Wheat bio-fertilizer with saline-alkali soil improvement effect and preparation method thereof

Abstract

This invention provides a wheat bio-fertilizer with saline-alkali soil improvement function and its preparation method, belonging to the field of agricultural fertilizer technology. The fertilizer comprises: mineral-loaded microbial granules, additives, organic materials, and a coating slow-release component, with the following weight ratio: mineral-loaded microbial granules: additives: organic materials: coating slow-release component = (10-20):(3-7):(5-10):2; the additives include at least one of seaweed polysaccharide, potassium humate, and desulfurized gypsum; the organic materials include straw biochar, wood vinegar, and well-rotted manure; the coating slow-release component is starch and carboxymethyl cellulose. The microorganisms in this fertilizer have a long survival time in the soil and exert a more lasting effect. Working synergistically with other components, it simultaneously achieves multiple goals of "soil improvement, growth promotion, and disease resistance," enhancing land productivity, wheat yield, and quality, and providing biological control of wheat diseases. It also improves saline-alkali soil and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer technology, and in particular to a wheat bio-fertilizer with saline-alkali soil improvement function and its preparation method. Background Technology

[0002] Hard wheat is a staple food of Inner Mongolia and one of the leading industries in the Bayannur National Agricultural High-tech Industrial Demonstration Zone. However, hard wheat cultivation in Inner Mongolia faces severe challenges. On the one hand, Bayannur suffers from severe soil salinization, with a large area of ​​saline-alkali land and a pH value of approximately 8.5 (of which more than 28% of the soil has a pH value greater than 8.5). The optimal pH for wheat growth is 6.5-7.5. The high salinity, high pH value, and poor physical structure of saline-alkali land severely inhibit crop growth. On the other hand, traditional wheat cultivation relies excessively on chemical fertilizers, which further exacerbates soil salinization and compaction. This results in an average wheat yield of only 350-400 kg per mu (approximately 0.067 hectares), 30-40% lower than in non-saline-alkali land, making it difficult to achieve significant yield breakthroughs. This has become a major obstacle to crop cultivation in the region and most parts of Inner Mongolia, restricting the sustainable green development of regional agricultural economy and society. On the other hand, the northward shift and expansion of the rain belt in recent years has been significant. The suitable temperature and humidity environment favors the occurrence of soil-borne diseases such as Fusarium head blight and stem rot. The use of chemical pesticides causes environmental pollution, and long-term use can lead to pesticide resistance in pathogens. Therefore, in addition to saline-alkali land management, there is an urgent need to establish key technologies for green agricultural planting based on bio-fertilizers and bio-pesticides.

[0003] Although existing technologies commonly use microbial agents or bio-fertilizers for saline-alkali land improvement or planting optimization, most of these agents or bio-fertilizers fail to effectively address the issue of slow-release of active ingredients. This results in short effective durations, requiring frequent application, increasing costs and labor intensity, and failing to fundamentally improve soil structure. Furthermore, most microorganisms are added directly without protective treatment, leading to low survival rates and poor adaptability in saline-alkali environments. Their effective period is relatively short, making it difficult to sustainably and effectively increase yields and prevent diseases over the long term.

[0004] Therefore, in order to effectively alleviate the limitations of soil salinization on wheat production, it is urgent to carry out research on fertilizer technology that combines saline-alkali land improvement with disease control. Summary of the Invention

[0005] This invention provides a wheat bio-fertilizer and its preparation method that can improve land productivity, wheat yield and quality, and biologically control wheat diseases, and improve saline-alkali land. It is used to solve problems in wheat planting such as saline-alkali land obstacles, nutrient imbalance and deficiency, low survival rate of exogenous microorganisms, poor adaptability and short improvement cycle.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a wheat bio-fertilizer with saline-alkali soil improvement function, comprising: mineral-loaded microbial particles, additives, organic materials, and a coating slow-release component, wherein the weight ratio is as follows: mineral-loaded microbial particles: additives: organic materials: coating slow-release component = (10-20):(3-7):(5-10):2; the additives include at least one of seaweed polysaccharide, potassium humate, and desulfurized gypsum; the organic materials include straw biochar, wood vinegar, and composted manure; and the coating slow-release component is starch and carboxymethyl cellulose.

[0007] The microorganisms in the wheat bio-fertilizer of this invention have a long survival time in the soil and exert a more lasting effect. They work synergistically with other components to simultaneously achieve multiple goals of "soil improvement, growth promotion, and disease resistance." They provide essential nutrients for crop growth, promote crop growth, enhance root vitality, improve the crop's own disease resistance and lodging resistance, increase wheat emergence rate, achieve disease control effect of over 80%, reduce the use of pesticides and chemical fertilizers, achieve effective prevention and control of wheat diseases, and increase wheat yield and quality. They also complete the systematic regulation of "soil structure-nutrient supply-microbial ecological regulation" to synergistically repair and improve saline-alkali soil.

[0008] According to the present invention, a method for preparing mineral-loaded microbial particles includes the following steps: 1) Mix all the raw materials in the natural minerals evenly, granulate, and dry until the moisture content does not exceed 10% to obtain mineral carrier particles with a particle size not exceeding 2mm; 2) After separately expanding the culture of Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus, they were added to liquid culture medium for mixed co-culture to obtain a compound bacterial solution; 3) Place the mineral carrier particles into the composite bacterial solution, stir and react, then centrifuge and dry at low temperature to obtain the bacterial-carrying particles; 4) Add the coating component to sterile water and stir until dissolved to obtain a coating solution. Spray the coating solution onto the bacterial-loaded particles and dry at low temperature to obtain mineral-loaded microbial particles.

[0009] Each natural mineral raw material has a porous structure, which makes it easier to adsorb salts and load nutrients, providing a good habitat for microorganisms. Loading various microorganisms into the pores of natural minerals enhances the structural stability of mineral-loaded microbial particles, which helps to improve the colonization ability of microorganisms in crop rhizosphere and saline-alkali soil, and improves problems such as low survival rate, poor adaptability and short improvement cycle of exogenous microorganisms. At the same time, microbial metabolites (such as extracellular polysaccharides) can also be loaded on the surface of the carrier, exerting a longer-lasting effect of promoting growth and preventing diseases, and extending the fertilizer's action time.

[0010] According to the present invention, the mass-to-volume ratio of mineral carrier particles to composite bacterial solution is 1g:(10-15)mL; the concentration of the coating solution is 5-10wt%, and the mass-to-volume ratio of bacterial particles to coating solution is 1g:(2-5)mL.

[0011] According to the present invention, the stirring speed is 60-80 r / min, the temperature is 28-32℃, and the time is 1-2 days; the temperature for low-temperature drying does not exceed 45℃.

[0012] According to the present invention, the specific operation of the mixed co-culture is as follows: the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus are inoculated into liquid culture medium respectively, and cultured for 3-5 days at a temperature of 28-32℃, a shaking speed of 180-200 rpm, a system pH of 7.0-7.2, and a dissolved oxygen content of 30-50%; then cultured for 2-4 days at a temperature of 28-30℃, a shaking speed of 110-140 rpm, a system pH of 6.5-6.8, and a dissolved oxygen content of 5-15%; the inoculation amount of the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus is 5-15%.

[0013] During the co-cultivation process, a high aeration rate is maintained in the early stage to promote the proliferation of aerobic bacteria, and then gradually reduced in the later stage to promote and induce anaerobic metabolism. This encourages microorganisms to secrete more diverse metabolites, increasing the diversity of active ingredients, including various antibacterial substances, thereby increasing fertilizer efficiency and pest and disease resistance. The compound microorganisms can reduce surface salt accumulation and soil pH by secreting acidic metabolites, produce polysaccharides to solidify soil particles, and also act as biocontrol bacteria to inhibit the growth and metabolism of harmful microorganisms in the soil, creating a beneficial microbial environment. Simultaneously, they can promote seed germination and plant growth, increase root biomass, improve fertilizer absorption and utilization, and exhibit synergistic effects with other components. This results in functions such as reducing soil salinity, improving soil structure, enhancing soil fertility, optimizing community structure, and strengthening plant salt and alkali resistance, achieving integrated improvement of saline-alkali land and disease control, ultimately improving crop yield and quality.

[0014] According to the present invention, the natural minerals contain the following raw materials and their weight parts: vermiculite 5-8 parts, calcium-based bentonite 10-15 parts, and diatomaceous earth 7-12 parts, all with a particle size of 100 mesh. In addition to serving as a carrier for microorganisms and their metabolic products, the natural minerals themselves can also react with salt and alkali ions in the soil, promoting the transformation of salts into stable mineral phases in the soil, rapidly reducing soil alkalinity and salinity. Their porous structure can also effectively adsorb salt ions, improve soil permeability, prevent compaction, thereby continuously activating and improving soil structure, refining saline-alkali soil, and providing long-lasting effects, thus improving the stability of fertilizer desalination and salt fixation.

[0015] According to the present invention, the coating component is a mixture of chitosan and calcium alginate in a weight ratio of 1:(0.5-1), and the chitosan has a molecular weight of 50-60 kDa. Chitosan and calcium alginate can serve as a nutrient source for microorganisms to improve their survival rate and lifespan in fertilizers, significantly extending the microbial activity cycle. They also possess a certain water retention capacity, forming hydrogels in the soil to improve soil structure, alleviate physiological drought in saline-alkali soils, and mitigate the impact of the external environment on internal microorganisms, significantly enhancing the comprehensiveness and durability of the fertilizer effect.

[0016] According to the present invention, the additive is a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide comprises 5-10 parts by weight, the potassium humate comprises 5-15 parts by weight, and the desulfurized gypsum comprises 1-5 parts by weight. Appropriate addition of the additive can further enhance the improvement and yield-increasing effects. These additive components are rich in active substances, which can integrate salt ions, improve soil structure, and enhance water and fertilizer retention capacity. Simultaneously, they can promote root development, enhance crop salt tolerance, reduce crop dependence on chemical fertilizers, and improve nutrient utilization. They also synergistically enhance the effects of use by chelating nutrients with microorganisms, organic materials, and other components.

[0017] According to this invention, the straw biochar is selected from at least one of corn straw biochar and sunflower straw biochar; the decomposed manure is selected from at least one of decomposed sheep manure and decomposed cow manure, with a decomposition degree >90%; the wood vinegar has a pH value of 2.5-3.5 and a water content of less than 15%. Straw biochar and decomposed manure can improve soil aggregate structure and replace soil salts, enhancing the stability of the soil micro-ecosystem and the efficiency of mineralization and salt fixation. Wood vinegar also plays a significant role in improving soil, promoting plant growth, enhancing stress resistance, preventing and controlling pests and diseases, and improving the quality of agricultural products. In the fertilizer, natural minerals and straw biochar and decomposed manure provide different porous environments, synergistically forming meandering channels within the fertilizer, which can reduce the rate of salt migration, delay the migration of salts to the surface, and convert harmful metals into stable mineral phases through ion exchange, thereby enhancing the fertilizer's effect on improving saline-alkali soils.

[0018] According to the present invention, the weight ratio of starch to carboxymethyl cellulose in the coating slow-release component is (0.5-1.5):1. The function of the coating slow-release component is to further enhance the water retention and slow-release capacity of the fertilizer granules, ensure that other components in the fertilizer granules are slowly released into the soil, and prolong the action time, so that it can effectively exert its functions of acid production, yield increase, and disease prevention, and help reduce the frequency of application and planting costs.

[0019] Secondly, the present invention provides a method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function, comprising the following steps: 1) Mix mineral-loaded microbial particles, additives, and organic materials evenly, granulate, and obtain a premix; 2) Prepare a coating solution by using sterile water to prepare the coating slow-release component, spray it onto the premix, and dry it at low temperature to obtain the aforementioned wheat bio-fertilizer with saline-alkali soil improvement effect.

[0020] The fertilizer granules prepared by this method contain ≥500 million viable bacteria per gram. Through processes such as mixing, granulation, and coating, stable binding between the components is ensured, preventing separation during use and guaranteeing consistent product quality. Simultaneously, the microorganisms in the fertilizer maintain high activity even in high-salt and high-alkali environments, enhancing crop disease resistance, promoting crop growth, and significantly increasing yield. Furthermore, the fertilizer improves soil aggregate structure and increases organic matter content through minerals and organic materials. The combined effects of physical, chemical, and biological amendments rapidly improve soil quality and microbial biomass, providing a favorable microenvironment for crop growth. This preparation method is simple, has low application costs, and demonstrates significant improvement effects on saline-alkali land, contributing to increased wheat yields.

[0021] According to the present invention, the granulation and low-temperature drying temperature does not exceed 45°C, the particle size of the premix is ​​2-4 mm, and the weight gain of the coating liquid is 8-15%. The granulation and slow-release coating technology ensures the functional stability of the fertilizer product. The coating can achieve the phased and sustained release of fertilizer nutrients, and at the same time, it helps to ensure that the microbial community applied to the soil has high activity, large quantity, and long duration of disease resistance, significantly extending the time of fertilizer effect, so as to show stable salinity improvement and growth promotion effects in the soil.

[0022] According to the present invention, the present invention also provides an application of the aforementioned wheat bio-fertilizer with saline-alkali soil improvement function in saline-alkali soil improvement and wheat planting. The application rate of the wheat bio-fertilizer is 45-90 kg / mu, applied as a base fertilizer. In practical application, this fertilizer can be used in conjunction with chemical fertilizers or alone. It can replace traditional chemical fertilizers and pesticides, reduce the amount of pesticides and chemical fertilizers used, and alleviate the residue and resistance problems caused by the large-scale use of chemical fertilizers and pesticides.

[0023] The present invention provides a wheat bio-fertilizer with saline-alkali soil improvement function and its preparation method. First, by deeply integrating the physical structure of the natural mineral carrier, the biochemical activity of the additives, the functional microorganisms and their metabolites, as well as the slow-release function of the coating components and the slow-release components, a compound fertilizer integrating "soil improvement, growth promotion and disease resistance" is prepared. This achieves systematic regulation of soil health and crop growth, and can match the wheat production stage to maximize the effect and optimize resources, thereby achieving effective prevention and control of wheat diseases and increasing wheat yield and quality.

[0024] Secondly, this bio-fertilizer contains a high number of viable bacteria, and its multi-layered coating structure enhances storage and quality stability. When used as a base fertilizer, the dosage per unit is small, and it is less affected by the environment after application. The microorganisms are slowly released and effectively colonize the plant rhizosphere for a long time, forming a local dominance and providing a certain biocontrol effect against diseases. It can replace traditional chemical fertilizers and pesticides, reducing the amount of insecticides and chemical fertilizers used and lowering the cost of wheat cultivation. In addition, this bio-fertilizer is not limited to wheat cultivation; it can also be used in the cultivation of other crops (such as sunflowers and tomatoes), as a base fertilizer or seedling fertilizer, and can also be used alone as a soil conditioner for saline-alkali soil, making it widely applicable. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A comparison of individual wheat seedlings treated with different fertilizers; Figure 2 A field comparison of wheat seedlings treated with different fertilizers; Figure 3 A schematic diagram showing the germination rate and whole plant fresh weight of wheat seedlings after applying different fertilizers; Figure 4 A schematic diagram showing the results of root length and root-shoot ratio measurements of wheat seedlings treated with different fertilizers; Figure 5 This is a schematic diagram of the degradation rate curves for different fertilizers. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of the present invention.

[0028] The following examples use conventional instruments and equipment in the art. Unless otherwise specified, the experimental materials and reagents used in the following examples are commercially available and conform to conventional specifications in the art. Any techniques or conditions not specifically described in the following examples can be performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0029] It should be noted that, in this invention and the following embodiments, unless otherwise specified, concentration, ratio, etc. are all weight concentration, weight ratio, etc., "%" all represent weight percentage, and "parts" all represent weight parts. These are common writing habits used by those skilled in the art, and therefore will not be repeated in this invention.

[0030] As a preferred embodiment, the propagation conditions for Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus are: temperature 25-30℃, time 1-3 days, rotation speed 100-200 r / min, with the bacterial cell count in each culture reaching 0.5 × 10⁻⁶. 10 -2.0×10 10 cfu / g is sufficient.

[0031] As a preferred embodiment, both the expansion culture and the co-culture are carried out using LB liquid medium.

[0032] As a preferred implementation method, each microbial strain needs to be activated using PDA / LB slant medium before expansion culture; specifically: activation culture temperature 28-32℃, shaking speed 180-200rpm, culture time 12h.

[0033] This invention does not impose any special limitations on the source of the raw materials and components; conventional or commercially available products known to those skilled in the art can be used. Specifically, the *Trichoderma harzianum*, *Bacillus subtilis*, and *Lactobacillus acidophilus* used in the examples were all commercially available.

[0034] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Example 1

[0035] A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were activated using LB slant medium, respectively; specifically: activation culture temperature 28℃, shaking speed 180rpm, culture time 12h.

[0036] 2) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were cultured separately using LB liquid medium. The culture conditions were: temperature 25℃, time 1 day, and rotation speed 100 r / min. The bacterial cell count in each culture reached 0.5 × 10⁻⁶. 10 -2.0×10 10 cfu / g is sufficient.

[0037] 3) Inoculate the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus into the liquid culture medium at an inoculation rate of 5%, and culture for 3 days at a temperature of 28℃, a shaking speed of 180 rpm, a system pH of 7.0-7.2, and a dissolved oxygen content of 30%. Then, culture for 2 days at a temperature of 28℃, a shaking speed of 110 rpm, a system pH of 6.5-6.8, and a dissolved oxygen content of 5% to obtain the compound bacterial solution.

[0038] 4) Mix all the raw materials in the natural minerals evenly, granulate, and dry until the moisture content does not exceed 10% to obtain mineral carrier particles with a particle size not exceeding 2mm; the raw materials contained in the natural minerals and their weight parts are as follows: vermiculite 5 parts, calcium-based bentonite 10 parts, diatomite 7 parts, all with a particle size of 100 mesh.

[0039] 5) The mineral carrier particles were placed in the composite bacterial solution, stirred and reacted, then centrifuged and dried at low temperature to obtain the bacterial-carrying particles. The stirring speed was 60 r / min, the temperature was 28℃, and the time was 1 day. The low-temperature drying temperature did not exceed 45℃. The mass-to-volume ratio of the mineral carrier particles to the composite bacterial solution was 1 g: 10 mL.

[0040] 6) Add the coating component to sterile water and stir until dissolved to obtain a 5wt% coating solution. Spray the coating solution onto the bacterial-loaded particles and dry at low temperature to obtain mineral-loaded microbial particles. The mass-to-volume ratio of bacterial-loaded particles to coating solution is 1g:2mL. The coating component is a mixture of chitosan and calcium alginate in a weight ratio of 1:0.5, and the chitosan has a molecular weight of 50-60kDa.

[0041] 7) The mineral-loaded microbial particles, additives, and organic materials are uniformly mixed and granulated to obtain a premix. The additives are a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide, potassium humate, and desulfurized gypsum are each present in 5 parts by weight. The organic materials include straw biochar, wood vinegar, and well-rotted manure. The straw biochar is corn straw biochar; the well-rotted manure is well-rotted sheep manure with a decomposition degree >90%; the wood vinegar has a pH of 2.5-3.5 and a moisture content of less than 15%. The premix has a particle size of 2 mm.

[0042] 8) Prepare a coating solution using sterile water for the slow-release coating component, spray it onto the premix, and dry at low temperature to obtain the wheat bio-fertilizer with saline-alkali soil improvement effect described above. The slow-release coating component consists of starch and carboxymethyl cellulose, with a weight ratio of starch to carboxymethyl cellulose of 0.5:1. The granulation and low-temperature drying temperature does not exceed 45℃, and the coating solution has a weight gain of 8%. The weight ratio of mineral-loaded microbial particles, additives, organic materials, and slow-release coating component is as follows: mineral-loaded microbial particles: additives: organic materials: slow-release coating component = 10:3:5:2. Example 2

[0043] A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were activated using LB slant medium, respectively; specifically: activation culture temperature 32℃, shaking speed 200rpm, culture time 12h.

[0044] 2) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were cultured separately using LB liquid medium. The culture conditions were: temperature 30℃, time 3 days, and rotation speed 200 r / min. The bacterial cell count in each culture reached 0.5 × 10⁻⁶. 10 -2.0×10 10 cfu / g is sufficient.

[0045] 3) Inoculate the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus into the liquid culture medium at an inoculation rate of 15%, and culture for 5 days at a temperature of 32℃, a shaking speed of 200 rpm, a system pH of 7.0-7.2, and a dissolved oxygen content of 50%. Then, culture for 4 days at a temperature of 30℃, a shaking speed of 140 rpm, a system pH of 6.5-6.8, and a dissolved oxygen content of 15% to obtain the compound bacterial solution.

[0046] 4) Mix all the raw materials in the natural mineral evenly, granulate, and dry until the moisture content does not exceed 10% to obtain mineral carrier particles with a particle size not exceeding 2mm; the raw materials contained in the natural mineral and their weight parts are as follows: vermiculite 8 parts, calcium-based bentonite 15 parts, diatomite 12 parts, all with a particle size of 100 mesh.

[0047] 5) The mineral carrier particles were placed in the composite bacterial solution, stirred and reacted, then centrifuged and dried at low temperature to obtain the bacterial-carrying particles. The stirring speed was 80 r / min, the temperature was 32℃, and the time was 2 days. The low-temperature drying temperature did not exceed 45℃. The mass-to-volume ratio of the mineral carrier particles to the composite bacterial solution was 1 g: 15 mL.

[0048] 6) Add the coating component to sterile water and stir until dissolved to obtain a 10wt% coating solution. Spray the coating solution onto the bacterial-loaded particles and dry at low temperature to obtain mineral-loaded microbial particles. The mass-to-volume ratio of bacterial-loaded particles to coating solution is 1g:5mL. The coating component is a mixture of chitosan and calcium alginate in a weight ratio of 1:1, and the chitosan has a molecular weight of 50-60kDa.

[0049] 7) The mineral-loaded microbial particles, additives, and organic materials are uniformly mixed and granulated to obtain a premix. The additives are a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide is 10 parts by weight, the potassium humate is 15 parts by weight, and the desulfurized gypsum is 5 parts by weight. The organic materials include straw biochar, wood vinegar, and well-rotted manure; the straw biochar is sunflower straw biochar; the well-rotted manure is well-rotted cow manure with a degree of rot >90%; the wood vinegar has a pH of 2.5-3.5 and a moisture content of less than 15%. The particle size of the premix is ​​4 mm.

[0050] 8) Prepare a coating solution using sterile water for the slow-release coating component, spray it onto the premix, and dry at low temperature to obtain the wheat bio-fertilizer with saline-alkali soil improvement effect described above. The slow-release coating component consists of starch and carboxymethyl cellulose, with a weight ratio of starch to carboxymethyl cellulose of 1.5:1. The granulation and low-temperature drying temperature should not exceed 45℃, and the weight gain of the coating solution is 15%. The weight ratio of mineral-loaded microbial particles, additives, organic materials, and slow-release coating component is as follows: mineral-loaded microbial particles: additives: organic materials: slow-release coating component = 20:7:10:2. Example 3

[0051] A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were activated using LB slant medium, respectively; specifically: activation culture temperature 30℃, shaking speed 180rpm, culture time 12h.

[0052] 2) Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were cultured separately using LB liquid medium. The culture conditions were: temperature 30℃, time 2 days, and rotation speed 180 r / min, until the bacterial cell count in each culture reached 0.5 × 10⁻⁶. 10 -2.0×10 10 cfu / g is sufficient.

[0053] 3) Inoculate the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus into the liquid culture medium at an inoculation rate of 10%, and culture for 4 days at a temperature of 32℃, a shaking speed of 180 rpm, a system pH of 7.0-7.2, and a dissolved oxygen content of 40%. Then, culture for 3 days at a temperature of 28℃, a shaking speed of 130 rpm, a system pH of 6.5-6.8, and a dissolved oxygen content of 10% to obtain the compound bacterial solution.

[0054] 4) Mix all the raw materials in the natural minerals evenly, granulate, and dry until the moisture content does not exceed 10% to obtain mineral carrier particles with a particle size not exceeding 2mm; the raw materials contained in the natural minerals and their weight parts are as follows: vermiculite 6 parts, calcium-based bentonite 13 parts, diatomite 10 parts, all with a particle size of 100 mesh.

[0055] 5) The mineral carrier particles were placed in the composite bacterial solution, stirred and reacted, then centrifuged and dried at low temperature to obtain the bacterial-carrying particles. The stirring speed was 70 r / min, the temperature was 30℃, and the time was 2 days. The low temperature drying temperature did not exceed 45℃. The mass-to-volume ratio of the mineral carrier particles to the composite bacterial solution was 1 g: 13 mL.

[0056] 6) Add the coating component to sterile water and stir until dissolved to obtain an 8wt% coating solution. Spray the coating solution onto the bacterial-loaded particles and dry at low temperature to obtain mineral-loaded microbial particles. The mass-to-volume ratio of bacterial-loaded particles to coating solution is 1g:4mL. The coating component is a mixture of chitosan and calcium alginate in a weight ratio of 1:0.8, and the chitosan has a molecular weight of 50-60kDa.

[0057] 7) The mineral-loaded microbial particles, additives, and organic materials are uniformly mixed and granulated to obtain a premix. The additives are a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide accounts for 7.5 parts by weight, the potassium humate accounts for 12.5 parts by weight, and the desulfurized gypsum accounts for 3 parts by weight. The organic materials include straw biochar, wood vinegar, and well-rotted manure; the straw biochar is sunflower straw biochar; the well-rotted manure is well-rotted sheep manure with a degree of rot >90%; the wood vinegar has a pH of 2.5-3.5 and a moisture content of less than 15%. The particle size of the premix is ​​3 mm.

[0058] 8) Prepare a coating solution using sterile water for the slow-release coating component, spray it onto the premix, and dry at low temperature to obtain the wheat bio-fertilizer with saline-alkali soil improvement effect described above. The slow-release coating component consists of starch and carboxymethyl cellulose, with a weight ratio of starch to carboxymethyl cellulose of 1:1. The granulation and low-temperature drying temperature should not exceed 45℃, and the weight gain of the coating solution should be 10%. The weight ratio of mineral-loaded microbial particles, additives, organic materials, and slow-release coating component is as follows: mineral-loaded microbial particles: additives: organic materials: slow-release coating component = 17:5:10:2.

[0059] Comparative Example 1: A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Same as 1) in Example 3.

[0060] 2) Same as 2) in Example 3.

[0061] 3) Same as 3) in Example 3.

[0062] 4) Same as 4) in Example 3.

[0063] 5) Same as 5) in Example 3, the bacterial-loaded particles are not coated, so the bacterial-loaded particles are mineral-loaded microbial particles.

[0064] 6) Same as 7) in Example 3.

[0065] 7) Same as 8) in Example 3.

[0066] Comparative Example 2: A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Same as 1) in Example 3.

[0067] 2) Same as 2) in Example 3.

[0068] 3) Same as 3) in Example 3.

[0069] 4) Same as 4) in Example 3.

[0070] 5) Same as 5) in Example 3.

[0071] 6) Same as 6) in Example 3.

[0072] 7) The mineral-loaded microbial particles, additives, organic materials, and coating slow-release components are uniformly mixed, granulated, and the premix is ​​obtained; it is then dried at low temperature to obtain the above-mentioned wheat bio-fertilizer with saline-alkali soil improvement effect. That is, in this preparation method, the coating slow-release components do not undergo a coating operation and directly participate in granulation.

[0073] The additive is a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide accounts for 7.5 parts by weight, potassium humate accounts for 12.5 parts by weight, and desulfurized gypsum accounts for 3 parts by weight. The organic materials include straw biochar, wood vinegar, and well-rotted manure; the straw biochar is sunflower straw biochar; the well-rotted manure is well-rotted sheep manure with a decomposition degree >90%; the wood vinegar has a pH of 2.5-3.5 and a moisture content of less than 15%. The premix has a particle size of 3 mm. The coating slow-release component is starch and carboxymethyl cellulose, with a weight ratio of starch to carboxymethyl cellulose of 1:1. The granulation and low-temperature drying temperature does not exceed 45℃. The weight ratio of mineral-loaded microbial particles, additives, organic materials, and coating slow-release components is as follows: mineral-loaded microbial particles: additives: organic materials: coating slow-release components = 17:5:10:2.

[0074] Comparative Example 3: A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function includes the following steps: 1) Same as 1) in Example 3.

[0075] 2) Same as 2) in Example 3.

[0076] 3) Same as 3) in Example 3.

[0077] 4) Same as 4) in Example 3.

[0078] 5) Same as 5) in Example 3, the bacterial-loaded particles are not coated, so the bacterial-loaded particles are mineral-loaded microbial particles.

[0079] 6) The mineral-loaded microbial particles, additives, organic materials, and coating slow-release components are uniformly mixed, granulated, and the premix is ​​obtained; it is then dried at low temperature to obtain the above-mentioned wheat bio-fertilizer with saline-alkali soil improvement effect. That is, in this preparation method, the coating slow-release components do not undergo a coating operation and directly participate in granulation.

[0080] The additive is a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide accounts for 7.5 parts by weight, potassium humate accounts for 12.5 parts by weight, and desulfurized gypsum accounts for 3 parts by weight. The organic materials include straw biochar, wood vinegar, and well-rotted manure; the straw biochar is sunflower straw biochar; the well-rotted manure is well-rotted sheep manure with a decomposition degree >90%; the wood vinegar has a pH of 2.5-3.5 and a moisture content of less than 15%. The premix has a particle size of 3 mm. The coating slow-release component is starch and carboxymethyl cellulose, with a weight ratio of starch to carboxymethyl cellulose of 1:1. The granulation and low-temperature drying temperature does not exceed 45℃. The weight ratio of mineral-loaded microbial particles, additives, organic materials, and coating slow-release components is as follows: mineral-loaded microbial particles: additives: organic materials: coating slow-release components = 17:5:10:2.

[0081] Experimental Example 1: Wheat planting experiment Experimental location: A farm in Linhe District, Bayannur City. The wheat variety was Bamai 13. A large-scale experimental design was adopted. The wheat bio-fertilizers in Examples 1-3 and Comparative Examples 1-3 were applied as base fertilizers, while the control group used a combination of chemical fertilizers, including urea (containing 46% N), diammonium phosphate (containing 18% N and 46% P2O5), and potassium sulfate (containing 50% K2O), all applied at a rate of 50 kg / mu. Each experimental plot was 1.5 mu in size. 5 kg of urea was applied as topdressing at the wheat jointing stage. Except for the different fertilization measures, the methods of tillage, rotary tillage, sowing, weeding, pest and disease control, and mechanical harvesting were the same.

[0082] Main measurement indicators and methods of the experiment: (1) Soil indicators: Before sowing and land preparation and after harvest, the 0-20cm soil samples were collected using the ten-point sampling method to determine soil organic matter, soil pH, EC, total nitrogen, available phosphorus and available potassium.

[0083] (2) Physiological indicators: Twelve days after seed planting, the germination rate, root length, whole plant fresh weight and root-to-shoot ratio of seedlings were measured. At the time of wheat harvest, the actual yield per mu of each treatment was measured and the yield increase rate was calculated. The calculation method is as follows: Yield increase rate (%) = (wheat yield per mu of experimental group - wheat yield per mu of control group) / wheat yield per mu of control group × 100%.

[0084] (3) Biocontrol indicators: Ten-point sampling method was used to sample 30 plants at each point to investigate wheat stem base rot and Fusarium head blight. The incidence rate and control rate were recorded and statistically analyzed. The calculation method is as follows: Incidence rate (%) = (number of diseased plants / total number of plants investigated) × 100%; Control rate (%) = (incidence rate of control group - incidence rate of experimental group) / incidence rate of control field × 100%.

[0085] Experimental results and analysis: (1) The effects of different fertilizers on the physical and chemical properties of wheat planting soil are shown in Table 1.

[0086] Table 1

[0087] The comparison shows that the control group did not have a positive effect on the restoration of soil salinity after using conventional fertilizers, while the fertilizer in the example showed nitrogen fixation, which can increase soil organic matter and reduce salt content. Long-term use is beneficial for the restoration and improvement of saline-alkali soil.

[0088] (2) The effects of different fertilizers on wheat yield are shown in Table 2.

[0089] Table 2

[0090] The comparison shows that the yield per acre of each embodiment is significantly higher than that of the comparative and control groups. This indicates that the bio-fertilizer has a significant effect on promoting growth and increasing yield. Compared with the comparative, the yield increase rate is also significantly higher. This is likely because the fertilizer granules are prepared by different methods. Due to the different forms of microbial loading and coating structures, their effects are also different. The preparation method of the embodiments can prolong the action time of microorganisms and maintain high activity, which also significantly prolongs the effect of the fertilizer and is conducive to increasing crop yield.

[0091] (3) Effects of different fertilizers on growth traits of wheat seedlings Figure 1 A comparison of individual wheat seedlings treated with different fertilizers; Figure 2 A field comparison of wheat seedlings treated with different fertilizers; Figure 3 A schematic diagram showing the germination rate and whole plant fresh weight of wheat seedlings after applying different fertilizers; Figure 4 This is a schematic diagram showing the results of root length and root-shoot ratio measurements of wheat seedlings treated with different fertilizers.

[0092] As shown in the figure, the fertilizer in the embodiment significantly promoted the germination and growth of wheat seedlings, and its growth-promoting effect was the most comprehensive. In the comparative example, due to the different forms of microbial loading and coating structures, the effects of each fertilizer were different. Overall, the fertilizer in the embodiment can also promote root development, enhance root vitality, and increase the wheat emergence rate.

[0093] (4) The effects of different fertilizers on the control of wheat stem base rot and Fusarium head blight are shown in Table 3.

[0094] Table 3

[0095] The results show that the effects of the microbial loading and coating structures in the examples and comparative examples are different. The preparation method of the examples can prolong the action time of the microorganisms and maintain high activity, and also significantly improve the disease control effect, which is conducive to reducing the amount of pesticides used.

[0096] Experimental Example 2: Fertilizer degradation test Experimental Method: The fertilizer granules prepared in Example 3 and Comparative Examples 1-3 were dried to constant weight and divided into 6 equal parts, each with a weight recorded as m1. Each part was immersed in water at 25℃. One part was taken out at intervals and recorded as d5, d10, d15, d25, d35, and d50. These parts were dried to constant weight and their mass recorded as m2. The degradation rate was calculated using the formula: Degradation rate (%) = (m1 - m2) / m1 × 100%. The results are as follows: Figure 5 As shown.

[0097] Figure 5 The figure shows the degradation rate curves of different fertilizers. As can be seen from the figure, the degradation rate of different fertilizers gradually increased with time in the degradation experiment. However, the degradation rate of the fertilizer in Example 3 was relatively low during the experiment, indicating that the fertilizer can provide wheat and soil with a longer-lasting nutrient supply and also helps to reduce the seedling burn caused by excessive fertilizer application in the early stage. The comparative examples showed different degradation rates due to different microbial loading forms and coating structures. The degradation rate was too fast, which means that the fertilizer could not meet the needs of the crop throughout its entire growth period. In the middle and late stages, the effective nutrients in the soil were easily depleted, resulting in nutrient deficiency and premature aging, which directly affected the yield and quality. This performance is also consistent with the yield in Table 2.

[0098] It should be noted that some detailed steps of the operation are not described in this invention, but are prior art known to those skilled in the art, and therefore will not be repeated here. Furthermore, in this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. In this invention, not all possible combinations of the various technical features in each embodiment or implementation are described. As long as the combinations of these technical features do not contradict each other, the various technical features in each embodiment or implementation can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wheat bio-fertilizer with saline-alkali soil improvement function, characterized in that, include: The weight ratio of mineral-supported microbial particles, additives, organic materials, and coated sustained-release components is as follows: mineral-supported microbial particles: additives: organic materials: coated sustained-release components = (10-20):(3-7):(5-10):2; The additives include at least one of seaweed polysaccharide, potassium humate, and desulfurized gypsum. The organic materials include straw biochar, wood vinegar, and well-rotted manure; The coating sustained-release components are starch and carboxymethyl cellulose.

2. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 1, characterized in that, The method for preparing the mineral-loaded microbial particles includes the following steps: 1) Mix all the raw materials in the natural minerals evenly, granulate, and dry until the moisture content does not exceed 10% to obtain mineral carrier particles with a particle size not exceeding 2mm; 2) After separately expanding the culture of Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus, they were added to liquid culture medium for mixed co-culture to obtain a compound bacterial solution; 3) Place the mineral carrier particles into the composite bacterial solution, stir and react, then centrifuge and dry at low temperature to obtain the bacterial-carrying particles; 4) Add the coating component to sterile water and stir until dissolved to obtain a coating solution. Spray the coating solution onto the bacterial-loaded particles and dry at low temperature to obtain mineral-loaded microbial particles.

3. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 2, characterized in that, The mass-to-volume ratio of the mineral carrier particles to the composite bacterial solution is 1g:(10-15)mL; the concentration of the coating solution is 5-10wt%, and the mass-to-volume ratio of the bacterial carrier particles to the coating solution is 1g:(2-5)mL.

4. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 2, characterized in that, The specific operation of the mixed co-culture is as follows: The expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus were inoculated into liquid culture medium and cultured for 3-5 days at a temperature of 28-32℃, a shaking speed of 180-200 rpm, a system pH of 7.0-7.2, and a dissolved oxygen content of 30-50%. Subsequently, they were cultured for 2-4 days at a temperature of 28-30℃, a shaking speed of 110-140 rpm, a system pH of 6.5-6.8, and a dissolved oxygen content of 5-15%. The inoculation amount of the expanded Trichoderma harzianum, Bacillus subtilis, and Lactobacillus acidophilus was 5-15%.

5. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 2, characterized in that, The natural minerals contain the following raw materials and their weight parts: vermiculite 5-8 parts, calcium-based bentonite 10-15 parts, diatomaceous earth 7-12 parts, all with a particle size of 100 mesh; the coating component is a mixture of chitosan and calcium alginate in a weight ratio of 1:(0.5-1), and the chitosan has a molecular weight of 50-60 kDa.

6. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 1, characterized in that, The additive is a mixture of seaweed polysaccharide, potassium humate, and desulfurized gypsum, wherein the seaweed polysaccharide is 5-10 parts by weight, the potassium humate is 5-15 parts by weight, and the desulfurized gypsum is 1-5 parts by weight.

7. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 1, characterized in that, The straw biochar is selected from at least one of corn straw biochar and sunflower straw biochar; the decomposed manure is selected from at least one of decomposed sheep manure and decomposed cow manure, with a decomposition degree >90%; the wood vinegar has a pH value of 2.5-3.5 and a water content of less than 15%.

8. The wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 1, characterized in that, In the coated sustained-release component, the weight ratio of starch to carboxymethyl cellulose is (0.5-1.5):

1.

9. A method for preparing a wheat bio-fertilizer with saline-alkali soil improvement function, characterized in that, Includes the following steps: 1) Mix mineral-loaded microbial particles, additives, and organic materials evenly, granulate, and obtain a premix; 2) Prepare a coating solution by using sterile water to prepare the coating slow-release component, spray it onto the premix, and dry it at low temperature to obtain the wheat bio-fertilizer with saline-alkali soil improvement function as described in any one of claims 1-8.

10. The method for preparing wheat bio-fertilizer with saline-alkali soil improvement effect according to claim 9, characterized in that, The granulation and low-temperature drying temperatures do not exceed 45°C, the particle size of the premix is ​​2-4 mm, and the weight gain of the coating liquid is 8-15%.

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