Special compound fertilizer for grain crops and preparation method and application thereof

Abstract

The application discloses a kind of special compound fertilizer of grain crops and its preparation method and application, belong to organic and microbial fertilizer technical field.The compound fertilizer includes base fertilizer and organic biological fertilizer source, wherein base fertilizer is composed of sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate and oyster shell powder;Organic biological fertilizer source is composed of vinasse fermentation, microbial active protective agent and lignin sulfonate.The vinasse fermentation is obtained by using the three-stage solid-state fermentation of vinasse with the composite bacteria suspension of halophilic bacillus and ocean sedimentous bacillus.The present application realizes the synergistic effect of nutrient efficient release, soil improvement and crop stress resistance improvement by functional strain synergistic fermentation, microbial active protective agent compounding and the introduction of slow-release nitrogen source and stress resistance components.The compound fertilizer is suitable for wheat, rice and other grain crops, can significantly improve root activity, yield and stress resistance, and has wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of organic and microbial fertilizer technology, specifically relating to a compound fertilizer for grain crops and its preparation method. Background Technology

[0002] Chemical fertilizers have played an irreplaceable role in the steady increase in grain yields. However, it should also be noted that the continuous increase in grain yield per unit area has been accompanied by a year-on-year increase in the amount of chemical fertilizers used. Environmental problems such as water pollution and eutrophication caused by excessive use of chemical fertilizers are gradually becoming prominent, posing a significant challenge to the sustainable development of agriculture.

[0003] At the same time, long-term use of chemical fertilizers alone has led to soil degradation problems such as soil compaction, decreased organic matter content, and imbalance of microbial communities, which seriously affect crop root development and nutrient absorption.

[0004] While simple bio-organic fertilizers can improve soil structure and enhance microbial activity, their nutrient release is slow and the total amount is limited, making it difficult to meet the high-efficiency nutrient supply requirements of grain crops for high yields. In particular, nutrient supply lag is likely to occur during critical growth periods.

[0005] Compound fertilizer is a type of chemical fertilizer containing two or more of the following nutrients: nitrogen, phosphorus, and potassium. It has advantages such as high nutrient content, few by-products, and good physical properties. Its main raw materials include ammonium sulfate, ammonium nitrate, ammonium carbonate, ammonium chloride, urea, potassium sulfate, potassium chloride, and ammonium phosphate. The nutrients are in granular form, which facilitates storage and application, making it particularly suitable for mechanized fertilization.

[0006] The main functions of compound fertilizers include balanced fertilization, improved fertilizer utilization, and promotion of high and stable crop yields. Value-added compound fertilizers, on the other hand, are made by adding humic acid, biological agents, and organic fertilizers to traditional compound fertilizers, and through improved raw material ratios and processing techniques. Compared to traditional compound fertilizers, value-added compound fertilizers can more comprehensively and fully meet the diverse needs of crop growth. On the one hand, they reduce the use of purely chemical raw materials; on the other hand, they enhance the soil's water and fertilizer retention capacity and promote the reproduction of rhizosphere microorganisms, thereby significantly improving the soil's micro-ecological environment while increasing crop nutrient absorption efficiency.

[0007] For example, CN201510463846.3 discloses an organic-inorganic compound fertilizer and its preparation method. The compound fertilizer contains 75-100% effective components, 35-47% total nitrogen, phosphorus, and potassium nutrients, 20-42% organic matter, 10-20% total humic acid, 1-2% amino acids, and a carbon-to-nitrogen ratio of 0.48-1.87. This invention provides an organic-inorganic compound fertilizer that mixes organic matter, inorganic fertilizer, and humic acid—three major effective components—into a composite and complexed form, resulting in a high content of effective components and a reasonable carbon-to-nitrogen ratio.

[0008] For example, CN202110764904.1 discloses a rice-specific organic-inorganic compound fertilizer containing humic acid. It includes: nitrogen fertilizer, phosphate fertilizer, potassium fertilizer, secondary element fertilizer, micronutrient fertilizer, and humic acid; the humic acid content is ≥20wt%; the nitrogen fertilizer is composed of organic and inorganic nitrogen fertilizers, wherein the mass ratio of organic to inorganic nitrogen fertilizer is 1:(0.1-0.2); the organic nitrogen fertilizer includes cooked soybeans, which account for 5-10wt% of the total mass of the compound fertilizer; the secondary element fertilizer is silicon fertilizer; the mass ratio of soluble to water-soluble silicon fertilizer is 1:(0.1-0.15), and silica accounts for 50-60wt% of the total mass of the silicon fertilizer; the micronutrient fertilizer is soluble zinc salt. This invention can significantly improve the nutrient utilization rate of compound fertilizer in rice crops and achieve effective utilization of biomass.

[0009] However, these organic-inorganic compound fertilizers still suffer from uneven fertilizer release, nutrient imbalance, and easy fixation in the soil, leading to decreased crop absorption rates. Furthermore, their fertility maintenance effects are limited and lack specificity, making it difficult to meet the dual demands of sustained high yields in grain crops and ecological protection.

[0010] How to reduce fertilizer use while ensuring fertilizer efficiency and effectively improve the yield and quality of grain crops is a technical problem that urgently needs to be solved. Summary of the Invention

[0011] This invention addresses the problems existing in existing technologies by screening two functional microorganisms to perform solid-state fermentation of distiller's grains. The metabolites from these microorganisms enhance the activity of organic matter in the distiller's grains. Simultaneously, sulfur-coated urea is added, effectively slowing down nitrogen release through sulfur coating technology. Combined with the active ingredients in the fermented distiller's grains and the effects of microbial protectants, the overall performance of the fertilizer is significantly improved. This compound fertilizer not only meets the nutrient requirements of grain crops during their growth but also promotes root growth and enhances crop resistance. This innovative design allows the fertilizer to continuously release nutrients for a prolonged period after application, thus achieving the dual goals of efficient nutrient supply and environmental protection.

[0012] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0013] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 10-15 parts sulfur-coated urea, 20-30 parts urea, 15-25 parts superphosphate, 10-20 parts potassium chloride, 2-5 parts sodium metasilicate, and 3-8 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35-40 parts distillers' grains fermentation product, 5-8 parts microbial activity protectant, and 3-5 parts lignin sulfonate.

[0014] Furthermore, the preparation method of the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed by paraffin treatment, with the coating thickness controlled at 0.1-0.3mm.

[0015] Furthermore, the preparation method of the fermented lees is as follows:

[0016] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0017] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5-8% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0018] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0019] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0020] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0021] (6) Third stage (post-maturation period, 72 hours to day 7): Control the temperature at 35-40°C and stir once every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is less than 0.15% after 7-10 days. Dry the fermented lees to a moisture content of no more than 12%, and then crush and sieve to obtain the fermented lees.

[0022] Furthermore, the composite bacterial suspension is composed of *Bacillus halophyte* (…). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0023] Furthermore, the strain of *Haloxylon ammodendron*, with CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010; the strain of *Bacillus vesicatoria* from ocean sediments, with CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains can be obtained through public channels from the collection centers and do not require biological preservation.

[0024] Furthermore, the microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30-40 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0025] Furthermore, the lignin sulfonate is sodium lignin sulfonate or calcium lignin sulfonate.

[0026] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0027] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0028] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0029] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%.

[0030] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0031] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0032] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0033] Furthermore, in step c, the mixing speed of the twin-shaft mixer is 30-40 revolutions per minute.

[0034] The application of a compound fertilizer specifically for grain crops, when used in the planting of wheat or rice, can significantly improve crop root vitality, enhance stress resistance, and increase yield.

[0035] Beneficial effects:

[0036] (1) This invention selects two specific functional strains, *Bacillus halophyte* and *Bacillus vesicularis*, in a 1:1 volume ratio to form a compound bacterial suspension for solid-state fermentation of distiller's grains. The two strains exhibit a good synergistic effect during fermentation. *Bacillus halophyte* has a strong ability to degrade proteins and starches, while *Bacillus vesicularis* can efficiently decompose cellulose and hemicellulose. The two complement each other, jointly promoting the rapid humification and mineralization of organic matter in the distiller's grains. During this process, microbial metabolism produces a large amount of organic acids, active enzymes, amino acids, small molecule peptides, and plant hormones (such as indoleacetic acid), significantly increasing the types and content of active ingredients in the fermented distiller's grains. These active substances are not only easily absorbed by crops but also stimulate root development and enhance root vitality. After being applied to the soil, the strong biofilm-forming ability of the microbial strains can effectively colonize the rhizosphere and root surface, continuously and effectively promoting growth.

[0037] (2) This invention specifically adds a microbial activity protectant composed of pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. After the fertilizer is applied to the soil, this protectant plays a crucial role: pullulan, as a film-forming agent, can form a protective layer on the surface of microorganisms, reducing the damage to the microorganisms caused by environmental stress; the yeast extract is rich in nutrients such as amino acids and nucleotides, providing initial energy and growth factors for functional microorganisms; and citric acid can regulate the pH of the rhizosphere microenvironment, enhance nutrient solubility, and inhibit the growth of harmful microorganisms. The three work synergistically to effectively protect the survival rate and activity of functional microorganisms in the fertilizer (including those remaining in the fermentation product and added microbial agents) in the soil, enabling them to continuously colonize, reproduce, and exert a growth-promoting effect, thus extending the fertilizer's effective period.

[0038] (3) Thanks to the abundant active substances and continuously protected functional microorganisms in the fermented distillers' grains, this compound fertilizer can significantly stimulate the growth and development of crop roots, and significantly enhance root vitality (indicated by the activity of stress-resistant enzymes). The developed root system enhances the crop's ability to absorb water and nutrients. At the same time, the addition of sodium metasilicate and oyster shell powder further strengthens the crop's stem strength and cell wall thickness, effectively improving the crop's resistance to adverse stresses such as drought and salinity.

[0039] (4) Through the combined effects of the above-mentioned raw materials, this compound fertilizer can fully meet the nutrient requirements of grain crops such as wheat and rice during their critical growth stages. In particular, through the reasonable ratio of slow-release nitrogen source (sulfur-coated urea) and readily available nutrients, as well as the continuous biological growth-promoting effect, it achieves the synchronization of nutrient supply and crop demand. Field trials show that the final yield of wheat and rice treated with this compound fertilizer is significantly higher than that treated with conventional compound fertilizer.

[0040] (5) In summary, this compound fertilizer achieves efficient activation of organic fertilizer sources and long-term protection of soil by functional microorganisms through multiple physical, chemical and biological mechanisms. It not only significantly improves soil fertility and biological activity, but also effectively promotes crop growth and development and stress resistance, ensuring the simultaneous improvement of crop yield and quality, and providing a practical and feasible technical path for food security and sustainable agricultural development. Attached Figure Description

[0041] Figure 1 This is a test diagram of the antagonistic effect between Halophytic Bacillus and Oceanic Sediment Bacillus in this invention;

[0042] Figure 2 The protein content of rice grains obtained in the embodiments and comparative examples of the present invention;

[0043] Figure 3 The protein content of wheat grains obtained in the embodiments and comparative examples of the present invention is shown. Detailed Implementation

[0044] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0045] Example 1

[0046] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 10 parts sulfur-coated urea, 22 parts urea, 15 parts superphosphate, 10 parts potassium chloride, 2 parts sodium metasilicate, and 3 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35 parts distillers' grains fermentation product, 8 parts microbial activity protectant, and 3 parts lignin sulfonate.

[0047] The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

[0048] The preparation method of the fermented lees is as follows:

[0049] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0050] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0051] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0052] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0053] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0054] (6) Third stage (post-ripening period, 72 hours to day 7): Control the temperature at 35-40°C, and stir every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is below 0.15% after 7-10 days. Dry the fermented lees until the moisture content is no higher than 12%, then crush and sieve to obtain the fermented lees product. The effective viable bacteria count in the fermented lees product should be no less than 2.0 × 10⁻⁶. 8 CFU / g, organic matter content ≥45%.

[0055] The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0056] The *Haloxylon ammodendron* strain, CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010. The *Bacillus vesicularis* strain, CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains were obtained through open channels from the collection centers and did not require biological preservation.

[0057] Antagonistic effect test: *Bacillus halophyte* and *Bacillus vesicularis* from ocean sediments were streaked onto the same LB solid medium (repeated twice). After incubation at 30-37℃ for 48 hours, no obvious inhibition zone was observed, indicating no antagonistic effect between the two strains and that they can coexist symbiotically. (Culture diagram shown below.) Figure 1 As shown, both strains grew well on the culture medium, with clear colony morphology and neat edges.

[0058] The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0059] The lignin sulfonate is sodium lignin sulfonate.

[0060] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0061] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0062] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0063] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to control the moisture content of the materials at 12%-15%.

[0064] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0065] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0066] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0067] In step c, the mixing speed of the twin-shaft mixer is 30 revolutions per minute.

[0068] Example 2

[0069] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 12 parts sulfur-coated urea, 25 parts urea, 24 parts superphosphate, 20 parts potassium chloride, 3 parts sodium metasilicate, and 5 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 38 parts distillers' grains fermentation product, 7 parts microbial activity protectant, and 4 parts lignin sulfonate.

[0070] The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

[0071] The preparation method of the fermented lees is as follows:

[0072] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0073] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 6% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0074] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0075] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0076] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0077] (6) Third stage (post-ripening period, 72 hours to day 7): Control the temperature at 35-40°C, and stir every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is below 0.15% after 7-10 days. Dry the fermented lees until the moisture content is no higher than 12%, then crush and sieve to obtain the fermented lees product. The effective viable bacteria count in the fermented lees product should be no less than 2.0 × 10⁻⁶. 8 CFU / g, organic matter content ≥45%.

[0078] The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminisThe mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0079] The *Haloxylon ammodendron* strain, CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010. The *Bacillus vesicatoria* strain, CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains were obtained through open channels from the collection centers and did not require biological preservation.

[0080] The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0081] The lignin sulfonate is calcium lignin sulfonate.

[0082] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0083] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0084] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0085] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%.

[0086] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0087] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0088] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0089] In step c, the mixing speed of the twin-shaft mixer is 40 revolutions per minute.

[0090] Example 3

[0091] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 15 parts sulfur-coated urea, 20 parts urea, 23 parts superphosphate, 15 parts potassium chloride, 2 parts sodium metasilicate, and 4 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35 parts distillers' grains fermentation product, 6 parts microbial activity protectant, and 5 parts lignin sulfonate.

[0092] The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

[0093] The preparation method of the fermented lees is as follows:

[0094] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0095] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 7% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0096] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0097] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0098] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0099] (6) Third stage (post-ripening period, 72 hours to day 7): Control the temperature at 35-40°C, and stir every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is below 0.15% after 7-10 days. Dry the fermented lees until the moisture content is no higher than 12%, then crush and sieve to obtain the fermented lees product. The effective viable bacteria count in the fermented lees product should be no less than 2.0 × 10⁻⁶. 8 CFU / g, organic matter content ≥45%.

[0100] The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0101] The *Haloxylon ammodendron* strain, CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010. The *Bacillus vesicatoria* strain, CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains were obtained through open channels from the collection centers and did not require biological preservation.

[0102] The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 40 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0103] The lignin sulfonate is sodium lignin sulfonate.

[0104] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0105] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0106] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0107] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%.

[0108] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0109] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0110] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0111] In step c, the mixing speed of the twin-shaft mixer is 40 revolutions per minute.

[0112] Example 4

[0113] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 13 parts sulfur-coated urea, 30 parts urea, 22 parts superphosphate, 20 parts potassium chloride, 4 parts sodium metasilicate, and 7 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 38 parts distillers' grains fermentation product, 5 parts microbial activity protectant, and 4 parts lignin sulfonate.

[0114] The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

[0115] The preparation method of the fermented lees is as follows:

[0116] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0117] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 6% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0118] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0119] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0120] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0121] (6) Third stage (post-ripening period, 72 hours to day 7): Control the temperature at 35-40°C, and stir every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is below 0.15% after 7-10 days. Dry the fermented lees until the moisture content is no higher than 12%, then crush and sieve to obtain the fermented lees product. The effective viable bacteria count in the fermented lees product should be no less than 2.0 × 10⁻⁶. 8 CFU / g, organic matter content ≥45%.

[0122] The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0123] The *Haloxylon ammodendron* strain, CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010. The *Bacillus vesicatoria* strain, CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains were obtained through open channels from the collection centers and did not require biological preservation.

[0124] The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30-40 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0125] The lignin sulfonate is calcium lignin sulfonate.

[0126] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0127] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0128] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0129] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%.

[0130] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0131] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0132] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0133] In step c, the mixing speed of the twin-shaft mixer is 40 revolutions per minute.

[0134] Example 5

[0135] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 15 parts sulfur-coated urea, 30 parts urea, 25 parts superphosphate, 20 parts potassium chloride, 5 parts sodium metasilicate, and 8 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 40 parts distillers' grains fermentation product, 5 parts microbial activity protectant, and 5 parts lignin sulfonate.

[0136] The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

[0137] The preparation method of the fermented lees is as follows:

[0138] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0139] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 8% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0140] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0141] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0142] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0143] (6) Third stage (post-ripening period, 72 hours to day 7): Control the temperature at 35-40°C, and stir every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is below 0.15% after 7-10 days. Dry the fermented lees until the moisture content is no higher than 12%, then crush and sieve to obtain the fermented lees product. The effective viable bacteria count in the fermented lees product should be no less than 2.0 × 10⁻⁶. 8 CFU / g, organic matter content ≥45%.

[0144] The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanisediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension.

[0145] The *Haloxylon ammodendron* strain, CGMCC No. 1.10449, was purchased from the China General Microbiological Culture Collection Center (CGMCC) on March 27, 2010. The *Bacillus vesicatoria* strain, CGMCC No. 1.10115, was also purchased from the CGMCC on June 23, 2009. Both strains were obtained through open channels from the collection centers and did not require biological preservation.

[0146] The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 40 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0147] The lignin sulfonate is sodium lignin sulfonate.

[0148] A method for preparing a compound fertilizer specifically for grain crops includes the following steps:

[0149] a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture;

[0150] b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture;

[0151] c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%.

[0152] d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation;

[0153] e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%;

[0154] f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

[0155] In step c, the mixing speed of the twin-shaft mixer is 30 revolutions per minute.

[0156] Comparative Example 1

[0157] In this comparative example, except that only ordinary brewing yeast was used for fermentation in the preparation of the distiller's grains, all other process steps were the same as in Example 1. That is:

[0158] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 10 parts sulfur-coated urea, 22 parts urea, 15 parts superphosphate, 10 parts potassium chloride, 2 parts sodium metasilicate, and 3 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35 parts distillers' grains fermentation product, 8 parts microbial activity protectant, and 3 parts lignin sulfonate.

[0159] The preparation method of the fermented lees is as follows:

[0160] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0161] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5% brewing yeast by weight of the material, and mix thoroughly with a mixer.

[0162] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0163] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0164] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0165] (6) Third stage (post-maturation period, 72 hours to day 7): Control the temperature at 35-40°C and stir once every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is less than 0.15% after 7-10 days. Dry the fermented lees to a moisture content of no more than 12%, and then crush and sieve to obtain the fermented lees.

[0166] The brewing yeast was purchased from Jinan Jinyuyuan Biotechnology Co., Ltd., with an effective live bacteria count of 20 billion / gram.

[0167] Comparative Example 2

[0168] This comparative example is identical to Example 1 except that it uses *Haloxylon ammodendron* for fermentation in the preparation of the distiller's grains. That is:

[0169] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 10 parts sulfur-coated urea, 22 parts urea, 15 parts superphosphate, 10 parts potassium chloride, 2 parts sodium metasilicate, and 3 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35 parts distillers' grains fermentation product, 8 parts microbial activity protectant, and 3 parts lignin sulfonate.

[0170] The preparation method of the fermented lees is as follows:

[0171] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0172] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5% of the bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0173] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0174] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0175] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0176] (6) Third stage (post-maturation period, 72 hours to day 7): Control the temperature at 35-40°C and stir once every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is less than 0.15% after 7-10 days. Dry the fermented lees to a moisture content of no more than 12%, and then crush and sieve to obtain the fermented lees.

[0177] The bacterial suspension is *Bacillus halophyte* (Haloxylon ammodendron). Virgibacillus salinus The preparation method is as follows: *Haloxylon ammodendron* is inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD... 600 When the value reaches 2.0-3.0, a bacterial suspension is obtained.

[0178] The strain of *Haloxylon ammodendron* was numbered CGMCC No. 1.10449 and was purchased from the China General Microbiological Culture Collection Center, with an original deposit date of March 27, 2010.

[0179] Comparative Example 3

[0180] In this comparative example, except that only *Bacillus vesicularis* from ocean sediments was used for fermentation in the preparation of the distiller's grains, all other process steps were the same as in Example 1. That is:

[0181] A compound fertilizer specifically for grain crops comprises a base fertilizer and an organic bio-fertilizer source. The base fertilizer, by weight, includes: 10 parts sulfur-coated urea, 22 parts urea, 15 parts superphosphate, 10 parts potassium chloride, 2 parts sodium metasilicate, and 3 parts oyster shell powder. The organic bio-fertilizer source, by weight, includes: 35 parts distillers' grains fermentation product, 8 parts microbial activity protectant, and 3 parts lignin sulfonate.

[0182] The preparation method of the fermented lees is as follows:

[0183] (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%;

[0184] (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5% of the bacterial suspension by weight of the material, and mix thoroughly with a mixer.

[0185] (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm.

[0186] (4) First stage (aerobic fermentation period, 0-36 hours): control the temperature at 35-38°C, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours;

[0187] (5) Second stage (high temperature stabilization period, 36-72 hours): Stop forced ventilation, let the material enter a semi-aerobic state, the temperature will naturally rise to 45-50°C, and maintain this temperature to continue fermentation for 36 hours;

[0188] (6) Third stage (post-maturation period, 72 hours to day 7): Control the temperature at 35-40°C and stir once every 24 hours; fermentation is complete when the material moisture content drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is less than 0.15% after 7-10 days. Dry the fermented lees to a moisture content of no more than 12%, and then crush and sieve to obtain the fermented lees.

[0189] The bacterial suspension is *Bacillus vesicularis* from ocean sediments (… Cytobacillus oceanisediminis The preparation method is as follows: *Bacillus vesicatoria* from ocean sediments is inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD... 600When the value reaches 2.0-3.0, a bacterial suspension is obtained.

[0190] The strain of *Bacillus vesicatoria* from the ocean sediments was numbered CGMCC No. 1.10115, and was also purchased from the China General Microbiological Culture Collection Center, with an original deposit date of June 23, 2009.

[0191] Comparative Example 4

[0192] In this comparative example, except that pullulan was not used in the microbial activity protectant, the preparation process and parameters were the same as in Example 1. That is:

[0193] The microbial activity protectant includes yeast extract and citric acid in a mass ratio of 2:5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding citric acid to the yeast extract in a certain proportion and mixing them evenly.

[0194] Comparative Example 5

[0195] In this comparative example, except that yeast extract was not used in the microbial activity protectant, the preparation process and parameters were the same as in Example 1. That is:

[0196] The microbial activity protectant includes pullulan and citric acid in a mass ratio of 1:5; the microbial activity protectant is obtained by mixing pullulan and citric acid evenly in a certain proportion.

[0197] Comparative Example 6

[0198] In this comparative example, except for the absence of citric acid in the microbial activity protectant, the preparation process and parameters are the same as in Example 1. That is:

[0199] The microbial activity protectant includes pullulan polysaccharide and yeast extract in a mass ratio of 1:2. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan polysaccharide to the yeast extract in a certain proportion and mixing them evenly.

[0200] Performance testing

[0201] Strain alcohol tolerance test:

[0202] Bacillus halophyte strain CGMCC No. 1.10449 and Bacillus vesicularis strain CGMCC No. 1.10115 were inoculated into LB medium containing 10% vol ethanol. After incubation at 35-37℃ with shaking for 24 hours, growth was observed and OD values ​​were measured. 600 The values ​​were measured simultaneously. The activities of protease, amylase, and cellulase were also detected. The results showed that both strains could grow in 10% alcohol. Amylase activity was determined using the anthrone colorimetric method; protease activity was determined using the Folin-Ciocalteu method; and cellulase activity was determined using the DNS method. The results are shown in Table 1.

[0203] Table 1 Results of strain performance testing

[0204]

[0205] As shown in Table 1, both strains exhibited good growth capacity and enzyme activity in a medium containing 10% alcohol. Among them, Bacillus vesicatoria from ocean sediments showed higher cellulase activity, while Bacillus halophyte showed more prominent amylase activity, indicating that the two strains have complementary potential in the construction of complex enzyme systems and are suitable for synergistic degradation in the complex substrate environment of distiller's grains.

[0206] Growth-promoting effect test of strains:

[0207] The growth-promoting characteristics of the strain were evaluated by measuring its phosphorus-solubilizing ability, nitrogen-fixing ability, siderophore production ability, and IAA production ability. Phosphorus-solubilizing ability was determined using the inorganic phosphorus medium detection method; colonies producing a clear zone indicated this ability. Nitrogen-fixing ability was determined using the Assab medium method; the strain exhibited this ability if it grew. Siderophore production ability was determined using the chromaine detection solid medium method; colonies producing an orange-yellow halo indicated this ability. IAA production ability was determined using the Salkowski colorimetric method; the strain was inoculated into NB liquid culture medium containing L-tryptophan; the culture medium reacted with the Salkowski colorimetric solution and turned red in the dark, indicating this ability. The OD value was then measured. 530 Quantify the IAA yield of the strain.

[0208] Biofilm formation ability: Biofilm formation ability is an important indicator for evaluating the environmental adaptability and colonization ability of bacterial strains. The biofilm formation ability of two bacterial strains was detected using the 96-well plate method. 100 μL of LB medium was added to each 96-well plate, and the bacterial suspension (OD) of the test strain was inoculated. 600=1.0), with LB medium alone as a control, and cultured at 37°C for 24 h. Then, the medium was aspirated, and the wells were washed three times with 200 μL of sterile PBS buffer. Next, 100 μL of methanol was added for fixation for 15 min, then the methanol was aspirated and air-dried. 100 μL of 1% crystal violet solution was added for staining for 5 min, aspirated and rinsed thoroughly, dried at 37°C, and then 100 μL of 33% glacial acetic acid was added and the crystal violet was dissolved at 37°C for 30 min. Each experiment was repeated in triplicate. OD was measured using a microplate reader. 590 OD 590 The higher the value, the stronger the biofilm formation ability of the strain.

[0209] The test results are shown in Table 2:

[0210] Table 2 Growth-promoting ability of strains

[0211]

[0212] Note: "-" indicates that the strain does not have the corresponding ability, and "+" indicates that the strain has the corresponding ability.

[0213] As shown in Table 2, both strains screened in this invention possess phosphate-solubilizing and IAA-producing abilities. *Bacillus halophyte* exhibits superior siderophore production and biofilm formation capabilities, while *Bacillus vesicularis* from ocean sediments demonstrates nitrogen-fixing ability. Furthermore, both strains demonstrate strong colonization potential in biofilm formation, effectively colonizing plant rhizospheres or soil environments, enhancing their adaptability and sustained growth-promoting effects under adverse conditions.

[0214] Fertilizer Efficacy Experiment:

[0215] The field trial employed a randomized block design, with 13 treatments, each replicated three times. Each experimental plot was 20 m² in size. 2 (4 m × 5 m), a 1 m wide protective ring is set up around the perimeter of the area. The treatment groups are as follows:

[0216] A1: Apply 40 kg of the compound fertilizer prepared in Example 1 as a base fertilizer per mu;

[0217] A2: Apply 40 kg of the compound fertilizer prepared in Example 2 as a base fertilizer per mu;

[0218] A3: Apply 40 kg of the compound fertilizer prepared in Example 3 as a base fertilizer per mu;

[0219] A4: Apply 40 kg of the compound fertilizer prepared in Example 4 as a base fertilizer per mu;

[0220] A5: Apply 40 kg of the compound fertilizer prepared in Example 5 as a base fertilizer per mu;

[0221] A6: Apply 40 kg of the fertilizer prepared in Comparative Example 1 as a base fertilizer per mu;

[0222] A7: Apply 40 kg of the fertilizer prepared in Comparative Example 2 as a base fertilizer per mu;

[0223] A8: Apply 40 kg of the fertilizer prepared in Comparative Example 3 as a base fertilizer per mu;

[0224] A9: Apply 40 kg of the fertilizer prepared in Comparative Example 4 as a base fertilizer per mu;

[0225] A10: Apply 40 kg of the fertilizer prepared in Comparative Example 5 as a base fertilizer per mu;

[0226] A11: Apply 40 kg of the fertilizer prepared in Comparative Example 6 as a base fertilizer per mu;

[0227] A12: Apply ordinary compound fertilizer (N:P2O5:K2O=15:15:15) as base fertilizer, following the conventional standard, at a rate of 60 kg / mu. The ordinary compound fertilizer is produced by Jiangsu Aolaite Ecological Fertilizer Co., Ltd. A blank control group was also set up, i.e., no fertilizer was applied.

[0228] Base fertilizer should be applied to the soil surface once, three days before rice transplanting or wheat sowing.

[0229] Before maturity, complete plants were taken, and the roots were rinsed with clean water to remove the soil attached to the roots. For each treatment, a portion of the roots was placed in a constant temperature drying oven at 115℃ for 30 min to kill the green, and then dried at 80℃ to constant weight for the determination of root biochemical indicators.

[0230] The activities of superoxide dismutase, peroxidase, catalase, malondialdehyde (MDA) content, and free proline content in the roots of rice and wheat were determined according to the methods described in "Principles and Techniques of Plant Physiological and Biochemical Experiments". Superoxide dismutase activity was determined using the nitroblue tetrazolium method, peroxidase activity was determined using the guaiacol method, catalase activity was determined using the ultraviolet absorption method, free proline content was determined using the sulfosalicylic acid extraction-acid ninhydrin colorimetric method, and MDA content was determined using the thiobarbituric acid colorimetric method.

[0231] After the crops matured, they were manually harvested, threshed, and dried before being weighed to determine yield. The protein content of rice and wheat grains was determined using the biuret method. Twenty panicles were randomly collected from each plot for indoor testing, and the weight of 1000 grains was investigated.

[0232] The experimental results are shown in Table 3:

[0233] Table 3 Wheat and Rice Yields and Quality

[0234]

[0235] Table 4. Stress resistance activity of rice roots

[0236]

[0237] Table 5. Stress resistance activity of wheat roots

[0238]

[0239] As can be seen from the data in Tables 3-5, the compound fertilizers prepared in Examples 1 to 5 all showed significant advantages in terms of yield and quality of rice and wheat. Compared with the comparative example and ordinary fertilizers, the yield, thousand-grain weight, and grain protein content were significantly improved. Figures 2 - 3 Both the microbial activity and root stress resistance were significantly improved. This indicates that the proper ratio of microbial activity protectants in compound fertilizers has a significant impact on fertilizer efficiency, demonstrating its superior overall performance.

[0240] As shown in Tables 4 and 5, after applying the compound fertilizer from Examples 1 to 5, the activities of superoxide dismutase and peroxidase in the roots of rice and wheat were significantly increased, while the malondialdehyde content was relatively low, indicating that the antioxidant capacity and stress resistance of crops under adverse conditions were effectively enhanced. In contrast, Comparative Examples 1-3 lacked core functional strains, and Comparative Example 4 lacked certain key components, so its effects were significantly weaker than those of the Example groups, further verifying the importance of the synergistic effect of the components in the formula.

[0241] In summary, the compound fertilizer provided by this invention can not only significantly increase crop yield, but also improve crop quality and enhance stress resistance, making it particularly suitable for the planting needs of grain crops. This result provides a scientific basis and technical support for subsequent optimization of compound fertilizer formulations and their widespread application.

[0242] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A compound fertilizer specifically for grain crops, characterized in that, It comprises basic fertilizer and organic bio-fertilizer source, wherein the basic fertilizer includes, by weight: 10-15 parts sulfur-coated urea, 20-30 parts urea, 15-25 parts superphosphate, 10-20 parts potassium chloride, 2-5 parts sodium metasilicate, and 3-8 parts oyster shell powder; the organic bio-fertilizer source includes, by weight: 35-40 parts distillers' grains fermentation product, 5-8 parts microbial activity protectant, and 3-5 parts lignin sulfonate; the preparation method of the distillers' grains fermentation product is as follows: (1) Take fresh distiller's grains, sterilize them, and adjust their pH value to 6.8-7.2 and their moisture content to 50%-55%; (2) By weight, add 5 parts wheat bran, 2 parts molasses and 1 part potassium dihydrogen phosphate to every 100 parts of treated lees, mix evenly and then add 5-8% of the compound bacterial suspension by weight of the material, and mix thoroughly with a mixer. (3) Transfer the inoculated material to a solid fermentation tank or fermentation box, and control the material layer thickness at 30-50 cm; (4) First stage fermentation: control the temperature at 35-38℃, provide oxygen through forced ventilation, maintain the relative humidity of the air at 80%-85%, and ferment for 36 hours; (5) Second stage fermentation: Stop forced ventilation and let the material enter a semi-aerobic state. The temperature will naturally rise to 45-50°C and maintain this temperature for 36 hours. (6) Third stage fermentation: Control the temperature at 35-40°C and stir once every 24 hours; ferment for 7-10 days, when the moisture content of the material drops to 28%-32%, the pH value stabilizes at 7.0-7.5, and the ammonium nitrogen content is less than 0.15%, indicating that the fermentation is complete. Dry the fermented lees to a moisture content of no more than 12%, and then crush and sieve to obtain the fermented lees product. The compound bacterial suspension is composed of Haloxylon ammodendron (Bacillus halophilus). Virgibacillus salinus ) and ocean sediment Bacillus vesicularis ( Cytobacillus oceanizediminis The mixture is prepared by mixing Bacillus halophyte and Bacillus vesicularis from ocean sediments in a 1:1 volume ratio. The preparation method is as follows: Bacillus halophyte and Bacillus vesicularis from ocean sediments are separately inoculated into LB liquid medium and cultured with shaking at 35-37℃ until OD reaches [value missing]. 600 When the value reaches 2.0-3.0, the two bacterial solutions are mixed at a volume ratio of 1:1 to obtain a compound bacterial suspension. The strain of *Haloxylon ammodendron* was CGMCC No. 1.10449 and was purchased from the China General Microbiological Culture Collection Center; the strain of *Bacillus vesicatoria* from ocean sediments was CGMCC No. 1.10115 and was also purchased from the China General Microbiological Culture Collection Center. The microbial activity protectant includes pullulan, yeast extract, and citric acid in a mass ratio of 1:2:

5. The yeast extract is prepared by heat-treating yeast cells at 80-85℃ for 30-40 minutes to induce autolysis, centrifuging to collect the supernatant, and then spray-drying to obtain a powdered product. The microbial activity protectant is obtained by adding pullulan and citric acid to the yeast extract in a certain proportion and mixing them evenly.

2. The compound fertilizer for grain crops according to claim 1, characterized in that, The method for preparing the sulfur-coated urea is as follows: urea particles are heated to 60-70℃, molten sulfur is sprayed on to form a coating layer, and then sealed with paraffin wax. The coating thickness is controlled at 0.1-0.3mm.

3. The compound fertilizer for grain crops according to claim 1, characterized in that, The lignin sulfonate is sodium lignin sulfonate or calcium lignin sulfonate.

4. A method for preparing a compound fertilizer specifically for grain crops according to any one of claims 1-3, characterized in that, Includes the following steps: a. Weigh out each basic fertilizer raw material according to the weight parts, including sulfur-coated urea, urea, superphosphate, potassium chloride, sodium metasilicate, and oyster shell powder, and mix them evenly to obtain a basic fertilizer mixture; b. Weigh out the fermented distillers' grains, lignin sulfonate, and microbial activity protectant by weight, and premix them evenly to obtain an organic bio-fertilizer mixture; c. Add the basic fertilizer mixture obtained in step a and the organic-biological fertilizer mixture obtained in step b into a twin-shaft mixer and mix for 15-25 minutes until homogeneous. During the mixing process, spray an appropriate amount of water into the materials to maintain the moisture content at 12%-15%. d. The wet material obtained in step c is fed into a double-roll granulator for extrusion granulation; e. Dry the granular fertilizer obtained in step d until the moisture content of the fertilizer granules is below 10%; f. The dried fertilizer granules obtained in step e are sieved through a vibrating screen to obtain qualified granules with a particle size of 2-4 mm. After cooling, the special compound fertilizer for grain crops is obtained.

5. The preparation method according to claim 4, characterized in that, In step c, the mixing speed of the twin-shaft mixer is 30-40 revolutions per minute.

6. The application of a compound fertilizer specifically for grain crops as described in any one of claims 1-3, characterized in that, When applied to the cultivation of wheat or rice, it can significantly improve crop root vitality, enhance stress resistance, and increase yield.

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