Saline-alkali tolerant bacillus pumilus and application thereof in saline-alkali soil improvement

Abstract

The invention belongs to the technical field of microorganisms and soil improvement, and particularly relates to saline-alkali tolerant bacillus pumilus and application thereof in saline-alkali soil improvement. The biochar, the humified agricultural and animal husbandry waste and the saline-alkali tolerant microorganisms are used for improving the saline-alkali soil, compared with a method for improving the saline-alkali soil by singly using the humified agricultural and animal husbandry waste or the biochar, the method has a better soil improvement effect, meanwhile, crops are planted in the improved saline-alkali soil, and the saline-alkali soil is improved. The growth of various crops including corn can also be promoted. Furthermore, the bacillus pumilus L13 which is obtained through self-separation and has saline-alkali tolerance and growth promotion effects is applied to the saline-alkali soil improvement method, and the saline-alkali soil improvement effect is better.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms and soil improvement, and particularly relates to salt-alkali tolerant Bacillus pumilus and application thereof in saline-alkali land improvement. Background Art

[0002] Soil salinization is caused by high salinity, high pH, ​​poor aeration and nutrient deficiency, which greatly reduces agricultural productivity. At present, many remediation technologies have been developed, including substrate drainage, chemical precipitation and adsorption, to improve soil salinization problems, but the cost, effectiveness and potential secondary pollution of these technologies often limit the sustainability of these technologies.

[0003] The application of biochar-based salt-alkali tolerant microorganisms is considered to be an effective method for improving saline-alkali land. Biochar is a product with large surface area, porosity and rich functional groups produced by pyrolysis of biomass under high temperature and oxygen-limited conditions. It has the ability to provide porous habitats for salt-alkali tolerant microorganisms, enhance soil structure and accelerate salt loss. Some existing studies have proposed methods for the synergistic restoration of salinized soils by biochar and microorganisms. However, biochar often contains inorganic components such as CaO, MgO and CaCO3, which show alkalinity. There is a risk of secondary alkalinization when it is directly applied in saline-alkali land. At the same time, although the types of salt-alkali tolerant microorganisms are relatively wide, and there are also some schemes for soil improvement with salt-alkali tolerant microorganisms in existing studies, the effect of some salt-alkali tolerant microorganisms in improving soil salinization is poor. The main reasons are: first, the survival rate of the strains in soil environments such as saline-alkali land is low; second, the salt-alkali tolerance and growth promotion ability of the strains themselves are not high.

[0004] Biochar combined with acidic substance humic acid has also become an important direction of current research on salinized soil remediation. Some existing studies have proposed methods of using biochar and humic acid to remediate salinized soil. In addition, some existing studies have also proposed the use of biochar, humic acid and other materials in conjunction with microbial agents to remediate salinized soil. However, as a product that needs to be extracted from natural soil, peat or other organic materials, the application of humic acid is also limited by complex extraction processes and high costs. Summary of the invention

[0005] The purpose of the present invention is to provide salt-alkali tolerant Bacillus pumilus and application thereof in saline-alkali land improvement. The salt-alkali tolerant Bacillus pumilus cooperates with biochar and humified agricultural and animal husbandry waste to significantly improve the saline-alkali land.

[0006] The present invention provides a method for improving saline-alkali land, comprising the following steps:

[0007] mixing biochar, humified agricultural and animal husbandry waste and saline-alkali soil to obtain mixed saline-alkali soil;

[0008] Salt-alkali tolerant microorganisms are applied to the mixed saline-alkali soil for mixed cultivation to obtain improved saline-alkali land.

[0009] Preferably, the amount of biochar used is 1.44-2.40 tons per mu of saline-alkali land; the amount of humified agricultural and animal husbandry waste used is 7.67-11.51 tons per mu of saline-alkali land; the amount of salt-alkali tolerant microorganisms used is calculated in terms of salt-alkali tolerant microbial liquid, the mass ratio of the volume of the salt-alkali tolerant microbial liquid to the saline-alkali soil is 1-2 mL: 10-20 g, and the effective concentration of the salt-alkali tolerant microbial liquid is 1×10 8 CFU / mL.

[0010] Preferably, the biochar comprises crop straw biochar; the preparation step of the crop straw biochar comprises: calcining the crop straw at 450-500° C. for 1.5-2 h to obtain the crop straw biochar.

[0011] Preferably, the preparation step of the humified agricultural and animal husbandry waste comprises: mixing animal feces, crop straw and mature bacterial strains and then composting them until they are mature, thereby obtaining the humified agricultural and animal husbandry waste;

[0012] The mature strains include Acetobacter and Pichia pastoris, the volume ratio of Acetobacter to Pichia pastoris is 1-2:1-2, and the effective live bacteria concentrations of Acetobacter and Pichia pastoris are both (0.5-1)×10 8 CFU / mL; the inoculation amount of the bacterial solution of the mature strain is 15% to 20% (v / m) of the total dry matter of the animal feces and crop straw;

[0013] The dry matter mass ratio of the animal excrement to the crop straw is 1:1-2.

[0014] Preferably, the mixed culture period is 15 to 20 days.

[0015] Preferably, the salt-alkali tolerant microorganism comprises Bacillus pumilus.

[0016] Preferably, the Bacillus pumilus includes Bacillus pumilus L13, and the deposit number of the Bacillus pumilus L13 is CGMCC No.32044.

[0017] The present invention also provides application of the saline-alkali land improvement method described in the above technical solution in promoting crop growth.

[0018] The invention provides a strain of Bacillus pumilus L13, and the deposit number of the Bacillus pumilus L13 is CGMCC No.32044.

[0019] The present invention also provides the use of the Bacillus pumilus L13 described in the above technical solution in soil improvement and / or promoting plant growth.

[0020] Beneficial effects:

[0021] The present invention provides a method for improving saline-alkali land, comprising the following steps: mixing biochar, humified agricultural and animal husbandry waste and saline-alkali soil to obtain mixed saline-alkali soil; applying salt-alkali tolerant microorganisms to the mixed saline-alkali soil for mixed cultivation to obtain improved saline-alkali land. The present invention uses biochar, humified agricultural and animal husbandry waste and salt-alkali tolerant microorganisms to improve saline-alkali soil, which not only has a better soil improvement effect than the method of using humified agricultural and animal husbandry waste or biochar alone to improve saline-alkali land, but also can promote the growth of various crops including corn by planting crops in the improved saline-alkali land.

[0022] Furthermore, the salt-alkali resistance and growth-promoting Bacillus pumilus L13 obtained by the present invention is applied to the above-mentioned saline-alkali land improvement method, and the saline-alkali land improvement effect is better.

[0023] Biological deposit information

[0024] Bacillus pumilus L13, biologically classified as Bacillus pumilus, was deposited in the China General Microbiological Culture Collection (CGMCC) on September 23, 2024, with the culture collection number CGMCC No. 32044. The deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, Postal Code 100101. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0026] Figure 1 The results of screening for the salt-alkali tolerant strain L13 in Example 1;

[0027] Figure 2 The results of the plant growth promotion performance test of the salt-alkali tolerant strain L13 in Example 1;

[0028] Figure 3 is the phylogenetic tree of Bacillus pumilus L13 in Example 1;

[0029] Figure 4 The colony diagram of Bacillus pumilus L13 in Example 1;

[0030] Figure 5The effects of biochar, humified agricultural and animal husbandry waste materials and Bacillus pumilus on corn phenotype, plant height and biomass in Example 2;

[0031] Figure 6 The effects of biochar, humified agricultural and animal husbandry waste materials and Bacillus pumilus on the geochemical properties of saline-alkali land in Example 2;

[0032] Figure 7 This is the effect of biochar, humified agricultural and animal husbandry waste and Bacillus pumilus on the nutrient components of saline-alkali land in Example 2. DETAILED DESCRIPTION

[0033] The present invention provides a method for improving saline-alkali land, comprising the following steps:

[0034] mixing biochar, humified agricultural and animal husbandry waste and saline-alkali soil to obtain mixed saline-alkali soil;

[0035] Salt-alkali tolerant microorganisms are applied to the mixed saline-alkali soil for mixed cultivation to obtain improved saline-alkali land.

[0036] As an embodiment, the present invention prepares biochar. As an embodiment, the biochar may be crop straw biochar; the preparation step of the crop straw biochar comprises: calcining the crop straw at 450-500°C for 1.5-2h to obtain the crop straw biochar. As an embodiment, the calcination temperature is 500°C and the time is 2h. As an embodiment, the calcination is carried out in a muffle furnace. As an embodiment, the crop straw includes but is not limited to corn straw.

[0037] As an embodiment, the present invention prepares humified agricultural and animal husbandry waste; the preparation step of the humified agricultural and animal husbandry waste includes: mixing animal manure, crop straw and mature strains and then composting until mature to obtain the humified agricultural and animal husbandry waste. As an embodiment, the dry matter (water content is 0%, the water content of the following dry matter is the same) mass ratio of the animal manure and the crop straw is 1:1-2; as another embodiment, the dry matter mass ratio of the animal manure and the crop straw is 1:2. As an embodiment, the animal manure includes but is not limited to sheep manure. As an embodiment, the inoculation amount of the bacterial solution of the mature strain is 15% to 20% of the total dry matter of the animal manure and the crop straw; as another embodiment, the volume of the bacterial solution of the mature strain is 20% (v / m=mL / g) of the total dry matter of the animal manure and the crop straw. As one embodiment, the mature strains are Acetobacter and Pichia pastoris, and the volume ratio of Acetobacter to Pichia pastoris is 1-2:1-2; as another embodiment, the volume ratio of Acetobacter to Pichia pastoris is 1:1, and the effective live bacterial concentrations of Acetobacter and Pichia pastoris are (0.5-1)×10 8 CFU / mL; As another embodiment, the effective viable bacterial concentrations of Acetobacter and Pichia pastoris are both 10 8 CFU / mL. As an embodiment, the Acetobacter of the present invention may be Acetobacter aceti; the Pichia pastoris may be Pichia membranacea. The advantage of using Acetobacter and Pichia pastoris as the mature strains of the present invention is that both have the ability to efficiently degrade organic matter, and the coordinated treatment of the two can also adjust the pH of the pile and increase the microbial diversity in the pile. As an embodiment, the composting time of the present invention is 45 to 60 days; as another embodiment, the composting time is 50 days. As an embodiment, the initial moisture content of the composting is 60% to 70%; as another embodiment, the initial moisture content of the composting is 65%. As an embodiment, the humified agricultural and animal husbandry waste of the present invention has the advantages of high organic matter content, high effective nutrient content and rich in a variety of beneficial microorganisms.

[0038] After obtaining the biochar and humified agricultural and animal husbandry waste, the present invention mixes the biochar, humified agricultural and animal husbandry waste and saline-alkali soil to obtain mixed saline-alkali soil. As an embodiment, the amount of the biochar used is 1.44 to 2.40 tons per mu of saline-alkali land; as another embodiment, the amount of the biochar used is 1.92 tons per mu of saline-alkali land. As an embodiment, the amount of the humified agricultural and animal husbandry waste used is 7.67 to 11.51 tons per mu of saline-alkali land; as another embodiment, the amount of the humified agricultural and animal husbandry waste used is 9.59 tons per mu of saline-alkali land. As an embodiment, the pH value of the saline-alkali soil is 8.5 to 9.5; the salt content is 5 to 7 g / kg.

[0039] After obtaining the mixed saline-alkali soil, the present invention applies salt-alkali tolerant microorganisms to the mixed saline-alkali soil for mixed culture to obtain improved saline-alkali land. As an embodiment, the salt-alkali tolerant microorganisms are sprayed into the mixed saline-alkali soil in the form of salt-alkali tolerant microorganism liquid. As an embodiment, the amount of the salt-alkali tolerant microorganisms used is calculated in terms of salt-alkali tolerant microorganism liquid, and the mass ratio of the volume of the salt-alkali tolerant microorganism liquid to the saline-alkali soil is 1-2 mL: 10-20 g; as another embodiment, the mass ratio of the volume of the salt-alkali tolerant microorganism liquid to the saline-alkali soil is 1 mL: 10 g. As an embodiment, the effective concentration of the salt-alkali tolerant microorganism liquid is 1×10 8 CFU / mL. As an embodiment, the salt-alkali tolerant microorganism may be Bacillus pumilus; as another embodiment, the Bacillus pumilus is Bacillus pumilus L13, and the deposit number of the Bacillus pumilus L13 is CGMCC No.32044. As an embodiment, the mixed culture time may be 15 to 20 days. The Bacillus pumilus L13 described in the present invention is a strain isolated from severely saline-alkali soil, has good salt-alkali resistance, and can be used for the improvement of saline-alkali land.

[0040] The present invention uses biochar, humified agricultural and animal husbandry waste and salt-alkali tolerant microorganisms to synergistically improve saline-alkali soil. The biochar, humified agricultural and animal husbandry waste and salt-alkali tolerant microorganisms synergistically optimize the soil physical structure (reduce soil bulk density, increase soil water holding capacity and total porosity) and improve soil fertility (increase the content of effective nutrients such as alkaline hydrolyzable nitrogen and effective phosphorus), and have an excellent improvement effect on saline-alkali soil.

[0041] The present invention also provides an application of the saline-alkali land improvement method described in the above technical solution in promoting crop growth. After the saline-alkali land is improved by the saline-alkali land improvement method described in the above technical solution of the present invention, crops are planted on the improved saline-alkali land to promote the growth of crops.

[0042] The invention provides a strain of Bacillus pumilus L13, and the deposit number of the Bacillus pumilus L13 is CGMCC No.32044.

[0043] The present invention also provides the use of the Bacillus pumilus L13 described in the above technical solution in soil improvement and / or promoting plant growth. As an embodiment, the soil improvement is saline-alkali land improvement.

[0044] In order to further illustrate the present invention, the technical solution provided by the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0045] Example 1

[0046] Screening and identification of salt-alkali tolerant microorganisms

[0047] 1. Mix 5g of heavy saline-alkali soil collected from Bayannur City, Inner Mongolia with 45mL of physiological saline and put it into a 100mL conical flask. Oscillate at 180rpm for 30min at 28℃. After standing for 5min, take the supernatant. Dilute the supernatant gradually according to the concentration gradient. Take 10 -1 , 10 -2 , 10 -3 and 10 -4 100 μL of the diluent was spread on beef extract peptone solid medium and cultured at 28° C. for 48 h. Strains with different morphologies were selected and purified multiple times until a monoclonal strain was obtained.

[0048] When identifying the salt-alkali tolerance of the strain, beef extract peptone solid culture medium with NaCl mass concentrations of 2%, 8% and 14% and pH values ​​of 8, 9, 10, 11 and 12 was prepared respectively, the monoclonal strain was inoculated on the beef extract peptone solid culture medium, and cultured at 28°C for 48h. The naturally grown strain was used as a control, and a highly salt-alkali tolerant strain that could grow in an environment of 8% salt concentration and pH 11 was screened out and named L13. Figure 1 L13 was made into bacterial liquid for plant growth promotion experiment.

[0049] 2. Preparation of bacterial solution: beef extract peptone liquid medium was used for propagation at 28°C. After 48 hours of propagation, the bacteria were collected by centrifugation and the concentration of the bacterial solution was adjusted to 1×10 8 CFU / mL, and the bacterial solution was prepared.

[0050] Plant growth promotion test: Two-week-old corn plants were transplanted into pots (mouth diameter 12.7 × bottom diameter 9 × pot height 11 cm) filled with 500 g of saline-alkali soil (salt content 6.37 g / kg, pH 9.05). The strain L13 was prepared into bacterial solution according to the above "Bacterial solution preparation" steps, and the treatment groups were named: CK blank group and L9 group. The L9 treatment group was sprayed with 30 mL of bacterial solution (10 8 CFU / mL), and the CK blank group was added with the same amount of water at the same time.

[0051] CK group: salinized soil, without any addition;

[0052] L13 group: salinized soil, only the bacterial solution prepared by L13 strain was added;

[0053] The above test was used to study the growth promotion of corn using L9. After 30 days, the effect of L13 on corn growth promotion was as follows: Figure 2 shown.

[0054] Depend on Figure 2 It can be concluded that in the same saline-alkali soil, compared with the CK group, the growth of corn in the L9 group was relatively good, that is, it had a certain growth-promoting effect. The L13 strain was identified by whole genome sequencing (WGS).

[0055] 3. The L13 strain was sequenced and identified by whole genome sequencing, and the obtained sequencing data was compared in the NCBI database. The phylogenetic tree results are as follows: Figure 3 At the same time, the colony growth diagram of L13 strain grown in beef extract peptone solid medium for 48 hours is shown in Figure 4 shown.

[0056] Depend on Figure 3 It can be concluded that the bootstrap value of the branch node between the L13 strain and Bacillus pumilus NDY-10 in the phylogenetic tree is 68, indicating that the two have a high degree of similarity (a bootstrap value greater than 50 is considered credible in microorganisms). It can be seen that the L13 strain and Bacillus pumilus NDY-10 sequences are highly homologous. At the same time, through comparison, it was found that the 16S rRNA hypervariable region gene sequence similarity is 100%. Figure 4 The colony diagram of the middle colony with milky white color, relatively smooth surface and branched bacterial body characteristics shows that the strain L13 with growth-promoting ability was identified as Bacillus pumilus by WGS identification and phenotype identification. The strain was named Bacillus pumilus L13 and preserved in China General Microbiological Culture Collection Center (CGMCC), with strain collection number: CGMCC No. 32044;

[0057]

[0058] Example 2

[0059] A method for improving saline-alkali land, comprising the following steps:

[0060] 1. Preparation of biochar

[0061] The air-dried corn stalks were cut into pieces of about 2 cm and placed in a muffle furnace for pyrolysis at 500 °C for 2 h. The prepared biochar was then ground and passed through a 100-mesh sieve to obtain corn stalk biochar.

[0062] 2. Preparation of humified agricultural and animal husbandry waste

[0063] Sheep manure, crop straw, Acetobacter aceti (effective concentration 10 8 CFU / mL, purchased from China General Microbial Culture Collection Center, strain name is Acetobacter aceti) and Pichia pastoris (effective concentration 10 8 CFU / mL, purchased from China General Microbial Culture Collection Center (CGMCC), the strain name is Pichia membranifuciens) after mixing, adjusting the initial moisture content of the composting system to 65%, composting for 50 days, and obtaining humified agricultural and animal husbandry waste materials after complete decomposition;

[0064] The inoculation volume ratio of Acetobacter aceti and Pichia pastoris was 1:1, and the inoculation volume of the bacterial solution of the two bacteria was 20% (mL / g) of the total dry matter of the mixture of sheep manure and crop straw.

[0065] 3. Improve the salinized soil in Hetao, Inner Mongolia, and set up five treatments: CK blank group, SB group, SBM group, SH group and SHBM group to determine the improvement effect of each experimental group on salinized soil; the salt content of salinized soil is 6.37g / kg, and the pH value is 9.05. In the following treatment groups, the biochar is the biochar prepared in step 1; the humified agricultural and animal husbandry waste is prepared in step 2; the Bacillus pumilus liquid is the Bacillus pumilus L13 liquid, and the effective concentration is 10 8 CFU / mL. The percentage of each substance is calculated relative to salinized soil.

[0066] CK group: salinized soil, without any addition;

[0067] SB group: salinized soil, only 2% biochar was added (w / w);

[0068] SBM group: saline-alkali soil, added with 2% biochar (w / w) and 10% Bacillus pumilus L13 solution (v / m = mL / g, concentration of 10 8 CFU / mL);

[0069] SH group: saline-alkali soil, only 10% humified agricultural and animal husbandry waste was added (w / w);

[0070] SHBM group: salinized soil, added with 2% biochar (w / w), 10% humified agricultural and animal husbandry waste (w / w), and 10% Bacillus pumilus L13 bacterial solution (v / m = mL / g);

[0071] The above five groups of experiments were used to improve the saline-alkali land in Hetao, Inner Mongolia. Specifically, biochar, humified agricultural and animal husbandry waste were evenly mixed with saline-alkali soil, and then Bacillus pumilus L13 solution was sprayed. After mixed cultivation for 15 days, corn was planted.

[0072] The phenotype of corn seedlings was observed from the time of germination to the 20th day of growth. After the 20th day of cultivation, the height of the aboveground and underground parts of the corn seedlings, as well as the biomass of the plants, such as fresh weight and dry weight, were measured at the same time. Figure 5 As shown, Figure 5 Different letters in B and C indicate significant differences (P < 0.05).

[0073] in accordance with Figure 5 The CK group, SH group and SHBM group with large phenotypic differences and strong representativeness were selected to measure soil physical and chemical indicators (physical structure and chemical properties).

[0074] 4. Determination of soil physical and chemical indicators:

[0075] A portion of fresh soil samples was reserved for ammonium nitrogen (NH4 + -N) and nitrate nitrogen (NO 3- -N) content was determined, and the remaining soil samples were air-dried; a portion of the air-dried soil samples were ground and passed through a 100-mesh sieve, and the sieved samples were retained. Soil bulk density, soil mass water content, maximum water holding capacity (MWHC), capillary water holding capacity, minimum water holding capacity (WHC), non-capillary pores, capillary pores, and total pores were determined by the ring knife method; ammonium nitrogen (NH4 + -N) and nitrate nitrogen (NO3 --N); the pH value and conductivity of the soil were determined by a pH meter (FE28, Mettler-Toledo, Switzerland) and an electrical conductivity (EC) meter (DDS-307, Shanghai, China) at a soil: water = 1:5 (w / v); the total salt content was determined by the gravimetric method; the organic matter content was determined by the potassium dichromate oxidation method; the total nitrogen (TN) was determined by the Kjeldahl method; the total phosphorus (TP), total potassium (TK) and available potassium (AK) were determined by inductively coupled plasma mass spectrometry (AVIO 200, PerkinElmer, USA); the available phosphorus (AP) was determined by sodium bicarbonate extraction-molybdenum antimony anti-spectrophotometry; the alkaline nitrogen was determined by the alkali diffusion method. The experimental results are shown in Figures 6-7 As shown, in Figures 6-7 "*", "**" and "***" indicate significant differences (P < 0.05), P < 0.01 and P < 0.001, respectively; ns indicates no significant difference.

[0076] Depend on Figure 6 It can be concluded that compared with the CK treatment group, the soil bulk density of the SH and SHBM treatment groups decreased by 6.73% and 11.85%, respectively, while the mass water content (6.53%, 14.15%), MWHC (8.82%, 14.43%), capillary water holding capacity (9.23%, 14.78%) and WHC (6.53%, 14.15%) of the two groups increased significantly. It is worth noting that the results of the combined SHBM treatment greatly exceeded the results obtained by adding a single humified agricultural and animal husbandry waste. In addition, the SHBM treatment also significantly increased the soil capillary pores and total pores by 5.42% and 5.11%, respectively. The synergistic benefits of biochar, humified agricultural and animal husbandry waste and strain L13 in soil improvement are highlighted. Compared with the soil after CK treatment, the pH value of the soil treated with SH and SHBM was significantly reduced. Soil organic matter is an important indicator of soil quality and agricultural sustainability. The organic matter of the SH and SHBM groups increased by 0.63 and 2.04 times compared with the CK group, respectively. The SHBM group significantly increased the soil organic matter to 30.40 g / kg, which was 0.87 times that of the SH group. The EC and total salt of the soils improved by SH and SHBM were not significantly different from those of the CK soil. Obviously, the significant growth of maize after the combined application of biochar, humified agricultural and animal husbandry waste, and strain L13 indicated that it may not have a particularly obvious advantage in improving soil salinity, but it is superior in reducing soil pH and increasing soil organic matter.

[0077] Depend on Figure 7 It can be concluded that compared with the CK group and the SH group, the alkaline nitrogen content of the SHBM group increased by 3.32 times and 1.07 times, respectively, and NO 3- -N content increased by 5.39 times and 4.82 times, NH4 +-N content did not differ significantly between all treatments. In addition, TN in the SHBM-treated soil was also significantly increased by 0.66 and 0.15 times compared with the CK and SH treatments. AP and AK in the SHBM group were 1.35 and 0.48 times higher than those in the CK group, and 0.20 and 0.14 times higher than those in the SH group, respectively. Meanwhile, TP and TK in the SHBM group were 0.31 and 0.43 times lower than those in the CK group, and 0.29 and 0.35 times lower than those in the SH group. This result suggests that TP and TK were more efficiently converted into AP and AK due to the synergistic effects of biochar, humified agro-pastoral waste, and strain L13 in the soil. Apparently, AN, AP, and AK can be directly absorbed by plants, and biochar, humified agro-pastoral waste, and strain L13 synergistically accelerated the nutrient decomposition rate, which was reflected in the highest growth of corn in the SHBM group.

[0078] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for improving saline-alkali land, characterized in that: The steps include: mixing biochar, humified agricultural and animal husbandry waste and saline-alkali soil to obtain mixed saline-alkali soil; Salt-alkali tolerant microorganisms are applied to the mixed saline-alkali soil for mixed cultivation to obtain improved saline-alkali land.

2. The method for improving saline-alkali land according to claim 1, characterized in that: The amount of biochar used is 1.44-2.40 tons per mu of saline-alkali land; the amount of humified agricultural and animal husbandry waste used is 7.67-11.51 tons per mu of saline-alkali land; the amount of salt-alkali tolerant microorganisms used is calculated in terms of salt-alkali tolerant microbial liquid, the mass ratio of the volume of the salt-alkali tolerant microbial liquid to the saline-alkali soil is 1-2 mL: 10-20 g, and the effective concentration of the salt-alkali tolerant microbial liquid is 1×10 8 CFU / mL.

3. The method for improving saline-alkali land according to claim 1 or 2, characterized in that: The biochar includes crop straw biochar; the preparation step of the crop straw biochar includes: calcining the crop straw at 450-500° C. for 1.5-2 hours to obtain the crop straw biochar.

4. The method for improving saline-alkali land according to claim 1 or 2, characterized in that: The preparation steps of the humified agricultural and animal husbandry waste include: mixing animal feces, crop straw and mature bacterial strains and then composting them until they are mature, thereby obtaining the humified agricultural and animal husbandry waste; The mature strains include Acetobacter and Pichia pastoris, the volume ratio of Acetobacter to Pichia pastoris is 1-2:1-2, and the effective live bacteria concentrations of Acetobacter and Pichia pastoris are both (0.5-1)×10 8 CFU / mL; the inoculation amount of the bacterial solution of the mature strain is 15% to 20% v / m of the total dry matter of the animal feces and crop straw; The dry matter mass ratio of the animal excrement to the crop straw is 1:1-2.

5. The method for improving saline-alkali land according to claim 1, characterized in that: The mixed culture time is 15 to 20 days.

6. The method for improving saline-alkali land according to claim 1 or 2, characterized in that: The salt-alkali tolerant microorganisms include Bacillus pumilus.

7. The method for improving saline-alkali land according to claim 6, characterized in that: The Bacillus pumilus includes Bacillus pumilus L13, and the deposit number of the Bacillus pumilus L13 is CGMCC No.32044.

8. Use of the saline-alkali land improvement method according to any one of claims 1 to 7 in promoting crop growth.

9. A strain of Bacillus pumilus L13, the deposit number of which is CGMCC No.32044.

10. Use of the Bacillus pumilus L13 according to claim 9 in soil improvement and / or plant growth promotion.

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