Stress-resistant growth-promoting bio-organic fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a stress-resistant growth-promoting bio-organic fertilizer as well as a preparation method and application thereof, and belongs to the technical field of bio-organic fertilizers. The bio-organic fertilizer is prepared from a microbial agent, potassium fulvate, wheat straw, organic acid, mushroom residues, dry sheep manure, corncob, urea, fly ash, a synergist and a hawthorn extract. According to the bio-organic fertilizer disclosed by the invention, various substances synergistically play a role through the hawthorn extract, the compound microbial agent, the synergist and other components, so that the salinity and alkalinity of soil are effectively reduced, the soil fertility is remarkably improved, meanwhile, the stress resistance of corn plants is improved, the growth of the corn plants is promoted, the corn yield is increased, and the planting benefits are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological organic fertilizers, and particularly relates to a stress-resistant and growth-promoting biological organic fertilizer, a preparation method thereof, and an application thereof. Background Art

[0002] Saline-alkali land is an important reserve land resource in China, characterized by a large area and wide distribution. Coastal saline-alkali land has a high soil pH and salt content, small soil porosity, poor soil structure, poor water-holding capacity, affects the transformation of organic matter, reduces soil fertility, limits the absorption of nutrients by plants, causes waste of agricultural resources, and results in serious economic losses and secondary hazards.

[0003] Biological organic fertilizer is a fertilizer that combines the effects of traditional organic fertilizers and microbial fertilizers, and contains a large amount of organic matter and beneficial soil bacteria. After deep loosening of the cultivated land and applying biological organic fertilizer into the soil, a large amount of organic acids can be produced under the influence of soil microorganisms and soil enzyme activities, which can reduce the soil pH value; a large number of metabolites are produced during the growth and reproduction of beneficial bacteria, promoting the decomposition and transformation of organic matter, and can directly or indirectly provide various nutrients and stimulatory substances for crops, promoting and regulating crop growth; increasing soil organic matter not only changes the physical and chemical properties of the soil, but also improves the soil's water-holding, fertilizer-holding, and fertilizer-supplying capabilities. Soil conditioner is a product mainly made of natural minerals and processed by high-temperature calcination and extraction, with functions such as improving soil, water retention and drought resistance, enhancing the disease resistance of crops, increasing crop yields, improving the quality of agricultural products, and restoring the original ecology of crops. Biological organic fertilizers can improve the physical and chemical properties of the soil, but most studies focus on the improvement effects of single types of organic materials on saline-alkali land. Currently, there is a lack of research on the growth of crops and the physical and chemical properties of the soil after applying biological organic fertilizers to coastal saline-alkali land. Summary of the Invention

[0004] The purpose of the present invention is to provide a stress-resistant and growth-promoting biological organic fertilizer, which can effectively reduce the salinity of the soil, significantly improve soil fertility, while enhancing the stress resistance of crops, promoting crop growth, increasing crop yields, and improving the planting efficiency of crops.

[0005] To achieve the above technical objectives, the technical solution adopted by the present invention is as follows: A stress-resistant and growth-promoting biological organic fertilizer is prepared from the following raw materials in parts by weight: 12 - 18 parts of microbial inoculum, 10 - 15 parts of potassium fulvate, 75 - 90 parts of wheat straw, 5 - 10 parts of organic acid, 45 - 55 parts of mushroom residue, 28 - 36 parts of dry sheep manure, 16 - 22 parts of corn cob, 0.5 - 1 part of urea, 3 - 5 parts of fly ash, 8 - 10 parts of synergist, and 5 - 8 parts of hawthorn extract.

[0006] Further, the microbial inoculant is Sinorhizobium canariense, Bacillus megaterium, and Pseudomonas chengduensis with a mass ratio of 1:1:1.

[0007] Furthermore, the Sinorhizobium canariense was purchased from the China General Microbiological Culture Collection Center, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The preservation number is CGMCC No. 1.15558, and the original preservation date is December 30, 2015; the Bacillus megaterium was purchased from the China General Microbiological Culture Collection Center, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The preservation number is CGMCC No. 1.10466, and the original preservation date is March 18, 2010; the Pseudomonas chengduensis was purchased from the China General Microbiological Culture Collection Center, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The preservation number is CGMCC No. 1.15626, and the original preservation date is February 25, 2015.

[0008] Further, the organic acid is citric acid and malic acid with a mass ratio of 1:1.

[0009] Further, the organic acid is diluted 5 times before use.

[0010] Further, the synergist includes 5 parts of potassium nitrate, 2 parts of catechin, and 3 parts of alginic acid.

[0011] A preparation method of a stress-resistant and growth-promoting biological organic fertilizer includes the following preparation steps: (1) Preparation of microbial inoculant: After activating Sinorhizobium canariense, Pseudomonas chengduensis, and Bacillus megaterium, they were respectively inoculated into LB liquid medium and cultured at 28°C, 30°C, and 30°C until OD 600 = 0.6 to obtain seed liquid. The seed liquid of Sinorhizobium canariense was inoculated into the nitrogen-fixing medium at a rate of 1%, and Pseudomonas chengduensis and Bacillus megaterium were respectively inoculated into LB liquid medium at a rate of 1%. They were cultured in the medium until the viable count reached 1×10 9 cfu·mL -1 Three kinds of bacterial liquids were obtained, and then the three kinds of bacterial liquids were mixed evenly according to the mass ratio of 1:1:1 and freeze-dried into freeze-dried powder to obtain the microbial inoculant; (2) Fermentation and composting: The mushroom residue, corn cob, and dry sheep manure were crushed and passed through a 50-mesh sieve, then mixed evenly, put into the fermentation tank and water was added. After mixing evenly, the water content was controlled between 50% - 60%. Then urea was put into the fermentation tank and stirred evenly. The fermentation tank was sealed with a plastic film, and the pile was turned over once every 7 days during the fermentation process. After 3 times of turning over, the fermentation was completed to obtain the fermented organic matter; (3) Preparation of compound biochar: The wheat straw is dried and crushed to 2 cm, then added to a reaction kettle and carbonized anaerobically at 300 - 500 °C for 2 h. After carbonization is completed, it is cooled to room temperature, crushed and passed through an 80-mesh sieve, and a synergist is added and mixed evenly to obtain a compound biochar; (4) Pelletizing: The microbial inoculant prepared in step (1) is mixed evenly with the biochar prepared in step (3), and the mixture is added to the fermented organic matter prepared in step (2). Then, potassium humate, organic acid, fly ash and hawthorn extract are added in sequence, stirred and mixed evenly, dried until the water content ≤ 15%, pelletized by a granulator, and the pellets with a particle size of 3 - 5 mm are screened out to obtain the stress-resistant and growth-promoting bio-organic fertilizer.

[0012] The present invention also provides the application of the stress-resistant and growth-promoting bio-organic fertilizer in promoting the stress resistance and growth of corn in saline-alkali soil.

[0013] In the microbial inoculant, there are Bradyrhizobium canariense, Pseudomonas chengduensis and Bacillus megaterium. Bradyrhizobium canariense can improve the soil nitrogen supply through nitrogen fixation, and at the same time synthesize various osmotic adjustment substances such as proline to help plants cope with salt stress; Bacillus megaterium has strong salt tolerance and phosphorus-solubilizing effect, can improve the physical and chemical properties of the soil and promote plant growth; Pseudomonas chengduensis can improve the soil nutrient status, dissolve nutrients such as phosphorus and nitrogen in the soil to provide sufficient nutrients for plants, can improve the tolerance of plants to various abiotic stresses, and in addition, can produce plant hormones such as indoleacetic acid, which has an important role in the root development and overall growth of plants. The three functional strains work together synergistically to significantly improve the soil quality, increase the soil fertility, enhance the stress resistance of plants and promote plant growth.

[0014] In the organic fertilizer of the present invention, an organic acid is added. The organic acid can reduce the pH value of the soil, improve the soil acidity and alkalinity, making it more suitable for crop growth. In addition, the organic acid can react with minerals in the soil to release required nutrients such as phosphorus and potassium, increasing the soil fertility; the organic acid can also be directly absorbed and utilized by crops as a carbon source to promote crop photosynthesis and material accumulation. At the same time, the organic acid can stimulate the growth of crop roots, increase the absorption capacity of roots for water and nutrients, and promote crop growth and development.

[0015] Wheat straw biochar can significantly improve the physical properties of soil, such as enhancing the water and fertilizer retention capacity and air permeability of the soil, while reducing the bulk density and density of the soil, thereby providing a more suitable growth environment for plants. Adding synergists to biochar, the potassium ions in potassium nitrate can improve the osmotic adjustment ability of plants, reduce the damage of salts to plants, and can also increase the photosynthesis efficiency and stomatal conductance of plants, thereby enhancing the absorption of water and mineral nutrients by plants. Catechins can increase the antioxidant enzyme activity of plants, thereby reducing the damage of salt stress to plants. Alginate can reduce the surface tension of water, making nutrients more easily absorbed by plants, and can promote root development, increase photosynthesis efficiency. At the same time, as a polysaccharide extracted from seaweed, it provides energy for microorganisms and ensures the high viability of microorganisms.

[0016] Hawthorn extract is rich in a variety of beneficial components, mainly including organic acids, flavonoids, vitamins and trace elements, which also have a promoting effect on plant growth and development. Hawthorn extract can regulate the levels of plant hormones, promote cell division and elongation, and enhance the growth rate of plants. The phenolic compounds in hawthorn extract have significant antioxidant, anti-inflammatory and stress resistance activities. These components can help plants resist environmental stresses, such as adverse conditions like salinity. In addition, the flavonoids in hawthorn extract can enhance the antioxidant capacity of plants, reduce the damage of oxidative stress to plant cells, thereby improving the stress resistance of plants and facilitating the maintenance of normal physiological activities of plants in adverse environments.

[0017] Beneficial effects The biological organic fertilizer of the present invention, through the synergistic action of hawthorn extract, compound microbial inoculant, synergist and other components, effectively reduces the salinity and alkalinity of the soil, significantly improves soil fertility, while enhancing the stress resistance of crops, promoting crop growth, increasing crop yield, and improving planting benefits. Specific implementation manners

[0018] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but are not limited thereto.

[0019] Example 1 An anti-stress and growth-promoting biological organic fertilizer is prepared from the following raw materials in parts by weight: 12 parts of microbial inoculant, 10 parts of fulvic acid potassium, 75 parts of wheat straw, 5 parts of organic acid, 45 parts of mushroom residue, 28 parts of dry sheep manure, 16 parts of corn cob, 0.5 part of urea, 3 parts of fly ash, 8 parts of synergist, and 5 parts of hawthorn extract.

[0020] The microbial inoculant is Canariensis Bradyrhizobium, Bacillus megaterium, and Pseudomonas chengduensis with a mass ratio of 1:1:1.

[0021] The strain number of the described Bradyrhizobium canariense is CGMCC No. 1.15558; the strain number of the described Bacillus megaterium is CGMCC No. 1.10466; the strain number of the described Pseudomonas chengduensis is CGMCC No. 1.15626.

[0022] The organic acid is citric acid and malic acid with a mass ratio of 1:1.

[0023] The organic acid is diluted 5 times before use.

[0024] The synergist includes 5 parts of potassium nitrate, 2 parts of catechin, and 3 parts of alginic acid.

[0025] A preparation method of an anti-stress and growth-promoting biological organic fertilizer includes the following preparation steps: (1) Preparation of microbial inoculum: After activating Bradyrhizobium canariense, Pseudomonas chengduensis, and Bacillus megaterium, they are respectively inoculated into LB liquid medium and cultured at 28 °C, 30 °C, and 30 °C until OD 600 = 0.6 to obtain seed liquid. The seed liquid of Bradyrhizobium canariense is inoculated into the nitrogen-fixing medium at a ratio of 1%, and Pseudomonas chengduensis and Bacillus megaterium are respectively inoculated into LB liquid medium at a ratio of 1%. They are cultured in the medium until the viable count reaches 1×10 9 cfu·mL -1 Three kinds of bacterial liquids are obtained, and then the three kinds of bacterial liquids are mixed evenly according to the mass ratio of 1:1:1 and freeze-dried into freeze-dried powder to obtain the microbial inoculum; (2) Fermentation and composting: The mushroom residue, corn cob, and dry sheep manure are crushed and passed through a 50-mesh sieve and then mixed evenly. After adding water into the fermentation tank and mixing evenly, the water content is controlled between 50% - 60%. Then urea is put into the fermentation tank and stirred evenly. The fermentation tank is sealed with a plastic film, and the fermentation tank is turned over once every 7 days during the fermentation process. After 3 times of turning over, the fermentation is completed to obtain the fermented organic matter; (3) Preparation of compound biochar: The wheat straw is dried and crushed to 2 cm, added to the reaction kettle, and carbonized anaerobically at 300 - 500 °C for 2 h. After carbonization is completed, it is cooled to room temperature, crushed and passed through an 80-mesh sieve, and the synergist is added and mixed evenly to obtain the compound biochar; (4) Granulation: The microbial inoculum prepared in step (1) is mixed evenly with the biochar prepared in step (3), added to the fermented organic matter prepared in step (2), and then potassium fulvate, organic acid, fly ash, and hawthorn extract are added in sequence, stirred and mixed evenly, dried until the water content ≤ 15%, granulated by a granulator, and the particles with a particle size of 3 - 5 mm are screened out to obtain the anti-stress and growth-promoting biological organic fertilizer.

[0026] Example 2 An anti-stress and growth-promoting biological organic fertilizer is prepared from the following raw materials in parts by weight: 15 parts of microbial inoculum, 12 parts of potassium humate, 82 parts of wheat straw, 7 parts of organic acid, 50 parts of mushroom residue, 32 parts of dried sheep manure, 18 parts of corn cob, 0.8 part of urea, 4 parts of fly ash, 9 parts of synergist, and 6 parts of hawthorn extract.

[0027] The microbial inoculum is Bradyrhizobium canariense, Bacillus megaterium, and Pseudomonas chengduensis with a mass ratio of 1:1:1.

[0028] The strain number of Bradyrhizobium canariense is CGMCC No. 1.15558; the strain number of Bacillus megaterium is CGMCC No. 1.10466; the strain number of Pseudomonas chengduensis is CGMCC No. 1.15626.

[0029] The organic acid is citric acid and malic acid with a mass ratio of 1:1.

[0030] The organic acid is diluted 5 times before use.

[0031] The synergist includes 5 parts of potassium nitrate, 2 parts of catechin, and 3 parts of alginic acid.

[0032] A preparation method of an anti-stress and growth-promoting biological organic fertilizer includes the following preparation steps: (1) Preparation of microbial inoculum: After activating Bradyrhizobium canariense, Pseudomonas chengduensis, and Bacillus megaterium, they are respectively inoculated into LB liquid medium and cultured at 28°C, 30°C, and 30°C until OD 600 = 0.6 to obtain seed liquid. The Bradyrhizobium canariense seed liquid is inoculated into nitrogen-fixing medium according to 1% amount, and Pseudomonas chengduensis and Bacillus megaterium are respectively inoculated into LB liquid medium according to 1% amount, and cultured in the medium until the viable count reaches 1×10 9 cfu·mL -1 Three kinds of bacterial liquids are obtained, and then the three kinds of bacterial liquids are mixed evenly according to the mass ratio of 1:1:1 and freeze-dried into freeze-dried powder to obtain the microbial inoculum; (2) Fermentation and composting: The mushroom residue, corn cob, and dried sheep manure are crushed, screened through a 50-mesh sieve, and then mixed evenly. After being put into the fermentation tank, water is added and mixed evenly to control the water content between 50% and 60%. Then urea is put into the fermentation tank and stirred evenly. The fermentation tank is sealed with plastic film, and the fermentation tank is turned over once every 7 days during the fermentation process. After 3 times of turning over, the fermentation is completed to obtain the fermented organic matter; (3) Preparation of compound biochar: The wheat straw is dried and crushed to 2 cm, added to a reaction kettle, and carbonized anaerobically at 300 - 500 °C for 2 h. After carbonization is completed, it is cooled to room temperature, crushed and passed through an 80-mesh sieve, and a synergist is added and mixed evenly to obtain a compound biochar; (4)Pelletizing: The microbial inoculant prepared in step (1) is mixed evenly with the biochar prepared in step (3), added to the fermented organic matter prepared in step (2), and then potassium fulvate, organic acid, fly ash, and hawthorn extract are added in sequence, stirred and mixed evenly, dried to a water content of ≤ 15%, pelletized by a granulator, and particles with a particle size of 3 - 5 mm are screened out to obtain an anti-stress and growth-promoting bio-organic fertilizer.

[0033] Example 3 An anti-stress and growth-promoting bio-organic fertilizer is prepared from the following raw materials in parts by weight: 18 parts of microbial inoculant, 15 parts of potassium fulvate, 90 parts of wheat straw, 10 parts of organic acid, 55 parts of mushroom residue, 36 parts of dry sheep manure, 22 parts of corn cob, 1 part of urea, 5 parts of fly ash, 10 parts of synergist, and 8 parts of hawthorn extract.

[0034] The microbial inoculant is Sinorhizobium canariense, Bacillus megaterium, and Pseudomonas chengduensis with a mass ratio of 1:1:1.

[0035] The strain number of Sinorhizobium canariense is CGMCC No. 1.15558; the strain number of Bacillus megaterium is CGMCC No. 1.10466; the strain number of Pseudomonas chengduensis is CGMCC No. 1.15626.

[0036] The organic acid is citric acid and malic acid with a mass ratio of 1:1.

[0037] The organic acid is diluted 5 times before use.

[0038] The synergist includes 5 parts of potassium nitrate, 2 parts of catechin, and 3 parts of alginic acid.

[0039] A preparation method of an anti-stress and growth-promoting bio-organic fertilizer includes the following preparation steps: (1)Preparing microbial inoculant: Sinorhizobium canariense, Pseudomonas chengduensis, and Bacillus megaterium are activated and then inoculated into LB liquid medium and cultured at 28 °C, 30 °C, and 30 °C until OD 600 = 0.6 to obtain seed liquid. The seed liquid of Sinorhizobium canariense is inoculated into nitrogen-fixing medium according to 1% amount, and Pseudomonas chengduensis and Bacillus megaterium are respectively inoculated into LB liquid medium according to 1% amount, and cultured in the medium until the viable count reaches 1×10 9 cfu·mL -1Three kinds of bacterial solutions are obtained, and then the three kinds of bacterial solutions are mixed evenly according to the mass ratio of 1:1:1 and freeze-dried into freeze-dried powder to obtain a microbial inoculant; (2) Fermentation and composting: The mushroom residue, corn cob, and dry sheep manure are crushed and passed through a 50-mesh sieve, then mixed evenly, put into a fermentation tank and water is added. After mixing evenly, the water content is controlled between 50% and 60%. Then urea is put into the fermentation tank and stirred evenly. The fermentation tank is sealed with a plastic film, and the pile is turned over once every 7 days during the fermentation process. After 3 times of turning over, the fermentation is completed to obtain the fermented organic matter; (3) Preparation of compound biochar: The wheat straw is dried and crushed to 2 cm, added to a reaction kettle, and carbonized anaerobically at 300 - 500 °C for 2 h. After carbonization, it is cooled to room temperature, crushed and passed through an 80-mesh sieve, and a synergist is added and mixed evenly to obtain compound biochar; (4) Pelletizing: The microbial inoculant prepared in step (1) is mixed evenly with the biochar prepared in step (3), added to the fermented organic matter prepared in step (2), and then potassium humate, organic acid, fly ash, and hawthorn extract are added in sequence, stirred and mixed evenly, dried to a water content ≤ 15%, granulated by a granulator, and particles with a particle size of 3 - 5 mm are screened out to obtain an anti-stress and growth-promoting biological organic fertilizer.

[0040] Comparative Example 1 Compared with Example 3, in this comparative example, except that the synergist is not used, the other raw materials and steps are the same as those in Example 3.

[0041] Comparative Example 2 Compared with Example 3, in this comparative example, except that catechin is not used as the synergist, the other raw materials and steps are the same as those in Example 3.

[0042] Comparative Example 3 Compared with Example 3, in this comparative example, except that alginic acid is not used as the synergist, the other raw materials and steps are the same as those in Example 3.

[0043] Comparative Example 4 Compared with Example 3, in this comparative example, except that potassium nitrate is not used as the synergist, the other raw materials and steps are the same as those in Example 3.

[0044] Comparative Example 5 Compared with Example 3, in this comparative example, except that Bradyrhizobium canariense is not used in the preparation process of the microbial inoculant, the other raw materials and steps are the same as those in Example 3.

[0045] Comparative Example 6 Compared with Example 3, in this comparative example, except that Pseudomonas chengduensis is not used in the preparation process of the microbial inoculant, the other raw materials and steps are the same as those in Example 3.

[0046] Comparative Example 7 In this comparative example, compared with Example 3, except that Bacillus megaterium was not used in the preparation process of the microbial inoculum, the other raw materials and steps were the same as those in Example 3.

[0047] Comparative Example 8 In this comparative example, compared with Example 3, except that hawthorn extract was not used, the other raw materials and steps were the same as those in Example 3.

[0048] Performance Test Field Test: A field experiment was carried out on saline-alkali land in Xiaobotou Town, Wudi County, Binzhou City, Shandong Province. The soil was brown soil, with an average soil pH of 8.5, a soil organic matter content of 7.2 g / kg, a soil bulk density of 1.54 g / cm 3 , a field water holding capacity of 16.7%, and a water-soluble salt of 3.1 g / kg.

[0049] The test was set up with a total of 12 treatment groups, each treatment group covering 2 mu. The bio-organic fertilizers prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention were applied to each test field, and 1 test field was used as a control group to apply conventional compound fertilizer (the ratio of nitrogen, phosphorus, and potassium was 32:10:5). Before sowing corn, the organic fertilizer and compound fertilizer were evenly spread on the ground surface, and then a rotary tiller was used to incorporate them into the soil layer. The rotary tillage depth was about 15 cm, and the application rates of the organic fertilizer and conventional fertilizer were 100 kg per mu. The corn variety was Huangjinliang MY73, and the corn sowing density was 4,000 plants per mu. During the corn planting period, a unified field management method was adopted. After the corn matured, 5 sample points were selected in each treatment group, and 10 ear cobs were continuously taken from each sample point to measure the plant height and stem diameter of each group of corn; an area of 10 m × 10 m was selected in each treatment group to harvest the ear cobs. After the ear cobs were dried, they were threshed, and the thousand-grain weight was measured after drying the grains and the yield was calculated. The statistical data are shown in Table 1.

[0050] Table 1 Corn Agronomic Traits and Yield

[0051] According to the data in Table 1, compared with the control group applying conventional fertilizer, the plant height and stem diameter of the corn plants applying the bio-organic fertilizers prepared in Examples 1-3 of the present invention were significantly increased, and the thousand-grain weight and yield of the corn were also significantly improved. However, for Comparative Examples 1-8 with the components of the bio-organic fertilizer changed, the plant traits and yield decreased to varying degrees, indicating that the components of the bio-organic fertilizer prepared by the present invention synergistically played a role and could effectively promote the growth of corn plants and increase the yield.

[0052] After the corn harvest, the physical and chemical properties of the soil were detected for 12 treatment groups. Soil samples from the 0-20 cm soil layer near the corn roots of each experimental group were collected. Five points were randomly selected from each experimental group for collection, and 1 kg of mixed samples were taken to measure the pH value, organic matter, bulk density, total amount of water-soluble salts, and field water holding capacity. The statistical data are shown in Table 2.

[0053] The specific detection methods are as follows: pH value: The pH meter method was used (water:soil = 5:1); Bulk density and field water holding capacity: The bulk density was measured by the core cutter method, and the field water holding capacity was calculated; Organic matter: The potassium dichromate method was used; Total amount of water-soluble salts: The conductivity of the solution after extraction was measured by a conductivity meter, and the total salt content rate of the soil was converted.

[0054] Table 2 Physical and chemical properties of the soil

[0055] It can be seen from the data in Table 2 that applying the biological organic fertilizers prepared in Examples 1-3 of the present invention can significantly reduce the pH value of the soil, reduce the bulk density of the soil, reduce the total amount of water-soluble salts, increase the soil organic matter and field water holding capacity, and significantly improve the physical and chemical properties of the soil. Compared with the original soil, after applying the biological organic fertilizers of Examples 1-3 of the present invention, the pH of the soil decreased by about 1, and the total amount of water-soluble salts also decreased significantly, indicating that using the biological organic fertilizer of the present invention can improve the salinity of the soil. In addition, the improvement of the field water holding capacity and bulk density increased the looseness of the soil, effectively improving the physical and chemical properties of the saline-alkali soil. Compared with the biological organic fertilizer applied in Example 3, after applying the biological organic fertilizers of Comparative Examples 1-8 with changed composition components, each index weakened to varying degrees. Therefore, each component of the microbial inoculant, hawthorn extract, and synergist plays an essential role in the improvement of saline-alkali land, and the effect will be weakened if any one is missing.

[0056] It should be noted that the above-mentioned embodiments are only some embodiments of the preferred ways to implement the present invention, rather than all embodiments. Obviously, based on the above-mentioned embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims

1. A stress-resistant and growth-promoting biological organic fertilizer, characterized in that, It is prepared from the following raw materials in parts by weight: 12-18 parts of microbial inoculum, 10-15 parts of potassium fulvate, 75-90 parts of wheat straw, 5-10 parts of organic acid, 45-55 parts of mushroom residue, 28-36 parts of dry sheep manure, 16-22 parts of corn cob, 0.5-1 part of urea, 3-5 parts of fly ash, 8-10 parts of synergist, and 5-8 parts of hawthorn extract.

2. The stress-resistant and growth-promoting biological organic fertilizer according to claim 1, wherein The microbial inoculum mentioned above is Sinorhizobium meliloti from the Canary Islands ( Bradyrhizobium canariense ), Bacillus megaterium ( Bacillus megaterium ), and Pseudomonas chengduensis ( Pseudomonas chengduensis ) with a mass ratio of 1:1:

1.

3. The stress-resistant and growth-promoting biological organic fertilizer according to claim 1, wherein The strain number of the Bradyrhizobium canariense is CGMCC No. 1.15558; the strain number of the Bacillus megaterium is CGMCC No. 1.10466; the strain number of the Pseudomonas chengduensis is CGMCC No. 1.15626.

4. The stress-resistant and growth-promoting biological organic fertilizer according to claim 1, characterized in that, The organic acid is citric acid and malic acid with a mass ratio of 1:

1.

5. The stress-resistant and growth-promoting biological organic fertilizer according to claim 1, wherein, The organic acid is diluted 5 times before use.

6. The stress-resistant and growth-promoting biological organic fertilizer according to claim 1, wherein The synergist includes 5 parts of potassium nitrate, 2 parts of catechin, and 3 parts of alginic acid.

7. A method for preparing the stress-resistant and growth-promoting biological organic fertilizer according to any one of claims 1-6, characterized in that, It includes the following preparation steps: (1) Prepare the microbial inoculum: After activating Ensifer canariensis, Pseudomonas chengduensis, and Bacillus megaterium, they were respectively inoculated into LB liquid medium and cultured at 28 °C, 30 °C, and 30 °C until OD6 00 = 0.6 to obtain seed solutions. The Ensifer canariensis seed solution was inoculated into the nitrogen fixation medium at a ratio of 1%, and Pseudomonas chengduensis and Bacillus megaterium were respectively inoculated into LB liquid medium at a ratio of 1%. They were cultured in the medium until the viable cell count reached 1×10 9 cfu·mL -1 Three kinds of bacterial solutions were obtained. Then, the three kinds of bacterial solutions were mixed evenly according to the mass ratio of 1:1:1 and freeze-dried into freeze-dried powder to obtain a microbial inoculant; (2) Ferment and decompose: Crush the mushroom residue, corn cob, and dry sheep manure through a 50-mesh sieve, mix them evenly, add water after putting them into the fermentation tank, mix evenly to control the water content between 50%-60%, then put urea into the fermentation tank and stir evenly, seal the fermentation tank with a plastic film, turn the pile once every 7 days during the fermentation process, and complete the fermentation after 3 times of turning the pile to obtain the fermented organic matter; (3) Prepare the compound biochar: Dry the wheat straw and crush it to 2 cm, add it to the reaction kettle, carry out anaerobic carbonization at 300-500 °C for 2 h, cool to room temperature after carbonization is completed, crush it through an 80-mesh sieve, add the synergist, and mix evenly to obtain the compound biochar; (4) Granulate: Mix the microbial inoculum prepared in step (1) with the biochar prepared in step (3) evenly, add it to the fermented organic matter prepared in step (2), then add potassium fulvate, organic acid, fly ash, and hawthorn extract in sequence, stir and mix evenly, dry to a water content of ≤15%, granulate with a granulator, and screen out particles with a particle size of 3-5 mm to obtain the stress-resistant and growth-promoting biological organic fertilizer.

8. Application of the stress-resistant and growth-promoting biological organic fertilizer according to any one of claims 1-6 in promoting stress resistance and growth of corn in saline-alkali land.

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