Preparation of potassium-dissolving bacterial agent and application of potassium-dissolving bacterial agent in saline-alkali soil remediation

Abstract

The invention discloses preparation of a potassium-dissolving bacterial agent and application of the potassium-dissolving bacterial agent in saline-alkali soil remediation, and relates to the technical field of biology. The potassium-dissolving microbial agent comprises a potassium-dissolving microbial composition, the potassium-releasing microorganism composition is prepared from the following components: Sporidiobolus salmoninus CICC 32895 and bacillus aryabhattai CICC 24483. According to the present invention, the research results show that after the Sporidiobolus salmoninus CICC 32895 and the Bacillus aryabhattai CICC 24483 are combined, the synergistic interaction effect is generated; on the basis, the potassium microbial inoculum is developed, the charcoal in the microbial inoculum is rich in alkaline functional groups and can neutralize soil acidic ions, and meanwhile, the porous structure of the charcoal can adsorb soil salt; the microbial composition secretes organic acid, amino acid and other substances in the growth and metabolism process, insoluble potassium ore can be decomposed, the pH value of soil can be adjusted, and the soil permeability and the water and fertilizer retention capacity can be improved.

Description

Technical Field

[0001] This invention relates to the field of biotechnology, and in particular to the preparation of a potassium-solubilizing agent and its application in the remediation of saline-alkali land. Background Technology

[0002] Saline-alkali land is a widely distributed soil type globally. Its high salinity and high pH value lead to low soil fertility and imbalanced microbial communities, severely restricting the sustainable development of agricultural production. Affected by natural factors and human activities, the degree of salinization is still intensifying, urgently requiring the development of efficient and environmentally friendly saline-alkali land improvement technologies.

[0003] Potassium is one of the essential nutrients for plant growth and development, participating in various physiological processes such as photosynthesis and nutrient transport. However, over 95% of the potassium in saline-alkali soils exists in the form of insoluble minerals, which cannot be directly absorbed and utilized by plants. Traditional methods for improving saline-alkali soils, such as applying chemical potassium fertilizers to supplement readily available potassium, suffer from high costs, secondary pollution, and damage to soil structure. Single microbial agents have limited potassium-releasing capacity and low survival rates under saline-alkali stress, making it difficult to achieve ideal improvement results. Therefore, developing a compound microbial agent that can adapt to saline-alkali environments, has high potassium-releasing efficiency, and also improves soil structure is of great significance for the effective utilization of saline-alkali land resources and sustainable agricultural development. Summary of the Invention

[0004] The purpose of this invention is to provide a potassium-solubilizing bacterial agent for preparation and its application in saline-alkali land remediation, thereby solving the problems existing in the prior art. This potassium-solubilizing bacterial agent can effectively decompose insoluble potassium ore, increase the content of available potassium in the soil, and is suitable for agricultural development and remediation of saline-alkali land.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a potassium-solubilizing microbial ensemble for saline-alkali land remediation, comprising Sporidiobolus salmonicolor CICC 32895 and Bacillus aryabhattai CICC 24483.

[0007] Furthermore, the ratio of the number of *Saccharomyces cerevisiae* CICC 32895 to the number of *Bacillus auricula-judae* CICC 24483 is 1:1.

[0008] The present invention also provides the application of the above-mentioned potassium-solubilizing microbial combination in the preparation of potassium-solubilizing bacterial agents for saline-alkali land remediation.

[0009] The present invention also provides a potassium-solubilizing agent for saline-alkali land remediation, comprising the above-mentioned potassium-solubilizing microbial combination.

[0010] Furthermore, the potassium-solubilizing agent also includes an agent carrier.

[0011] Furthermore, the microbial agent carrier is biochar.

[0012] Furthermore, the biochar is prepared by high-temperature pyrolysis of crop straw under anaerobic conditions.

[0013] The present invention also provides a method for preparing the above-mentioned potassium-solubilizing bacterial agent, comprising the steps of mixing the bacterial agent carrier with a bacterial suspension containing the potassium-solubilizing microbial combination evenly, and drying it until the moisture content is less than 10% to obtain the potassium-solubilizing bacterial agent.

[0014] The present invention also provides the application of the above-mentioned potassium-solubilizing agent in the remediation of saline-alkali land.

[0015] The present invention also provides a method for remediating saline-alkali land, which includes the step of applying the above-mentioned potassium-solubilizing agent to the soil to be remediated.

[0016] The present invention discloses the following technical effects:

[0017] This invention found that when *Saccharomyces cerevisiae* CICC 32895 is used in combination with *Bacillus aureus* CICC 24483, the potassium solubilization rate reaches 71.5%, and the soluble potassium content is significantly increased, which is significantly higher than the potassium solubilization efficiency of a single strain, achieving a synergistic effect of 1+1>2.

[0018] This invention develops a potassium-solubilizing bacterial agent based on *Saccharomyces cerevisiae* CICC 32895 and *Bacillus aspergillus* CICC 24483. The biochar in this agent is rich in alkaline functional groups, which can neutralize soil acidic ions, while its porous structure can adsorb soil salts. During the growth and metabolism of the microbial assemblage, it secretes organic acids, amino acids and other substances, which can decompose insoluble potassium minerals, regulate soil pH, and improve soil permeability and water and fertilizer retention capacity.

[0019] The potassium-releasing microbial agent prepared by this invention uses crop straw biochar as a carrier, which has a wide range of raw material sources, low cost, and avoids secondary pollution caused by chemical amendments. After application, it can reduce the amount of chemical potassium fertilizer used, reduce agricultural production costs, and meet the needs of green agricultural development. This microbial agent can adapt to the extreme environment of saline-alkali land, not only increasing the content of available potassium in the soil, but also improving the soil microbial community structure and promoting crop growth. It is suitable for agricultural development and restoration of various types of saline-alkali land. 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. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of 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] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] Currently, various remediation technologies, including physical, chemical, biological, and agronomic techniques, have been developed for saline-alkali land of different regions and degrees. Some of these technologies have been implemented effectively and have demonstrated their value for large-scale promotion. The following is a detailed introduction to various existing remediation technologies:

[0026] 1. Physical Restoration Techniques

[0027] The core of this type of technology is to regulate salt distribution by optimizing soil physical structure and constructing salt discharge channels. It has the characteristics of wide applicability and mature operation, and is a basic means of saline-alkali land restoration.

[0028] Subsurface drainage technology: By laying perforated pipes 40-60 cm underground, saline groundwater is drained using natural slopes or auxiliary pumps. Combined with an IoT smart system, soil salinity data can be monitored in real time, dynamically adjusting the drainage intensity. This technology can reduce soil salinity from 0.8% to 0.3%, increasing crop yields by 50%-80%. When combined with well irrigation and drainage technologies, a three-dimensional drainage network can be constructed, effectively preventing secondary salinization. Currently used new biodegradable corrugated pipes have a degradation cycle precisely matched to drainage needs, solving the environmental pollution problems associated with long-term use of traditional PVC pipes.

[0029] Aperture drainage and salt improvement technology: Designed for moderately saline-alkali land, this technology involves drilling holes of fixed depth and diameter at a specific density, then filling them with topsoil, straw, and fine sand in layers to create a "straw-sand layer" infiltration channel. This technology can improve irrigation infiltration efficiency by 20%, and by using gravity to leach salts, it can reduce soil salinity by approximately 20%. Compared to traditional engineering methods, its cost can be reduced by 40%, making it suitable for agricultural production in moderately saline-alkali areas.

[0030] Deep burial of straw and salt-barrier layering technology: By turning shredded straw into the soil layer, the straw forms a natural salt barrier during decomposition, which not only blocks the upward flow of salt but also increases the organic matter content of the soil. Combined with the process of turning and composting, 300 kg of straw per acre is turned in, supplemented with urea and composting agents, and winter irrigation, the salinity of the topsoil can be reduced by 25%. After two years of improvement, saline-alkali land that was previously difficult to produce corn can achieve stable corn yields, becoming an effective low-cost physical improvement path for severely saline-alkali land.

[0031] Soil replacement method: An emergency improvement technique for severely saline-alkali land. By excavating the topsoil and replacing it with high-quality soil or mixed improvement materials, it can quickly improve the basic soil conditions. After treatment, the soil pH value can be reduced from 9.5 to 7.5. However, due to the large amount of materials required, this technique is more suitable for the priority improvement of small areas of severely saline-alkali land.

[0032] 2. Chemical remediation technology

[0033] These technologies rely on chemical principles such as acid-base neutralization and ion replacement. Many of these technologies innovatively transform industrial by-products into improved materials, combining remediation effects with resource recycling value.

[0034] Industrial by-product improvement technology: Iron tailings are mixed with humic acid, aluminum sulfate, and other substances to create soil amendments. When used to improve saline-alkali dryland, crop yields can be more than three times that of untreated plots. Another technology combines industrial by-product citrate-sulfur gypsum with straw to create "clean organic fertilizer." Calcium sulfate replaces sodium ions to lower soil pH, while calcium citrate accelerates salt leaching. Simultaneously, microbial agents decompose straw cellulose to form humus, achieving dual optimization of soil structure and salinity.

[0035] Functional improvers and fertilizer technology: Organosilicon functional fertilizer technology combines new organosilicon materials with fertilizers to regulate soil pH, lowering soil pH from above 10 to 7-8, thus helping grain crops achieve high yields. Related demonstration plantings have set world records for yield per unit area in large-scale plantings. Additionally, novel bio-based modifying materials developed from natural biomass can promote soil aggregate formation, increase porosity, and thereby improve salt leaching efficiency, opening up new pathways for the remediation of severely saline-alkali land.

[0036] In-situ ultra-stable mineralization technology: A groundbreaking chemical improvement technology developed based on the low solubility characteristics of layered bimetallic composite hydroxides. Its core involves applying acidic metal salt mineralizers containing divalent and trivalent metal ions into the soil, where they react in situ with basic and basic anions in the soil to form a mineralized structure with extremely low solubility. Simultaneously, the electrostatic attraction of cationic clay fixes sodium ions, acting like a "molecular cage" to lock in the salt and alkali ions and prevent their re-release. This technology eliminates the need for freshwater leaching, and after improvement, the soil pH can drop from above 10.0 to below 8.0, reducing the salt and alkali ion content by more than 60%, with no salinity rebound for five consecutive years. In contrast, traditional desulfurization gypsum-improved soils are prone to salinity rebound after just one year.

[0037] Salt ion balance regulation technology: This technology improves sulfate- and chloride-type saline-alkali land by selectively supplementing specific ions. For example, sulfate-type land can be treated with agricultural potassium chloride combined with phosphogypsum and organic fertilizer, while chloride-type land can be treated with ferrous sulfate and citric acid. Although the direct salt reduction effect is limited, the technology can mitigate the damage of salt to crop roots through ion exchange, ensuring stable crop growth.

[0038] 3. Bioremediation technology

[0039] This technology focuses on soil microecological reconstruction and crop salt tolerance enhancement. It achieves sustainable restoration through gene modification and microbial regulation, and is the mainstream direction for green restoration of saline-alkali land.

[0040] Salt-tolerant crop breeding technology: Breakthroughs in crop salt tolerance have been achieved through gene editing technology. For example, the introduction of the wild rice Saltol gene, combined with CRISPR-Cas9 technology to enhance the crop's proline synthesis pathway, has resulted in the "Dongdao 122" seawater rice variety, which can grow stably in environments with a salinity of 6‰ and yields up to 600 kg per mu. Currently, more than 50 salt-tolerant crop varieties have been promoted, covering multiple categories such as food and cash crops, providing diversified options for planting in saline-alkali land.

[0041] Microbial inoculant remediation technology: By screening salt-tolerant bacteria and developing salt- and alkali-tolerant rhizosphere growth-promoting microbial preparations, the soil microecology can be reconstructed. When salt-tolerant bacteria work synergistically with biochar, they can increase soil organic matter content and improve rice milling rate; salt- and alkali-tolerant rhizosphere growth-promoting bacteria can enhance crop root vitality, contributing to increased yield. Furthermore, breakthroughs in Trichoderma solid-state fermentation technology have solved the problem of high production costs for microbial preparations. It can decompose straw cellulose to form humus, promoting the large-scale application of microbial fertilizers.

[0042] 4. Agronomic Restoration Techniques

[0043] These technologies achieve synergistic effects of salt control and yield increase by optimizing planting and farming management models. They are suitable for the routine improvement of mild to moderate saline-alkali land and are easy to combine with other remediation technologies.

[0044] Mulching and dense planting technologies: Using reusable mulch film in conjunction with acidic water-soluble fertilizer can reduce soil pH by 0.3 and salinity by 10%. High-ridge salt-accumulating furrow mulching technology, through the combination of non-woven fabric on the ridge surface and mulch film in the furrows, can increase soil temperature by 2-3℃ while reducing soil salinity by 15%. Wide-ridge double-row dense planting combined with shallow-buried drip irrigation and fertigation technology enables precise fertilization and efficient moisture retention, significantly increasing crop yield and substantially improving corn yield per acre.

[0045] Intercropping with green manure: This technique involves using narrow-film mulch to cover the main crop and intercropping with green manure crops such as arrowhead peas. Each acre can yield 1000-1500 kg of fresh green manure. After being plowed and returned to the field, this method can increase soil organic matter by 0.2% and reduce salinity by 15% over three years. This model reduces surface water evaporation and inhibits salt return through crop mulching, while returning green manure to the field activates soil nutrients, forming an ecological cycle improvement system.

[0046] The Four-Dimensional Soil Improvement Method integrates four key elements: an IoT system, soil-oriented regulators, plant growth regulators, and stress-resistant crops. These elements can be freely combined and customized to create the optimal improvement plan based on soil salinization levels. This technology is not only suitable for improving saline-alkali land but also applicable to the remediation of land contaminated with heavy metals and agricultural residues, providing flexible solutions for personalized saline-alkali land restoration.

[0047] 5. Digital-assisted repair technology

[0048] These technologies provide data support for the precise remediation of saline-alkali land, driving the transformation of remediation models from "experience-based" to "intelligent." By integrating satellite remote sensing, drone patrols, and ground-based sensor networks, an "integrated air-space-ground monitoring" system can be constructed, accurately capturing dynamic changes in soil salinity. The application of a digital twin platform can build soil salinity prediction models, enabling real-time early warning of soil conductivity and prediction of salinization risks. These technologies allow for more targeted implementation of physical and chemical remediation measures, significantly reducing ineffective inputs. For example, through precise drip irrigation control, the tasseling period of maize can be advanced, resulting in a significant increase in biomass.

[0049] The culture medium and strain information involved in the following examples are as follows:

[0050] The LB liquid culture medium consists of the following components: 5 g / L yeast extract, 10 g / L tryptone, and 10 g / L sodium chloride, pH 7.2.

[0051] The LB solid medium consists of the following components: 5 g / L yeast extract, 10 g / L tryptone, 10 g / L sodium chloride, and 15 g / L agar powder, pH 7.2.

[0052] The NA liquid culture medium consists of the following components: 10 g / L peptone, 3 g / L beef extract, and 5 g / L sodium chloride, pH 7.2.

[0053] The NA solid culture medium consists of the following components: 10 g / L peptone, 3 g / L beef extract, 5 g / L sodium chloride, and 15 g / L agar powder, pH 7.2.

[0054] Sporidiobolus salmonicolor was purchased from the China Industrial Microbial Culture Collection Center (CICC), strain number CICC 32895; Bacillus aryabhattai was purchased from the China Industrial Microbial Culture Collection Center, strain number CICC 24483.

[0055] Example 1 Potassium solubilization performance test

[0056] Potassium solubilization performance test medium: glucose 10g, Na2·HPO4 0.2g, MgSO4·7H2O 0.2g, NaCl 0.2g, CaSO4·2H2O 0.2g, CaCO3 5g, potassium feldspar powder 0.1g, distilled water 1000mL, pH 7.2, sterilized at 115℃ for 15min.

[0057] 1. Strain activation and inoculation

[0058] *Saccharomyces cerevisiae* CICC 32895 was inoculated onto NA solid medium and cultured at 30°C for 3 days; *Bacillus aureus* CICC 24483 was inoculated onto LB solid medium and cultured at 37°C for 1 day. Single colonies were picked and inoculated onto their respective liquid media, and cultured with shaking until the bacterial concentration reached 10⁻⁶. 7 CFU / mL. After centrifugation to obtain bacterial cells, they were resuspended in sterile physiological saline to obtain bacterial suspensions of two strains, each with a concentration of 10. 6 CFU / mL

[0059] 2. Potassium solubilization performance test: As shown in Table 1, the bacterial cultures of the two strains were inoculated separately or jointly into the potassium solubilization performance test medium. Each treatment was repeated in triplicate, and the blank control group was inoculated with an equal volume of sterile physiological saline. After 5 days of incubation, the soluble potassium content in the medium was determined by atomic absorption spectrophotometry, and the potassium solubilization rate was calculated according to the formula:

[0060] Potassium solubility rate = (soluble potassium content in the experimental group - soluble potassium content in the blank group) / total potassium content in potassium feldspar × 100%.

[0061] Table 1. Experimental Grouping for Potassium Solubilization Performance Test

[0062]

[0063] 3. Experimental results: The soluble potassium content in the culture medium of the blank control group was 2.35 mg / L; the soluble potassium content in group B was 9.68 mg / L, with a potassium solubilization rate of 55.2%; the soluble potassium content in group A was 4.00 mg / L, with a potassium solubilization rate of 12.4%; and the soluble potassium content in group C was 11.85 mg / L, with a potassium solubilization rate of 71.5%.

[0064] The results showed that although the potassium solubilization rate of *Saccharomyces cerevisiae* CICC 32895 was low, its potassium solubilization rate could be significantly improved when used in combination with *Bacillus aureus* CICC 24483. This invention suggests that the two have a synergistic effect.

[0065] Example 2 Preparation of potassium-solubilizing bacteria

[0066] 1. Biochar preparation: Collect wheat straw, cut it into 1-2 cm pieces, put it into a pyrolysis furnace, pyrolyze it at 500℃ for 1 hour under anaerobic conditions, cool it to room temperature, crush it, and pass it through a 20-mesh sieve to obtain biochar carrier.

[0067] 2. Preparation of bacterial suspension

[0068] (1) Salmonella Cyclostome suspension: Activated salmonella Cyclostome CICC 32895 was inoculated into NA liquid medium and cultured at 30℃ and 150 rpm for 3 days with shaking. The cells were collected by centrifugation (8000 rpm, 10 min), resuspended in sterile physiological saline, and the concentration was adjusted to 10.8 CFU / mL.

[0069] (2) Bacillus aureus suspension: Activated Bacillus aureus CICC 24483 was inoculated into LB liquid medium and cultured at 37°C with shaking at 180 rpm for 2 days. The cells were collected by centrifugation (8000 rpm, 10 min), resuspended in sterile physiological saline, and the concentration was adjusted to 10. 8 CFU / mL.

[0070] 3. Preparation of mixed bacterial agent: Mix the two bacterial suspensions mentioned above at a volume ratio of 1:1 to obtain a mixed bacterial agent.

[0071] 4. Preparation of immobilized bacterial agent: Mix biochar and mixed bacterial agent at a mass ratio of 1:1, and air dry in a well-ventilated environment (temperature 25-30℃, humidity 40-50%) until the moisture content is less than 10% to obtain potassium-solubilizing bacterial agent.

[0072] Comparative Example 1

[0073] 1. Biochar preparation: Collect wheat straw, cut it into 1-2 cm pieces, put it into a pyrolysis furnace, pyrolyze it at 500℃ for 1 hour under anaerobic conditions, cool it to room temperature, crush it, and pass it through a 20-mesh sieve to obtain biochar carrier.

[0074] 2. Preparation of bacterial suspension

[0075] Bacillus aureus suspension: Activated Bacillus aureus CICC 24483 was inoculated into LB liquid medium and cultured at 37°C with shaking at 180 rpm for 2 days. The cells were collected by centrifugation (8000 rpm, 10 min), resuspended in sterile physiological saline, and the concentration was adjusted to 10. 8 CFU / mL.

[0076] 3. Preparation of immobilized bacterial agent: Mix biochar and Bacillus aureus suspension at a mass ratio of 1:1, and air dry in a well-ventilated environment (temperature 25-30℃, humidity 40-50%) until the moisture content is less than 10% to obtain potassium-solubilizing bacterial agent.

[0077] Comparative Example 2

[0078] 1. Biochar preparation: Collect wheat straw, cut it into 1-2 cm pieces, put it into a pyrolysis furnace, pyrolyze it at 500℃ for 1 hour under anaerobic conditions, cool it to room temperature, crush it, and pass it through a 20-mesh sieve to obtain biochar carrier.

[0079] 2. Preparation of bacterial suspension

[0080] Salmonella Cyclostome suspension: Activated salmonella Cyclostome CICC 32895 was inoculated into NA liquid medium and cultured at 30°C with shaking at 150 rpm for 3 days. The cells were collected by centrifugation (8000 rpm, 10 min), resuspended in sterile physiological saline, and the concentration was adjusted to 10. 8 CFU / mL.

[0081] 3. Preparation of immobilized bacterial agent: Mix biochar and salmonid yeast suspension at a mass ratio of 1:1, and air dry in a well-ventilated environment (temperature 25-30℃, humidity 40-50%) until the moisture content is less than 10% to obtain potassium-solubilizing bacterial agent.

[0082] Example 3: Application of potassium-solubilizing bacteria in saline-alkali land remediation and potato cultivation

[0083] 1. Overview of the test site

[0084] The experiment was conducted in saline-alkali soil. The basic physical and chemical properties of the soil were: pH value 8.8, water-soluble salt content 2.1 g / kg, available potassium content 85 mg / kg, and organic matter content 10.2 g / kg.

[0085] 2. Experimental Design

[0086] Six processing groups were set up, each with an area of ​​20m². 2 3 repetitions, randomized block arrangement:

[0087] (1) Blank control group (CK): No microbial agents or potassium fertilizer were applied;

[0088] (2) Single application of Bacillus aureus group (T1): application of potassium-solubilizing agent of Comparative Example 1 (3 kg / mu) + half amount of potassium fertilizer (potassium sulfate 10 kg / mu).

[0089] (3) Single application of salmon-colored yeast group (T2): Apply potassium-solubilizing agent (3 kg / mu) of Comparative Example 2 + half amount of potassium fertilizer (10 kg / mu of potassium sulfate).

[0090] (4) Compound microbial agent + half-potassium fertilizer group (T3): Apply potassium-releasing microbial agent (3 kg / mu) from Example 2 + half-potassium fertilizer (10 kg / mu of potassium sulfate).

[0091] (5) Compound microbial agent + sufficient potassium fertilizer group (T4): Apply potassium-relieving microbial agent of the present invention (3kg / mu) + sufficient potassium fertilizer (potassium sulfate 20kg / mu).

[0092] (6) Conventional sufficient potassium fertilizer group (T5): Only 20 kg / mu of potassium sulfate was applied.

[0093] 3. Planting and Management

[0094] Each treatment group planted potatoes (variety: Jizhangshu 12) using conventional methods, and carried out unified field management such as irrigation and weeding. The planting cycle was 120 days.

[0095] 4. Measurement Indicators and Methods

[0096] (1) Soil indicators: After harvest, the soil pH value was determined by potentiometric method, the water-soluble salt content was determined by electrical conductivity method, the available potassium content was determined by atomic absorption spectrophotometry, and the organic matter content was determined by potassium dichromate oxidation-external heating method.

[0097] (2) Crop indicators: Plant height and stem diameter were measured using a ruler, and the yield per plant and the total yield of the plot were calculated and converted into yield per hectare.

[0098] 5. Results

[0099] The results of soil physicochemical property measurements for each treatment group are shown in Table 2. Table 2 shows that the soil pH values ​​of groups T3 and T4 decreased to 7.7 and 7.5, respectively, significantly lower than the control group (CK). The water-soluble salt contents were 1.36 g / kg and 1.30 g / kg, respectively, decreasing by 35.2% and 38.1% compared to the CK group (2.1 g / kg). The available potassium contents reached 149 mg / kg and 161 mg / kg, respectively, increasing by 75.3% and 89.4% compared to the CK group (85 mg / kg). The organic matter contents were 12.8 g / kg and 13.1 g / kg, respectively, increasing by 25.5% and 28.4% compared to the CK group (10.2 g / kg), significantly better than groups T1, T2, and T5.

[0100] Table 2. Results of soil physicochemical properties for each treatment group (mean ± standard deviation)

[0101]

[0102] Note: Different lowercase letters after the data in the same column indicate significant differences between treatments (P<0.05).

[0103] (2) Crop growth and yield: The results of potato growth and yield measurements for each treatment group are shown in Table 3. As shown in Table 3, the potato plant height and stem diameter of the T4 group reached 78.2 cm and 15.6 mm, respectively, which were 32.5% and 28.9% higher than those of the CK group (59.0 cm and 12.1 mm), respectively; the yield per plant was 0.78 kg, and the yield per mu (667 m²) reached 3473 kg / mu, which was 42.3% higher than that of the CK group (2440 kg / mu). The plant height and stem diameter of the T3 group were 75.5 cm and 14.8 mm, respectively, and the yield per plant was 0.75 kg, which was 3320 kg / mu, which was 36.1% higher than that of the CK group, and the yield was higher than that of the T5 group (3233 kg / mu), achieving high yield even after reducing the application of potassium fertilizer.

[0104] Table 3. Results of potato growth and yield indicators for each treatment group (mean ± standard deviation)

[0105]

[0106] Note: Different lowercase letters after the data in the same column indicate significant differences between treatments (P<0.05).

[0107] The above embodiments demonstrate that the potassium-releasing bacteria agent of the present invention can effectively increase the available potassium content in saline-alkali soil, improve soil physicochemical properties, promote potato growth and increase yield, and has important application value in saline-alkali land restoration and agricultural production.

[0108] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A potassium-solubilizing microbial ensemble for saline-alkali land remediation, characterized in that, This includes Sporidiobolus salmonicolor CICC 32895 and Bacillus aryabhattai CICC 24483.

2. The potassium-solubilizing microbial assemblage according to claim 1, characterized in that, The ratio of the number of *Saccharomyces cerevisiae* CICC 32895 to the number of the number of *Bacillus auricula-judae* CICC 24483 is 1:

1.

3. The use of a potassium-solubilizing microbial ensemble as described in claim 1 or 2 in the preparation of a potassium-solubilizing bacterial agent for saline-alkali land remediation.

4. A potassium-solubilizing bacterial agent for saline-alkali land remediation, characterized in that, Includes the potassium-solubilizing microbial assemblages as described in claim 1 or 2.

5. The potassium-solubilizing bacterial agent according to claim 4, characterized in that, The potassium-solubilizing bacterial agent also includes a bacterial agent carrier.

6. The potassium-solubilizing bacterial agent according to claim 5, characterized in that, The carrier for the microbial agent is biochar.

7. The potassium-solubilizing bacterial agent according to claim 6, characterized in that, The biochar is prepared by high-temperature pyrolysis of crop straw under anaerobic conditions.

8. A method for preparing a potassium-solubilizing bacterial agent as described in any one of claims 4-7, characterized in that, The process includes the steps of uniformly mixing a bacterial agent carrier with a bacterial suspension containing the potassium-solubilizing microbial combination, and then drying it until the moisture content is less than 10% to obtain the potassium-solubilizing bacterial agent.

9. The application of a potassium-solubilizing agent as described in any one of claims 4-7 in the remediation of saline-alkali land.

10. A method for remediating saline-alkali land, characterized in that, The step includes applying the potassium-solubilizing agent according to any one of claims 4-7 to the soil to be remediated.

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