Microbial-inorganic combined fertilizer and its preparation method

Abstract

The application discloses a kind of microorganism-inorganic combination fertilizer and preparation method thereof, belong to fertilizer preparation technical field, the combination fertilizer is composed of combination fertilizer A, combination fertilizer B, after glycerol is added in microbial liquid, combination fertilizer A is prepared using biochar and is loaded, biochar, glycerol can protect microorganism and provide nutrition, promote microorganism good proliferation growth;Using calcium-based bentonite embedding potassium magnesium sulfate fertilizer is made into granule to obtain combination fertilizer B, and the granule of calcium-based bentonite embedding potassium magnesium sulfate fertilizer is treated, ensure that fertilizer component in it slowly and uniformly release in long time;The application is embedded after being prepared into combination fertilizer by blending respectively to potassium magnesium sulfate fertilizer, microorganism, solves the problem that microorganism bacteria and potassium magnesium sulfate fertilizer are incompatible, combination fertilizer A, combination fertilizer B combined action provides the nutrition of entire growth cycle for crop, in reducing fertilizer waste, improve fertilizer absorption rate, reduce fertilization operating cost simultaneously, with good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fertilizer preparation, and particularly relates to a microbial-inorganic combined fertilizer and a preparation method thereof. BACKGROUND

[0002] Soil fertility is a measure of the ability of soil to provide various nutrients required for crop growth, which determines crop yield and quality. Fertilization is the most basic and most commonly used method to rapidly improve soil fertility. Microorganisms are widely used in agricultural production due to their important role in improving soil and promoting nutrient absorption of crops. In actual production application, microbial bacteria are usually combined with fertilizers for application, which can improve soil fertility, effectively improve soil physical and chemical properties, promote nutrient absorption of plants, and improve fertilizer utilization rate.

[0003] Potassium magnesium sulfate fertilizer is a natural mineral fertilizer, which is a multi-element potassium fertilizer containing potassium, sulfur, magnesium, calcium, silicon, boron, iron, zinc and other elements. It is known as the "white gold potassium" for crop fertilization, and is suitable for all crops with very obvious yield increasing effect. Potassium magnesium sulfate fertilizer is usually used as base fertilizer, but due to its strong water solubility, short duration and easy loss with water in soil, the plant absorption utilization rate is reduced, which cannot meet the needs of the whole growth cycle of crops, resulting in waste and easy pollution to the environment and water body. In addition, when microbial bacteria are directly mixed with potassium magnesium sulfate fertilizer for application, the high salt environment of potassium magnesium sulfate fertilizer can easily cause microbial bacteria to be inactivated, thereby reducing the effect.

[0004] Therefore, it is necessary to find a fertilizer preparation method to solve the problems that microbial bacteria and potassium magnesium sulfate fertilizer cannot be compatible, and the strong water solubility of potassium magnesium sulfate fertilizer leads to easy loss and waste of nutrients, improve the utilization rate of potassium magnesium sulfate fertilizer in soil, and then improve the yield and quality of crops. SUMMARY

[0005] In view of this, the purpose of the present application is to provide a microbial-inorganic combined fertilizer and a preparation method thereof, which solves the problems that potassium magnesium sulfate fertilizer and microbial bacteria cannot be compatible under the conventional mixed application method, resulting in reduced effect, and potassium magnesium sulfate fertilizer nutrients are easy to lose and waste.

[0006] The present application solves the above technical problems through the following technical means:

[0007] A microbial-inorganic combined fertilizer, the combined fertilizer comprises the following raw materials:

[0008] Microbial bacteria solution, potassium magnesium sulfate fertilizer, urea, biochar, glycerol, sodium alginate, 2wt% calcium chloride solution, xanthan gum, cinnamamide, diglycolamine, calcium bentonite, gum arabic, and stearic acid.

[0009] Further, the microbial liquid is prepared by mixing Metarrhizium anisopliae liquid, Trichoderma harzianum liquid and Bacillus amyloliquefaciens liquid according to a mass ratio of 1:1:2.

[0010] Further, the concentration of Metarrhizium anisopliae liquid is 1-5*10 9 cfu / mL, the concentration of Trichoderma harzianum liquid is 2-4*10 9 cfu / mL, and the concentration of Bacillus amyloliquefaciens liquid is 1-5*10 10 cfu / mL.

[0011] The application further discloses a preparation method of the combined fertilizer.

[0012] A: glycerol is added into the microbial liquid and slowly mixed uniformly, then biochar is added and shaken together for culture, sodium alginate is dissolved in water and added, a microbial mixed liquid is obtained, the microbial mixed liquid is dropped into a 2wt% calcium chloride solution to form solidified balls through gelation, the solidified balls are washed with water for 2-3 times to obtain the combined fertilizer A;

[0013] B: xanthan gum is dissolved in water, then cinnamamide and diglycol amine are added and mixed uniformly, and then the mixture is heated to 65-75 DEG C and stirred for 10-15 min, then the pH is adjusted to 3-4, urea is added and mixed uniformly, the mixture is cooled to room temperature and left to stand for 4-6 h to make the xanthan gum gelate, then the xanthan gum embedded microparticles are obtained by drying, crushing and passing through a 200 mesh sieve;

[0014] C: calcium-based bentonite is added into water and stirred and dispersed, then potassium sulfate magnesium fertilizer is added and mixed uniformly, then gum arabic and stearic acid are added in sequence and mixed uniformly to obtain a bentonite mixture, the xanthan gum embedded microparticles are added into the bentonite mixture and mixed uniformly, then the mixture is put into a granulator to be granulated, and then the combined fertilizer B is obtained by drying, and the combined fertilizer B is mixed with the combined fertilizer A to obtain the combined fertilizer.

[0015] Potassium sulfate magnesium fertilizer is easy to be lost with water after being applied to soil, which not only causes waste of the fertilizer, but also pollutes the environment and water quality, therefore, the calcium-based bentonite is used as a carrier and gum arabic is used as a binder to embed the potassium sulfate magnesium fertilizer to prepare the granular slow-release combined fertilizer B, after being applied to soil, the water in the soil enters the granules and gradually dissolves the granules, so that the granules are slowly diffused out of the granules into the soil for plant absorption and utilization, and the loss of the fertilizer is inhibited, so that the absorption and utilization rate of the plant is improved.

[0016] Potassium magnesium sulfate fertilizer is usually used as base fertilizer, and it is necessary to ensure that it meets the needs of the whole growth cycle of crops as much as possible. Therefore, the present application adds hydrophobic stearic acid to the calcium-based bentonite when preparing granular fertilizer by embedding potassium magnesium sulfate fertilizer, so that the stearic acid is embedded in the granular fertilizer. Due to the presence of stearic acid, the water in the soil needs to bypass the stearic acid embedding area to enter the fertilizer particles to dissolve the potassium magnesium sulfate fertilizer and make it diffuse out for plant use. Therefore, the presence of stearic acid increases the mass transfer resistance of the combined fertilizer B particles, thereby reducing the slow-release amount of potassium magnesium sulfate fertilizer in the early stage of the combined fertilizer B with high potassium magnesium sulfate fertilizer content, to ensure the supply of fertilizer in the later stage.

[0017] With the increase of time, potassium magnesium sulfate fertilizer is gradually released into the soil and absorbed and utilized by crops, and the content of potassium magnesium sulfate fertilizer in the combined fertilizer B decreases, so that the amount of potassium magnesium sulfate fertilizer that can enter the soil gradually decreases. In order to ensure uniform release and later supply of fertilizer, xanthan gum embedded particles are added to the combined fertilizer B, which are obtained by embedding xanthan gum with cinnamamide, diglycolamine and urea. Xanthan gum has good acid-base stability and biological degradation resistance, and slowly releases cinnamamide, diglycolamine and urea in the combined fertilizer B. Urea itself as a fertilizer provides nutrients for plant growth, and also acts on the adhesive arabic gum in the combined fertilizer B particles to destroy its chemical bonds and thus reduce its viscosity, so that the structure of the combined fertilizer B particles gradually becomes loose; cinnamamide acts on the embedding material calcium-based bentonite in the combined fertilizer B, increases the spacing between the molecules of bentonite, increases the swelling rate of bentonite, and thus increases the pore diameter, so that more water enters the interior of the particles to dissolve potassium magnesium sulfate fertilizer and make it release better, increasing the slow-release amount of fertilizer in the middle and later stages; further, diglycolamine acts on stearic acid, adjusts the substructure of stearic acid, reduces its stability in the soil and makes it gradually decompose, gradually eliminating the mass transfer resistance of stearic acid; the combined action of urea, cinnamamide and diglycolamine improves the release rate and release amount of fertilizer in the middle and later stages. Through the combined action of various components in the combined fertilizer B, the embedded potassium magnesium sulfate fertilizer can be slowly and uniformly released for a long time, and thus long-acting nutrient supply effect is achieved.

[0018] Since the high salt environment of the potassium magnesium sulfate fertilizer can harm the microorganism bacteria, the protective agent glycerol is added in the microorganism bacteria liquid, and then the microorganism bacteria liquid mixed with the biochar is co-cultured, and then the sodium alginate is added and mixed, and then the mixture is dropped into the calcium chloride to be gelled to prepare the granular combined fertilizer A, the biochar and the glycerol can protect the microorganism bacteria, provide a suitable living environment and nutrition, and ensure that the microorganism bacteria grow well in the high salt environment of the potassium magnesium sulfate fertilizer, so that the nutrients in the combined fertilizer B are efficiently absorbed by crops, a good rhizosphere environment is created, the soil properties are improved, and at the same time, the microorganism bacteria release organic acid and other substances to neutralize the alkalinity of the potassium magnesium sulfate fertilizer and urea and other substances in the combined fertilizer B, so that the stability of the soil pH is maintained. Through the combined action of the combined fertilizers A and B, the absorption and utilization rate of the fertilizer is improved, the soil properties are improved, the crop yield and quality are improved, the fertilizer waste is reduced, the fertilizer action time is prolonged, and the fertilization operation cost is reduced.

[0019] Further, the mass ratio of the microorganism bacteria liquid, the glycerol, the biochar and the sodium alginate in step A is (1-2):(0.25-0.5):(4-8):(0.1-0.2).

[0020] Further, the mass ratio of the xanthan gum, the cinnamamide, the diglycol amine and the urea in step B is (1-2):(0.3-0.5):(0.3-0.5):(0.5-0.8).

[0021] Further, the mass ratio of the calcium-based bentonite, the potassium magnesium sulfate fertilizer, the stearic acid, the gum arabic and the xanthan gum embedded microparticles in step C is (20-30):(15-25):(0.2-0.6):(0.5-1):(2-3.5).

[0022] Further, the mass ratio of the combined fertilizer A to the combined fertilizer B in the combined fertilizer is (1-2):(7-11).

[0023] Further, the particle size of the granulation in step C is 0.2-0.5 cm.

[0024] Beneficial effects:

[0025] 1. The potassium magnesium sulfate fertilizer with multiple nutrient elements is used as the main effective component, the calcium-based bentonite is used for embedding to prepare the slow-release granular fertilizer combined fertilizer B, and the xanthan gum embedded microparticles prepared by adding the cinnamamide and other raw materials in the granular fertilizer are prepared, so that the potassium magnesium sulfate fertilizer in the combined fertilizer B is slowly and uniformly released for a long time, the needs of crops in the whole growth cycle are met, and the crop yield and quality are effectively improved.

[0026] 2.The application also adopts Metarhizium anisopliae, Trichoderma harzianum and Bacillus amyloliquefaciens to prepare a microbial bacteria mixture, and adopts biochar and sodium alginate to prepare a combined fertilizer A, which can create a good rhizosphere environment, improve soil properties, promote the absorption and utilization of nutrients in a combined fertilizer B by plants, improve the soil physical and chemical conditions through the combined action of each component in the combined fertilizer, and improve crop yield and quality, thus having a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 : is a picture of the growth condition of citrus plants after one year of planting in Example 1 in the experiment of the application;

[0028] Figure 2 : is a picture of the growth condition of citrus seeds after one year in the blank control group in the experiment of the application. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with specific examples:

[0030] The application discloses a microbial-inorganic combined fertilizer and a preparation method thereof. 9 The concentration of the Metarhizium anisopliae bacteria liquid is about 2x10 9 The concentration of the Trichoderma harzianum bacteria liquid is about 3x10 10 The concentration of the Bacillus amyloliquefaciens bacteria liquid is about 2x10

[0031] Example 1: Preparation of combined fertilizer one

[0032] Preparation method:

[0033] A: 0.35 kg of glycerol is added to 1.5 kg of the microbial bacteria liquid, and after being slowly stirred and uniformly mixed, 6 kg of biochar is added, sterile water is injected just to cover the biochar, and then the mixture is cultured at a rotation speed of 200 r / min for 24 h in a shaking table, then 0.15 kg of sodium alginate is dissolved in 0.75 kg of water and added, to obtain a microbial mixture, the microbial mixture is slowly dropped into a 2 wt% calcium chloride solution to form solidified balls with a particle size of about 0.3 cm, and the solidified balls are washed with water for 3 times to obtain the combined fertilizer A;

[0034] B: 1.5 kg of xanthan gum is dissolved in 7.5 kg of water, then 0.4 kg of cinnamamide and 0.4 kg of diglycolamine are mixed uniformly, and then the temperature is raised to 70°C for stirring reaction for 12 min, then the pH is adjusted to 3.5, and then 0.6 kg of urea is mixed uniformly, and then the temperature is cooled to room temperature, and then it is left to stand for 5 h to gelatinize the xanthan gum, and then it is dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0035] C: 25 kg of calcium bentonite is added to 75 kg of water and stirred and dispersed, then 20 kg of potassium sulfate magnesium fertilizer is added and mixed uniformly, then 0.4 kg of gum arabic and 0.6 kg of stearic acid are added in sequence and mixed uniformly to obtain a bentonite mixture, 2.5 kg of xanthan gum embedded microparticles is added to the bentonite mixture and mixed uniformly, and then it is put into a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then it is dried at 45°C to obtain combined fertilizer B, and then combined fertilizer B is mixed with combined fertilizer A in a mass ratio of 9:1.5 to obtain the combined fertilizer.

[0036] Example 2: Preparation of combined fertilizer two

[0037] Preparation method:

[0038] A: 0.25 kg of glycerol is added to 1 kg of microbial liquid, and then it is mixed uniformly by slow stirring, and then 4 kg of biochar is added, and then sterile water is injected to just cover the biochar, and then it is shaken and cultured at a speed of 200 r / min for 24 h, and then 0.1 kg of sodium alginate is dissolved in 0.5 kg of water and then added to obtain a microbial mixture, and then the microbial mixture is slowly dripped into a 2 wt% calcium chloride solution to gelatinize and form solidified balls with a particle size of about 0.3 cm, and then the solidified balls are washed with water for 3 times to obtain combined fertilizer A;

[0039] B: 1 kg of xanthan gum is dissolved in 5 kg of water, then 0.3 kg of cinnamamide and 0.3 kg of diglycolamine are mixed uniformly, and then the temperature is raised to 65°C for stirring reaction for 15 min, then the pH is adjusted to 3, and then 0.5 kg of urea is mixed uniformly, and then the temperature is cooled to room temperature, and then it is left to stand for 4 h to gelatinize the xanthan gum, and then it is dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0040] C: 20 kg of calcium bentonite is added to 60 kg of water and stirred and dispersed, then 15 kg of potassium sulfate magnesium fertilizer is added and mixed uniformly, then 0.2 kg of gum arabic and 0.5 kg of stearic acid are added in sequence and mixed uniformly to obtain a bentonite mixture, 2 kg of xanthan gum embedded microparticles is added to the bentonite mixture and mixed uniformly, and then it is put into a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then it is dried at 45°C to obtain combined fertilizer B, and then combined fertilizer B is mixed with combined fertilizer A in a mass ratio of 7:1 to obtain the combined fertilizer.

[0041] Example 3: Preparation of combined fertilizer three

[0042] Preparation method:

[0043] A: 0.5 kg of glycerol was added to 2 kg of microbial liquid, and after being mixed uniformly by slow stirring, 8 kg of biochar was added. Sterile water was injected just to cover the biochar, and the mixture was cultured for 24 h under shaking at a speed of 200 r / min. Then, 0.2 kg of sodium alginate was dissolved in 1 kg of water and added, to obtain a microbial mixture. The microbial mixture was slowly dripped into a 2 wt% calcium chloride solution to form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water for 3 times to obtain the combined fertilizer A;

[0044] B: 2 kg of xanthan gum was dissolved in 10 kg of water, and then 0.5 kg of cinnamamide and 0.5 kg of diglycolamine were added and mixed uniformly. The mixture was heated to 75 °C and stirred for 10 min. Then, the pH was adjusted to 4, 0.8 kg of urea was added and mixed uniformly, and the mixture was cooled to room temperature and stood for 6 h to gel the xanthan gum. Then, the mixture was dried at 45 °C, crushed and sieved through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0045] C: 30 kg of calcium bentonite was added to 90 kg of water and stirred and dispersed, and then 25 kg of potassium sulfate magnesium fertilizer was added and mixed uniformly. Then, 0.6 kg of gum arabic and 1 kg of stearic acid were added and mixed uniformly to obtain a bentonite mixture. 3.5 kg of xanthan gum embedded microparticles were added to the bentonite mixture and mixed uniformly, and then put into a granulator to prepare granules with a particle size of 0.4 cm. Then, the granules were dried at 45 °C to obtain the combined fertilizer B. The combined fertilizer B and the combined fertilizer A were mixed in a mass ratio of 11:2 to obtain the combined fertilizer.

[0046] Comparative Example 1: Preparation of combined fertilizer

[0047] In comparison with Example 1, the only difference is that in Comparative Example 1, no biochar was added in step A during the preparation of the combined fertilizer, but an equal amount of sterile water was added, as shown below:

[0048] A: 0.5 kg of glycerol was added to 2 kg of microbial liquid, and after being mixed uniformly by slow stirring, 8 kg of biochar was added. Sterile water was injected just to cover the biochar, and the mixture was cultured for 24 h under shaking at a speed of 200 r / min. Then, 0.2 kg of sodium alginate was dissolved in 1 kg of water and added, to obtain a microbial mixture. The microbial mixture was slowly dripped into a 2 wt% calcium chloride solution to form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water for 3 times to obtain the combined fertilizer A;

[0049] B-C: Same as Example 1.

[0050] Comparative Example 2: Preparation of combined fertilizer

[0051] Compared with Example 1, the only difference is that glycerol was not added in step A during the preparation of the compound fertilizer in Comparative Example 2, as shown below:

[0052] A: Add 6 kg of biochar to 1.5 kg of microbial culture, and pour in sterile water just enough to cover the biochar. Shake and culture for 24 h at 200 r / min. Then, dissolve 0.15 kg of sodium alginate in 0.75 kg of water and add it to the culture to obtain a microbial mixture. Slowly drip the microbial mixture into a 2 wt% calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. Wash the solidified balls with water three times to obtain compound fertilizer A.

[0053] BC: Same as in Example 1.

[0054] Comparative Example 3: Preparation of Combined Fertilizer

[0055] Compared with Example 1, the only difference is that glycerol was not added during the preparation of the compound fertilizer in Comparative Example 3, and biochar was replaced with an equal amount of sterile water, as shown below:

[0056] A: Add 6 kg of sterile water to 1.5 kg of microbial culture and shake in a shaker at 200 r / min for 24 h. Then, dissolve 0.15 kg of sodium alginate in 0.75 kg of water and add it to the culture to obtain a microbial mixture. Slowly drip the microbial mixture into a 2 wt% calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. Wash the solidified balls with water three times to obtain compound fertilizer A.

[0057] BC: Same as in Example 1.

[0058] Comparative Example 4: Preparation of Combined Fertilizer

[0059] Compared with Example 1, the only difference is that cinnamamide was not added in step B of the preparation of the compound fertilizer in Comparative Example 4, as shown below:

[0060] A: Same as Example 1;

[0061] B: Dissolve 1.5 kg xanthan gum in 7.5 kg of water, then add 0.4 kg of diethylene glycolamine and mix well. Heat to 70°C and stir for 12 min. Adjust the pH to 3.5 and add 0.6 kg of urea and mix well. Cool to room temperature and let stand for 5 h to gel the xanthan gum. Then dry at 45°C, pulverize and pass through a 200-mesh sieve to obtain xanthan gum-encapsulated microparticles.

[0062] C: Same as in Example 1.

[0063] Comparative Example 5: Preparation of Combined Fertilizer

[0064] In contrast to Example 1, the only difference is that no diethanolamine is added in step B during the preparation of the compound fertilizer in Comparative Example 5, as shown below:

[0065] A: Same as Example 1;

[0066] B: 1.5 kg of xanthan gum is dissolved in 7.5 kg of water, then 0.4 kg of cinnamic amide is added and mixed uniformly, and then heated to 70°C and stirred for 12 min, then cooled to room temperature and left to stand for 5 h to gel the xanthan gum, then dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0067] C: Same as Example 1.

[0068] Comparative Example 6: Preparation of compound fertilizer

[0069] In contrast to Example 1, the only difference is that no urea is added in step B during the preparation of the compound fertilizer in Comparative Example 6, as shown below:

[0070] A: Same as Example 1;

[0071] B: 1.5 kg of xanthan gum is dissolved in 7.5 kg of water, then 0.4 kg of cinnamic amide and 0.4 kg of diethanolamine are added and mixed uniformly, and then heated to 70°C and stirred for 12 min, then cooled to room temperature and left to stand for 5 h to gel the xanthan gum, then dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0072] C: Same as Example 1.

[0073] Comparative Example 7: Preparation of compound fertilizer

[0074] In contrast to Example 1, the only difference is that no pH adjustment is made in step B during the preparation of the compound fertilizer in Comparative Example 7, as shown below:

[0075] A: Same as Example 1;

[0076] B: 1.5 kg of xanthan gum is dissolved in 7.5 kg of water, then 0.4 kg of cinnamic amide and 0.4 kg of diethanolamine are added and mixed uniformly, and then heated to 70°C and stirred for 12 min, then 0.6 kg of urea is added and mixed uniformly, cooled to room temperature and left to stand for 5 h to gel the xanthan gum, then dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0077] C: Same as Example 1.

[0078] Comparative Example 8: Preparation of compound fertilizer

[0079] In comparison with Example 1, the only difference is that in Comparative Example 8, xanthan gum is not used in Step B when preparing the compound fertilizer, but gum arabic is used to prepare gum arabic-embedded microparticles, which are added in Step C, as shown below:

[0080] A: Same as Example 1;

[0081] B: 1.5 kg of gum arabic is dissolved in 7.5 kg of water, then 0.4 kg of cinnamic amide and 0.4 kg of diglycol amine are added and mixed uniformly, and then the temperature is raised to 70°C and stirred for 12 min, then the pH is adjusted to 3.5, and then 0.6 kg of urea is added and mixed uniformly, and then the temperature is lowered to room temperature, and then the gum arabic is allowed to gelate by standing for 5 h, and then it is dried at 45°C, crushed, and passed through a 200-mesh sieve to obtain gum arabic-embedded microparticles;

[0082] C: Same as Example 1.

[0083] Comparative Example 9: Preparation of a compound fertilizer

[0084] In comparison with Example 1, the only difference is that in Comparative Example 9, gum arabic is not added in Step C when preparing the compound fertilizer, as shown below:

[0085] A-B: Same as Example 1;

[0086] C: 25 kg of calcium-based bentonite is added to 75 kg of water and stirred to disperse, then 20 kg of potassium-magnesium sulfate fertilizer is added and mixed uniformly, then 0.6 kg of stearic acid is added and mixed uniformly to obtain a bentonite mixture, then 2.5 kg of xanthan gum-embedded microparticles is added to the bentonite mixture and mixed uniformly, then the mixture is placed in a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then the mixture is dried at 45°C to obtain compound fertilizer B, and then compound fertilizer B is mixed with compound fertilizer A at a mass ratio of 9:1.5 to obtain a compound fertilizer.

[0087] Comparative Example 10: Preparation of a compound fertilizer

[0088] In comparison with Example 1, the only difference is that in Comparative Example 10, stearic acid is not added in Step C when preparing the compound fertilizer, as shown below:

[0089] A-B: Same as Example 1;

[0090] C: 25 kg of calcium-based bentonite is added to 75 kg of water and stirred to disperse, then 20 kg of potassium-magnesium sulfate fertilizer is added and mixed uniformly, then 0.4 kg of gum arabic is added and mixed uniformly to obtain a bentonite mixture, then 2.5 kg of xanthan gum-embedded microparticles is added to the bentonite mixture and mixed uniformly, then the mixture is placed in a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then the mixture is dried at 45°C to obtain compound fertilizer B, and then compound fertilizer B is mixed with compound fertilizer A at a mass ratio of 9:1.5 to obtain a compound fertilizer.

[0091] Preparation of the compound fertilizer

[0092] In contrast to Example 1, the only difference is that in Comparative Example 11, instead of gum arabic, xanthan gum is used in step C when preparing the compound fertilizer, as shown below:

[0093] A-B: same as Example 1;

[0094] C: 25 kg of calcium-based bentonite is added to 75 kg of water and stirred to disperse, then 20 kg of potassium sulfate magnesium fertilizer is added and mixed evenly, then 0.4 kg of xanthan gum and 0.6 kg of stearic acid are added and mixed evenly to obtain a bentonite mixture, 2.5 kg of xanthan gum embedded particles are added to the bentonite mixture and mixed evenly, then put into a granulator to granulate to prepare particles with a particle size of 0.4 cm, then dried at 45°C to obtain compound fertilizer B, and then compound fertilizer B and compound fertilizer A are mixed in a mass ratio of 9:1.5 to obtain the compound fertilizer.

[0095] Preparation of the compound fertilizer

[0096] In contrast to Example 1, the only difference is that in Comparative Example 12, instead of embedding cinnamamide, diglycolamine and urea with xanthan gum, they are directly added in step C when preparing the compound fertilizer, as shown below:

[0097] A: same as Example 1;

[0098] B: 25 kg of calcium-based bentonite is added to 75 kg of water and stirred to disperse, then 20 kg of potassium sulfate magnesium fertilizer is added and mixed evenly, then 0.4 kg of gum arabic and 0.6 kg of stearic acid are added and mixed evenly to obtain a bentonite mixture, 0.4 kg of cinnamamide, 0.4 kg of diglycolamine and 0.6 kg of urea are added to the bentonite mixture and mixed evenly, then put into a granulator to granulate to prepare particles with a particle size of 0.4 cm, then dried at 45°C to obtain compound fertilizer B, and then compound fertilizer B and compound fertilizer A are mixed in a mass ratio of 9:1.5 to obtain the compound fertilizer.

[0099] Preparation of the compound fertilizer

[0100] In contrast to Example 1, the only difference is that in Comparative Example 13, step B is missing when preparing the compound fertilizer, that is, no xanthan gum embedded particles are added when preparing compound fertilizer B, as shown below:

[0101] A: same as Example 1;

[0102] B: 25 kg of calcium bentonite was added into 75 kg of water and stirred to disperse, then 20 kg of potassium sulfate magnesium fertilizer was added and mixed evenly, then 0.4 kg of Arabic gum and 0.6 kg of stearic acid were added in sequence and mixed evenly to obtain a bentonite mixture, 2.5 kg of xanthan gum embedded microparticles were added into the bentonite mixture and mixed evenly, and then the mixture was put into a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then dried at 45°C to obtain the compound fertilizer B.

[0103] Comparative Example 14: Preparation of a compound fertilizer

[0104] In contrast to Example 1, the only difference is that in Comparative Example 14, the compound fertilizer is prepared without the original Step A, i.e., the compound fertilizer B is a compound fertilizer, which is prepared as follows:

[0105] A: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, then 0.4 kg of cinnamamide and 0.4 kg of diglycolamine were added and mixed evenly, and then the temperature was raised to 70°C and stirred for 12 min, then the pH was adjusted to 3.5, and then 0.6 kg of urea was added and mixed evenly, and then the temperature was cooled to room temperature, and then the mixture was left to stand for 5 h to gel the xanthan gum, and then the mixture was dried at 45°C, crushed and passed through a 200 mesh sieve to obtain xanthan gum embedded microparticles;

[0106] B: 25 kg of calcium bentonite was added into 75 kg of water and stirred to disperse, then 20 kg of potassium sulfate magnesium fertilizer was added and mixed evenly, then 0.4 kg of Arabic gum and 0.6 kg of stearic acid were added in sequence and mixed evenly to obtain a bentonite mixture, 2.5 kg of xanthan gum embedded microparticles were added into the bentonite mixture and mixed evenly, and then the mixture was put into a granulator to be granulated to prepare particles with a particle size of 0.4 cm, and then dried at 45°C to obtain the compound fertilizer B.

[0107] Experiment: Effect detection of the compound fertilizer

[0108] 1. The application effect of the compound fertilizers prepared in Example 1 and Comparative Examples 1-14 was determined, and the specific method was as follows: soil was collected from a citrus field in the research institute of Southwest University in Chongqing, and then the soil was mixed evenly to obtain experimental soil, and the initial available potassium content and initial pH of the experimental soil were measured (the available potassium content was 125.4 mg / kg, and the pH was 6.5), then the experimental soil was put into pots, 20 kg per pot, and the pots containing the experimental soil were divided into 16 groups: corresponding to Example 1, Comparative Examples 1-14, and a blank control, 3 pots per group. Then the compound fertilizers of Example 1 and Comparative Examples 1-14 were applied to the corresponding groups of pots, wherein 1050 g of the compound fertilizer was applied in Example 1 and Comparative Examples 1-13, and 900 g of the compound fertilizer of Comparative Example 14 was applied in Comparative Example 14 without the compound fertilizer A, and no compound fertilizer was applied in the blank control group; then citrus seedlings (Jinqiu sandaranges) with consistent growth conditions were planted in the pots, and the pots were placed in the outdoor natural environment, and the same method was used for management and maintenance.

[0109] 2. After 30 days of citrus planting, the viable cell numbers of Metarrhizium anisopliae, Trichoderma harzianum and Bacillus amyloliquefaciens in the soil of Example 1, Comparative Examples 1-3 and the blank control group were detected by dilution plate counting method, and the average data are shown in Table 1.

[0110] 3. The potassium available content in the soil of each group of flower pots was determined again at 10 days, 30 days and 70 days after the citrus planting; the soil pH was determined again after 6 months, and the height growth of the citrus seedlings in each group was counted, and the average data are shown in Table 2.

[0111] Table 1

[0112]

[0113] Table 2

[0114]

[0115]

[0116] According to the data analysis of Table 1, it can be known that:

[0117] (1) The viable cell number of Metarrhizium anisopliae in the soil of Example 1 is 6.1x10 5 cfu / g, the viable cell number of Trichoderma harzianum is 2.4x10 6 cfu / g, and the viable cell number of Bacillus amyloliquefaciens is 1.4x10 7 cfu / g, and the viable cell numbers of each strain remain a high amount, which indicates that the addition of glycerol protective agent and the loading of biochar according to the method of the application can provide a good survival environment for the microbial bacteria, thereby ensuring that the microorganisms can grow and reproduce well in the high-salt environment of the combined fertilizer B of potassium sulfate magnesium fertilizer, and better play the effect, and better solve the problem of incompatibility of the microbial bacteria and the potassium sulfate magnesium fertilizer.

[0118] According to the data analysis of Table 2, it can be known that:

[0119] (2) The potassium available content in the soil after 10 days, 30 days and 70 days after the application of the combined fertilizer prepared by the application increases obviously, which indicates that the prepared combined fertilizer can slowly release for a long time and then provide nutrients required for crop growth for a long time; and the combined fertilizer A and the combined fertilizer B have a synergistic effect, which can maintain the stability of the soil pH and promote the absorption of nutrients by crops while ensuring the long-acting effect of the fertilizer, and better promote the growth of the citrus crops and the height growth of the seedlings.

[0120] (3) The activity of the microbial bacteria in the combined fertilizer A in Comparative Example 1 is affected because no biochar is added during preparation of the combined fertilizer A, the activity of the microbial bacteria in the combined fertilizer A in Comparative Example 2 is affected because no glycerol is added during preparation of the combined fertilizer A, and the activity of the microbial bacteria in the combined fertilizer A in Comparative Example 3 is affected because no glycerol and no biochar are added during preparation of the combined fertilizer A. In the case where the nutrient content in the soil remains at a high level, the plant height increases by different degrees, and the pH changes significantly, which indicates that the microbial bacteria have an important promoting effect on improving the fertilizer utilization rate.

[0121] (4) The swelling performance of bentonite, the embedding material of the combined fertilizer B in Comparative Example 4, is low in the middle and late stages, which inhibits the release of the internal potassium-magnesium sulfate fertilizer, and thus the soil available potassium content decreases at 30 days and 70 days. The release rate of the potassium-magnesium sulfate fertilizer is low in the middle and late stages in the combined fertilizer B in Comparative Example 5 because of the mass transfer hindering effect of the embedded stearic acid in the particles, and thus the soil available potassium content decreases at 30 days and 70 days. The performance of the adhesive arabic gum is good, the structure of the combined fertilizer particles is relatively stable and complete, and thus the release of the internal potassium-magnesium sulfate fertilizer is inhibited in the combined fertilizer B in Comparative Example 6 because no urea is added during preparation of the combined fertilizer B. The release amount of urea is too large under the condition of a high pH, which increases the looseness of the embedded particles and further causes the high release amount of the potassium-magnesium sulfate fertilizer in the early stage and the reduction of the nutrient supply in the late stage in the combined fertilizer B in Comparative Example 7 because the pH of the xanthan gum embedded particles is not adjusted.

[0122] (5) The combined fertilizer B in Comparative Example 8 is prepared by replacing the xanthan gum with the arabic gum, and the combined fertilizer B in Comparative Example 9 is prepared without adding the adhesive arabic gum. The stability of the arabic gum in the soil is poor in Comparative Example 8, which causes the rapid release of the cinnamon amide, the diglycol amine and the urea in the early and middle stages, promotes the rapid release of the potassium-magnesium sulfate fertilizer in the early and middle stages of the combined fertilizer B particles, and reduces the available nutrients in the late stage. The particle forming performance of the calcium bentonite is poor in Comparative Example 9, which causes the structure of the particles to be unstable and the internal fertilizer components to be rapidly released in the middle stage.

[0123] (6) The combined fertilizer B in Comparative Example 12 is prepared without using the xanthan gum to embed the cinnamon amide and the like, but directly adding the cinnamon amide and the like in step C, which causes the rapid release of the cinnamon amide and the like, reduces the viscosity and eliminates the mass transfer hindering effect, causes the large release of the fertilizer in the early stage, and reduces the nutrient release and supply in the middle and late stages.

[0124] The above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all of them should be covered in the scope of the claims of the present application. The technical, shape and structure parts not described in detail in the present application are well-known technologies.

Claims

1. A microbial-inorganic compound fertilizer, characterized in that, The compound fertilizer comprises the following raw materials: Microbial inoculum, potassium magnesium sulfate fertilizer, urea, biochar, glycerin, sodium alginate, calcium chloride, xanthan gum, cinnamamide, diethylene glycolamine, calcium bentonite, gum arabic, stearic acid; The method for preparing the combined fertilizer is as follows: A: Add glycerol to the microbial inoculum and mix well. Then add biochar and shake to culture. Dissolve sodium alginate in water and add it to the mixture to obtain a microbial mixture. Add the microbial mixture to a 2wt% calcium chloride solution to gel and form solidified balls. Wash the solidified balls with water 2-3 times to obtain compound fertilizer A. B: Dissolve xanthan gum in water, then add cinnamamide and diethylene glycolamine and mix well. Heat to 65-75℃ and stir for 10-15 minutes. Then adjust the pH to 3-4 and add urea and mix well. Cool to room temperature and let stand for 4-6 hours to gel the xanthan gum. Then dry, pulverize and pass through a 200-mesh sieve to obtain xanthan gum-encapsulated microparticles. C: Add calcium-based bentonite to water and stir to disperse. Then add potassium magnesium sulfate fertilizer and mix thoroughly. Then add gum arabic and stearic acid in sequence and mix thoroughly to obtain a bentonite mixture. Add xanthan gum-encapsulated microparticles to the bentonite mixture and mix well. Then put it into a granulator for granulation and dry to obtain compound fertilizer B. Mix compound fertilizer B with compound fertilizer A to obtain compound fertilizer.

2. The microbial-inorganic combined fertilizer according to claim 1, characterized in that, The microbial culture solution was prepared by mixing Metarhizium anisopliae culture solution, Trichoderma harzianum culture solution and Bacillus amyloliquefaciens culture solution in a mass ratio of 1:1:

2.

3. The microbial-inorganic combined fertilizer according to claim 2, characterized in that, The concentration of Metarhizium anisopliae bacterial suspension during the preparation of the microbial culture is 1-5 × 10⁻⁵. 9 cfu / mL, Trichoderma harzianum concentration 2-4×10 9 fu / mL, Bacillus amyloliquefaciens bacterial culture concentration 1-5×10 10 cfu / mL.

4. The microbial-inorganic combined fertilizer according to claim 3, characterized in that, In step A, the mass ratio of microbial inoculum, glycerol, biochar, and sodium alginate is (1-2):(0.25-0.5):(4-8):(0.1-0.2).

5. The microbial-inorganic combined fertilizer according to claim 4, characterized in that, In step B, the mass ratio of xanthan gum, cinnamamide, diethylene glycolamine, and urea is (1-2):(0.3-0.5):(0.3-0.5):(0.5-0.8).

6. The microbial-inorganic combined fertilizer according to claim 5, characterized in that, In step C, the mass ratio of calcium-based bentonite to potassium magnesium sulfate fertilizer, stearic acid, gum arabic, and xanthan gum-encapsulated microparticles is (20-30): (15-25): (0.2-0.6): (0.5-1): (2-3.5).

7. The microbial-inorganic combined fertilizer according to claim 6, characterized in that, The mass ratio of compound fertilizer A to compound fertilizer B in the compound fertilizer is (1-2):(7-11).

8. The microbial-inorganic combined fertilizer according to claim 7, characterized in that, In step C, the granulation particle size is 0.2-0.5 cm.

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