Organic and inorganic acid compounded stable microbial liquid fertilizer as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of agricultural fertilizers, and particularly relates to an organic and inorganic acid compounded stable microbial liquid fertilizer and a preparation method thereof. The liquid fertilizer comprises the following components in percentage by weight: 3%-5% of phosphoric acid, 5%-15% of ammonium polyphosphate, 1%-3% of potassium fulvate, 0.5%-1.5% of glycine, 1%-2% of glucose, phosphorus-solubilizing microorganisms which take bacillus megaterium as a main material and have the bacterium content of 107-108 CFU / mL, 2%-4% of plant source amino acid liquid or humus liquid and the balance of water. The fertilizer has fast-acting property and slow-release property, constructs a synergistic phosphorus dissolving system of a phosphoric acid source, an organic chelating agent and microorganisms, can effectively improve the effectiveness of phosphorus in soil and the absorption and utilization efficiency of crops on phosphorus, is suitable for modern agricultural fertilization modes such as drip irrigation, flushing application and water and fertilizer integration, has the advantages of lasting fertilizer efficiency, remarkable root promotion, high utilization rate and the like, and has wide application prospects. Good popularization prospects are realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of agricultural fertilizer and microbial preparation, and relates to an organic and inorganic acid compound stable microbial liquid fertilizer and a preparation method thereof. BACKGROUND

[0002] Phosphorus is an essential element for crop growth, and plays an important role in yield, quality and stress resistance. In order to ensure crop yield, excessive application of phosphorus fertilizer is a common phenomenon in agricultural planting. However, phosphorus has poor mobility in soil, is easily fixed and precipitated, and other problems. The phosphorus fertilizer applied to the soil is mostly combined with soil minerals, clay or organic matter to be converted into non-effective phosphorus, resulting in a large amount of phosphorus accumulation in the soil.

[0003] At present, about 75% to 90% of the phosphorus fertilizer applied to farmland is converted into non-effective phosphorus, of which Fe-P, Al-P and Ca-P account for more than 60%, directly leading to a phosphorus utilization rate of only 10% to 25% for crops in the same season. The soil in northern China is mainly calcareous soil (carbonate soil) and neutral to slightly alkaline soil, with high content of free calcium carbonate and active iron and aluminum compounds in the soil, and the soil pH value is mostly between 7.0 and 8.5. Under this environment, the applied phosphorus fertilizer (especially water-soluble phosphorus fertilizer) is easily fixed by calcium, iron and aluminum ions to form compounds such as insoluble calcium phosphate, iron phosphate and aluminum phosphate, resulting in a significant decrease in phosphorus availability. Statistical data shows that the utilization rate of phosphorus fertilizer in northern soil is generally only 10% to 20%, which is far lower than the international advanced level, which not only increases the agricultural input cost, but also causes the problems of phosphorus resource waste and environmental phosphorus load increase.

[0004] In recent years, more and more researches have focused on liquid fertilizer through the cooperation of organic acid and inorganic acid to improve the availability and utilization rate of phosphorus. Low molecular weight organic acids (such as citric acid, oxalic acid, malic acid) can chelate with Ca 2+ , Fe 3+ , Al 3+The cations form stable complexes, destroy the crystal structure of calcium phosphate and other insoluble phosphorus compounds, and promote the release of insoluble phosphorus; inorganic acids (such as phosphoric acid and nitric acid) can quickly reduce the local pH of the soil and increase the solubility of phosphorus minerals in the soil. The complex liquid fertilizer of organic acid and inorganic acid has a "chemical-complexing double phosphorus dissolution mechanism", the inorganic acid provides an acidic environment to speed up the mineral dissolution rate, and the organic acid maintains the active concentration of phosphorus ions in the phosphate solution through complexation and chelation, thereby significantly improving the utilization efficiency of phosphorus fertilizer. The single organic acid system has the problems of slow release and poor stability; the single inorganic acid system has the problems of high corrosion, easy volatilization and easy loss of phosphorus. The traditional organic acid or inorganic acid phosphorus dissolution system has its own advantages, but all faces the limitations of low phosphorus dissolution efficiency, poor stability and weak environmental adaptability. Therefore, it is urgent to build a new type of liquid fertilizer system with a synergistic mechanism of "organic complexing + inorganic acid dissolution" to realize the efficient, controllable and green utilization of phosphorus resources.

[0005] In addition, the liquid fertilizer is more easily combined with water and fertilizer integration facilities, and is suitable for fertilization methods such as drip irrigation and sprinkler irrigation, thereby reducing the loss and fixation risk of phosphorus. Under the soil conditions in northern China, the research and development and popularization of the liquid fertilizer with improved phosphorus effectiveness through organic and inorganic acid complexing have significant application prospects and economic benefits, and the present application provides an effective technical means to solve the problem of low utilization rate of phosphorus fertilizer.

[0006] However, the liquid fertilizer with improved phosphorus effectiveness through organic and inorganic acid complexing still has deficiencies: the phosphorus source, organic acid and inorganic acid used can only realize single function, lack of mutual synergistic effect between components, and still limit the absorption of phosphorus by crops. SUMMARY

[0007] The present application aims to solve the problem that the existing phosphorus fertilizer is easily fixed by calcium, iron, aluminum and other ions in the soil, resulting in low availability and poor utilization efficiency of phosphorus, and provides an organic and inorganic acid complex stable microbial liquid phosphorus fertilizer and a preparation method thereof. The present application scientifically complex inorganic acid phosphorus source with organic acid, organic chelating agent, carbon source and phosphorus-dissolving microorganism to build a liquid system with multiple mechanisms for synergistic release and activation of phosphorus, thereby significantly improving the absorption efficiency of phosphorus by crops and having good agronomic performance and popularization value.

[0008] Inorganic acid phosphorus source: mainly refers to soluble phosphate such as phosphoric acid (H3PO4) and liquid polyammonium phosphate (APP), which has the functions of rapid release of phosphorus, rapid reduction of pH and dissolution of insoluble phosphorus minerals in the soil.

[0009] Organic acid: such as potassium fulvic acid, humic acid, aminoacetic acid and the like, which has weak acidity and complexing and buffering capacity, can complex with metal ions (Ca 2+ , Fe 3+ ) to prevent the fixation of phosphorus.

[0010] Organic chelating agent: aminoacetic acid, plant source amino acid liquid, etc. Rich in active groups such as carboxyl and amino, can form stable organic metal complex, keep phosphorus in soluble state, reduce precipitation.

[0011] Carbon source: such as glucose, fulvic acid, etc. Provide available energy substrate for phosphorus-dissolving microorganisms, promote their metabolism and growth, and stimulate the phosphorus-dissolving capacity of microorganisms.

[0012] Phosphorus-dissolving microorganisms: can secrete organic acids or phosphatase substances, activate the insoluble phosphorus source in the soil, and release the absorbable phosphorus.

[0013] Scientific compounding: refers to the design of reasonable proportioning and synergistic mechanism, not simple mixing, but considering the synergy, stability, biological activity and other factors between components to achieve the optimal fertilizer efficiency.

[0014] The present application aims at the above technical problems, and provides an organic and inorganic acid compounded stable microbial liquid fertilizer, which comprises the following components in percentage by weight: phosphoric acid 3-5%, polyphosphoric acid ammonium 5-15%, potassium fulvate 1-3%, aminoacetic acid 0.5-1.5%, glucose 1-2%, phosphorus-dissolving microorganisms: bacteria content 10 7 ~ 10 8 CFU / mL, organic nutrient supplement 2-4%, the organic nutrient supplement being plant source amino acid liquid or humic substance liquid, and water making up to 100%.

[0015] Preferably, the phosphoric acid is 4%, the polyphosphoric acid ammonium is 10%, the potassium fulvate is 2%, the aminoacetic acid is 1%, and the glucose is 1.5%.

[0016] Further, the phosphoric acid is 85% industrial phosphoric acid.

[0017] High-concentration 85% industrial phosphoric acid is used to ensure an acidic environment and quickly dissolve mineral phosphorus.

[0018] Further, the polyphosphoric acid ammonium is N>10% and P2O5>34% liquid polyphosphoric acid ammonium.

[0019] High nitrogen (N>10%) promotes crop growth and synergizes with phosphorus; high P2O5 (>34%) provides sufficient phosphorus source, and the liquid form is easy to compound and apply.

[0020] Further, the aminoacetic acid is glycine with a purity of 98.5%.

[0021] High-purity glycine has good solubility in liquid fertilizer and is not prone to precipitation reaction with other components (such as phosphoric acid and polyphosphoric acid ammonium), ensuring the uniformity and stability of the system.

[0022] Further, the phosphorus-dissolving microorganisms include Bacillus megaterium, Aspergillus niger, and Penicillium spp.

[0023] The phosphorus-dissolving microorganisms (such as Bacillus megaterium) secrete organic acids (such as citric acid and oxalic acid) to directly dissolve soil-insoluble phosphorus (such as calcium phosphate and iron phosphate), and also secrete phosphatase to hydrolyze organic phosphorus (such as phytic phosphorus) into absorbable inorganic phosphorus. Bacillus megaterium can efficiently secrete organic acids and phosphatase, and is suitable for a pH environment of 5.5-6.5.

[0024] Further, the plant-derived amino acid liquid is soybean meal hydrolysate. Preferably, the soybean meal hydrolysate is 3%.

[0025] The plant-derived amino acid liquid is added to enhance the nutritional effect, improve the system stability, and activate the microbial activity. The soybean meal hydrolysate is one of the best choices in terms of functionality, low cost, and agricultural sustainability among many amino acid sources, and other solid waste hydrolysates can also be used instead.

[0026] Further, the humic substance liquid is a mineral humic acid original liquid with yellow humic acid ≥ 50%, humic acid ≥ 55%, and K2O ≥ 12%.

[0027] A preparation method of the organic and inorganic acid compounded stable microbial liquid fertilizer is provided, which comprises the following steps:

[0028] S1. In a reaction kettle, 50%-60% of the total amount of water is added, the temperature is controlled at 30-40°C, phosphoric acid is first added to make it fully dispersed in water, when the pH of the system decreases to 2.5-3.5, ammonium polyphosphate is added under stirring to make the phosphorus source completely dissolved, and then the pH of the system is adjusted to 4.5-5.5 to obtain a basic premixed solution;

[0029] Preferably, the total amount of water added in the reaction kettle is 55%, the temperature is controlled at 35°C, and the pH of the system is adjusted to 5.

[0030] Here, the pH decreases to 2.5-3.5 after the addition of phosphoric acid, because the first ionization of phosphoric acid is very strong, combined with high concentration, not yet neutralized, limited amount of water in the system, and other factors, leading to a rapid increase in the concentration of H + , thus showing a strong acidic environment. The strong acid environment can provide a low-pH environment for dissolving ammonium polyphosphate, which helps to stabilize its structure, and also provides an initial acid inhibition environment for microbial contamination for some organic components. This is a common pH performance after the first addition of phosphoric acid in typical fertilizer preparation.

[0031] The pH of the system is adjusted to 4.5-5.5 to provide a suitable pH environment for the subsequent addition of microbial strains and active expression. The pH at which the added microorganisms can survive is generally between 4.5 and 7.0. The complex state of the organic components and metal ions is stabilized, and the system is more stable.

[0032] S2. The temperature is controlled at 30-40°C, and potassium fulvate is added to the basic premixed solution under stirring to fully dissolve the potassium fulvate and form partial complex with the phosphorus source. Subsequently, aminoacetic acid, glucose, and organic nutrient supplements are added in sequence, and the solution is fully stirred until it is uniform and transparent or stably dispersed to obtain an organic and inorganic complex system.

[0033] The temperature is controlled at 30-40°C to optimize the reaction diffusion of phosphoric acid and ammonium polyphosphate in a safe and stable physical and chemical environment, avoid thermal damage to organic components, lay a foundation for the survival and function of subsequent strains, and ensure the physicochemical stability and biological activity of the entire liquid fertilizer system.

[0034] The partial complexation of potassium fulvate powder or solution with phosphorus stabilizes the phosphorus form, prevents precipitation and passivation, enhances the slow-release property and utilization rate of phosphorus. Potassium fulvate, as a natural organic complexing agent and carrier, can inhibit the aggregation of precipitated particles, form a stable colloidal system, reduce the viscosity of the system, and synergistically chelate other nutrients to construct a nutrient complex and improve the fertilizer efficiency.

[0035] S3. The organic and inorganic complex system is cooled to 25-30°C, and phosphorus-dissolving microorganisms are added under stirring until the mixture is uniform. Subsequently, the pH is adjusted to 5.5-6.5, and the water is supplemented to 100% to prepare an organic and inorganic acid complex stable microbial liquid fertilizer.

[0036] Preferably, the organic and inorganic complex system is cooled to 25°C.

[0037] The pH of the liquid fertilizer is limited to 5.5-6.5 because it is the optimal pH for the growth and metabolism of phosphorus-dissolving microorganisms (such as Bacillus megaterium). When the pH is lower than 5.5, the microbial activity is inhibited, and when the pH is higher than 6.5, the ability of some strains to secrete organic acids and phosphatase decreases. Within this pH range, phosphatase and organic acid synthase have the highest activity, and the microorganisms efficiently secrete organic acids such as citric acid and oxalic acid to dissolve insoluble phosphates in the soil. At the same time, the microorganisms secrete phosphorus-dissolving enzymes to hydrolyze organic phosphorus and activate the soil phosphorus pool. The microorganisms can maintain high activity for a long time and continuously secrete organic acids and phosphorus-dissolving enzymes, thereby activating the insoluble phosphorus in the soil and improving the reutilization efficiency of the soil phosphorus pool.

[0038] The invention also provides an application of the above-mentioned organic and inorganic acid compound stabilized microbial liquid fertilizer in enhancing crop phosphorus absorption capacity, promoting root development, or extending fertilizer effect period, wherein the organic and inorganic acid compound stabilized microbial liquid fertilizer is used as base fertilizer or top dressing.

[0039] Furthermore, the application rate of the fertilizer is 5 kg to 8 kg per mu. Preferably, the application rate of the fertilizer is 7 kg per mu.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] (1) In this invention, phosphoric acid is a readily available acidic phosphorus source, providing readily available water-soluble phosphorus. After dissolving, phosphoric acid rapidly lowers the local pH of the soil, inhibiting the growth of calcium in the soil under acidic conditions. 2+ Fe 3+ Al 3+ Phosphorus fixation reduces phosphorus chemical precipitation and promotes the dissolution of mineral phosphorus (such as Ca-P and Fe-P). Ammonium polyphosphate serves as a slow-release phosphorus source, gradually releasing orthophosphate through hydrolysis, extending the phosphorus supply cycle and preventing excessive phosphorus loss or fixation in the short term. Furthermore, polyphosphate ions can also react with Ca... 2+ Mg 2+ When metal ions form soluble complexes, phosphorus fixation is reduced, overcoming the problem of easy fixation of traditional phosphorus sources. Therefore, the combination of phosphoric acid and ammonium polyphosphate combines rapid and slow-release properties, extending the fertilizer effect cycle. Rapidly available phosphorus meets the early needs of crops, while slow-release phosphorus supports mid-to-late-stage growth. This solves the contradiction of traditional phosphate fertilizers being "rapid-acting but short-lived" or "slow-release but inefficient," and overcomes the problem of traditional single phosphorus sources only providing phosphorus while neglecting the uneven release of phosphorus in the mid-to-late stages.

[0042] (2) By introducing organic chelating components such as potassium humate and aminoacetic acid, the binding of phosphorus and Fe in the soil is effectively inhibited. 3+ Al 3+ Ca 2+ The binding of isocations reduces the risk of phosphorus fixation and enhances the mobility and absorbability of phosphorus in the soil.

[0043] Fulvic acid is the smallest and most reactive component of humic acids. It can complex with metal ions including trivalent cations such as Fe. 3+ Al 3+ With divalent cations: Ca 2+ Mg 2+ Cu 2+ Zn 2+ etc. In the soil with Fe 3+ Al 3+ They form coordination complexes to prevent them from reacting with H2PO4. - HPO4 2-It combines to form iron / aluminum phosphate precipitate; protects phosphate ions in the soluble state and maintains their active concentration.

[0044] Glycine is one of the simplest amino acid-type small molecule chelating agents, and the cations it can stabilize include: Fe 3+ Al 3 + Ca 2+ Mg 2+ Cu 2+ Zn 2+ Trace elements can inhibit the reaction between metal ions and phosphate ions; they can form water-soluble amino acid-metal complexes, thus preserving phosphorus activity.

[0045] Potassium humate provides a large molecular slow-release complexation framework; glycine acts as a small molecular fast-acting metal chelator; the synergistic use of the two can cover the rapid-medium-term-long-term metal ion complexation regulation mechanism and minimize phosphorus fixation.

[0046] (3) The present invention has optimized the pH (controlled at 5.5 to 6.5), temperature, carbon source and buffer system of the liquid system so that the added phosphorus-solubilizing microorganisms (such as Bacillus megaterium) can maintain high activity for a long time and continuously secrete organic acids and phosphorus-solubilizing enzymes, thereby activating the insoluble phosphorus in the soil and improving the reuse efficiency of the soil phosphorus pool.

[0047] A pH range of 5.5–6.5 is the optimal range for physiological activity. The optimal growth pH for Bacillus megaterium added to this patented system is 5.5–7.0, within which its cellular metabolic enzyme activity is strongest. The phosphatases and organic acid decarboxylases secreted by Bacillus megaterium exhibit the strongest activity at a slightly acidic pH (5.5–6.5). This pH also helps maintain the dissociated state of organic acids, effectively dissolving insoluble phosphate rock.

[0048] Temperature control (not exceeding 30℃, preferably 25℃) is crucial to prevent heat inactivation and ensure metabolic function. Above 35℃, the activity of phosphate-solubilizing bacteria decreases significantly, especially in liquid conditions where they are more prone to inactivation. 25℃ is the optimal metabolic temperature for Bacillus megaterium, allowing for stable secretion of extracellular acids and enzymes. Temperature control protects the bacterial cells and prevents enzyme inactivation, thus maintaining the continuous "biological phosphate solubilization" process.

[0049] Carbon sources (such as glucose) provide energy substrates for bacterial cells. The production of organic acids by microorganisms depends on carbon sources for energy. Glucose, as a highly efficient soluble carbon source, can enter the bacterial cell to produce citric acid, oxalic acid, etc. Sufficient carbon sources are a prerequisite for the secretion of lysozymes and organic acids. Glucose can also significantly increase the growth rate of bacterial cells, maintain bacterial population density, and prevent bacterial autolysis or metabolic inhibition caused by "carbon starvation".

[0050] The liquid fertilizer may be caused by water source, mixing, application conditions, etc. during storage or application; the buffer system ensures that the fertilizer is kept in the micro-acid stable interval of 5.5-6.5 for a long time. In addition, the organic acid will be converted into an inactive form in a strong acid or strong alkali environment, and the buffer system can prevent it from being "deactivated".

[0051] (4) The amino acid liquid provides small molecule nitrogen source and growth hormone, stimulates root development, and enhances the phosphorus absorption capacity of crops. The humic acid liquid improves the soil aggregate structure and enhances the water and fertilizer retention capacity. By introducing plant-derived amino acid liquid or humic acid liquid, a variety of small molecule nutrients and physiological active substances can be provided for the rhizosphere of crops, promoting root development, improving rhizosphere enzyme activity, and at the same time, improving the soil micro-ecological environment and enhancing the stress resistance of crops.

[0052] (5) The liquid fertilizer of the present application improves the effectiveness of phosphorus in the soil through the synergistic effect of inorganic phosphoric acid source, organic chelating agent and phosphorus-dissolving microorganisms. The phosphoric acid and ammonium polyphosphate have both quick-acting and slow-releasing properties, ensuring continuous absorption of crops; the introduced potassium fulvate and aminoacetic acid can effectively chelate cations such as Fe 3+ , Al 3+ , Ca 2+ in the soil, reducing the precipitation of phosphate, thereby inhibiting fixation. At the same time, the introduction of phosphorus-dissolving bacteria can secrete organic acids and phosphatase to activate the insoluble phosphorus minerals in the soil and improve the release efficiency of the potential phosphorus pool. The three work together to enhance the mobility of phosphorus and activate the soil phosphorus cycle, effectively increasing the content of available phosphorus in the soil and the phosphorus absorption efficiency of crops.

[0053] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. DETAILED DESCRIPTION

[0054] The present application will be further described below in conjunction with specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0055] Example 1

[0056] 1. The components of the organic and inorganic acid compounded stable microbial liquid fertilizer include:

[0057] Phosphoric acid 4%, ammonium polyphosphate 10%, potassium fulvate 2%, aminoacetic acid 1%, glucose 1.5%, phosphorus-dissolving microorganisms mainly Bacillus megaterium, with a bacterial content of 10 7CFU / mL 5%, soybean meal hydrolysate (total amino acids > 10%) 3%, water to make up to 100%.

[0058] 2. Preparation of organic and inorganic acid complex stable microbial liquid fertilizer:

[0059] S1. Premixing of the base solution: Add about 55% of the total amount of softened water to a clean reaction kettle, start the stirring system, control the temperature at 35°C, slowly add 4% phosphoric acid, stir to fully disperse it in water, continue to add ammonium polyphosphate (liquid type APP, commonly 10-34-0) under stirring, maintain stirring for 15 minutes, adjust the system pH to 5.

[0060] Here, maintain stirring for 15 minutes to promote complete dissolution of the phosphorus source. According to the test results, add deionized water or potassium hydroxide / sodium citrate as a weak base to adjust the pH, providing a suitable environmental basis for subsequent biological components.

[0061] S2. Add organic complexing and conditioning components: Slowly add potassium fulvate powder 2%, aminoacetic acid 1% under stirring, then add glucose 1.5%, maintain stirring for 25 minutes.

[0062] Here, the addition of potassium fulvate powder allows it to fully dissolve and form partial complexation with phosphorus; aminoacetic acid serves as an auxiliary chelating agent and buffer, while also having certain root-promoting functions; the addition of glucose as a soluble carbon source promotes the activity of phosphorus-dissolving microorganisms; maintaining stirring ensures that the components are fully integrated to form a stable organic and inorganic complex system.

[0063] S3. Microbial addition and final pH adjustment: Stop heating and naturally cool the system temperature to not higher than 30°C, slowly add 5% of the phosphorus-dissolving bacteria liquid with Bacillus megaterium as the main component, stir for 5 minutes and then stand. Adjust the final pH of the system to 6, add softened water to 100% volume, and gently stir for 5 minutes.

[0064] Here, the system temperature is controlled at not higher than 30°C to prevent high temperature from killing live bacteria; slow stirring and slow addition of the bacterial liquid avoid shear inactivation of the bacteria caused by vigorous stirring; standing allows observation of system color, bubbles, and other indicators to ensure uniform distribution of microorganisms; using sodium citrate or sodium bicarbonate as a buffer adjusts the pH, and the buffer system can stabilize the pH fluctuations to avoid inactivation of microorganisms due to sudden changes in pH, and this pH is optimal for long-term stable survival of microorganisms.

[0065] S4. Impurity removal and packaging: Use a 80-mesh screen for coarse filtration, and then use a 120-mesh screen for secondary filtration.

[0066] Here, the prepared liquid fertilizer is packaged in a clean environment and stored in plastic barrels or corrosion-resistant containers.

[0067] Example 2

[0068] 1. Organic, inorganic acid complex stable microbial liquid fertilizer components include:

[0069] Phosphoric acid 3%, polyphosphoric acid ammonium 5%, potassium fulvic acid 1%, aminoacetic acid 0.5%, glucose 1%, phosphorus-dissolving microorganisms mainly Bacillus megaterium, bacteria content 10 7 CFU / mL 6%, soybean meal hydrolysate (total amino acid ≥10%) 2%, water to 100%.

[0070] 2. Preparation of organic, inorganic acid complex stable microbial liquid fertilizer:

[0071] S1. Premix the base solution: Add about 50% of the total amount of softened water to a clean reaction kettle, start the stirring system, control the temperature at 30°C, slowly add phosphoric acid 3%, stir to disperse it in water, continue to add polyphosphoric acid ammonium (liquid type APP, commonly 10-34-0) under stirring, maintain stirring for 15 minutes, adjust the system pH to 4.5.

[0072] S2. Add organic complexing and conditioning components: Slowly add potassium fulvic acid powder 1%, aminoacetic acid 0.5% under stirring, then add glucose 1%, maintain stirring for 20 minutes.

[0073] S3. Microbial addition and final pH adjustment: Stop heating, naturally cool the system temperature to not higher than 30°C, slowly add phosphorus-dissolving bacteria liquid 6% with Bacillus megaterium as the main component, stir for 5 minutes and then stand. Adjust the final pH of the system to 5.5, add softened water to 100% volume, and stir gently for 5 minutes.

[0074] S4. Impurity removal and packaging: Use a 60-mesh screen for coarse filtration, and then use a 120-mesh screen for secondary filtration.

[0075] Example 3

[0076] 1. Organic, inorganic acid complex stable microbial liquid fertilizer components include:

[0077] Phosphoric acid 5%, polyphosphoric acid ammonium 15%, potassium fulvic acid 3%, aminoacetic acid 1.5%, glucose 2%, phosphorus-dissolving microorganisms mainly Bacillus megaterium, bacteria content 10 8 CFU / mL 8%, soybean meal hydrolysate (total amino acid ≥10%) 4%, water to 100%.

[0078] 2. Preparation of organic, inorganic acid complex stable microbial liquid fertilizer:

[0079] S1. Premixing of base solution: Add about 60% of total amount of soft water in a clean reactor, start the stirring system, control the temperature at 40°C, slowly add phosphoric acid 15%, stir to disperse it in water, continue to add ammonium polyphosphate (liquid type APP, commonly 10-34-0) under stirring, maintain stirring for 15 minutes, adjust the pH of the system to 5.5.

[0080] S2. Adding organic complexing and conditioning components: Slowly add potassium fulvate powder 3%, aminoacetic acid 1.5% under stirring, then add glucose 2.0%, maintain stirring for 30 minutes.

[0081] S3. Microbial addition and final pH adjustment: Stop heating, naturally cool the system temperature to below 30°C, slowly add phosphorus-solubilizing bacteria liquid 8% with Bacillus megaterium as the main component, stir for 5 minutes and then stand. Adjust the final pH of the system to 6.5, add soft water to 100% volume, and stir gently for 5 minutes.

[0082] S4. Impurity removal and packaging: Coarse filtration is performed using a 100-mesh screen, and then secondary filtration is performed using a 120-mesh screen.

[0083] 3. Effect test

[0084] To further illustrate the effect of the present application, the following experiments and comparisons are made:

[0085] Example 1

[0086] 1. Components of the organic and inorganic acid compounded stable microbial liquid fertilizer include:

[0087] Phosphoric acid 4%, ammonium polyphosphate 10%, potassium fulvate 2%, aminoacetic acid 1%, glucose 1.5%, phosphorus-solubilizing microorganisms mainly Bacillus megaterium, with a bacterial content of 10 7 CFU / mL 5%, soybean meal hydrolysate (total amino acid ≥10%) 3%, and water to make up to 100%.

[0088] 2. Preparation of the organic and inorganic acid compounded stable microbial liquid fertilizer:

[0089] S1. Premixing of base solution: Add about 60% of total amount of soft water in a clean reactor, start the stirring system, control the temperature at 40°C, slowly add phosphoric acid 15%, stir to disperse it in water, continue to add ammonium polyphosphate (liquid type APP, commonly 10-34-0) under stirring, maintain stirring for 15 minutes, adjust the pH of the system to 5.5.

[0090] S2. Add organic complexing and conditioning components: slowly add potassium fulvate powder 2%, aminoacetic acid 1% under stirring, then add glucose 1.5%, maintain stirring for 25 minutes.

[0091] S3. Microbial addition and final pH adjustment: stop heating, naturally cool the system temperature to below 30°C, slowly add phosphorus-solubilizing bacteria liquid 5% with Bacillus megaterium as the main component, stir for 5 minutes and then stand. Adjust the final pH of the system to 6, add soft water to 100% volume, and gently stir for 5 minutes.

[0092] S4. Impurity removal and packaging: use a 80 mesh screen for rough filtration, then use a 120 mesh screen for secondary filtration.

[0093] Example 2

[0094] 1. The components of the stable microbial liquid fertilizer of organic and inorganic acid complex include:

[0095] Phosphoric acid 3%, polyphosphoric acid ammonium 5%, potassium fulvate 1%, aminoacetic acid 0.5%, glucose 1%, phosphorus-solubilizing microorganisms with Bacillus megaterium as the main component, with a bacterial content of 10 7 CFU / mL 6%, soybean hydrolysate (total amino acid ≥10%) 2%, and water to make up to 100%.

[0096] 2. Preparation of stable microbial liquid fertilizer of organic and inorganic acid complex:

[0097] S1. Premix the base solution: add about 50% of the total amount of soft water to a clean reaction kettle, start the stirring system, control the temperature at 30°C, slowly add phosphoric acid 3%, stir to disperse it in water, continue to add polyphosphoric acid ammonium (liquid type APP, commonly 10-34-0) under stirring, maintain stirring for 15 minutes, and adjust the pH of the system to 4.5.

[0098] S2. Add organic complexing and conditioning components: slowly add potassium fulvate powder 1%, aminoacetic acid 0.5% under stirring, then add glucose 1%, maintain stirring for 20 minutes.

[0099] S3. Microbial addition and final pH adjustment: stop heating, naturally cool the system temperature to below 30°C, slowly add phosphorus-solubilizing bacteria liquid 6% with Bacillus megaterium as the main component, stir for 5 minutes and then stand. Adjust the final pH of the system to 5.5, add soft water to 100% volume, and gently stir for 5 minutes.

[0100] S4. Impurity removal and packaging: use a 60 mesh screen for rough filtration, then use a 120 mesh screen for secondary filtration.

[0101] Example 3

[0102] 1. The component of the organic and inorganic acid complex stable microbial liquid fertilizer includes:

[0103] 5% of phosphoric acid, 15% of polyphosphoric acid ammonium, 3% of potassium fulvate, 1.5% of aminoacetic acid, 2% of glucose, 8% of phosphorus-dissolving microorganisms mainly composed of Bacillus megaterium, and 4% of soybean meal hydrolysate (total amino acid ≥10%). 8 CFU / mL 8%, soybean meal hydrolysate (total amino acid ≥10%) 4%, and water to 100%.

[0104] 2. Preparation of the organic and inorganic acid complex stable microbial liquid fertilizer:

[0105] S1. Premixing of the base solution: In a clean reaction kettle, about 60% of the total amount of softened water is added, the stirring system is started, the temperature is controlled at 40°C, 15% of phosphoric acid is slowly added, and stirring is performed to fully disperse the phosphoric acid in the water. Polyphosphoric acid ammonium (liquid type APP, commonly 10-34-0) is continuously added under stirring for 15 minutes, and the pH of the system is adjusted to 5.5.

[0106] S2. Adding organic complexing and conditioning components: Under stirring, 3% of potassium fulvate powder, 1.5% of aminoacetic acid, and then 2.0% of glucose are slowly added in sequence, and stirring is maintained for 30 minutes.

[0107] S3. Microbial addition and final pH adjustment: Stop heating and naturally cool the system to control the temperature below 30°C, slowly add 8% of the phosphorus-dissolving bacteria liquid mainly composed of Bacillus megaterium, stir for 5 minutes, and then stand still. The final pH of the system is adjusted to 6.5, and softened water is added to 100% volume, and gently stirred for 5 minutes.

[0108] S4. Impurity removal and packaging: Coarse filtration is performed using a 100-mesh screen, and then secondary filtration is performed using a 120-mesh screen.

[0109] Comparative Example 1

[0110] The traditional phosphoric acid type liquid fertilizer contains 5% of phosphoric acid, 10% of polyphosphoric acid ammonium, and softened water to 100%.

[0111] The organic and inorganic acid complex stable microbial liquid fertilizer prepared in Examples 1-3 and the traditional phosphoric acid type liquid fertilizer prepared in Comparative Example 1 are respectively subjected to corresponding effect tests according to the following method, and the experimental data in Tables 1 and 2 are obtained.

[0112] (1) Test of flowering cabbage growth conditions

[0113] Select the consistent growth of flowering Chinese cabbage seedlings, the test in the greenhouse. To ensure the consistency of the root system growth environment, all use potting substrate cultivation, each treatment 10 pots, each 3 repeats, control is not fertilization treatment. Each embodiment and the comparative example are quantitatively applied, and other agronomic measures remain the same. Measure the relevant indicators at the mature stage, and the measurement results are shown in Table 1.

[0114] Table 1 Growth of flowering Chinese cabbage in each embodiment and the comparative example

[0115]

[0116] As can be seen from the results in Table 1, the plant height, leaf area, main root length and single plant weight of the embodiments compared with the control group all show a significant increasing trend. Compared with the control group, the indicators of the fertilizer treatment of Example 2 are the best, followed by Example 1. At the same time, it can be seen that the growth indicators of all the embodiments are also significantly higher than those of Comparative Example 1, and the plant height, leaf area, main root length and single plant weight of Example 2, which has the best effect, are increased by 37.6%, 25.9%, 28.3% and 39.4% compared with Comparative Example 1.

[0117] (2) Corn growth and phosphorus absorption under different treatments

[0118] Through the pot experiment, the differences between the liquid fertilizer of the application and the conventional phosphoric acid type liquid fertilizer in the phosphorus absorption capacity of crops and the soil phosphorus availability are compared, and the technical effect of the application in improving the phosphorus utilization efficiency is verified.

[0119] Select the consistent growth of corn seedlings, the test in the greenhouse. To ensure the consistency of the root system growth environment, all use acid red soil (pH 4.7), organic matter 1.1%, each treatment 10 pots, each 3 repeats, control is not fertilization treatment. Each embodiment and the comparative example are quantitatively applied, and the total P2O5 input amount of each treatment is kept consistent, and other agronomic measures remain the same. Measure the relevant indicators at 45 days after planting, and the measurement results are shown in Table 2.

[0120] Table 2 Corn growth and phosphorus absorption under different treatments

[0121]

[0122]

[0123] As can be seen from the results of Table 2, each treatment significantly increased the phosphorus content of the plants and the available phosphorus level in the soil. Among them, Example 2 showed the best performance, with the phosphorus content of the plants reaching 1.68 mg / g, the available phosphorus in the soil being 12.7 mg / g, and the phosphorus fertilizer utilization rate being 62.7%, which was significantly higher than the 40.8% of Comparative Example 1. In comparison, Examples 1 and 3 also showed good results, with the phosphorus content of the plants being 1.51 mg / g and 1.37 mg / g, respectively, and the phosphorus utilization rates being 55.9% and 50.2%, respectively. The blank control group had a phosphorus content of the plants of only 0.71 mg / g and an available phosphorus in the soil of only 5.3 mg / g, indicating that the absorption of phosphorus by crops was severely limited in the absence of effective phosphorus application.

[0124] The liquid fertilizer of the present application improves the availability of phosphorus in the soil through the synergistic effect of inorganic phosphoric acid sources, organic chelating agents, and phosphorus-dissolving microorganisms. The phosphoric acid is combined with ammonium polyphosphate, which has both quick-acting and slow-release properties, ensuring continuous absorption by crops. The introduced potassium fulvate and aminoacetic acid can effectively chelate cations such as Fe 3+ , Al 3+ , Ca 2+ , etc. in the soil, reducing the precipitation of phosphate and thereby inhibiting fixation. At the same time, the application of Bacillus megaterium and other phosphorus-dissolving bacteria can secrete organic acids and phosphatases, activating the poorly soluble phosphorus minerals in the soil and improving the release efficiency of the potential phosphorus pool. The combination of the three not only enhances the mobility of phosphorus but also activates the phosphorus cycle in the soil, effectively increasing the available phosphorus content in the soil and the phosphorus absorption efficiency of crops.

[0125] The above has described various embodiments of the present application, and the above-described embodiments of the present application are merely examples for clearly illustrating the present application, are exemplary, are not exhaustive, and are not limited to the disclosed embodiments. Other different forms of changes or variations can be made by those of ordinary skill in the art based on the above description, and it is not necessary or possible to exhaust all embodiments. Any modifications, equivalent replacements, and improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application. The selection of the terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A stable microbial liquid fertilizer composed of organic and inorganic acids, characterized in that, It includes the following components by weight percentage: phosphate 3%–5%, ammonium polyphosphate 5%–15%, potassium humate 1%–3%, glycine 0.5%–1.5%, glucose 1%–2%, and phosphate-solubilizing microorganisms: bacterial content 10. 7 ~10 8 CFU / mL, 2%–4% organic nutrient supplement, wherein the organic nutrient supplement is plant-derived amino acid liquid or humic liquid, and water is added to make up to 100%.

2. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The phosphoric acid is 85% industrial phosphoric acid.

3. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The ammonium polyphosphate is liquid ammonium polyphosphate with N>10% and P2O5>34%.

4. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The aminoacetic acid is glycine with a purity of 98.5%.

5. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The phosphate-solubilizing microorganisms include one or more of Bacillus megaterium, Aspergillus niger, and Penicillium spp.

6. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The plant-derived amino acid solution is a soybean meal hydrolysate.

7. The organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 1, characterized in that, The humic liquid is a mineral-derived fulvic acid stock solution containing ≥50% fulvic acid, ≥55% humic acid, and ≥12% K2O.

8. A method for preparing a stable microbial liquid fertilizer composed of organic and inorganic acids as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Add 50% to 60% of the total amount of water to the reactor, control the temperature at 30℃ to 40℃, add phosphoric acid first to fully disperse it in the water, and when the pH of the system drops to 2.5 to 3.5, add ammonium polyphosphate while stirring to completely dissolve the phosphorus source. Then adjust the pH of the system to 4.5 to 5.5 to obtain the basic premixed solution. S2. Control the temperature at 30℃~40℃, add potassium humate to the basic premixed solution under stirring, so that the potassium humate is fully dissolved and forms a partial complex with the phosphorus source. Then add glycine, glucose and organic nutrient supplement in sequence, and stir thoroughly until the solution is uniform, transparent or in a stable dispersion state to obtain an organic and inorganic compound system. S3. Cool the organic-inorganic compound system to 25℃~30℃, add phosphorus-solubilizing microorganisms while stirring until they are evenly mixed, then adjust the pH to 5.5~6.5 and add water to 100% to obtain a stable microbial liquid fertilizer composed of organic and inorganic acids.

9. The application of the organic and inorganic acid compound stabilized microbial liquid fertilizer according to claim 8 in enhancing crop phosphorus absorption capacity, promoting root development, or extending fertilizer effect period, wherein the organic and inorganic acid compound stabilized microbial liquid fertilizer is used as base fertilizer or top dressing.

10. The application according to claim 9, characterized in that, The application rate of the fertilizer is 5 kg to 8 kg per mu.

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