Meizhou shaddock special organic fertilizer based on animal manure and preparation method thereof

Abstract

The application belongs to the technical field of fertilizers, and particularly relates to a Meizhou pomelo special-purpose organic fertilizer based on animal manure and a preparation method thereof. The Meizhou pomelo special-purpose organic fertilizer comprises, by weight fraction, 50-70 parts of animal manure, 10-20 parts of peanut meal, 20-30 parts of compound modified wood ash, 8-18 parts of compound modified chaff, and 0.1-0.5 parts of fermentation agent. The Meizhou pomelo special-purpose organic fertilizer takes into account the nutrient supply and the soil improvement demand by using animal manure, peanut meal, compound modified wood ash and compound modified chaff. The compound modified wood ash and the compound modified chaff respectively optimize the defects of traditional waste and improve the potassium-calcium slow-release property and the organic matter utilization rate. The fermentation agent cooperatively accelerates the humification of organic matter and reduces the harmful substance residue. The product is rich in organic matter, nitrogen, potassium and trace elements, can improve the rhizosphere microenvironment of Meizhou pomelo, promote the balanced absorption of nutrients, enhance the stress resistance of the tree body, and realize the double goals of yield increase and resource utilization of agricultural waste.

Description

Technical Field

[0001] This invention relates to the field of fertilizer technology, specifically to a special organic fertilizer for Meizhou pomelo based on animal manure and its preparation method. Background Technology

[0002] As a Chinese national geographical indication product, the quality improvement and sustainable development of Meizhou pomelo depend heavily on scientific fertilization management. While traditional application of chemical fertilizers can increase yields in the short term, long-term use can easily lead to soil acidification, compaction, decline in organic matter, and imbalance of micronutrients, which in turn restricts further improvement in the intrinsic quality of pomelo, such as sugar content and flavor. Moreover, fertilizer utilization is low, creating a risk of non-point source pollution.

[0003] Currently, farmers often use ordinary organic fertilizer made from livestock and poultry manure compost as an improvement measure. However, this type of conventional organic fertilizer has the following significant drawbacks: The raw materials are crudely formulated and have a single function: most are simply fermented animal manure, lacking a refined design tailored to the physiological needs of pomelo trees. Their nutrient release pattern is not synchronized with the pomelo tree's (especially during fruit enlargement) "nitrogen and potassium peak" requirements, making it difficult to support the formation of high-quality pomelos.

[0004] Improper use of key auxiliary materials can have side effects. While wood ash is an excellent source of potassium, its strong alkalinity can exacerbate the fixation of micronutrients such as calcium, magnesium, and zinc in the soil of southern pomelo orchards, and may burn the roots, contradicting the slightly acidic growing environment of pomelo trees. Rice husks are usually only used as physical conditioners in composting; their huge specific surface area and porous structure potential remain untapped, failing to achieve nutrient loading and slow release, and limiting their ability to retain water and fertilizer. Furthermore, their fermentation efficiency and fertilizer stability are insufficient, and their ability to decompose materials with high lignocellulose content (such as rice husks) is limited, resulting in incomplete decomposition and failure to effectively enrich beneficial metabolites that promote plant growth.

[0005] Therefore, there is an urgent need for a special organic fertilizer for Meizhou pomelo that can overcome the above-mentioned shortcomings and integrate balanced nutrition, slow release and enhanced efficiency, and soil improvement. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a special organic fertilizer for Meizhou pomelo based on animal manure and its preparation method. This organic fertilizer for Meizhou pomelo improves the slow-release properties of potassium and calcium and the utilization rate of organic matter, accelerates the humification of organic matter, reduces harmful residues, and is rich in organic matter, nitrogen, potassium, and trace elements. It can improve the rhizosphere microenvironment of Meizhou pomelo—adjusting acidity, increasing oxygen, and retaining water—promoting balanced nutrient absorption, enhancing tree resistance, and achieving the dual goals of increasing yield and quality while utilizing agricultural waste resources.

[0007] The technical solution of the present invention to solve the above problems is as follows: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising, by weight, 50-70 parts animal manure, 10-20 parts peanut bran, 20-30 parts compound modified wood ash, 8-18 parts compound modified rice husk, and 0.1-0.5 parts fermentation agent; The preparation method of the composite modified plant ash is as follows: Step 1: Mix wood ash and phosphogypsum evenly to obtain dry powder. Take 40-60% of the total amount of citric acid, add water to prepare citric acid solution, spray the dry powder with citric acid solution, and then let it stand at 25-30℃ for 5-10 minutes to obtain pre-neutralized material. Dissolve ferrous sulfate and the remaining citric acid in water, spray it into the pre-neutralized material, and stir and react at 25-45℃ for 30-60 minutes to obtain material 1. Step 2: The material 1 obtained in Step 1 is tumbled at a low speed of 15-25 rpm, and the water glass solution is sprayed onto the material 1 in the form of atomization at a spraying rate of 10-25 mL / min. The spraying method is intermittent: after spraying for 2-5 minutes, the spraying is stopped and tumbling is maintained for 3-8 minutes. This process is repeated for 3-8 cycles until all the water glass solution is added, and wet particles are obtained. Step 3: Dry and solidify the wet granules at 50-70℃ until the moisture content of the granules is ≤15%, then cool to room temperature to obtain the final product.

[0008] Preferably, in step 1, the mass ratio of wood ash to phosphogypsum is 5-15:1-5, the amounts of citric acid and ferrous sulfate are 0.5%-2.0% and 0.1%-0.5% of the total weight of wood ash and phosphogypsum, respectively, the mass ratio of citric acid to water in the citric acid solution is 1:1-2, and the mass ratio of water to ferrous sulfate is 3-5:1 during the dissolution of ferrous sulfate and the remaining citric acid with water.

[0009] Preferably, in step 2, the mass ratio of material 1 to water glass is 100-115:5-15, and the volume ratio of water glass to water in the water glass solution is 1:0.5-1.

[0010] Preferably, the method for preparing the composite modified rice husk is as follows: Step a: Crush the rice husks using a crusher. Then, mix the crushed rice husks with a sodium hydroxide solution and stir at 30-60 rpm for 60-120 minutes at 80-95℃. After the reaction, drain the alkaline solution and rinse the rice husks with hot water at 60-70℃ until the pH of the rinsing solution is 8.5-9.0. Transfer the washed wet rice husks to a sealable container, add urea solution, and vacuum at 75-85℃ to -0.06 to -0.08 MPa for 25-35 minutes. Then restore normal pressure and continue soaking for 1-2 hours. Filter out the rice husks and dry them at 55-65℃ to reduce their moisture content to 18%-22%. Step b: Place the dried rice husks from step a at 25-35℃ and atomize and spray the ethanol solution of the silane coupling agent at a rate of 0.5-1.05 mL / min. After spraying, let the rice husks stand at room temperature for 30-60 minutes to complete the curing. Step c: First, treat the solidified rice husks at 90-100℃ for 10-20 minutes, then raise the temperature to 130-150℃ and heat treat at this temperature for 30-60 minutes. Then, quickly cool the material to below 40℃ and finally pass it through a 2 mm sieve to obtain the final product.

[0011] Preferably, in step a, the mass ratio of the rice husk, sodium hydroxide solution, and urea is 10:15-25:2-4, the concentration of the sodium hydroxide solution is 25-28%, and the mass ratio of urea to water in the urea solution is 1:5-8.

[0012] Preferably, in step b, the mass ratio of the silane coupling agent to the rice husk in step a is 0.05-0.20:10, and in the ethanol solution of the silane coupling agent, the mass ratio of anhydrous ethanol to the silane coupling agent is 5-10:1.

[0013] Preferably, the fermentation agent is one or more of Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae.

[0014] Preferably, the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, with a mass ratio of 2:2:1.

[0015] The preparation method of the above-mentioned Meizhou pomelo-specific organic fertilizer based on animal manure is as follows: animal manure, peanut bran, compound modified wood ash, compound modified rice husk, and fermentation agent are mixed evenly, and the moisture content of the materials is controlled at 55%-65%. The mixture is piled up for high-temperature aerobic fermentation, with the core temperature of the pile at 55-70℃ for 15-25 days. The fermented material is then aged for 20-30 days. The aged material is then crushed to a particle size of ≤10mm to obtain the finished product.

[0016] The present invention has the following beneficial effects: This invention relates to a special organic fertilizer for Meizhou pomelo, which precisely combines animal manure, peanut bran, and composite modified wood ash and rice husks to address both nutrient supply and soil improvement needs. The composite modified wood ash and rice husks address the shortcomings of traditional waste treatments (wood ash is too alkaline, and rice husks are difficult to degrade), improving potassium and calcium slow-release properties and organic matter utilization. Fermentation agents synergistically accelerate the humification of organic matter, reducing harmful residues. The product is rich in organic matter, nitrogen, potassium, and trace elements, improving the rhizosphere microenvironment of Meizhou pomelo (adjusting acidity, increasing oxygen, and retaining water), promoting balanced nutrient absorption, enhancing tree resistance, and ultimately achieving the dual goals of increased yield and quality while utilizing agricultural waste resources.

[0017] Since raw wood ash is highly alkaline, direct application can easily cause soil alkalization. This solution employs a compound modification treatment of wood ash using citric acid and phosphogypsum. Firstly, citric acid reacts rapidly with potassium carbonate and potassium hydroxide in the wood ash to neutralize its strong alkalinity. Simultaneously, it reacts with calcium carbonate and potassium hydroxide in the phosphogypsum. 2+ Calcium citrate is generated, lowering the system's pH. Simultaneously, the addition of ferrous sulfate forms an ferric citrate complex, further consuming alkaline substances and stabilizing the pH at a slightly acidic state. This transforms the final wood ash from a "disruptor" of the soil into a "regulator" of the acid-loving environment of Meizhou pomelo. The calcium provided by phosphogypsum... 2+ The calcium citrate and ferric citrate complexes formed with citric acid can effectively chelate (complex) fixed calcium, iron, and aluminum ions in the soil, thereby releasing the fixed phosphorus and greatly improving the utilization rate of phosphate fertilizer. Then, in step 2, water glass (sodium silicate) is used to encapsulate and solidify the granules, forming a microporous gel membrane on the surface. This membrane ensures the slow release of potassium ions, avoiding leaching and fertilizer damage caused by a large release at once, while also introducing beneficial elements such as silicon and sodium. The addition of ferrous sulfate replenishes the easily deficient iron element. The composite modified wood ash fundamentally solves the problem of the strong alkalinity of wood ash, making it suitable for acid-loving Meizhou pomelo, and transforming its potassium release from fast-acting to slow-release, prolonging the fertilizer effect and improving potassium utilization. Simultaneously, it can activate fixed phosphorus in the soil, playing a "phosphorus release" role, and also simultaneously provides various micronutrients such as sulfur, calcium, iron, and silicon.

[0018] The composite modified rice husk is first treated with sodium hydroxide solution, which effectively dissolves some of the lignin and hemicellulose on the surface of the rice husk, significantly increasing its specific surface area and porosity. This not only creates space for subsequent nutrient loading but also exposes more active sites such as cellulose hydroxyl groups (-OH). Then, under vacuum conditions, the air inside the rice husk pores is expelled. When urea solution is added at normal pressure, the urea solution is forced into and fills these micropores under atmospheric pressure. The subsequent drying process fixes the urea crystals inside these pores, forming tiny "nitrogen fertilizer warehouses." After hydrolysis and condensation, the silane coupling agent KH-550 forms a dense organosilicon network film on the pore surface and inlet of the rice husk. This film effectively reduces the channel size for water and solute diffusion by partially blocking the pores; at the same time, its hydrophobic properties reduce the water permeation rate. The synergistic effect of these two factors slows down the dissolution and outward diffusion kinetics of urea crystals, thereby achieving a slow-release function of nitrogen. The final high-temperature treatment ensures more complete curing of the silane coupling agent and partial carbonization of the rice husk skeleton, resulting in a more stable structure and resistance to microbial decomposition, thus extending its slow-release function. The composite modified rice husk achieves slow-release of nitrogen, matching the slow-release of potassium from wood ash, making the release of fertilizer nutrients more synchronized and greatly improving the fertilizer's water retention capacity. Its porous structure can absorb several times its own weight in water, releasing it during drought and slowly degrading in the soil, thus playing a long-term role in improving soil aggregate structure.

[0019] The composite modified wood ash and composite modified rice husk form a highly efficient "slow-release-porous dual synergistic system" in fertilizer. The modified wood ash achieves slow release of potassium, while the modified rice husk achieves slow release of nitrogen. This perfectly matches the peak demand for nitrogen and potassium during the fruit expansion period of Meizhou pomelo, avoiding the problem of asynchronous nutrient supply in traditional fertilizers and providing precise nutrient supply to improve fruit quality. Although the modified wood ash itself is slightly acidic, the calcium ions it introduces (from phosphogypsum) and the humic acid produced by fermentation together form an "organic-inorganic composite colloid" system. The modified rice husk, through its persistent porous structure and the humic acid precursors formed by its gradual degradation in the soil, works synergistically to stably control the pH fluctuations of the rhizosphere soil within the optimal range of 6.0-6.5, creating an extremely stable acid-base environment for the slightly acidic root system of Meizhou pomelo. The combination of high porosity of modified rice husks and modified wood ash particles increases the aeration porosity of the fertilizer compost. This not only improves oxygen flux and promotes decomposition during the fermentation stage, but also significantly improves soil structure and increases saturated water conductivity after application, thus maintaining a loose and breathable growth environment for the roots in the long term.

[0020] The fermentation agent uses a combination of Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae to form a highly efficient and stable fermentation system: Bacillus subtilis and Bacillus licheniformis (primarily responsible for decomposition and inhibition): their functions complement each other, forming a fermentation relay. Bacillus subtilis rapidly starts up during the mesophilic phase (25-45℃), secreting proteases and amylases to quickly decompose organic matter and raise the temperature; Bacillus licheniformis, with its strong heat resistance (>60℃), takes over the dominant role during the high-temperature phase, continuing to decompose recalcitrant organic matter and producing antibacterial substances, jointly inhibiting pathogens and putrefactive bacteria, reducing odor, and ensuring safe and hygienic fermentation. Saccharomyces cerevisiae (enhancing and stabilizing) utilizes the simple sugars produced by the former two for growth, reducing the production of unpleasant sour odors and synthesizing vitamin B precursors, indirectly improving the rhizosphere microecology.

[0021] In summary, the organic fertilizer specifically for Meizhou pomelo of this invention improves the slow-release properties of potassium and calcium and the utilization rate of organic matter, accelerates the humification of organic matter, reduces harmful residues, and is rich in organic matter, nitrogen, potassium and trace elements. It can improve the rhizosphere microenvironment of Meizhou pomelo (adjust acidity, increase oxygen, retain water), promote balanced nutrient absorption, enhance the tree's resistance to stress, and achieve the dual goals of increasing yield and quality and resource utilization of agricultural waste. Attached Figure Description

[0022] Figure 1 The graph shows the results of the determination of organic matter and total nutrient content of the organic fertilizers obtained in Examples 1-3 and Comparative Examples 1-7. Figure 2 The graph shows the results of vitamin C and soluble sugar tests on pomelos obtained by applying fertilizers according to Examples 1-3 and Comparative Example 2. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] All of the following ingredients are commercially available.

[0025] Wood ash, potassium content 4.8-7.6%, Hebei Xiong'an Xinying Technology Co., Ltd.; Peanut bran, moisture ≤30%, Shijiazhuang Xiangnuo Fertilizer Co., Ltd.; Phosphogypsum, Lingshou Runming Mineral Products Co., Ltd.; Bacillus subtilis, active ingredient content 95%, Shandong Quansheng Chemical Technology Co., Ltd.; Bacillus licheniformis, brand: Tanmo Quality Inspection; Saccharomyces cerevisiae, pale yellow granules, Shandong Haizhou Bioengineering Co., Ltd.; Water glass, modulus 2.8, Jinan Jiyang Hongxing Chemical Business Department; Rice husk, Shijiazhuang Wangjing Mineral Products Co., Ltd.

[0026] Example 1: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising 60 parts by weight of animal manure, 15 parts of peanut bran, 25 parts of compound modified wood ash, 12 parts of compound modified rice husk, and 0.3 parts of fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, with a mass ratio of 2:2:1. The preparation method of the composite modified plant ash is as follows: Step 1: Sieve the wood ash to remove impurities, and pulverize the phosphogypsum twice and pass it through a 130-mesh sieve for later use. Mix the wood ash and phosphogypsum evenly to obtain a dry powder. Take 50% of the total citric acid and add water to prepare a citric acid solution. Spray the dry powder with the citric acid solution, and then let it stand at 28°C for 8 minutes until the pH of the system drops to 6.3, obtaining a pre-neutralized material. Dissolve ferrous sulfate and the remaining citric acid in water and spray it into the pre-neutralized material. Stir and react at 32°C for 45 minutes until the pH of the system is 4.8, obtaining material 1. The mass ratio of wood ash to phosphogypsum is 10:3, and the amounts of citric acid and ferrous sulfate are 1.5% and 0.3% of the total weight of wood ash and phosphogypsum, respectively. The mass ratio of citric acid to water in the citric acid solution is 1:1.5. During the dissolution of ferrous sulfate and the remaining citric acid in water, the mass ratio of water to ferrous sulfate is 4:1. Step 2: Transfer material 1 obtained in Step 1 to a granulator. Under low-speed tumbling at 20 rpm, spray water glass solution evenly onto the surface of material 1 in atomized form at a spray rate of 18 mL / min. Use an intermittent spraying method, that is, after spraying for 3 minutes, stop spraying and keep tumbling for 5 minutes to allow the liquid phase to migrate and distribute fully between particles. Repeat this process 5 times until all water glass solution is added to obtain wet granules. The mass ratio of material 1 to water glass is 108:10, and the volume ratio of water glass to water in the water glass solution is 1:0.8. Step 3: Spread the wet granules evenly on the drying tray with a thickness of 2.9 cm, and dry and solidify them under countercurrent hot air conditions at 60℃ until the moisture content of the granules is ≤15%. Cool to room temperature to obtain the final product. Wastewater treatment and reuse: Collect the acidic wastewater and rinsing water generated in step 1, add 0.02% polyaluminum chloride for flocculation and sedimentation, and the resulting supernatant can be recycled.

[0027] The preparation method of the composite modified rice husk is as follows: Step a: The rice husks are crushed using a pulverizer. Then, the crushed rice husks are mixed with sodium hydroxide solution and stirred at 85°C and 45 rpm for 90 minutes. After the reaction, the alkaline solution is discharged, and the rice husks are rinsed with hot water at 65°C until the pH of the rinsing solution is 8.8. The washed wet rice husks are transferred to a sealable container, urea solution is added, and the container is evacuated to -0.07 MPa at 80°C and maintained for 30 minutes. Then, the pressure is restored to normal and the container is soaked for another 1.5 hours. The rice husks are filtered out and dried at 60°C to reduce their moisture content to 20%. In step a, the mass ratio of rice husks, sodium hydroxide solution, and urea is 10:20:3, the concentration of sodium hydroxide solution is 26%, and the mass ratio of urea to water in the urea solution is 1:7. Step b: Place the dried rice husks from step a into a tumbling mixer. At 30°C, atomize and spray an ethanol solution of silane coupling agent KH-550 at a rate of 0.8 mL / min. After spraying, allow the rice husks to stand at room temperature for 45 minutes to complete the curing. In step b, the mass ratio of silane coupling agent KH-550 to rice husks in step a is 0.15:10, and the mass ratio of anhydrous ethanol to KH-550 in the ethanol solution of silane coupling agent KH-550 is 8:1. Step c: Spread the solidified rice husks in the oven to a thickness of 2cm. First, treat them at 95℃ for 15 minutes, then raise the temperature to 140℃ and heat treat them at this temperature for 45 minutes. Quickly cool the material to below 40℃, and finally pass it through a 2mm sieve to obtain the final product.

[0028] Step c is the same as in Example 1.

[0029] The preparation method of the above-mentioned organic fertilizer for Meizhou pomelo based on animal manure is as follows: animal manure, peanut bran, compound modified wood ash, compound modified rice husk and fermentation agent are mixed evenly, the moisture content of the material is controlled at 60%, the mixture is piled up for high-temperature aerobic fermentation, the core temperature of the pile is 65℃, the cycle is 20 days, the fermented material is aged and matured for 25 days, and the aged material is crushed to a particle size ≤10mm to obtain the finished product.

[0030] Example 2: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising 70 parts by weight of animal manure, 10 parts of peanut bran, 20 parts of compound modified wood ash, 18 parts of compound modified rice husk, and 0.1 parts of fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:1. The preparation method of the composite modified plant ash is as follows: Step 1: Sieve the wood ash to remove impurities, and pulverize the phosphogypsum twice and pass it through a 150-mesh sieve for later use. Mix the wood ash and phosphogypsum evenly to obtain a dry powder. Take 60% of the total citric acid and add water to prepare a citric acid solution. Spray the dry powder with the citric acid solution, and then let it stand at 25°C for 10 minutes until the pH of the system drops to 6.0 to obtain a pre-neutralized material. Dissolve ferrous sulfate and the remaining citric acid in water and spray it into the pre-neutralized material. Stir and react at 45°C for 30 minutes until the pH reaches 4.5 to obtain material 1. The mass ratio of wood ash to phosphogypsum is 15:5. The amounts of citric acid and ferrous sulfate are 2.0% and 0.1% of the total weight of wood ash and phosphogypsum, respectively. The mass ratio of citric acid to water in the citric acid solution is 1:2. During the dissolution of ferrous sulfate and the remaining citric acid in water, the mass ratio of water to ferrous sulfate is 3:1. Step 2: Transfer material 1 obtained in Step 1 to a granulator. Under low-speed tumbling at 25 rpm, spray water glass solution evenly onto the surface of material 1 in atomized form at a spray rate of 10 mL / min. Use an intermittent spraying method, that is, after spraying for 2 minutes, stop spraying and keep tumbling for 3 minutes to allow the liquid phase to migrate and distribute fully between the particles. Repeat this process 3 times until all the water glass solution is added to obtain wet granules. The mass ratio of material 1 to water glass is 115:5, and the volume ratio of water glass to water in the water glass solution is 1:1. Step 3: Spread the wet granules evenly on the drying tray with a thickness of 2.5cm, and dry and solidify them under countercurrent hot air conditions at 70℃ until the moisture content of the granules is ≤15%. Cool to room temperature to obtain the final product. Wastewater treatment and reuse are the same as in Example 1.

[0031] The preparation method of the composite modified rice husk is as follows: Step a: The rice husks are crushed using a pulverizer. Then, the crushed rice husks are mixed with sodium hydroxide solution and stirred at 30 rpm for 120 minutes at 95°C. After the reaction, the alkaline solution is discharged, and the rice husks are rinsed with hot water at 60°C until the pH of the rinsing solution is 9.0. The washed wet rice husks are transferred to a sealable container, urea solution is added, and a vacuum is drawn to -0.08 MPa at 85°C and maintained for 25 minutes. Then, the pressure is restored to normal, and the rice husks are soaked for another 2 hours. The rice husks are filtered out and dried at 65°C to reduce their moisture content to 22%. In step a, the mass ratio of rice husks, sodium hydroxide solution, and urea is 10:15:4, the concentration of sodium hydroxide solution is 26%, and the mass ratio of urea to water in the urea solution is 1:5. Step b: Place the dried rice husks from step a into a tumbling mixer. At 35°C, atomize and spray an ethanol solution of silane coupling agent KH-550 at a rate of 1.05 mL / min. After spraying, allow the rice husks to stand at room temperature for 30 minutes to complete the curing. In step b, the mass ratio of silane coupling agent KH-550 to rice husks in step a is 0.20:10, and the mass ratio of anhydrous ethanol to KH-550 in the ethanol solution of silane coupling agent KH-550 is 5:1. Step c is the same as in Example 1.

[0032] The preparation method of the above-mentioned Meizhou pomelo-specific organic fertilizer based on animal manure is the same as in Example 1.

[0033] Example 3: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising, by weight, 50 parts animal manure, 20 parts peanut bran, 30 parts compound modified wood ash, 8 parts compound modified rice husk, and 0.5 parts fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:1. The preparation method of the composite modified plant ash is as follows: Step 1: Sieve the wood ash to remove impurities, and pulverize the phosphogypsum twice and pass it through a 130-mesh sieve for later use. Mix the wood ash and phosphogypsum evenly to obtain a dry powder. Take 40% of the total citric acid and add water to prepare a citric acid solution. Spray the dry powder with the citric acid solution, and then let it stand at 30°C for 5 minutes until the pH of the system drops to 6.5 to obtain a pre-neutralized material. Dissolve ferrous sulfate and the remaining citric acid in water and spray it into the pre-neutralized material. Stir and react at 25°C for 60 minutes until the pH is 5.0 to obtain material 1. The mass ratio of wood ash to phosphogypsum is 5:1, and the amounts of citric acid and ferrous sulfate are 0.5% and 0.5% of the total weight of wood ash and phosphogypsum, respectively. The mass ratio of citric acid to water in the citric acid solution is 1:1. During the dissolution of ferrous sulfate and the remaining citric acid in water, the mass ratio of water to ferrous sulfate is 5:1. Step 2: Transfer material 1 obtained in Step 1 to a granulator. Under low-speed tumbling at 15 rpm, spray water glass solution evenly onto the surface of material 1 in atomized form at a spray rate of 25 mL / min. Use an intermittent spraying method, that is, after spraying for 5 minutes, stop spraying and keep tumbling for 8 minutes to allow the liquid phase to fully migrate and distribute between particles. Repeat this process 8 times until all water glass solution is added to obtain wet granules. The mass ratio of material 1 to water glass is 110:15, and the volume ratio of water glass to water in the water glass solution is 1:0.5. Step 3: Spread the wet granules evenly on the drying tray with a thickness of 2.8 cm, and dry and solidify them under countercurrent hot air conditions at 50°C until the moisture content of the granules is ≤15%. Cool to room temperature to obtain the final product. Wastewater treatment and reuse are the same as in Example 1.

[0034] The method for preparing the composite modified rice husk is as follows: Step a: The rice husks are crushed using a pulverizer. Then, the crushed rice husks are mixed with sodium hydroxide solution and stirred at 80°C for 60 minutes at 60 rpm. After the reaction, the alkaline solution is discharged, and the rice husks are rinsed with hot water at 70°C until the pH of the rinsing solution is 9.0. The washed wet rice husks are transferred to a sealable container, urea solution is added, and a vacuum is drawn to -0.08 MPa at 75°C and maintained for 35 minutes. Then, the pressure is restored to normal, and the rice husks are soaked for another hour. The rice husks are filtered out and dried at 55°C to reduce their moisture content to 18%. In step a, the mass ratio of rice husks, sodium hydroxide solution, and urea is 10:25:2, the concentration of sodium hydroxide solution is 26%, and the mass ratio of urea to water in the urea solution is 1:8. Step b: Place the dried rice husks from step a into a tumbling mixer. At 25°C, atomize and spray an ethanol solution of silane coupling agent KH-550 at a rate of 0.5 mL / min. After spraying, allow the rice husks to stand at room temperature for 60 minutes to complete the curing. In step b, the mass ratio of silane coupling agent KH-550 to rice husks in step a is 0.05:10, and the mass ratio of anhydrous ethanol to KH-550 in the ethanol solution of silane coupling agent KH-550 is 10:1. Step c is the same as in Example 1.

[0035] The preparation method of the above-mentioned Meizhou pomelo-specific organic fertilizer based on animal manure is the same as in Example 1.

[0036] Comparative Example 1: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising 60 parts by weight of animal manure, 15 parts of peanut bran, 25 parts of wood ash, 12 parts of compound modified rice husk, and 0.3 parts of fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:1; the rest is the same as in Example 1.

[0037] Comparative Example 2: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising 60 parts by weight of animal manure, 15 parts of peanut bran, 25 parts of compound modified wood ash, 12 parts of rice husk, and 0.3 parts of fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:1; the rest is the same as in Example 1.

[0038] Comparative Example 3: A special organic fertilizer for Meizhou pomelo based on animal manure, comprising 60 parts by weight of animal manure, 15 parts of peanut bran, 25 parts of wood ash, 12 parts of rice husk, and 0.3 parts of fermentation agent; the fermentation agent is Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:1; the rest is the same as in Example 1.

[0039] Comparative Example 4: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is Bacillus subtilis and Bacillus licheniformis in a mass ratio of 1:1; the rest is the same as in Example 1.

[0040] Comparative Example 5: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is Bacillus subtilis and Saccharomyces cerevisiae in a mass ratio of 3:2; the rest is the same as in Example 1.

[0041] Comparative Example 6: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is Bacillus licheniformis and Saccharomyces cerevisiae in a mass ratio of 3:2; the rest is the same as in Example 1.

[0042] Comparative Example 7: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is Bacillus subtilis, and the rest is the same as in Example 1.

[0043] Comparative Example 8: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is Bacillus licheniformis, and the rest is the same as in Example 1.

[0044] Comparative Example 9: A special organic fertilizer for Meizhou pomelo based on animal manure, wherein the fermentation agent is brewing yeast, and the rest is the same as in Example 1.

[0045] According to the methods described in the national standards NY / T 884-2012 "Bio-organic Fertilizer" and NT / T 525-2021 "Organic Fertilizer", the various indicators of Meizhou pomelo-specific organic fertilizer based on animal manure were tested, and the test results are shown in Table 1.

[0046] Table 1. Results of Fertilizer Nutrient Determination

[0047] Fertilizer efficacy determination: After harvesting the pomelos, 30 kg of the organic-inorganic compound fertilizer from Examples 1-3 and Comparative Example 2 was applied to each plant. After the pomelos matured, the average yield per plant, transverse diameter, and longitudinal diameter, as well as vitamin C, soluble sugar, and soluble solids were measured for different fertilization treatments. Soluble sugar was determined using the anthrone method, vitamin C was determined using the 2,6-dichlorophenolindophenol titration method, and soluble solids were determined using a WYT (0~80%) handheld saccharimeter.

[0048] Table 2. Determination of Pomelo Fruit

[0049] From Table 1 and Figure 1 It can be seen that the organic fertilizers specifically for Meizhou pomelo in Examples 1-3 are superior to the technical requirements and all comparative examples in terms of nutrient indicators, demonstrating the significant advantages of the compound modification process and the specific microbial agent formulation. The organic matter content of Examples 1-3 far exceeds the standard of ≥40.0%, indicating that after high-temperature aerobic fermentation and rice husk modification, the organic matter conversion efficiency of animal manure and peanut bran is high and the stability is strong; the moisture control meets the requirement of ≤30.0%, which is conducive to storage and application. The pH value is in the suitable range of 5.5-8.5, avoiding the strong alkalinity harm caused by unmodified wood ash, which is more in line with the characteristic of Meizhou pomelo preferring slightly acidic soil. In terms of hygiene indicators, the fecal coliform count of Examples 1-3 is far below the upper limit of ≤100 CFU / g, reflecting that the synergistic fermentation of Bacillus subtilis, Bacillus licheniformis and Saccharomyces cerevisiae (2:2:1) can effectively inhibit pathogens; while the comparative examples lacking compound modification or with a single microbial agent all have the risk of pathogens exceeding the standard. Regarding total nutrients, Examples 1-3 significantly exceeded the minimum requirement of ≥4.0%, indicating that the synergistic effect of modified wood ash slow-release potassium and calcium and peanut bran readily available nitrogen and phosphorus significantly improved the total nutrient content and the rationality of the ratio. In contrast, Comparative Examples 1-7 showed total nutrients of only 5.4%-7.2%, and some indicators (such as organic matter, pH, and pathogens) failed to meet the standards, limiting their practical application value. In summary, only a formula that simultaneously uses compound modified wood ash, compound modified rice husk, and a specific combination of three microorganisms can stably meet the multiple indicator requirements of high-quality bio-organic fertilizer.

[0050] From Table 2 and Figure 2It can be seen that the special fertilizers in Examples 1-3 are significantly superior to Comparative Example 2 in terms of increasing yield and overall quality. In terms of yield, the yield per plant in Examples 1-3 increased by approximately 6%-11% compared to Comparative Example 2, indicating that the modified fertilizer can more effectively meet the nutrient requirements of Meizhou pomelos throughout their entire growth cycle. In particular, the slow release of potassium and calcium and the continuous supply of organic matter promoted fruit enlargement and dry matter accumulation. Regarding fruit morphology, the transverse and longitudinal diameters of the examples were larger than those in Comparative Example 2, demonstrating that uniform nutrient supply is beneficial for cell expansion and a more symmetrical fruit shape. The differences in quality indicators are even more pronounced: Vitamin C in Examples 1-3 is significantly higher than in the Comparative Example, which is closely related to the increased organic matter, enhanced micronutrient availability, and improved rhizosphere microecology; the soluble sugar content and soluble solids content are both higher than in Comparative Example 2, indicating that sugar synthesis and transport in Examples 1-3 are more efficient, directly affecting the sweetness and taste of the fruit. To reiterate, the pH regulation and slow-release characteristics of the composite modified wood ash, the carbon-nitrogen synergy and structural improvement of the composite modified rice husk, and the safety assurance of the three-strain fermentation are the core technical support for achieving high-yield and high-quality pomelos. The test results fully demonstrate the promotion value of this special fertilizer in actual production.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0052] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A special organic fertilizer for Meizhou pomelo based on animal manure, characterized in that, The ingredients, by weight, include 50-70 parts animal manure, 10-20 parts peanut bran, 20-30 parts compound modified wood ash, 8-18 parts compound modified rice husk, and 0.1-0.5 parts fermentation agent. The preparation method of the composite modified plant ash is as follows: Step 1: Mix wood ash and phosphogypsum evenly to obtain dry powder. Take 40-60% of the total amount of citric acid, add water to prepare citric acid solution, spray the dry powder with citric acid solution, and then let it stand at 25-30℃ for 5-10 minutes to obtain pre-neutralized material. Dissolve ferrous sulfate and the remaining citric acid in water, spray it into the pre-neutralized material, and stir and react at 25-45℃ for 30-60 minutes to obtain material 1. Step 2: The material 1 obtained in Step 1 is tumbled at a low speed of 15-25 rpm, and the water glass solution is sprayed onto the material 1 in the form of atomization at a spraying rate of 10-25 mL / min. The spraying method is intermittent: after spraying for 2-5 minutes, the spraying is stopped and tumbling is maintained for 3-8 minutes. This process is repeated for 3-8 cycles until all the water glass solution is added, and wet particles are obtained. Step 3: Dry and solidify the wet granules at 50-70℃ until the moisture content of the granules is ≤15%, then cool to room temperature to obtain the final product.

2. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 1, characterized in that, In step 1, the mass ratio of wood ash to phosphogypsum is 5-15:1-5, the amount of citric acid and ferrous sulfate used is 0.5%-2.0% and 0.1%-0.5% of the total weight of wood ash and phosphogypsum, respectively, the mass ratio of citric acid to water in the citric acid solution is 1:1-2, and the mass ratio of water to ferrous sulfate is 3-5:1 during the dissolution of ferrous sulfate and the remaining citric acid with water.

3. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 1, characterized in that, In step 2, the mass ratio of material 1 to water glass is 100-115:5-15, and the volume ratio of water glass to water in the water glass solution is 1:0.5-1.

4. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 1, characterized in that, The method for preparing the composite modified rice husk is as follows: Step a: Crush the rice husks using a pulverizer. Then, mix the crushed rice husks with a sodium hydroxide solution and stir at 30-60 rpm for 60-120 minutes at 80-95℃. After the reaction, drain the alkaline solution and rinse the rice husks with hot water at 60-70℃ until the pH of the rinsing solution is 8.5-9.

0. Transfer the washed wet rice husks to a sealable container, add urea solution, and vacuum at 75-85℃ to -0.06 to -0.08 MPa for 25-35 minutes. Then, restore normal pressure and continue soaking for 1-2 hours. Filter out the rice husks and dry them at 55-65℃ to reduce their moisture content to 18%-22%. Step b: Place the dried rice husks from step a at 25-35℃ and atomize and spray the ethanol solution of the silane coupling agent at a rate of 0.5-1.05 mL / min. After spraying, let the rice husks stand at room temperature for 30-60 minutes to complete the curing. Step c: First, treat the solidified rice husks at 90-100℃ for 10-20 minutes, then raise the temperature to 130-150℃ and heat treat at this temperature for 30-60 minutes. Then, quickly cool the material to below 40℃ and finally pass it through a 2 mm sieve to obtain the final product.

5. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 4, characterized in that, In step a, the mass ratio of rice husk, sodium hydroxide solution, and urea is 10:15-25:2-4, the concentration of sodium hydroxide solution is 25-28%, and the mass ratio of urea to water in the urea solution is 1:5-8.

6. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 4, characterized in that, In step b, the mass ratio of the silane coupling agent to the rice husk in step a is 0.05-0.20:10, and the mass ratio of anhydrous ethanol to the silane coupling agent in the ethanol solution of the silane coupling agent is 5-10:

1.

7. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 1, characterized in that, The fermentation agent is one or more of Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae.

8. The Meizhou pomelo-specific organic fertilizer based on animal manure according to claim 7, characterized in that, The fermentation agent consists of three types: Bacillus subtilis, Bacillus licheniformis, and Saccharomyces cerevisiae, in a mass ratio of 2:2:

1.

9. The method for preparing Meizhou pomelo-specific organic fertilizer based on animal manure as described in any one of claims 1-8, characterized in that, Specifically, the mixture is prepared by mixing animal manure, peanut bran, compound modified wood ash, compound modified rice husk, and fermentation inoculant evenly, controlling the moisture content of the material to be between 55% and 65%, piling the mixture into a pile for high-temperature aerobic fermentation, with the core temperature of the pile at 55-70℃ for 15-25 days, aging the fermented material for 20-30 days, and then crushing the aged material to a particle size of ≤10mm to obtain the finished product.

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