Method for preparing fertilizer by using water bubble manure and black soil fertilization method

Abstract

The application discloses a method for preparing fertilizer by using water-bubble manure and a black soil fertilization method. The method for preparing fertilizer by using water-bubble manure comprises the following steps: (1) performing solid-liquid separation treatment on the water-bubble manure to obtain a solid part with a water content of less than or equal to 60% and a liquid part with a solid content of less than or equal to 1.5%; (2) using a synthetic bacterial agent to ferment the liquid part obtained in the step (1) to obtain fermented liquid manure; the synthetic bacterial agent comprises Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis and Saccharomyces cerevisiae; the ratio of the viable bacterial count of the Bacillus subtilis, the Bacillus mycoides, the Bacillus licheniformis and the Saccharomyces cerevisiae is 1:0.8-1.2:0.8-1.2:0.5-1.5; the total viable bacterial count in the synthetic bacterial agent is not less than 2.0*10 9 CFU / g; and (3) performing composting and maturation on the solid part obtained in the step (1) to obtain matured solid manure. The application effectively realizes the unification of resource utilization of water-bubble manure in large-scale pig farms, acceleration of straw decomposition and long-term fertilization of black soil.

Description

Technical Field

[0001] This invention relates to the field of soil improvement technology, and in particular to a method for preparing fertilizer using water-soaked manure and a method for improving the fertility of black soil. Background Technology

[0002] The Northeast Black Soil Region is an important commodity grain base and a superior area for pig farming in my country. In recent years, conservation tillage techniques, centered on straw mulching and no-till or reduced-till sowing, have been rapidly promoted in the Black Soil Region, achieving significant results in controlling soil degradation and sequestering carbon and improving fertility. However, with the increasing scale of livestock farming, the "water-soaked manure" process has generated a massive amount of liquid manure. Water-soaked manure is characterized by high water content (85%-92%), solid-liquid mixture, long storage period, and difficulty in treatment. Improper treatment not only causes serious non-point source pollution but also wastes its rich nitrogen, phosphorus, potassium, and organic matter resources.

[0003] Under existing conservation tillage conditions, there are several technical contradictions between returning manure to the field and mulching straw: First, the water-based manure application and straw mulching are incompatible. Conventional surface application of liquid manure can easily lead to straw floating, hindering sowing, and causing significant nitrogen and ammonia volatilization losses (the loss rate can reach 30%-50%). Second, there is a lack of specialized fermentation agents for the specific process of "water-based manure application." Conventional agents have low activity in the high moisture, low temperature, and facultative anaerobic environment of water-based manure, making it impossible to achieve in-situ reduction and targeted composting of manure during storage. Third, the amount of manure applied lacks a scientific basis based on C / N balance, which can easily lead to soil carbon and nitrogen imbalance, affecting straw decomposition and crop seedling growth. Fourth, although existing technologies involve furrow application of microbial agents and row placement of straw, they do not have a systematic design for the source treatment of water-based manure in large-scale pig farms and the precise injection of liquid manure, making it difficult to solve the technical bottleneck of large-scale water-based manure application. Summary of the Invention

[0004] The present invention aims to provide a method for preparing fertilizer using water-soaked manure from large-scale pig farms. Another objective is to provide a method for improving black soil fertility based on this water-soaked manure under conservation tillage, clarifying the key technical parameters for liquid manure injection and solid manure strip application, thereby achieving the dual goals of improving black soil fertility and reducing chemical fertilizer application.

[0005] To achieve the above objectives, the present invention provides a method for preparing fertilizer using water-soaked manure, comprising the following steps: (1) Solid-liquid separation treatment of water-flushed feces to obtain a solid part with a water content ≤60% and a liquid part with a solid content ≤1.5%; (2) Using a synthetic microbial agent, the liquid portion obtained in step (1) is fermented to obtain fermented liquid manure; the synthetic microbial agent comprises: Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae; the ratio of viable bacteria of Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae is: 1:0.8-1.2:0.8-1.2:0.5-1.5; the total number of viable bacteria in the synthetic microbial agent is not less than 2.0 × 10⁻⁶. 9 CFU / g; (3) Compost the solid part obtained in step (1) to obtain composted solid manure.

[0006] Optionally, in step (2), the liquid portion obtained in step (1) is transported to the fermentation tank and inoculated with the synthetic microbial agent at a volume of 0.5‰-1.5‰ of the liquid portion; after inoculation, it is allowed to stand for 12-24 hours for activation; during fermentation, an intermittent micro-aeration process is adopted, with an aeration rate of 0.2-0.5 VVM, aeration for 30 minutes and an interval of 60 minutes; stirring is performed once every 24 hours, and each stirring is performed for 15-30 minutes; the fermentation cycle is 7-10 days.

[0007] Optionally, the preparation method of the synthetic microbial agent is as follows: A. Take cryopreserved *Bacillus subtilis*, *Bacillus mycosisrinus*, *Bacillus licheniformis*, and *Saccharomyces cerevisiae*, and inoculate them into their respective liquid culture media for activation culture: *Bacillus subtilis* and *Bacillus licheniformis* were cultured on TSB medium at 30℃ and 180 rpm for 48 hours; *Bacillus mycosisrinus* was cultured on NB medium at 15℃ and 150 rpm for 72 hours; and *Saccharomyces cerevisiae* was cultured on YPD medium at 28℃ and 180 rpm for 48 hours. After activation culture, the concentration of each bacterial culture reached 1×10⁻⁶. 8 CFU / mL or higher; B. Take Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae bacterial cultures in a live bacteria ratio of 1:0.8-1.2:0.8-1.2:0.5-1.5, respectively, mix them thoroughly under aseptic conditions, and inoculate them into a solid-state fermentation substrate for solid-state fermentation. The solid-state fermentation adopts a staged temperature control mode, where 0-48 hours is the early fermentation stage, with the temperature controlled at 25-35℃; 48-72 hours is the middle fermentation stage, with the temperature increased to 35-40℃; and 72-96 hours is the late fermentation stage. In the first stage, the temperature is reduced to 15-20℃; the aeration rate during fermentation is controlled at 0.2-0.5 VVM, and an intermittent micro-aeration process is adopted, with aeration for 30 minutes followed by a 60-minute interval; the material moisture content is adjusted to 75%-92%, the C / N ratio to 22:1-28:1, and sodium humate (0.5%-1.5%) and manganese sulfate (0.1%-0.3%) are added according to the dry weight of the material; after 96 hours of fermentation, the fermentation product is dried at 35℃, pulverized, and passed through an 80-mesh sieve to obtain a total viable count of not less than 2.0 × 10⁻⁶. 9 The finished synthetic microbial agent product with CFU / g.

[0008] Optionally, the Bacillus subtilis is Bacillus subtilis CGMCC 1.3358; the Bacillus mycoides is Bacillus mycoides CICC 21473; the Bacillus licheniformis is Bacillus licheniformis CGMCC 1.813; and the Saccharomyces cerevisiae is Saccharomyces cerevisiae CGMCC 2.3965.

[0009] Optionally, the method for composting the solid part obtained in step (1) in step (3) is as follows: the moisture content of the solid part obtained in step (1) is adjusted to 55%-65%, the C / N ratio is adjusted to 25-30:1, windrow or trough composting is adopted, the temperature of the pile rises to above 55°C within 48 hours and is maintained for 5-7 days, the pile is turned over 2-3 times a week, and the composting cycle is 25-35 days.

[0010] Optionally, the method for solid-liquid separation of water-fluid feces in step (1) is as follows: the water-fluid feces are treated by a combination of inclined screen solid-liquid separator and screw extrusion solid-liquid separator. The screen aperture of the inclined screen solid-liquid separator is controlled within the range of 0.25-1.0 mm, the compression ratio of the screw extruder is controlled within the range of 3:1-5:1, the main shaft speed is 43-60 r / min, and the extrusion pressure is controlled within the range of 0.3-0.5 MPa, so as to obtain a solid part with a water content ≤60% and a liquid part with a solid content ≤1.5%.

[0011] In some embodiments, the liquid portion is fermented after inoculation, static activation, intermittent micro-aeration, and stirring; the solid portion is composted in windrows or troughs after the moisture content and carbon-nitrogen ratio are adjusted.

[0012] The present invention also provides fermented liquid manure and / or decomposed solid manure prepared by the above method, and the application of the fermented liquid manure and / or decomposed solid manure in black soil fertilization.

[0013] This invention also provides a method for improving the fertility of black soil, comprising the following steps: Using a wide-narrow row straw mulching pattern, the fermented liquid manure prepared by the above method is injected into the soil in autumn at a depth of 10-15 cm, with an application rate of 2.5-3.0 m. 3 / mu, so that the C / N ratio of the topsoil is maintained at 20-25:1; in spring, the decomposed solid manure prepared by the above method is mixed with chemical fertilizer and granulated to make organic-inorganic compound granular fertilizer with a particle size of 2-5 mm, and applied to the side and below the seeds at a depth of 15-20 cm. The proportion of decomposed solid manure replacing chemical nitrogen fertilizer is 10%-30%.

[0014] Optionally, in the wide-narrow row straw mulching mode, the straw is crushed to a length of 10-15 cm and fully covers the surface of the wide row, while the narrow row is the seedling strip. During sowing, the seedling strip maintains a bare width of 20-30 cm. The wide and narrow rows are alternated every other year, and the position of the seedling strip is adjusted to the straw mulching strip of the previous year when sowing in the following year.

[0015] Compared to directly returning water-soaked manure to the field or using a single treatment method, this invention first separates the water-soaked manure into a liquid portion suitable for injection and a solid portion suitable for composting. These are then fermented and composted separately, allowing for differentiated treatment of the two types of materials according to their material form and subsequent utilization needs. Thus, the liquid portion can be injected into the soil in autumn, while the solid portion can be mixed with chemical fertilizers, granulated, and then applied deeply in spring. This reduces the interference of liquid manure surface application with straw mulching and sowing operations, and improves the adaptability of manure return to the field.

[0016] The use of a synthetic microbial agent composed of Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae, with limited proportions and total viable counts, combined with a fermentation method of static activation, intermittent micro-aeration, and periodic stirring, helps maintain the stability of the fermentation system under conditions of high moisture content in water-soaked manure, promotes the degradation of cellulose in manure, and reduces nitrogen loss and ammonia emission during the fermentation process.

[0017] By combining the application of liquid manure in autumn, the side-deep application of well-rotted solid manure in spring, the use of straw mulching in wide and narrow rows, and the regulation of the carbon-nitrogen ratio in the topsoil, the supply of manure nutrients is coordinated with the spatiotemporal needs of straw decomposition, crop seedling growth, and root absorption. Under the continuous implementation conditions of the examples, soil organic matter, bulk density, and water-stable aggregates can be improved, and corn yield can be maintained or increased while reducing the amount of nitrogen fertilizer used.

[0018] Beneficial effects: This invention, through the systematic integration of three core technical components, forms a complete technical solution for the resource utilization of water-flushed manure and black soil fertilization in large-scale pig farms under conservation tillage, and has the following beneficial effects compared with existing technologies: 1. This invention effectively solves the problem of treating waterlogged manure in large-scale pig farms, achieving both manure reduction and resource utilization. Addressing the high water content and solid-liquid mixture characteristics of waterlogged manure, this invention employs a combined process of inclined screen solid-liquid separator and screw extrusion solid-liquid separator for pretreatment. The screen aperture is controlled at 0.25-1.0 mm, and the compression ratio is controlled at 3:1-5:1. This reduces the water content of the solid portion to ≤ 60%, and stabilizes the solid content of the liquid portion at ≤ 1.5%. The solid portion facilitates subsequent composting and transportation, while the liquid portion is suitable for pipeline transportation and injection fertilization, achieving both manure reduction and resource-based tiered utilization. After fermentation with synthetic microbial communities, the total nutrient loss rate of the liquid manure is reduced by more than 25%, and ammonia volatilization is reduced by 30%-40%, effectively reducing the environmental pollution risk during manure treatment.

[0019] 2. Significantly improved manure utilization efficiency and achieved precise nutrient regulation. The low-temperature resistant synthetic microbial community constructed in this invention is a compound of Bacillus subtilis CGMCC 1.3358, Bacillus mycoides CICC 21473, Bacillus licheniformis CGMCC 1.813, and Saccharomyces cerevisiae CGMCC 2.3965 in an optimized ratio, with a total viable count of not less than 2.0 × 10⁻⁶. 9CFU / g. This bacterial community maintains high activity even at low temperatures of 4-15 ℃. Through a fermentation process using segmented temperature control (25-30 ℃ in the early stage, 35-40 ℃ in the middle stage, and 15-20 ℃ in the later stage) and intermittent micro-aeration (0.2-0.5 VVM), efficient and stable treatment of manure is achieved. In autumn, the fermented liquid manure is injected into the soil at a depth of 10-15 cm, increasing nitrogen utilization by 18-25 percentage points compared to conventional surface application. In spring, solid manure is mixed with chemical fertilizer, granulated, and then applied 15-20 cm below and to the side of the seeds, improving the spatial matching of fertilizer nutrients with the root system by more than 30%, achieving precise spatiotemporal regulation of nutrients.

[0020] 3. This invention promotes the synergistic fertilization of straw and manure, significantly improving soil quality. Based on the principle of carbon-nitrogen balance, this invention determines the application rate of liquid manure to be 2.5-3.0 m³. 3 This method maintains the C / N ratio of the topsoil within the optimized range of 20-25:1 per mu (approximately 0.067 hectares), effectively resolving the conflict between straw decomposition and crop nitrogen competition. Combined with a wide-narrow row (120 cm wide rows, 40 cm narrow rows) conservation tillage pattern, straw is pulverized to a length of 10-15 cm and fully covered on the surface of the wide rows, achieving alternate-year straw mulching and seedling rotation. After two consecutive years of implementation, the straw decomposition rate increased by more than 35%, soil organic matter increased by 0.8-1.2 g / kg, soil bulk density decreased by 5%-8%, and the content of water-stable aggregates >0.25 mm increased by 15%-20%, resulting in significant improvements in soil physicochemical properties.

[0021] 4. This invention supports the reduction and efficiency improvement of chemical fertilizers, achieving stable and increased crop yields. Solid manure is mixed with chemical nitrogen, phosphorus, and potassium fertilizers and granulated to produce organic-inorganic compound granular fertilizer with a particle size of 2-5 mm. The organic nitrogen replaces 10%-30% of the chemical nitrogen fertilizer, with a preferred replacement ratio of 20%-25%. While ensuring crop yield, the amount of chemical nitrogen fertilizer used is reduced by 10%-30%, and the phosphorus and potassium fertilizers can be adjusted accordingly based on soil test results. Field trial results show that the corn yield using this invention's technical solution reaches over 11,800 kg / hm², a 5% increase compared to conventional fertilization (100% chemical fertilizer), with nitrogen fertilizer partial productivity increasing by over 30%, achieving a synergistic effect between black soil fertilization and yield enhancement.

[0022] 5. Highly compatible with conservation tillage techniques, forming a systematic solution for crop-livestock integration. This invention organically integrates three core technical links: solid-liquid separation pretreatment, synthetic microbial agent construction and fermentation, and phased return to the field. It is deeply integrated with the conservation tillage (straw mulching and no-till sowing) model widely promoted in the black soil region of Northeast China. The depth of liquid manure injection in autumn (10-15 cm) matches the depth of the soil tillage layer, and the depth of solid manure side-deep fertilization in spring (15-20 cm) coincides with the dense root layer of corn. The wide-narrow row planting pattern (120 cm + 40 cm) is coordinated with agronomic measures such as straw mulching, seedling strip sowing, and biennial rotation. The entire technical solution not only solves the problem of manure disposal in large-scale pig farms but also overcomes the technical difficulties of slow soil warming and low germination rate caused by long-term straw mulching, providing a complete technical path for the development of crop-livestock integrated agriculture in the black soil region. Attached Figure Description

[0023] Figure 1 The effect of different organic nitrogen substitution ratios on maize yield. Detailed Implementation

[0024] Example 1: A method for black soil fertilization in large-scale pig farms under conservation tillage, involving synergistic treatment of water-flushing manure and microbial agents, and phased return of the manure to the field. I. Pretreatment stage of water-based fecal solid-liquid separation Raw manure stored in the manure pits of livestock farms for 7-10 days, with a moisture content of approximately 90%, is collected and processed using a combination of an inclined screen solid-liquid separator and a screw extrusion solid-liquid separator. The inclined screen solid-liquid separator has a screen aperture of 0.5mm and a processing capacity of 60 m³ / h. 3 After separation, the liquid portion has a solids content reduced to 1.2% and is directly fed into the liquid manure fermentation system. The solid portion has a moisture content of approximately 75% and undergoes secondary dehydration in a screw press. The screw press features a variable diameter screw shaft design, a compression ratio of 4:1, a main shaft speed of 50 r / min, and a pressing pressure controlled at 0.4 MPa. After dehydration, the moisture content of the solid portion is reduced to 55%, facilitating subsequent composting and transportation. The entire separation system is automatically controlled, with the feed pump, mixer, and separator operating in tandem based on the manure tank level. The system has a power output of 7.5 kW.

[0025] II. Construction and Fermentation of Low-Temperature Resistant Synthetic Microbial Community (I) Preparation of synthetic microbial communities The synthetic microbial community used in this embodiment consists of the following strains: Bacillus subtilis (CGMCC 1.3358), Bacillus mycoides (CICC 21473), Bacillus licheniformis (CGMCC 1.813), and Saccharomyces cerevisiae (CGMCC 2.3965). All strains were purchased from the China General Microbiological Culture Collection Center (CGMCC) or the China Industrial Microbiological Culture Collection Center (CICC).

[0026] Four cryopreserved bacterial strains were inoculated into their respective liquid culture media for activation culture: Bacillus subtilis and Bacillus licheniformis were cultured on TSB medium (HB4114-41, Haibo Biotechnology) at 30 ℃ and 180 rpm for 48 hours; Bacillus mycosis fungoides was cultured on NB medium (HB0108, Haibo Biotechnology) at 15 ℃ and 150 rpm for 72 hours; and Saccharomyces cerevisiae was cultured on YPD medium (HB5193-1, Haibo Biotechnology) at 28 ℃ and 180 rpm for 48 hours. After culture, the concentration of each bacterial culture reached 1×10⁻⁶. 8 CFU / mL or higher.

[0027] Four bacterial solutions were taken in a live bacteria ratio of 1:1:1:1 and mixed evenly under aseptic conditions. The mixture was then inoculated into a solid-state fermentation substrate (wheat bran:soybean meal:peat moss mass ratio of 5:3:2) for solid-state fermentation. The fermentation temperature was controlled in stages: 28℃ (0-48 hours) in the early stage, 38℃ (48-72 hours) in the middle stage, and 18℃ (72-96 hours) in the later stage. The aeration rate was 0.3 VVM (30 minutes of aeration followed by a 60-minute interval). The material moisture content was 80%, the C / N ratio was 25:1, and sodium humate (1.0%) and manganese sulfate (0.2%) were added based on the dry weight of the material. After 96 hours of fermentation, the fermentation product was dried at 35℃, pulverized, and passed through an 80-mesh sieve to obtain a live bacteria count of 2.8 × 10⁻⁶. 9 The finished synthetic microbial agent product with CFU / g.

[0028] (II) Liquid manure fermentation treatment The liquid portion obtained from solid-liquid separation was transferred to a fermentation tank and inoculated with the aforementioned synthetic microbial agent at a volume ratio of 1.0‰. After inoculation, the tank was allowed to stand for 18 hours for activation. During fermentation, an intermittent micro-aeration process was used, with an aeration rate of 0.3 VVM, aeration for 30 minutes followed by a 60-minute interval. The tank was stirred once every 24 hours for 20 minutes each time. The fermentation cycle was 8 days.

[0029] After fermentation, samples were taken for testing. Compared with the control group that was not inoculated with microbial agents, the total nitrogen loss of liquid manure in the treatment group of this invention was reduced by 31.5%, the ammonia concentration was reduced by 37.8%, the degradation rate of cellulose in the manure was increased by 33.6%, and the manure was transformed from a foul-smelling and viscous state into a stable liquid with better fluidity, with the pH stable in the range of 7.2-7.8.

[0030] III. Phased Return-to-Field Operations under Conservation Tillage (a) Wide-narrow row conservation tillage straw mulching pattern A wide-narrow row planting pattern is adopted, with wide rows of 120 cm and narrow rows of 40 cm. After the previous year's corn harvest, the straw is shredded to a length of 12 cm and fully covered on the surface of the wide rows (120 cm). The narrow rows (40 cm) serve as the seedbed for the following year's planting. At the time of planting, the seedbed is kept 25 cm bare to facilitate soil temperature recovery and seedling emergence. The wide and narrow rows are alternated every other year, meaning that at the time of planting the following year, the position of the seedbed is adjusted to the straw-covered area of ​​the previous year, thus achieving the alternation of straw coverage and seedbed rotation.

[0031] (II) Deep application of liquid manure in autumn After the autumn corn harvest and before the soil freezes (October 15th-October 25th), liquid manure, fermented with synthetic microbial agents, is deeply applied using a specialized injection-type fertilizer applicator. The applicator integrates trenching, injection, and covering functions, with an injection depth of 12 cm and a row spacing of 55 cm, staggered from the next year's narrow-row seedling strip. After the trencher opens the trench, the liquid manure is injected, and then the covering device covers and compacts the soil, leaving no obvious manure residue on the surface after fertilization.

[0032] The application rate of liquid manure was determined based on the principle of carbon-nitrogen balance: Based on the soil's basic C / N ratio (12:1) and the amount of straw returned to the field (approximately 750 kg / mu of corn straw returned to the field), with the goal of maintaining the topsoil C / N ratio within the optimal range of 23:1, the calculated application rate of liquid manure was 2.8 m³. 3 / mu.

[0033] (III) Spring application of solid manure by side-deep fertilization and the ratio of organic to inorganic fertilizers (1) Solid manure composting The solid portion (55% moisture content) obtained from solid-liquid separation was composted. The moisture content was adjusted to 60%, and corn stalk powder was added to adjust the C / N ratio to 28:1. Windrow composting was used, with a pile width of 2.5 m and a height of 1.2 m. The pile temperature was raised to 58℃ within 36 hours and maintained at 55-65℃ for 6 days. The pile was turned three times a week (Monday, Wednesday, and Friday), with a composting period of 30 days. After composting, the solid manure had a moisture content of 28% and an organic matter content of 48.5%, meeting the standards for organic fertilizer.

[0034] (2) Preparation of organic-inorganic compound granular fertilizer Well-rotted solid manure was mixed with chemical nitrogen fertilizer (urea), phosphate fertilizer (superphosphate), and potassium fertilizer (potassium sulfate) at a nitrogen substitution ratio of 20% organic nitrogen and 80% chemical nitrogen, based on the measured total nitrogen content of the organic fertilizer. A rotary drum granulation process was used, with bentonite added as a binder at a controlled amount of 5% of the total material mass. After granulation, the particle size was controlled within the range of 2-5 mm, with 85% of the particles being 2-4 mm in diameter, resulting in a 93% particle formation rate.

[0035] (3) Side-deep fertilization operation Before spring sowing (April 25th - May 5th), use a no-till planter equipped with a side-deep fertilization device to apply the above-mentioned organic-inorganic compound granular fertilizer simultaneously with the sowing process. The fertilization depth is set to 18 cm (below and to the side of the seed), and the sowing depth is 4 cm. After fertilization, cover with soil and compact.

[0036] IV. Efficacy Verification Experiment: Three treatments were set up: ① The method of this invention (solid-liquid separation + microbial fermentation + staged return to the field); ② Control 1 (conventional surface application of liquid manure + straw return to the field); ③ Control 2 (single application of chemical fertilizer, CK). Each treatment area was 500 m², randomized block design, and replicated 3 times.

[0037] Yields were measured after maize maturity in 2024, and the method of this invention achieved a maize yield of 11,856 kg / hm². 2 Compared to control 1 (10,234 kg / hm) 2 Yield increased by 15.8%, compared to control 2 (11,024 kg / hm). 2 The yield increased by 7.5%. Soil testing results showed that after two consecutive years of implementation, the organic matter content in the 0-20 cm soil layer treated by the method of this invention increased from 22.5 g / kg to 24.3 g / kg, an increase of 1.2 g / kg compared to control 1 and 1.8 g / kg compared to control 2; the soil bulk density decreased from 1.38 g / cm³ to 1.29 g / cm³, a decrease of 6.5%; and the content of >0.25 mm water-stable aggregates increased from 42.3% to 51.6%, an increase of 21.9%. Nitrogen use efficiency measurements showed that the nitrogen use efficiency of the treatment by the method of this invention reached 49.2%, an increase of 16.7 percentage points compared to control 1 (32.5%) and 13.4 percentage points compared to control 2 (35.8%).

[0038] Example 2: Comparison Experiment of Different Microbial Community Ratios and Fermentation Parameters At the same test site, using the same basic conditions and operating procedures as in Example 1, different bacterial community ratios and fermentation parameters were set to verify the technical effect of the preferred scheme of the present invention.

[0039] (a) Comparison of bacterial community ratios Four microbial community ratios were set up for treatment: T1 (Bacillus subtilis: Mycosis fungoides: Lichen: Yeast = 1:1:1:1, the preferred ratio of this invention); T2 (1:0.5:1:0.5); T3 (1:1.5:1:1.5); T4 (single Bacillus subtilis). The fermentation conditions for each treatment were the same as in Example 1.

[0040] The liquid manure indicators were tested after 4 days of fermentation, and the results are shown in Table 1. Treatment T1 had the lowest total nitrogen loss rate (28.5%), the highest ammonia volatilization reduction rate (36.8%), and the highest cellulose degradation rate (35.2%), which were significantly better than other treatments, indicating that the 1:1:1:1 ratio is the optimal microbial community ratio of this invention.

[0041] Table 1. Effects of different microbial community ratios on the fermentation efficiency of liquid manure.

[0042] (II) Comparison of fermentation parameters Based on the T1 ratio, different temperature gradient treatments were set: F1 (initial stage 28℃ (0-48 hours), middle stage 38℃ (48-72 hours), and final stage 18℃ (72-96 hours), preferred in this invention); F2 (constant 25℃); F3 (constant 35℃); F4 (initial stage 20℃, middle stage 30℃, and final stage 25℃). After 4 days of fermentation, the F1 treatment showed the best cellulose degradation rate (35.8%) and total nitrogen loss rate (28.2%).

[0043] Different aeration rates were set up for treatment: A1 (0.3 VVM, aeration for 30 min / intermittent for 60 min, preferred in this invention); A2 (0.1 VVM, continuous aeration); A3 (0.5 VVM, continuous aeration); A4 (no aeration, static). The test results showed that treatment A1 had a moderate dissolved oxygen level, and the aerobic-facultative anaerobic environment was conducive to the synergistic effect of the bacterial community. It also showed the highest reduction rate of ammonia volatilization (37.2%) and energy consumption was reduced by more than 40% compared to continuous aeration.

[0044] Example 3: Comparative Experiment of Different Organic-Inorganic Ratios and Fertilization Depth At the same test site, using the technical process of Example 1, different organic-inorganic ratios and side-deep fertilization depths were set to verify the technical effect of the preferred scheme of the present invention.

[0045] (a) Comparison of organic and inorganic ratios Five organic nitrogen substitution ratio treatments were set up: R0 (0%, full-volume fertilizer, CK); R1 (10%); R2 (20%, preferred in this invention); R3 (30%); R4 (40%). The depth of side-deep fertilization in spring was uniformly 18 cm.

[0046] Yield was measured after the corn matured, and the results were as follows: Figure 1 As shown, R2 (20% replacement) and R3 (30% replacement) treatments yielded the highest outputs, at 11,856 kg / hm². 2 and 11,792 kg / hm 2 Compared to CK (11,024 kg / hm) 2 The yields increased by 7.5% and 7.0% respectively; the yield of the R4 (40% replacement) treatment was the same as that of the CK. Taking into account yield, fertilization effect and fertilizer cost, 20%-30% is the preferred replacement ratio range of this invention, of which 20% is the best economic ratio.

[0047] (II) Comparison of Fertilization Depth Based on R2 (20% replacement), four lateral fertilization depth treatments were set: D1 (10 cm); D2 (15 cm); D3 (18 cm, preferred in this invention); D4 (20 cm); D5 (25 cm). The sowing depth was uniformly 4 cm.

[0048] Emergence rate and root distribution were investigated during the maize seedling stage (30 days after sowing), and yield was measured at maturity. Results showed that the D3 (18 cm) and D2 (15 cm) treatments had the highest emergence rates (96.5% and 95.8%, respectively), with no seed burn. The D1 (10 cm) treatment showed slight seed burn in some plots, with an emergence rate of 92.3%. The D5 (25 cm) treatment exhibited weaker seedling growth and slightly lower yield in the later stages. At maturity, the D3 treatment had the highest yield (11,856 kg / hm²). 2 ), followed by D2 (11,672 kg / hm). 2 ) and D4 (11,583 kg / hm 2 This indicates that 15-20cm is the preferred fertilization depth range of this invention, with 18cm being the optimal depth.

[0049] Example 4: Comparative Experiment of Wide and Narrow Row Straw Mulching Patterns At the same test site, using the technical process of Example 1, different planting patterns were set up: P1 (120cm+40cm wide and narrow rows, rotated every other year, preferred in this invention); P2 (120cm+40cm wide and narrow rows, no rotation); P3 (65cm equal row spacing, full straw coverage); P4 (65cm equal row spacing, no straw coverage, CK).

[0050] Soil temperature at 0-10 cm depth during the spring sowing period (average from April 25th to May 5th) was measured. Results showed that the soil temperature in treatment P1 was 1.8℃ higher than that in treatment P3 and 0.5℃ lower than that in treatment P4. The emergence rate was 96.5% in treatment P1, 91.2% in treatment P3, and 97.3% in treatment P4. Yield at maturity was 11,856 kg / hm² in treatment P1.2 P2 treatment yielded 11,342 kg / hm² 2 P3 treatment yielded 10,856 kg / hm² 2 P4 treatment yielded 11,024 kg / hm² 2 This indicates that the wide-narrow row alternating rotation pattern of the present invention can effectively alleviate the problems of slow soil temperature recovery and low seedling emergence rate caused by straw mulching, while giving full play to the fertilization effect of straw and achieving yield increase.

[0051] Example 5: Verification of the effect of large-scale application From 2023 to 2024, a large-scale application verification was conducted on a 1,000-mu (approximately 67 hectares) scale at a maize planting base in Meilis District, Qiqihar City, Heilongjiang Province. A contiguous planting area of ​​1,000 mu (approximately 67 hectares) was selected, with 500 mu (approximately 33 hectares) using the technical solution of this invention (process of Example 1) and the other 500 mu (approximately 33 hectares) using the conventional planting method (straw removal + single application of chemical fertilizer) as a control. The maize variety used was Nendan 22. Other management measures were consistent with local conventional practices.

[0052] Large-scale application results show that the technical solution of this invention applies an average of 2.8 m³ of liquid manure per mu (approximately 0.067 hectares). 3 Fertilizer nitrogen usage decreased by 22.5%; the two-year average corn yield was 586.7 kg / mu (14% moisture content), an increase of 8.2% compared to the control (542.3 kg / mu); soil testing results showed that after two years of implementation, the organic matter content in the 0-20 cm soil layer increased by an average of 0.9 g / kg, the soil bulk density decreased by 5.8%, and the content of water-stable aggregates >0.25 mm increased by 17.6%. In livestock farms, 21,000 cubic meters of water-soaked manure were treated annually, achieving 100% resource utilization of manure, saving approximately 35 yuan / cubic meter in manure treatment costs compared to traditional methods, thus realizing the expected goals of integrated crop-livestock farming and circular development.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing fertilizer using water-soaked manure includes the following steps: (1) Solid-liquid separation treatment of water-flushed feces to obtain a solid part with a water content ≤60% and a liquid part with a solid content ≤1.5%; (2) Using a synthetic microbial agent, the liquid portion obtained in step (1) is fermented to obtain fermented liquid manure; the synthetic microbial agent comprises: Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae; the ratio of viable bacteria of Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae is: 1:0.8-1.2:0.8-1.2:0.5-1.5; the total number of viable bacteria in the synthetic microbial agent is not less than 2.0 × 10⁻⁶. 9 CFU / g; (3) Compost the solid part obtained in step (1) to obtain composted solid manure.

2. The method for preparing fertilizer using water-soaked manure according to claim 1, characterized in that: In step (2), the liquid portion obtained in step (1) is transported to the fermentation tank, and the synthetic microbial agent is inoculated at 0.5‰-1.5‰ of the volume of the liquid portion; after inoculation, it is allowed to stand for 12-24 hours for activation; during fermentation, an intermittent micro-aeration process is adopted, with an aeration rate of 0.2-0.5 VVM, aeration for 30 minutes and an interval of 60 minutes; stirring is performed once every 24 hours, and each stirring is performed for 15-30 minutes; the fermentation cycle is 7-10 days.

3. The method for preparing fertilizer using water-soaked manure according to claim 1 or 2, characterized in that: The preparation method of the synthetic microbial agent is as follows: A. Take cryopreserved *Bacillus subtilis*, *Bacillus mycosisrinus*, *Bacillus licheniformis*, and *Saccharomyces cerevisiae*, and inoculate them into their respective liquid culture media for activation culture: *Bacillus subtilis* and *Bacillus licheniformis* were cultured on TSB medium at 30℃ and 180 rpm for 48 hours; *Bacillus mycosisrinus* was cultured on NB medium at 15℃ and 150 rpm for 72 hours; and *Saccharomyces cerevisiae* was cultured on YPD medium at 28℃ and 180 rpm for 48 hours. After activation culture, the concentration of each bacterial culture reached 1×10⁻⁶. 8 CFU / mL or higher; B. Take Bacillus subtilis, Bacillus mycoides, Bacillus licheniformis, and Saccharomyces cerevisiae bacterial cultures in a live bacteria ratio of 1:0.8-1.2:0.8-1.2:0.5-1.5, respectively, mix them thoroughly under aseptic conditions, and inoculate them into a solid-state fermentation substrate for solid-state fermentation. The solid-state fermentation adopts a staged temperature control mode, where 0-48 hours is the early fermentation stage, with the temperature controlled at 25-35℃; 48-72 hours is the middle fermentation stage, with the temperature increased to 35-40℃; and 72-96 hours is the late fermentation stage. In the first stage, the temperature is reduced to 15-20℃; the aeration rate during fermentation is controlled at 0.2-0.5 VVM, and an intermittent micro-aeration process is adopted, with aeration for 30 minutes followed by a 60-minute interval; the material moisture content is adjusted to 75%-92%, the C / N ratio to 22:1-28:1, and sodium humate (0.5%-1.5%) and manganese sulfate (0.1%-0.3%) are added according to the dry weight of the material; after 96 hours of fermentation, the fermentation product is dried at 35℃, pulverized, and passed through an 80-mesh sieve to obtain a total viable count of not less than 2.0 × 10⁻⁶. 9 The finished synthetic microbial agent product with CFU / g.

4. The method for preparing fertilizer using water-soaked manure according to any one of claims 1-3, characterized in that: The Bacillus subtilis is Bacillus subtilis CGMCC 1.3358; the Bacillus mycoides is Bacillus mycoides CICC 21473; the Bacillus licheniformis is Bacillus licheniformis CGMCC 1.813; and the Saccharomyces cerevisiae is Saccharomyces cerevisiae CGMCC 2.3965.

5. The method for preparing fertilizer using water-soaked manure according to any one of claims 1-4, characterized in that: The method for composting the solid part obtained in step (1) in step (3) is as follows: the moisture content of the solid part obtained in step (1) is adjusted to 55%-65%, the C / N ratio is adjusted to 25-30:1, windrow or trough composting is adopted, the temperature of the pile rises to above 55℃ within 48 hours and is maintained for 5-7 days, the pile is turned over 2-3 times a week, and the composting cycle is 25-35 days.

6. The method for preparing fertilizer using water-soaked manure according to any one of claims 1-5, characterized in that: The method for solid-liquid separation of water-fluid feces in step (1) is as follows: the water-fluid feces are processed by a combination of inclined screen solid-liquid separator and screw extrusion solid-liquid separator. The screen aperture of the inclined screen solid-liquid separator is controlled within the range of 0.25-1.0 mm, the compression ratio of the screw extruder is controlled within the range of 3:1-5:1, the main shaft speed is 43-60 r / min, and the extrusion pressure is controlled within the range of 0.3-0.5 MPa, so as to obtain a solid part with a water content ≤60% and a liquid part with a solid content ≤1.5%.

7. Fermented liquid manure and / or well-rotted solid manure, characterized in that, It is prepared by the method of preparing fertilizer using water-soaked manure as described in any one of claims 1-6.

8. The application of the fermented liquid manure and / or decomposed solid manure as described in claim 7 in black soil fertilization.

9. A method for improving the fertility of black soil, comprising the following steps: Using a wide-narrow row straw mulching pattern, in autumn, the fermented liquid manure prepared by any one of the methods described in claims 1-6 is injected into the soil at a depth of 10-15 cm, with an application rate of 2.5-3.0 m. 3 / mu, so that the C / N ratio of the topsoil is maintained at 20-25:1; in spring, the decomposed solid manure prepared by any of the methods in claims 1-6 is mixed with chemical fertilizer and granulated to make organic-inorganic compound granular fertilizer with a particle size of 2-5 mm, and applied to the side below the seeds at a depth of 15-20 cm, wherein the proportion of decomposed solid manure replacing chemical nitrogen fertilizer is 10%-30%.

10. The method for improving black soil fertility according to claim 9, characterized in that: In the wide-narrow row straw mulching pattern, the straw is crushed to a length of 10-15 cm and fully covers the surface of the wide row. The narrow row is the seedling strip, and the seedling strip is kept with a bare width of 20-30 cm during sowing. The wide and narrow rows are rotated every other year, and the seedling strip is adjusted to the straw mulching strip of the previous year when sowing the following year.

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