salinized and alkalized soil. Based on the amount of salt and alkali in the soil, it can generally be divided into three categories: mild, moderate, and severe saline-alkali land. As an important land resource, soil salinization seriously affects the regional ecological environment and food production.

[0003] Saline-alkali soil is characterized by stickiness and poor aeration when wet, and hardness and poor water permeability when dry. In severe cases, salts seep from the surface, directly causing plants to wither and die. Soil salinization prevents large areas of land from being used effectively, seriously affecting agricultural production and the improvement of farmers' living standards. Soil improvement and restoration of saline-alkali land is imperative.

[0004] Currently, among the various measures for improving saline-alkali soil, water conservancy engineering, agricultural cultivation, halophytes, and chemical amendments are widely used, but the results are not ideal. While chemical amendments can quickly change soil structure, they may also cause secondary pollution; agricultural measures require a large amount of manpower, material resources, and financial resources; and biological amendments are slow to take effect and have a long cycle. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a microalgae-microorganism composite preparation for improving saline-alkali soil and its application. The microalgae-microorganism composite preparation effectively repairs saline-alkali soil, improves soil physicochemical properties, reduces soil bulk density, and alleviates soil compaction; it also increases soil cation exchange capacity, enhances soil fertility retention, and increases crop yield.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] In a first aspect, the present invention provides a microalgae-microorganism composite preparation for improving saline-alkali soil, wherein the microalgae-microorganism composite preparation includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosa, Bacillus lentigines and Pseudomonas.

[0008] Furthermore, the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus lentigines, and Pseudomonas is 0.8-1.2:0.8-1.2:0.8-1.2:1.2-1.8:1.5-2:1.5-2:

[0009] Furthermore, the density of the spirulina is ≥1×10⁻⁶. 7 cells / mL, density of Chlorella and Nostoc ≥1×10 7cells / mL, density of Scenedesmus obliqueis ≥1×10 7 cells / mL.

[0010] Furthermore, the viable count of the *Bacillus mucilaginosus* is ≥1×10⁻⁶. 8 cfu / mL, viable count of Bacillus jellyii ≥1×10 8 cfu / mL, viable count of Pseudomonas ≥6×10 8 cfu / mL.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned microalgae-microorganism composite preparation for improving saline-alkali soil. The preparation method is as follows: (1) preparing a microalgae solution; (2) preparing a composite microorganism agent; (3) mixing the prepared microalgae solution and the composite microorganism agent in proportion to obtain the microalgae-microorganism composite preparation for improving saline-alkali soil.

[0012] Thirdly, the present invention provides the application of the microalgae-microorganism composite preparation for improving saline-alkali soil obtained by the above preparation method in the remediation of saline-alkali soil.

[0013] The beneficial effects achieved by this invention are as follows:

[0014] The organic matter contained in Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus in the components of this invention can improve soil structure and increase soil aeration and water retention.

[0015] When the Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas aeruginosa of this invention are applied to the soil, they can form a dominant bacterial community, regulate the soil's micro-ecological environment, promote bacterial community balance, improve the soil, promote the absorption of effective nutrients by crops, increase fertilizer utilization, enhance photosynthesis, promote uniform and robust seedlings, and improve the survival rate of seedlings.

[0016] This invention provides a microalgae-microorganism compound preparation for improving saline-alkali soil. It is rich in Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus lentigines, and Pseudomonas. The combination of microalgae and microorganisms achieves a synergistic effect, improves the physical and chemical properties of the soil, enhances soil biological activity, and increases crop yield.

[0017] This invention relates to a microalgae-microorganism composite agent for improving saline-alkali soil. It increases the available phosphorus content and available potassium content in the soil, effectively improving the soil; it reduces soil bulk density and improves soil compaction; it increases soil cation exchange capacity, thereby enhancing the soil's fertility retention, which is beneficial to crop root growth and development, and significantly increases crop yield. It has broad application prospects. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the specific embodiments will be briefly described below.

[0019] Figure 1 The effects of each treatment on tomato yield were evaluated, with different lowercase letters indicating significant differences between different groups (P < 0.05). Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Unless otherwise specified, all reagents and raw materials used in the following examples and efficacy verifications are commercially available.

[0024] Example 1

[0025] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 1.0:1.0:1.5:1.5:1.8:1.8:1.8.

[0026] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0027] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0028] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0029] Example 2

[0030] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 0.8:1.2:1.2:1.2:1.5:2.0:1.5.

[0031] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0032] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0033] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0034] Example 3

[0035] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 1.2:1.0:1.8:1.8:2.0:1.8:2.0.

[0036] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0037] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0038] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0039] Example 4

[0040] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 1.2:0.8:1.5:1.5:1.5:1.5:1.5.

[0041] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0042] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0043] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0044] Example 5

[0045] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 1.0:1.2:1.8:1.8:2.0:1.8:1.8.

[0046] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0047] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0048] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0049] Example 6

[0050] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 1.0:0.8:1.5:1.5:2.0:1.5:1.8.

[0051] The composite microalgae-microorganism compound preparation consists of Bacillus licheniformis, Pseudomonas putida, and Bacillus thuringiensis in a mass ratio of 1:4:5.

[0052] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0053] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0054] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0055] Comparative Example 1

[0056] A microalgae-microorganism composite preparation for improving saline-alkali soil includes Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus mucilaginosus, and Pseudomonas, wherein the weight ratio of Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus mucilaginosus, and Pseudomonas is 1.5:1.5:1.8:1.8:1.8.

[0057] The preparation method is as follows: (1) Nostoc commune and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solution.

[0058] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0059] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0060] Compared with Example 1, the difference is that it does not contain spirulina or chlorella.

[0061] Comparative Example 2

[0062] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas is 1.0:1.0:1.8:1.8:1.8.

[0063] The preparation method is as follows: (1) Spirulina and Chlorella are cultured and proliferated in a culture medium to prepare microalgae solution.

[0064] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0065] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0066] Compared with Example 1, the difference is that it does not contain Nostoc commune or Scenedesmus obliquus.

[0067] Comparative Example 3

[0068] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Bacillus mucilaginosus, and Pseudomonas, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Bacillus mucilaginosus, and Pseudomonas is 1.0:1.0:1.5:1.8:1.8.

[0069] The preparation method is as follows: (1) Spirulina, Chlorella and Nostoc are cultured and proliferated in a culture medium to prepare microalgae solution.

[0070] (2) Mix Bacillus jellyoides and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0071] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0072] Compared with Example 1, the difference is that it does not contain Scenedesmus obliquus or Bacillus mucilaginosus.

[0073] Comparative Example 4

[0074] A microalgae-microorganism composite preparation for improving saline-alkali soil includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus megaterium, and Bacillus subtilis, wherein the weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus megaterium, and Bacillus subtilis is 1.0:1.0:1.5:1.5:1.8:1.8:1.8.

[0075] The preparation method is as follows: (1) Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solutions.

[0076] (2) Mix Bacillus mucilaginosus, Bacillus megaterium and Bacillus subtilis in the specified weight ratio to prepare a compound microbial agent.

[0077] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0078] Compared with Example 1, the difference is that Bacillus megaterium is used instead of Bacillus gelatinosa, and Bacillus subtilis is used instead of Pseudomonas.

[0079] Comparative Example 5

[0080] A microalgae-microorganism compound preparation for improving saline-alkali soil includes Spirulina, Microsheatha, Monofibrillaria, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas, wherein the weight ratio of Spirulina, Microsheatha, Monofibrillaria, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas is 1.0:1.0:1.5:1.5:1.8:1.8:1.8.

[0081] The preparation method is as follows: (1) Spirulina, Micrococcus, Monofibrillaria and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare microalgae solution.

[0082] (2) Mix Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa according to the weight ratio to prepare a compound microbial agent.

[0083] (3) The prepared microalgae solution and compound microbial agent are mixed in proportion to obtain a microalgae-microbial compound preparation for improving saline-alkali soil.

[0084] Compared with Example 1, the difference is that Microcoleinae is used instead of Chlorella, and Monofibrillaria is used instead of Nostoc.

[0085] Comparative Example 6

[0086] A microbial compound preparation for improving saline-alkali soil includes Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas, wherein the weight ratio of Bacillus mucilaginosus, Bacillus jellyoidis, and Pseudomonas is 1.8:1.8:1.8.

[0087] The preparation method is as follows: Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa are mixed in a weight ratio to obtain a microbial compound preparation for improving saline-alkali soil.

[0088] The difference from Example 1 is that it does not contain microalgae.

[0089] Experimental Study on the Remediation of Saline-Algae-Microorganism Composite Preparation of the Invention

[0090] 1. Experimental Methods

[0091] A field comparison experiment was conducted on silty loam soil. Nine treatments were set up: control group (CK), Example 1 group (A), Example 2 group (B), Comparative Example 1 group (C), Comparative Example 2 group (D), Comparative Example 3 group (E), Comparative Example 4 group (F), Comparative Example 5 group (G), and Comparative Example 6 group (H). Each treatment had three replicates, arranged in a randomized block design, with each plot measuring 15m. 2(5m×3m). A 1.5m wide protective row is set up around the perimeter of the area, with field ridges, and separate irrigation and drainage to prevent water and fertilizer from being mixed.

[0092] The seeds were soaked in a 1000-fold diluted solution of KMnO4 for disinfection, germination, sowing, and seedling cultivation. Transplanting was carried out on March 31, 2024, at a density of 667 m². 2 3700 seedlings were planted, and on April 5, 2024, after the seedlings had established themselves, the microalgae-microorganism compound preparation for groups AH (Example 1, Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6) was applied once, without further fertilization, at a rate of 2000 kg / hm². 2 The control group did not receive the microalgae-microorganism compound preparation. Field management, weeding, and pest and disease control were carried out according to local customs, and the treatments were completely consistent. Harvesting took place in July 2025.

[0093] 2. Measurement Indicators

[0094] 2.1 Effects on soil physicochemical properties

[0095] Available phosphorus: extracted with soil solution at a ratio of 1:10, and determined by molybdenum-antimony-scandium colorimetric method.

[0096] Available potassium: 2 mol / L HNO3 was used as an extractant and mixed with soil at a water-to-soil ratio of 20:1. The mixture was shaken for 0.5 hours, filtered, and then measured using a nutrient rapid analyzer.

[0097] Soil bulk density: determined using the ring sampler method.

[0098] Cation exchange capacity: determined by the NH4Cl-NH4OAc method.

[0099] 2.2 Impact on tomato yield

[0100] At harvest time, 50 fruits were randomly selected and weighed. The total tomato yield of the plot was calculated based on the harvest time and converted to yield per hectare.

[0101] 3. Data Processing

[0102] Data processing was performed using Graphpad Prism 7.0 software, and the measurement data was presented in the following format: ±s indicates the mean. Pairwise comparisons between groups were performed using SNK-q, and a p < 0.05 was considered statistically significant.

[0103] 4. Measurement Results

[0104] As shown in Table 1, compared with the control group (CK) without the application of the microalgae-microorganism compound preparation, the microalgae-microorganism compound preparation treatments in groups A and B significantly increased the available phosphorus content in the soil. Group A showed the most significant effect in increasing the available phosphorus content, with a 44.12% increase compared to the control group. Group B also showed a significant effect, with a 39.66% increase compared to the control group. The effects of groups A and B in increasing the available phosphorus content were significantly better than those of groups C, D, E, F, G, and H.

[0105] Table 1. Available phosphorus content in soil under different treatments

[0106] Group Available phosphorus content (mg / kg) CK group 25.34±2.24b Group A 36.52±2.23a Group B 35.39±1.96a Group C 28.43±1.22b Group D 29.78±3.31b Group E 30.35±2.94b Group F 30.15±1.34b Group G 28.50±3.24b Group H 28.06±2.11b

[0107] Note: Different lowercase letters indicate significant differences between different groups (P < 0.05).

[0108] As shown in Table 2, compared with the control group (CK) without the application of the microalgae-microorganism compound preparation, the microalgae-microorganism compound preparation treatments in groups A and B increased the available potassium content in the soil. Group A showed the most significant increase in available potassium content, with a 59.86% increase compared to the control group. Group B also showed a significant increase, with a 51.90% increase compared to the control group. The effects of groups A and B in increasing available potassium content were significantly better than those of groups C, D, E, F, G, and H.

[0109] Table 2. Soil available potassium content under different treatments

[0110] Group Available potassium content (mg / kg) CK group 98.24±3.04b Group A 157.05±7.82a Group B 149.23±13.23a Group C 111.09±8.88b Group D 121.69±3.49b Group E 123.05±11.65b Group F 121.18±3.89b Group G 115.04±15.02b Group H 119.29±13.19b

[0111] Note: Different lowercase letters indicate significant differences between different groups (P < 0.05).

[0112] As shown in Table 3, compared with the control group (CK) without the application of the microalgae-microorganism compound preparation, the microalgae-microorganism compound preparation treatments in groups A and B reduced soil bulk density. Group A showed the most significant effect in reducing soil bulk density, decreasing it by 25.80% compared to the control group. Group B also showed a significant effect, reducing soil bulk density by 25.34% compared to the control group. The effects of groups A and B in reducing soil bulk density were significantly better than those of groups C, D, E, F, G, and H.

[0113] Table 3 Soil bulk density under different treatments

[0114] Group <![CDATA[Soil bulk density (g / cm 3 )]]> CK group 1.52±0.09a Group A 1.13±0.03c Group B 1.14±0.06c Group C 1.34±0.02b Group D 1.31±0.04b Group E 1.37±0.03b Group F 1.35±0.03b Group G 1.41±0.04b Group H 1.32±0.08b

[0115] Note: Different lowercase letters indicate significant differences between different groups (P < 0.05).

[0116] As shown in Table 4, compared with the control group (CK) without the application of the microalgae-microorganism compound preparation, the microalgae-microorganism compound preparation treatments in groups A and B increased the soil cation exchange capacity. Group A showed the most significant increase in soil cation exchange capacity, with a 38.75% increase compared to the control group. Group B also showed a significant increase in soil cation exchange capacity, with a 35.50% increase compared to the control group. The effects of groups A and B in increasing soil cation exchange capacity were significantly better than those of groups C, D, E, F, G, and H.

[0117] Table 4 Soil cation exchange capacity under different treatments

[0118] Group Cation exchange capacity (cmol / kg) CK group 20.28±0.90b Group A 28.14±1.96a Group B 27.48±0.77a Group C 23.64±1.12b Group D 22.88±1.42b Group E 22.45±2.80b Group F 21.90±2.09b Group G 23.04±1.85b Group H 22.57±1.70b

[0119] Note: Different lowercase letters indicate significant differences between different groups (P < 0.05).

[0120] like Figure 1 As shown, compared with the CK group (without microalgae-microorganism compound treatment), the microalgae-microorganism compound treatment in groups A and B increased the yield per tomato plant. Group A showed the most significant increase in yield per tomato plant, and group B also showed a significant increase. The effects of groups A and B in increasing the yield per tomato plant were significantly better than those in groups C, D, E, F, G, and H.

[0121] After altering the components of the soil-improving microalgae-microorganism composite preparations in Comparative Examples 1-6, the soil improvement effect deteriorated. The applicant believes that the components of the soil-improving microalgae-microorganism composite preparation of the present invention have a synergistic effect, thereby achieving a significant improvement in the soil improvement effect.

[0122] This invention relates to a microalgae-microorganism composite agent for improving saline-alkali soil. It increases the available phosphorus content and available potassium content in the soil, effectively improving the soil; it reduces soil bulk density and improves soil compaction; it increases soil cation exchange capacity, thereby enhancing the soil's fertility retention, which is beneficial to crop root growth and development, and significantly increases crop yield. It has broad application prospects.

[0123] The present invention has been described in detail above with general descriptions and specific embodiments. However, modifications or improvements can be made to the present invention, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A microalgae-microorganism composite preparation for improving saline-alkali soil, characterized in that, The microalgae-microorganism compound preparation includes Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosa, Bacillus jellyoidis, and Pseudomonas.

2. The microalgae-microorganism composite preparation for improving saline-alkali soil according to claim 1, characterized in that, The weight ratio of Spirulina, Chlorella, Nostoc, Scenedesmus obliquus, Bacillus mucilaginosus, Bacillus jellyoidus, and Pseudomonas is 0.8-1.2:0.8-1.2:0.8-1.2:1.2-1.8:1.5-2:1.5-2:1.5-2.

3. The microalgae-microorganism composite preparation for improving saline-alkali soil according to claim 1, characterized in that, The density of the spirulina is ≥1×10 7 cells / mL, density of Chlorella and Nostoc ≥1×10 7 cells / mL, density of Scenedesmus obliqueis ≥1×10 7 cells / mL.

4. The microalgae-microorganism composite preparation for improving saline-alkali soil according to claim 1, characterized in that, The viable count of the *Bacillus mucilaginosus* is ≥1×10⁻⁶. 8 cfu / mL, viable count of Bacillus jellyii ≥1×10 8 cfu / mL, viable count of Pseudomonas ≥6×10 8 cfu / mL.

5. The microalgae-microorganism composite preparation for improving saline-alkali soil according to claim 1, characterized in that, The preparation method is as follows: (1) preparing microalgae solution; (2) preparing compound microbial agent; (3) mixing the prepared microalgae solution and compound microbial agent in proportion to obtain microalgae-microbial compound preparation for improving saline-alkali soil.

6. The method for preparing the microalgae-microorganism composite agent for improving saline-alkali soil according to claim 5, characterized in that, In step (1), Spirulina, Chlorella, Nostoc, and Scenedesmus obliquus are cultured and proliferated in a culture medium to prepare a microalgae solution.

7. The method for preparing the microalgae-microorganism composite agent for improving saline-alkali soil according to claim 5, characterized in that, In step (2), Bacillus mucilaginosus, Bacillus jellyoidis and Pseudomonas aeruginosa are mixed in a weight ratio to prepare a compound microbial agent.

8. The application of a microalgae-microorganism composite preparation for improving saline-alkali soil according to claim 1 in the remediation of saline-alkali soil.

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