Millet bio-organic fertilizer suitable for alkaline soil, preparation method and application thereof

Abstract

The application discloses millet bio-organic fertilizer suitable for alkaline soil and a preparation method and application thereof, and is characterized in that the organic fertilizer is composed of raw materials in the following proportions by weight: matured cow dung, zinc sulfate heptahydrate, bacillus megaterium, bacillus subtilis, bacillus mucilaginosus, bacillus amyloliquefaciens and bacillus thuringiensis in a proportion of 17000:75:34:85:85:34:85. The fertilizer is suitable for improving the soil effective zinc content during the growth period of millet in the special lime soil environment in the north of Shanxi, and can effectively improve the zinc content, millet xanthophyll content and millet yellow degree of millet in the region. The fertilizer ratio has important guiding value for reasonable fertilization of millet planting in the north of Shanxi.

Description

Technical Field

[0001] This invention belongs to the field of fertilizer technology, specifically relating to a millet bio-organic fertilizer suitable for alkaline soil, its preparation method, and its application. Background Technology

[0002] Zinc (Zn) is an essential micronutrient for maintaining normal physiological functions and plays a vital role in human growth and development. Zinc participates in the synthesis of at least 160 enzymes in the human body and is indispensable for maintaining many physiological activities. Zinc deficiency can affect memory and learning ability, impair the development of the nervous system, and damage brain function. According to surveys by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO), approximately 116,000 children under the age of five die globally each year due to zinc deficiency, and about 1.1 billion people are at risk of zinc deficiency. Zinc deficiency has become one of the major factors affecting global human health. Zinc in agricultural products remains the primary source of zinc for the human body through food; therefore, increasing the zinc content of agricultural products is of great significance for improving human zinc nutrition.

[0003] Millet (Setaria italica) is one of the most important drought-resistant crops and the sixth largest cereal crop in the world. Compared with other major cereals, millet is more resistant to pests and diseases, has a shorter growing season, and yields higher harvests under drought conditions. Millet has a long history of cultivation in China and is one of the important food crops in northern China. Northern Shanxi Province, as one of the main millet-growing areas in China, is an important region for producing high-quality millet. Increasing the zinc content of millet in northern Shanxi can effectively improve the zinc nutrition of the population in this region.

[0004] Compared to wheat and rice, millet is not only rich in nutrients such as protein, fat, dietary fiber, and vitamins, but also contains abundant functional active ingredients, such as phenols, active peptides, and carotenoids, which have various health benefits, including lowering blood sugar, blood lipids, and blood pressure. Yellow pigments are an important nutrient in millet, and their chemical composition is basically the same as that of corn yellow pigments, mainly including zeaxanthin (3,3′-dihydroxy-β-carotene), cryptoxanthin (3-hydroxy-β-carotene), and lutein (3,3′-dihydroxy-α-carotene), belonging to natural carotenoids. Numerous studies and clinical trials at home and abroad have proven that natural carotenoids not only protect vision and epithelial cells, but also enhance human immunity, quench excess free radicals in the body, prevent and treat various cancers, and have good therapeutic effects on oral ulcers and skin diseases. Therefore, increasing the yellow pigment content of millet is beneficial to improving its health-promoting functions and should be an important direction for improving millet quality. In addition, when choosing millet, people generally believe that the yellower the millet, the higher its nutritional value. Therefore, yellowness is also an important sensory quality of millet, and improving its yellowness is of great value in improving the sensory quality of millet.

[0005] Soil microorganisms participate in many ecosystem processes, promoting the release and enhancing the availability of minerals such as potassium, iron, magnesium, and zinc in the soil. Studies have reported that plant rhizosphere growth-promoting bacteria such as *Bacillus megaterium*, *Bacillus subtilis*, *Bacillus mucilaginosus*, *Bacillus amyloliquefaciens*, and *Bacillus thuringiensis* possess zinc-solubilizing abilities, and these Bacillus species have mature production processes and commercially available products. Furthermore, current agricultural production attempts involve combining microbial inoculants with organic fertilizers to create bio-organic fertilizers, combining the effects of both microbial and organic fertilizers. Research indicates that organic fertilizer significantly influences the zinc-solubilizing effect of implanted microbial strains, but the content of available zinc in the soil is related to the type of organic material. Currently, there are no reports on studies in northern Shanxi Province regarding the enhancement of available zinc content in local soil and millet zinc content through the combined application of Bacillus and organic fertilizers. Additionally, no studies have been reported on improving the yellow pigment and yellowness of millet through rational fertilization.

[0006] The soils in northern Shanxi are alkaline, with a significantly high pH value, generally above 8.4, and are typical calcareous soils. Zinc availability in these soils is very low. Therefore, this study, using Yunzhou District of Datong City, Shanxi Province as a pilot area, aimed to improve soil zinc deficiency by applying zinc fertilizer in combination with microbial agents and organic fertilizers. This increased the available zinc content in the soil during the millet growing season and enhanced the zinc and yellow pigment content of both millet and foxtail millet, thereby increasing the yellowness of the millet. Summary of the Invention

[0007] The purpose of this invention is to provide a millet bio-organic fertilizer suitable for alkaline soil, its preparation method and application. This organic fertilizer can effectively increase the content of available zinc in the soil during the growth period of millet, and increase the zinc content and yellow pigment content of millet and foxtail millet, as well as the yellowness of foxtail millet.

[0008] To achieve the above objectives, the technical solution of the present invention is summarized as follows:

[0009] A millet bio-organic fertilizer, wherein the weight ratio of N, Zn and microbial inoculant in the organic fertilizer is 200:15:3.8.

[0010] Preferably, the microbial agent is a mixture of Bacillus megaterium, Bacillus subtilis, Bacillus mucilage, Bacillus amyloliquefaciens, and Bacillus thuringiensis. More preferably, the weight ratio of Bacillus megaterium, Bacillus subtilis, Bacillus mucilage, Bacillus amyloliquefaciens, and Bacillus thuringiensis is 2:5:5:2:5.

[0011] Preferably, the N is provided by well-rotted cow dung, and the Zn is provided by zinc sulfate heptahydrate.

[0012] This study used Yunzhou District, Datong City, Shanxi Province, located in northern Shanxi, as a pilot area for a field experiment. Three different fertilizer treatments were established: application of only well-rotted cow manure (CM), application of zinc alone with well-rotted cow manure (ZnSO4+CM), and application of a combination of zinc, well-rotted cow manure, and microbial inoculant (ZnSO4+CM+MB g3). The fertilizer was applied as a base fertilizer to the soil before millet sowing. Sufficient irrigation was provided during the crop's growth period. Soil samples were collected at the seedling, jointing, heading, grain-filling, and maturity stages to determine soil indicators such as available zinc. Millet was harvested at maturity, and samples of both the plants and grains were collected to determine yield, zinc content, and quality indicators.

[0013] The experiment showed that fertilization treatments significantly affected the available zinc content in the soil during the millet growth period. The available zinc content in the soil treated with K3 (ZnSO4+CM+MB g3) was significantly higher than that in the control K1 (CM), with increases of 191.43%, 235.54%, 292.33%, 144.34%, and 229.90% respectively, according to the growth stage. Except for the seedling stage, the available zinc content in the soil treated with K3 was significantly higher than that in the zinc-only treatment K2 (ZnSO4+CM) at all millet growth stages, with increases of 42.93%, 56.06%, 29.34%, and 140.96% respectively, according to the growth stage. At the same time, the ZnSO4+CM+MB g3 group resulted in significantly higher quality indicators such as millet zinc content, millet yellow pigment content, and millet yellowness than other fertilization groups, and significantly higher millet zinc content than the control group (CM). However, the difference in millet yield between the two groups was not statistically significant, and the millet yield was relatively stable. Through various experiments, it can be concluded that:

[0014] The optimal fertilization method for millet in northern Shanxi is to apply a combination of zinc, well-rotted cow manure, and microbial inoculants before sowing. This significantly increases the available zinc content in the soil during the jointing-maturity stage of millet. Simultaneously, while maintaining a relatively stable millet yield, it significantly improves quality indicators such as zinc content and yellow pigment content, reaching 35.00 mg / kg and 63.96 mg / kg respectively. Therefore, the optimal fertilization formula for millet in northern Shanxi can be determined as: well-rotted cow manure : zinc sulfate heptahydrate : Bacillus megaterium : Bacillus subtilis : Bacillus mucilaginosus : Bacillus amyloliquefaciens : Bacillus thuringiensis = 17000 : 75 : 34 : 85 : 85 : 34 : 85.

[0015] The preparation method of the above-mentioned millet bio-organic fertilizer is as follows: Bacillus megaterium, Bacillus subtilis, Bacillus mucilaginosus, Bacillus amyloliquefaciens, and Bacillus thuringiensis are mixed evenly, and then added to well-rotted cow manure along with zinc sulfate heptahydrate and stirred thoroughly until evenly mixed.

[0016] When applying fertilizer specifically, follow the ratio of 1 hm².2 The calculated usage amounts of well-rotted cow manure, zinc sulfate heptahydrate, Bacillus megaterium, Bacillus subtilis, Bacillus mucilaginosus, Bacillus amyloliquefaciens, and Bacillus thuringiensis are 17,000 kg, 75 kg, 34 kg, 85 kg, 85 kg, 34 kg, and 85 kg, respectively. The usage amounts of Bacillus megaterium, Bacillus subtilis, Bacillus mucilaginosus, Bacillus amyloliquefaciens, and Bacillus thuringiensis are all calculated based on an effective viable bacterial count ≥ 100 billion.

[0017] In addition, this invention also protects the application of the above-mentioned organic fertilizer in increasing the zinc content, yellow pigment content and yellowness of millet grains.

[0018] Advantages of this invention:

[0019] The fertilizer of this invention is designed for the unique calcareous soil environment of northern Shanxi. Through reasonable experiments, it has been found to be suitable for increasing the available zinc content in the soil during the growth period of millet, and can effectively improve the zinc content, yellow pigment content and yellowness of millet in this region. It has very important guiding value for how to rationally fertilize millet in northern Shanxi. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer with the description. However, unless otherwise specified, the specific experimental methods involved in the following embodiments are conventional methods or implemented according to the conditions recommended in the manufacturer's instructions.

[0021] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the experimental methods in the following embodiments are all conventional methods. Unless otherwise specified, the reagents and materials used can be purchased commercially.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be used in this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0023] This study used Yunzhou District of Datong City, Shanxi Province, located in northern Shanxi, as a pilot area to conduct a field experiment to investigate the effects of different basal fertilizer applications on soil available zinc content, millet yield, zinc content in millet and foxtail millet, and yellow pigment content in foxtail millet. The specific experimental procedure is as follows:

[0024] 1. Materials and Methods

[0025] 1.1 Overview of the Experimental Site

[0026] The experimental site was located at the Organic Dryland Farming Experimental Station of China Agricultural University in Gudingqiao Village, Yunzhou District, Datong City, Shanxi Province (39°88′N, 113°50′E). The soil type of the experimental site was loess-type cultivated land of the Loess Plateau. The topsoil organic matter content was 8.6 g / kg, total nitrogen content was approximately 0.734 g / kg, available phosphorus content was approximately 8.06 mg / kg, available potassium content was 124 mg / kg, pH value was 8.40, and total zinc content was 33.482 mg / kg, which is considered low zinc level.

[0027] 1.2 Test Materials

[0028] The test crop was Zhangza 13 millet.

[0029] Experimental fertilizers: well-rotted cow manure; zinc sulfate heptahydrate; microbial agents (Bacillus megaterium, Bacillus subtilis, Bacillus mucilaginosus, Bacillus amyloliquefaciens, Bacillus thuringiensis).

[0030] Instruments and Reagents: Electronic balance (MTQ-100, Shenzhen Mobil Electronics Co., Ltd.); Electric heating drying oven (YDL-2000, Shanghai Qigong Instrument Equipment Co., Ltd.); Germ rice milling machine (JNPY-100, Shandong Yutai Jinli Grain and Oil Machinery Co., Ltd.); Universal grinder (DE-500, Wuyi Huacai Tools Co., Ltd.); Freeze dryer (SCIENTZ-18N, Ningbo Xinzhi Biotechnology Co., Ltd.); CNC ultrasonic cleaner (KQ-500DE, Kunshan Ultrasonic Instrument Co., Ltd.); Benchtop centrifuge (TG16-WS, Hunan Xiangyi Laboratory Instrument Development Co., Ltd.); Constant temperature water bath (DK-S26, Shanghai Jinghong Experimental Equipment Co., Ltd.); Automatic UV-Vis spectrophotometer (TU-1810plus, Shanghai Xipu Instrument Co., Ltd.); Millet thresher (Pintai Machinery Technology Co., Ltd.); Colorimeter (WSF, Shanghai Precision Scientific Instruments Co., Ltd.).

[0031] Concentrated nitric acid (superior grade, Shanghai testing); 30% hydrogen peroxide solution (superior grade, Shanghai testing); n-butanol (analytical grade, Shanghai testing); β-carotene standard (Shanghai Jiuxinyan Biotechnology Co., Ltd.).

[0032] 1.3. Test Plan

[0033] The preliminary experiment was conducted in pots at the Nanpingfang Greenhouse on the West Campus of China Agricultural University. Well-rotted cow manure was used as the organic fertilizer, and zinc sulfate heptahydrate (ZnSO4·7H2O) was used as the zinc source. Six different combinations of eight microbial agents—Bacillus megaterium, Bacillus mucilaginosus, Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus thuringiensis, Pseudomonas fluorescens, Azotobacter chrysophagus, and Trichoderma harzianum—were applied (Table 1). Specific dosages of each agent are shown in Table 2. The experiment concluded when the millet entered the jointing stage. At the end of the experiment, soil samples from the millet root zone were collected, and the available zinc content was determined.

[0034] The results (Table 3) show that the available zinc content in the soil treated with added microbial agents was significantly higher than that in the control treatment without added microbial agents. Specifically, the available zinc content in the soil treated with agents I4 (microbial agent combination 3) and I6 (microbial agent combination 5) was significantly higher than that in the other treatments. Furthermore, compared to agent combination 5, agent combination 3 can effectively increase the available zinc content in the soil with less microbial agent; therefore, agent combination 3 was selected as the suitable microbial agent combination.

[0035] Table 1 Pre-experimental treatments for millet potted plants

[0036]

[0037]

[0038] Note: Microbial agent combination 1: Bacillus megaterium + Bacillus mucilaginosus + Bacillus subtilis

[0039] Microbial agent combination 2: Bacillus megaterium + Bacillus mucilaginosus + Bacillus subtilis + Pseudomonas fluorescens

[0040] Microbial agent combination 3: Bacillus megaterium + Bacillus mucilaginosus + Bacillus subtilis + Bacillus amyloliquefaciens + Bacillus thuringiensis

[0041] Microbial agent combination 4: Bacillus megaterium + Bacillus mucilaginosus + Bacillus subtilis + Azotobacter chrysozoans + Trichoderma harzianum

[0042] Microbial agent combination 5: Bacillus megaterium + Bacillus mucilaginosus + Bacillus subtilis + Bacillus amyloliquefaciens + Bacillus thuringiensis + Pseudomonas fluorescens + Azotobacter chrysophagus + Trichoderma harzianum

[0043] Table 2. Amounts of each substance used in the preliminary experimental treatment.

[0044]

[0045] Note: 1. The usage of the above-mentioned microbial agents is calculated based on "effective live bacteria count ≥ 100 billion".

[0046] 2. The specific dosage of organic fertilizer should be calculated based on the nitrogen content of the fertilizer itself.

[0047] Table 3. Content of available zinc in soil during a preliminary pot experiment of millet (unit: mg / kg)

[0048]

[0049] Field Experiment: A field experiment was conducted in the millet experimental field of the Organic Dryland Farming Experimental Station of China Agricultural University in Datong City, Shanxi Province. Under the condition of using well-rotted cow manure as a supplementary fertilizer, different zinc application treatments (ZnSO4·7H2O) were set up. The specific dosage of the substance is shown in Table 4 below. The zinc fertilizer was applied to the soil before millet sowing, and the specific treatment methods are shown in Table 5 below. Sufficient irrigation was carried out during the crop growth period.

[0050] Soil samples were collected during the seedling, jointing, heading, grain-filling, and maturity stages of millet to determine soil indicators such as available zinc. Millet was harvested at maturity, and samples of both the plants and grains were collected to determine yield, zinc content, and quality indicators.

[0051] Table 4. Amount of each substance used in the experimental treatment

[0052]

[0053] Note: 1. The usage of the above-mentioned microbial agents is calculated based on "effective live bacteria count ≥ 100 billion".

[0054] 2. The specific dosage of organic fertilizer should be calculated based on the nitrogen content of the fertilizer itself.

[0055] Table 5. Treatments in the Millet Field Trial

[0056]

[0057] Note: Microbial agent combination 3: Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus mucilage, Bacillus thuringiensis, Bacillus amyloliquefaciens

[0058] 1.4 Measurement Items and Methods

[0059] 1.4.1 Soil available zinc content

[0060] The DTPA-AAS method was used for determination, and the specific operation method is as follows.

[0061] The soil samples obtained in the experiment were air-dried naturally and passed through a 1 mm sieve. 25 g of soil sample was weighed and then 50 mL of DTPA-TEA solution was added. The mixture was extracted at a liquid-to-soil ratio of 2:1 and shaken for 2 hours (180 reciprocating shakes per minute). The supernatant was then filtered through a 0.45 μm aqueous filter membrane, and the filtrate was collected and measured using an atomic absorption spectrophotometer (AAS method).

[0062] 1.4.2 Zinc content in plant organs

[0063] A number of representative plants were selected at maturity, placed in kraft paper bags, and brought back to the laboratory for washing. The samples were then separated according to stems, leaves, ears, and other organs, followed by blanching and drying to constant weight. Grain samples were dehulled twice using a germ rice milling machine to obtain millet. All plant samples were then pulverized, passed through a 100-mesh sieve, and stored in resealable bags for the determination of zinc content in the plant organs.

[0064] The determination of zinc content in plant organs should refer to GB / T 35876-2018, and the specific operation method is as follows.

[0065] Accurately weigh 0.5000g of powder sample and place it in a microwave digestion tube. Add 5mL of concentrated nitric acid and 1mL of 30% hydrogen peroxide. Cover with the inner cap, install the protective cover, and place the digestion vessel into the microwave digester. Set the microwave digestion program as follows:

[0066] Step 1: Power 600W, heating time 8min, temperature control 100℃, duration 5min;

[0067] Step 2: Power 600W, heating time 8min, temperature control 150℃, duration 15min;

[0068] Begin digesting the sample. After complete digestion, remove the inner container, wash the digestion solution in the inner container with water in small amounts several times, and transfer it to a 10 ml volumetric flask. Make up to volume and mix well. Then filter the supernatant through a 0.45 μm aqueous filter membrane, collect the filtrate, and determine the zinc content using an atomic absorption spectrophotometer (AAS method). Perform a reagent blank determination simultaneously.

[0069] 1.4.3 Production

[0070] Millet was harvested at maturity. Two rows of five-meter-long millet with uniform growth were selected from each plot and harvested manually. The number of effective ears was calculated, and the millet was threshed using a small millet thresher and weighed. The yield was converted to 14% moisture content as the actual yield.

[0071] 1.4.4 Yellow pigment content

[0072] (1) Determination of yellow pigment content in samples

[0073] First, n-butanol and purified water are mixed evenly in a 1:1 volume ratio and left to stand overnight to separate into layers, thus obtaining water-saturated n-butanol.

[0074] Select plump rice grains and grind them thoroughly with a grinder until they become fine powder. Then, dry them using a freeze dryer. After drying, accurately weigh 0.4000g of millet powder and place it in a 5mL brown centrifuge tube. Add 4mL of water-saturated n-butanol, tighten the cap, and place the tube on a reciprocating shaker to extract for 3 hours to fully extract the yellow pigment.

[0075] After shaking, the sample was centrifuged at 4°C and 8000 rpm for 15 min, and then the supernatant was collected. The absorbance of the supernatant at 450 nm was measured using a UV spectrophotometer.

[0076] (2) Construction of the standard curve for yellow pigment

[0077] Weigh 20 mg of β-carotene standard sample into a 200 mL volumetric flask, add 4 mL of chloroform to dissolve it, and then add water-saturated n-butanol solution to the mark to prepare a 0.1 mg / mL β-carotene standard solution. Then, pipette 0, 100, 200, 300, 400, and 500 μL of β-carotene solution into 10 mL centrifuge tubes, add water-saturated n-butanol solution to the mark to 10 mL, and obtain β-carotene standard solutions of 0 μg / mL, 1 μg / mL, 2 μg / mL, 3 μg / mL, 4 μg / mL, and 5 μg / mL, respectively. Use a UV spectrophotometer to detect the absorbance of the β-carotene standard solution at 450 nm and construct a standard curve.

[0078] 1.4.5 Grain color characteristics

[0079] The brightness (L*), red-green value (a*), and yellow-blue value (b*) of the hulled millet grains were measured using a colorimeter under a D65 light source and a 10 field of view.

[0080] 1.5 Data Analysis

[0081] Data were statistically analyzed using Excel 2023, and R 4.3.0 was used for data analysis and plotting. The LSD test was used for analysis of variance between groups, and p < 0.05 was considered statistically significant.

[0082] 2 Results and Analysis

[0083] 2.1 Effects of different fertilizer basal applications on soil available zinc content (Table 6)

[0084] The combined application of ZnSO4 with organic fertilizer and microbial agents (K3) significantly increased the soil available zinc content during the jointing-maturity stage of millet. Compared with no zinc application (K1), the K3 treatment significantly increased the soil available zinc content at all growth stages of millet, with increases of 191.43%, 235.54%, 292.33%, 144.34%, and 229.90%, respectively. Compared with the combined application of organic fertilizer and zinc (K2), the addition of microbial agents (K3) further significantly increased the soil available zinc content during the jointing-maturity stage of millet, with increases of 42.93%, 56.06%, 29.34%, and 140.96%, respectively.

[0085] Table 6. Soil available zinc content at different growth stages of millet (unit: mg / kg)

[0086]

[0087] 2.2 Effects of different basal fertilizers on millet yield and quality (Table 7)

[0088] The highest yield was achieved when ZnSO4 was applied in combination with organic fertilizer and microbial agents (K3), but the difference in millet yield among the treatments was not significant, and the millet yield was relatively stable.

[0089] The combined application of ZnSO4 with organic fertilizer and microbial agents (K3) significantly increased the zinc content in millet, with the highest zinc content reaching 35.00 mg / kg. The zinc content of millet treated with K3 increased by 19.32% compared with no zinc application (K1) and by 7.15% compared with the combined application of organic fertilizer and zinc (K2).

[0090] The combined application of ZnSO4 with organic fertilizer and microbial agents (K3) significantly increased the content of millet yellow pigment, with the highest content reaching 63.96 mg / kg, which was 7.77% higher than that without zinc application (K1) and 6.26% higher than that with the combined application of organic fertilizer and zinc (K2).

[0091] The combined application of ZnSO4 with organic fertilizer and microbial agents (K3) significantly improved the yellowness of millet, reaching the highest level of 45.48, which is 3.61% higher than that without zinc application (K1) and 2.78% higher than that with the combined application of organic fertilizer and zinc (K2).

[0092] Table 7 Millet Yield and Quality Indicators

[0093]

[0094] The embodiments described above are merely preferred embodiments of the present invention and are only used to explain the present invention. They are not intended to limit the scope of the present invention. For those skilled in the art, other implementation methods can be easily made by substitution or modification based on the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included within the scope of the patent application of the present invention.

Claims

1. The application of a millet bio-organic fertilizer suitable for alkaline soil in increasing the zinc content, yellow pigment content, and yellowness of millet grains, characterized in that... The organic fertilizer is composed of the following raw materials in the following weight ratio: well-rotted cow manure: zinc sulfate heptahydrate: Bacillus subtilis: Bacillus megaterium: Bacillus mucilaginosus: Bacillus amyloliquefaciens: Bacillus thuringiensis = 17000: 75: 34: 85: 85: 34:

85.

2. The application according to claim 1, characterized in that, The preparation method of the millet bio-organic fertilizer is as follows: Bacillus subtilis, Bacillus megaterium, Bacillus mucilaginosus, Bacillus amyloliquefaciens and Bacillus thuringiensis are mixed evenly, and then added to well-rotted cow manure along with zinc sulfate heptahydrate and stirred thoroughly until evenly mixed to obtain the final product.

3. The application according to claim 2, characterized in that, Based on 1 hm², the usage amounts of well-rotted cow manure, zinc sulfate heptahydrate, Bacillus subtilis, Bacillus megaterium, Bacillus mucilaginosus, Bacillus amyloliquefaciens, and Bacillus thuringiensis are 17,000 kg, 75 kg, 34 kg, 85 kg, 85 kg, 34 kg, and 85 kg, respectively.

4. The application according to claim 2, characterized in that, The usage of Bacillus subtilis, Bacillus megaterium, Bacillus mucilaginosus, Bacillus amyloliquefaciens, and Bacillus thuringiensis is calculated based on an effective live bacteria content of ≥100 billion.

5. The application according to claim 2, characterized in that, Before sowing millet, the organic fertilizer is applied to the soil as a base fertilizer.

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