Microorganism-inorganic compound fertilizer and preparation method thereof

Abstract

The invention discloses a microorganism-inorganic compound fertilizer and a preparation method thereof, and belongs to the technical field of fertilizer preparation.The compound fertilizer is composed of a compound fertilizer A and a compound fertilizer B. The compound fertilizer A is prepared by adding glycerin into a microorganism bacterium solution and then loading with charcoal, and the charcoal and the glycerin can protect microorganisms and provide nutrition; good proliferation and growth of microorganisms are promoted; calcium bentonite is adopted to embed potash magnesium sulphate fertilizer to prepare granules to obtain a combined fertilizer B, and the calcium bentonite embedded potash magnesium sulphate fertilizer granules are treated to ensure that fertilizer components in the granules are slowly released at a constant speed within a long time; the potash magnesium sulphate fertilizer and the microorganisms are embedded and blended to prepare the combined fertilizer, the problem that the microorganisms and the potash magnesium sulphate fertilizer are incompatible is solved, the combined fertilizer A and the combined fertilizer B jointly act to provide nutrients for crops in the whole growth cycle, fertilizer waste is reduced, the fertilizer absorption rate is increased, meanwhile, the fertilization operation cost is reduced, and the production cost is reduced. Good application prospects are realized.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, and in particular to a microorganism-inorganic combination fertilizer and a preparation method thereof. Background Art

[0002] Soil fertility is a measure of the ability of soil to provide various nutrients required for crop growth, which determines the yield and quality of crops. Fertilization is the most basic and most commonly used method to quickly improve soil fertility. Microorganisms are widely used in agricultural production because they play an important role in improving soil and promoting crop nutrient absorption. In actual production applications, microorganisms are usually used in combination with fertilizers. While improving soil fertility, they can also effectively improve soil physical and chemical properties, promote plant absorption of nutrients, and improve fertilizer utilization.

[0003] Potassium sulfate magnesium fertilizer is a natural mineral fertilizer and a multi-element potassium fertilizer. In addition to potassium, sulfur, and magnesium, it also contains calcium, silicon, boron, iron, zinc and other elements. It is known as the "platinum potassium" for crop fertilization and is suitable for all crops. The yield-increasing effect is very obvious. Potassium sulfate magnesium fertilizer is usually used as a base fertilizer, but due to its strong water solubility, short effective period, and easy loss with water in the soil, the plant absorption and utilization rate is reduced, which cannot meet the needs of the entire growth cycle of crops, resulting in waste and easily polluting the environment and water bodies. In addition, when microorganisms are directly mixed with potassium sulfate magnesium fertilizer and applied, the high salt environment of potassium sulfate magnesium fertilizer can easily cause the inactivation of microorganisms, thereby reducing the effect.

[0004] Therefore, there is a need to find a fertilizer preparation method to solve the problem that microorganisms are incompatible with potassium magnesium sulfate fertilizers and that potassium magnesium sulfate fertilizers are highly water-soluble, resulting in easy loss and waste of nutrients, so as to improve the utilization rate of potassium magnesium sulfate fertilizers in the soil and thereby increase crop yield and quality. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a microbial-inorganic combination fertilizer and a preparation method thereof, so as to solve the problems that potassium sulfate and magnesium fertilizer are incompatible with microorganisms under conventional mixed application methods, resulting in reduced effect, and nutrients in potassium sulfate and magnesium fertilizer are easily lost and wasted.

[0006] The present invention solves the above technical problems by the following technical means:

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

[0008] Microbial culture liquid, 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] Furthermore, the microbial culture liquid is prepared by mixing a culture liquid of Metarhizium anisopliae, a culture liquid of Trichoderma harzianum and a culture liquid of Bacillus amyloliquefaciens in a mass ratio of 1:1:2.

[0010] Furthermore, when the microbial liquid is mixed and prepared, the concentration of the Metarhizium anisopliae liquid is 1-5×10 9 cfu / mL, the concentration of Trichoderma harzianum liquid was 2-4×10 9 cfu / mL, the concentration of Bacillus amyloliquefaciens culture liquid is 1-5×10 10 cfu / mL.

[0011] The present invention also discloses a preparation method of the combined fertilizer, and the specific preparation method is as follows:

[0012] A: Add glycerol to the microbial liquid and mix it slowly and evenly, then add biochar and culture it together on a shaker, then dissolve sodium alginate in water and add it to obtain a microbial mixture, drop the microbial mixture into a 2wt% calcium chloride solution to gel and form solidified balls, and wash the solidified balls with water 2-3 times to obtain a combined fertilizer A;

[0013] B: Dissolve xanthan gum in water, then add cinnamamide and diglycolamine, mix well, heat to 65-75°C, stir and react for 10-15 minutes, then adjust pH to 3-4, add urea and mix well, cool to room temperature and let stand for 4-6 hours to gel the xanthan gum, then dry, crush and pass through a 200-mesh sieve to obtain xanthan gum embedded microparticles;

[0014] C: Add calcium-based bentonite into water, stir and disperse, add potassium magnesium sulfate fertilizer and mix well, then add gum arabic and stearic acid in sequence and mix well to obtain a bentonite mixture, add xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation, and then dry to obtain a combination fertilizer B, and mix the combination fertilizer B with the combination fertilizer A to obtain a combination fertilizer.

[0015] Potassium-magnesium sulfate fertilizer is easily lost with water after being applied to the soil, which not only causes a waste of fertilizer, but also pollutes the environment and water quality. Therefore, the present invention uses calcium-based bentonite as a carrier and gum arabic as a binder to embed potassium-magnesium sulfate fertilizer to prepare a granular slow-release combination fertilizer B. After being applied to the soil, the moisture in the soil enters the interior of the granules to gradually dissolve it, so that it slowly diffuses from the granules into the soil for absorption and utilization by plants, thereby inhibiting loss and improving the absorption and utilization rate of plants.

[0016] Potassium sulfate and magnesium fertilizer are often used as base fertilizer, and it is necessary to ensure that they meet the needs of the entire growth cycle of crops as much as possible. Therefore, the present invention uses calcium-based bentonite to embed potassium sulfate and magnesium fertilizer to prepare granular fertilizer, and hydrophobic stearic acid is added to embed it into the granular fertilizer. Due to the presence of stearic acid, the moisture in the soil needs to bypass the stearic acid embedding area to enter the fertilizer particles to dissolve potassium sulfate and magnesium fertilizer so that it can be diffused for plant use. Therefore, the presence of stearic acid increases the mass transfer resistance of the combined fertilizer B particles, and then reduces its slow release amount when the potassium sulfate and magnesium fertilizer content in the early combined fertilizer B is high, to ensure the fertilizer supply in the later stage.

[0017] As time goes by, potassium sulfate and magnesium fertilizer are gradually released into the soil and absorbed by crops. The content of potassium sulfate and magnesium fertilizer in combination fertilizer B decreases, and thus the amount that can enter the soil gradually decreases. In order to ensure the uniform release and later supply of fertilizers, xanthan gum-encapsulated microparticles are added to combination fertilizer B. Specifically, xanthan gum is used to encapsulate cinnamamide, diglycolamine and urea. Xanthan gum has good acid-base stability and anti-biodegradability. Cinnamamide, diglycolamine and urea are slowly released in combination fertilizer B. Urea itself acts as a fertilizer to provide nutrients for plant growth and acts on the binder gum arabic in the combination fertilizer B particles to destroy its chemical bonds, thereby reducing Its viscosity makes the structure of the combined fertilizer B particles gradually loose; cinnamamide acts on the calcium-based bentonite, the embedding material of combined fertilizer B, by increasing the distance between bentonite molecules to increase the expansion rate of bentonite, thereby increasing the pore diameter, allowing more water to enter the particles to dissolve potassium magnesium sulfate fertilizer and release it better, increasing the slow-release amount of fertilizer in the middle and late stages; further, diglycolamine acts on stearic acid, by adjusting the substructure of stearic acid, reducing its stability in the soil and gradually decomposing it, gradually eliminating the mass transfer barrier effect of stearic acid; urea, cinnamamide and diglycolamine work together to increase the release rate and amount of fertilizer in the middle and late stages. Through the joint action of the various components in combined fertilizer B, the embedded potassium magnesium sulfate fertilizer can be released slowly and evenly over a long period of time, thereby playing a long-term role in nutrient supply.

[0018] Since the high salt environment of potassium sulfate and magnesium fertilizer will harm microorganisms, the present invention adds protective agent glycerol to the microorganism liquid and mixes it with biochar for co-cultivation, then adds sodium alginate and mixes it and drips it into calcium chloride to gel to make granular combination fertilizer A, biochar and glycerol can protect microorganisms, provide a suitable living environment and nutrition, ensure that microorganisms grow well in the high salt environment of potassium sulfate and magnesium fertilizer, promote crops to absorb nutrients in combination fertilizer B efficiently, create a good rhizosphere environment, improve soil properties, and release organic acids and other substances to neutralize the alkalinity of potassium sulfate and magnesium fertilizer and urea in combination fertilizer B, and maintain the stability of soil pH. Through the combined action of combination fertilizers A and B, the absorption and utilization rate of fertilizers is improved, soil properties are improved, crop yield and quality are improved, and fertilizer waste is reduced, the fertilizer action time is extended, and the fertilization operation cost is reduced.

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

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

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

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

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

[0024] Beneficial effects:

[0025] 1. The present invention uses potassium sulfate and magnesium fertilizer with multiple nutrient elements as the main effective ingredient, and prepares a slow-release granular fertilizer combination fertilizer B by embedding it with calcium-based bentonite, and adds embedded microparticles made of raw materials such as xanthan gum and cinnamamide to the granular fertilizer, so that the potassium sulfate and magnesium fertilizer in the combination fertilizer B can be slowly and evenly released over a long period of time, meeting the needs of the entire growth cycle of crops and effectively improving crop yield and quality.

[0026] 2. The present invention also adopts Metarhizium anisopliae, Trichoderma harzianum and Bacillus amyloliquefaciens to prepare microorganisms by mixing, and adopts biochar and sodium alginate for fixation to prepare combined fertilizer A. Combined fertilizer A not only creates a good rhizosphere environment and improves soil properties, but also promotes plants to absorb and utilize nutrients in combined fertilizer B. Through the joint action of various components in the combined fertilizer, the physical and chemical conditions of the soil are improved, and the crop yield and quality are increased, which has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : This is a picture of the growth status of the citrus in Example 1 of the experiment of the present invention after one year of planting;

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

[0029] The present invention will be described in detail below with reference to specific embodiments:

[0030] The present invention discloses a microorganism-inorganic combination fertilizer and a preparation method thereof. Before preparing the microorganism-inorganic combination fertilizer, a microorganism liquid is prepared. Specifically, the microorganism liquid is prepared by mixing a Metarhizium anisopliae liquid, a Trichoderma harzianum liquid and a Bacillus amyloliquefaciens liquid in a mass ratio of 1:1:2. The concentration of the Metarhizium anisopliae liquid is about 2×10 9 cfu / mL, the concentration of Trichoderma harzianum liquid is about 3×10 9 cfu / mL, the concentration of Bacillus amyloliquefaciens culture liquid is about 2×10 10 cfu / mL; then the combined fertilizer was further prepared, as shown below.

[0031] Embodiment 1: combination fertilizer preparation one

[0032] Preparation method:

[0033] A: 0.35 kg of glycerol was added to 1.5 kg of microbial liquid, and 6 kg of biochar was added after slowly stirring and mixing. Sterile water was injected to just cover the biochar, and the mixture was cultured together at a shaking table at a speed of 200 r / min for 24 h. Then 0.15 kg of sodium alginate was dissolved in 0.75 kg of water and added to obtain a microbial mixed liquid. The microbial mixed liquid was slowly dripped into a 2 wt % calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water 3 times to obtain a combined fertilizer A;

[0034] B: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, and 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 reaction for 12 minutes, and then the pH was adjusted to 3.5 and 0.6 kg of urea was added and mixed evenly, and then cooled to room temperature and allowed to stand for 5 hours to gel the xanthan gum, and then dried at 45°C, crushed and passed through a 200-mesh sieve to obtain xanthan gum embedded microparticles;

[0035] C: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of gum arabic and 0.6 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 2.5 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A at a mass ratio of 9:1.5 to obtain combined fertilizer.

[0036] Embodiment 2: Combination fertilizer preparation two

[0037] Preparation method:

[0038] A: 0.25 kg of glycerol was added to 1 kg of microbial liquid, and 4 kg of biochar was added after slowly stirring and mixing. Sterile water was injected to just cover the biochar, and the mixture was cultured together on a shaker at 200 r / min for 24 h. Then 0.1 kg of sodium alginate was dissolved in 0.5 kg of water and added to obtain a microbial mixture. The microbial mixture was slowly dripped into a 2 wt % calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water 3 times to obtain a combined fertilizer A.

[0039] B: 1 kg of xanthan gum was dissolved in 5 kg of water, and then 0.3 kg of cinnamamide and 0.3 kg of diglycolamine were added and mixed evenly, and then the temperature was raised to 65°C and stirred for 15 minutes, and then the pH was adjusted to 3, 0.5 kg of urea was added and mixed evenly, and then cooled to room temperature and allowed to stand for 4 hours to gel the xanthan gum, and then dried at 45°C, crushed and passed through a 200-mesh sieve to obtain xanthan gum embedded microparticles;

[0040] C: Add 20 kg of calcium-based bentonite into 60 kg of water, stir and disperse, add 15 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.2 kg of gum arabic and 0.5 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 2 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A in a mass ratio of 7:1 to obtain combined fertilizer.

[0041] Embodiment 3: Combination fertilizer preparation three

[0042] Preparation method:

[0043] A: 0.5 kg of glycerol was added to 2 kg of microbial liquid, and 8 kg of biochar was added after slowly stirring and mixing. Sterile water was injected to just cover the biochar, and the mixture was cultured together on a shaker at 200 r / min for 24 h. Then 0.2 kg of sodium alginate was dissolved in 1 kg of water and added to obtain a microbial mixed liquid. The microbial mixed liquid was slowly dripped into a 2 wt % calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water 3 times to obtain a 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 evenly, and then the temperature was raised to 75°C and stirred for reaction for 10 min, and then the pH was adjusted to 4, 0.8 kg of urea was added and mixed evenly, and then cooled to room temperature and allowed to stand for 6 hours to gel the xanthan gum, and then dried at 45°C, crushed and passed through a 200-mesh sieve to obtain xanthan gum embedded microparticles;

[0045] C: Add 30 kg of calcium-based bentonite into 90 kg of water, stir and disperse, add 25 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.6 kg of gum arabic and 1 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 3.5 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A in a mass ratio of 11:2 to obtain combined fertilizer.

[0046] Comparative Example 1: Preparation of combined fertilizer

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

[0048] A: 0.35 kg of glycerol was added to 1.5 kg of microbial liquid, and 6 kg of sterile water was added after slowly stirring and mixing. The mixture was cultured together on a shaker at 200 r / min for 24 h, and then 0.15 kg of sodium alginate was dissolved in 0.75 kg of water and added to obtain a microbial mixed liquid. The microbial mixed liquid was slowly dripped into a 2 wt % calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water 3 times to obtain a combined fertilizer A;

[0049] BC: Same as Example 1.

[0050] Comparative Example 2: Preparation of combined fertilizer

[0051] In contrast to Example 1, the only difference is that no glycerol is added in step A when preparing the combined fertilizer in Comparative Example 2, as shown below:

[0052] A: 6 kg of biochar was added to 1.5 kg of microbial liquid, and sterile water was injected to just cover the biochar. The mixture was cultured on a shaker at 200 r / min for 24 h, and then 0.15 kg of sodium alginate was dissolved in 0.75 kg of water and added to obtain a microbial mixture. The microbial mixture was slowly dripped into a 2 wt % calcium chloride solution to gel and form solidified balls with a particle size of about 0.3 cm. The solidified balls were washed with water 3 times to obtain a combined fertilizer A;

[0053] BC: Same as Example 1.

[0054] Comparative Example 3: Preparation of combined fertilizer

[0055] In contrast to Example 1, the only difference is that in Comparative Example 3, glycerol is not added during the preparation of the combined fertilizer, and the biochar is replaced by an equal amount of sterile water, as shown below:

[0056] A: 6 kg of sterile water was added to 1.5 kg of microbial liquid, and the mixture was shaken and cultured at 200 r / min for 24 h. Then, 0.15 kg of sodium alginate was dissolved in 0.75 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 a solidified ball with a particle size of about 0.3 cm. The solidified ball was washed with water 3 times to obtain a combined fertilizer A.

[0057] BC: Same as Example 1.

[0058] Comparative Example 4: Preparation of combined fertilizer

[0059] In contrast to Example 1, the only difference is that cinnamamide is not added in step B when preparing the combined fertilizer in Comparative Example 4, as shown below:

[0060] A: Same as Example 1;

[0061] B: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, and then 0.4 kg of diglycolamine was added and mixed evenly, and the mixture was heated to 70°C and stirred for 12 min, and then the pH was adjusted to 3.5, and 0.6 kg of urea was added and mixed evenly, and the mixture was cooled to room temperature and allowed to stand for 5 h to gel the xanthan gum, and then dried at 45°C, crushed and passed through a 200-mesh sieve to obtain xanthan gum-embedded microparticles;

[0062] C: Same as Example 1.

[0063] Comparative Example 5: Preparation of combined fertilizer

[0064] In contrast to Example 1, the only difference is that in Comparative Example 5, no diglycolamine is added in step B when preparing the combined fertilizer, as shown below:

[0065] A: Same as Example 1;

[0066] B: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, and then 0.4 kg of cinnamamide was added and mixed evenly, and then the temperature was raised to 70°C and stirred for reaction for 12 min, and then the pH was adjusted to 3.5, and then 0.6 kg of urea was added and mixed evenly, and then cooled to room temperature and allowed to stand for 5 hours to gel the xanthan gum, and 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 combined fertilizer

[0069] In contrast to Example 1, the only difference is that urea is not added in step B when preparing the combined fertilizer in Comparative Example 6, as shown below:

[0070] A: Same as Example 1;

[0071] B: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, and then 0.4 kg of cinnamamide and 0.4 kg of diglycolamine were added and mixed evenly, and then the mixture was heated to 70°C and stirred for 12 min. Then the mixture was cooled to room temperature and allowed to stand for 5 h to gel the xanthan gum, and 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 combined fertilizer

[0074] In contrast to Example 1, the only difference is that the pH is not adjusted in step B when preparing the combined fertilizer in Comparative Example 7, as shown below:

[0075] A: Same as Example 1;

[0076] B: 1.5 kg of xanthan gum was dissolved in 7.5 kg of water, and then 0.4 kg of cinnamamide and 0.4 kg of diglycolamine were added and mixed evenly, and the mixture was heated to 70°C and stirred for 12 min, and then 0.6 kg of urea was added and mixed evenly, and the mixture was cooled to room temperature and allowed to stand for 5 h to gel the xanthan gum, and 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 combined fertilizer

[0079] In contrast to Example 1, the only difference is that in Comparative Example 8, when preparing the combined fertilizer, xanthan gum is not used in step B, but gum arabic is used to prepare gum arabic embedded microparticles and added in step C, as shown below:

[0080] A: Same as Example 1;

[0081] B: 1.5 kg of gum arabic was dissolved in 7.5 kg of water, and then 0.4 kg of cinnamamide and 0.4 kg of diglycolamine were added and mixed evenly, and then the mixture was heated 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. After cooling to room temperature, the mixture was allowed to stand for 5 h to gel the gum arabic, and then 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 combined fertilizer

[0084] In contrast to Example 1, the only difference is that gum arabic is not added in step C when preparing the combined fertilizer in Comparative Example 9, as shown below:

[0085] AB: Same as Example 1;

[0086] C: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.6 kg of stearic acid and mix well to obtain a bentonite mixture, add 2.5 kg of xanthan gum-encapsulated microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A at a mass ratio of 9:1.5 to obtain combined fertilizer.

[0087] Comparative Example 10: Preparation of combined fertilizer

[0088] In contrast to Example 1, the only difference is that stearic acid is not added in step C when preparing the combined fertilizer in Comparative Example 10, as shown below:

[0089] AB: Same as Example 1;

[0090] C: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of gum arabic and mix well to obtain a bentonite mixture, add 2.5 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A at a mass ratio of 9:1.5 to obtain combined fertilizer.

[0091] Comparative Example 11: Preparation of combined fertilizer

[0092] In contrast to Example 1, the only difference is that in the preparation of the combined fertilizer in Comparative Example 11, gum arabic is not used in step C, but xanthan gum is used, as shown below:

[0093] AB: Same as Example 1;

[0094] C: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of xanthan gum and 0.6 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 2.5 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A at a mass ratio of 9:1.5 to obtain combined fertilizer.

[0095] Comparative Example 12: Preparation of combined fertilizer

[0096] In contrast to Example 1, the only difference is that in Comparative Example 12, when preparing the combined fertilizer, xanthan gum is not used to embed cinnamamide, diglycolamine and urea, but they are directly added in step C, as shown below:

[0097] A: Same as Example 1;

[0098] B: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of gum arabic and 0.6 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 0.4 kg of cinnamamide, 0.4 kg of diglycolamine and 0.6 kg of urea to the bentonite mixture, mix well, put into a granulator for granulation to prepare particles with a particle size of 0.4 cm, and then dry at 45°C to obtain combined fertilizer B, and mix combined fertilizer B with combined fertilizer A in a mass ratio of 9:1.5 to obtain combined fertilizer.

[0099] Comparative Example 13: Preparation of combined fertilizer

[0100] In contrast to Example 1, the only difference is that the preparation of the combined fertilizer in Comparative Example 13 lacks step B, that is, xanthan gum is not added to embed the microparticles during the preparation of the combined fertilizer B, as shown below:

[0101] A: Same as Example 1;

[0102] B: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, then add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of gum arabic and 0.6 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, put the bentonite mixture into a granulator for granulation to prepare particles with a particle size of 0.4 cm, then dry at 45°C to obtain combined fertilizer B, and mix the combined fertilizer B with the combined fertilizer A in a mass ratio of 9:1.5 to obtain a combined fertilizer.

[0103] Comparative Example 14: Preparation of combined fertilizer

[0104] In contrast to Example 1, the only difference is that the original step A is missing when preparing the combined fertilizer in Comparative Example 14, that is, the combined fertilizer B is a combined fertilizer, which is specifically as follows:

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

[0106] B: Add 25 kg of calcium-based bentonite into 75 kg of water, stir and disperse, add 20 kg of potassium magnesium sulfate fertilizer and mix well, then add 0.4 kg of gum arabic and 0.6 kg of stearic acid in sequence and mix well to obtain a bentonite mixture, add 2.5 kg of xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation to prepare granules with a particle size of 0.4 cm, and then dry at 45°C to obtain a combined fertilizer.

[0107] Experiment: Testing the Effect of Combined Fertilizers

[0108] 1. The application effect of the combined fertilizer prepared in Example 1 and Comparative Examples 1-14 was measured, and the specific method was as follows: Soil was collected from the citrus field of the Chongqing Southwest University Research Institute, and the experimental soil was obtained by stirring and mixing. The initial available potassium content and initial pH (available potassium content 125.4 mg / kg; pH=6.5) in the experimental soil were measured, and then the experimental soil was put into flower pots, 20 kg per pot, and the flower pots filled with the experimental soil were divided into 16 groups: corresponding to Example 1, Comparative Examples 1-14, and blank control, 3 pots per group. Then, the combined fertilizer of Example 1 and Comparative Examples 1-14 was applied to the corresponding group of flower pots, wherein 1050 g of combined fertilizer was applied to Example 1 and Comparative Examples 1-13, and Comparative Example 14 had no combined fertilizer A, then only 900 g of combined fertilizer of Comparative Example 14 was applied, and the blank control group was not applied; then citrus seedlings (Golden Autumn Sugar Orange) with the same growth status were planted in the pots, placed in an outdoor natural open-air environment, and managed and maintained according to the same method.

[0109] 2. 30 days after the citrus trees were planted, the dilution plate count method was used to detect the number of live bacteria of Metarhizium anisopliae, Trichoderma harzianum and Bacillus amyloliquefaciens in the soil of Example 1, Comparative Examples 1-3 and the blank control group, and the average data were shown in Table 1.

[0110] 3. The available potassium content in the soil of each group of flowerpots was measured again on the 10th, 30th and 70th day after citrus planting; the soil pH was measured again after 6 months, and the height growth of citrus seedlings in each group was counted. The average data is shown in Table 2.

[0111] Table 1

[0112]

[0113] Table 2

[0114]

[0115]

[0116] According to the data analysis in Table 1:

[0117] (1) The number of viable Metarhizium anisopliae in the soil of Example 1 was 6.1×10 5 cfu / g, viable count of Trichoderma harzianum 2.4×10 6 cfu / g, Bacillus amyloliquefaciens live bacteria 1.4×10 7 cfu / g, and the number of live bacteria of each strain remained at a high level, indicating that adding glycerol protective agent according to the method of the present invention and using biochar for loading can provide a good living environment for microorganisms, thereby ensuring that the microorganisms can grow and reproduce well in the high-salt environment of potassium sulfate and magnesium fertilizer in combination fertilizer B, and better play the effect, which better solves the problem of incompatibility between microorganisms and potassium sulfate and magnesium fertilizers.

[0118] According to the data analysis in Table 2:

[0119] (2) The content of available potassium in the soil increased significantly 10 days, 30 days and 70 days after the application of the combination fertilizer prepared by the present invention, indicating that the prepared combination fertilizer can slowly release nutrients for a long time and thus provide nutrients required for crop growth in a long-term manner; and the combination fertilizer A and the combination fertilizer B act synergistically, while ensuring the long-term effect of the fertilizer, maintaining the stability of soil pH and promoting the absorption of nutrients by crops, which better promotes the growth of citrus crops and significantly increases plant height.

[0120] (3) In comparative example 1, no biochar was added during the preparation of combined fertilizer A, in comparative example 2, no glycerol was added during the preparation of combined fertilizer A, and in comparative example 3, no glycerol and biochar were added during the preparation of combined fertilizer A. The activity growth of microorganisms in comparative examples 1-3 was affected. While the nutrient content in the soil remained high, the plant height growth rate decreased to varying degrees, and the pH change range was more obvious, indicating that microorganisms play an important role in improving fertilizer utilization.

[0121] (4) In comparative example 4, no cinnamamide was added during the preparation of the combined fertilizer B. The bentonite encapsulating material of the combined fertilizer B had low swelling performance in the middle and late stages, which inhibited the release of the internal potassium sulfate and magnesium fertilizer, and the available potassium content in the soil decreased when measured at 30 days and 70 days. In comparative example 5, no diglycolamine was added during the preparation of the combined fertilizer B. The mass transfer barrier effect of the stearic acid embedded in the particles resulted in a low release rate of the potassium sulfate and magnesium fertilizer in the middle and late stages, and the available potassium content in the soil decreased when measured at 30 days and 70 days. In comparative example 6, no urea was added during the preparation of the combined fertilizer B. The performance of the binder gum arabic was better, and the structure of the combined fertilizer particles was more stable and complete, which inhibited the release of the internal potassium sulfate and magnesium fertilizer. In comparative example 7, the pH was not adjusted when the xanthan gum was embedded in the microparticles. Under high pH conditions, the excessive release of urea increased the looseness of the embedded particles, which further resulted in a high release of potassium sulfate and magnesium fertilizer in the early stage and a reduction in nutrient supply in the later stage.

[0122] (5) In comparative example 8, xanthan gum was replaced with gum arabic during the preparation of combined fertilizer B, and in comparative example 9, gum arabic as a binder was not added during the preparation of combined fertilizer B. In comparative example 8, gum arabic had poor stability in the soil, and thus rapidly released cinnamamide, diglycolamine, and urea in the early and middle stages, prompting the combined fertilizer B particles to rapidly release potassium magnesium sulfate fertilizer in the early and middle stages, and the available nutrients were reduced in the later stages. In comparative example 9, no binder was added, and the granulation property of calcium-based bentonite was poor, resulting in an unstable particle structure and a rapid release of internal fertilizer components in the middle stage.

[0123] (6) In the preparation of the combined fertilizer B in comparative example 12, xanthan gum was not used to embed cinnamamide and the like, but was directly added in step C, resulting in that cinnamamide and the like components took effect quickly, reduced viscosity, and eliminated mass transfer obstacles, resulting in a large amount of fertilizer release in the early stage, and a reduction in the amount of nutrient release in the middle and late stages.

[0124] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A microbial-inorganic combined fertilizer, characterized in that: The combined fertilizer comprises the following raw materials: Microbial culture fluid, potassium magnesium sulfate fertilizer, urea, biochar, glycerol, sodium alginate, calcium chloride, xanthan gum, cinnamamide, diglycolamine, calcium bentonite, gum arabic, and stearic acid.

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

2.

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

4. A method for preparing a microbial-inorganic combined fertilizer, characterized in that: The method for preparing the combined fertilizer is as follows: A: Add glycerol to the microbial liquid and mix evenly, then add biochar and culture together on a shaker, then dissolve sodium alginate in water and add to obtain a microbial mixed liquid, drop the microbial mixed liquid into a 2wt% calcium chloride solution to gel and form solidified balls, wash the solidified balls with water 2-3 times to obtain a combined fertilizer A; B: After dissolving xanthan gum in water, add cinnamamide and diglycolamine and mix evenly, heat to 65-75°C and stir to react for 10-15 minutes, then adjust the pH to 3-4 and add urea and mix evenly, cool to room temperature and let stand for 4-6 hours to gel the xanthan gum, then dry and grind through a 200-mesh sieve to obtain xanthan gum embedded microparticles; C: Add calcium-based bentonite into water, stir and disperse, add potassium magnesium sulfate fertilizer and mix well, then add gum arabic and stearic acid in sequence and mix well to obtain a bentonite mixture, add xanthan gum-embedded microparticles into the bentonite mixture, mix well, put into a granulator for granulation, and then dry to obtain a combination fertilizer B, and mix the combination fertilizer B with the combination fertilizer A to obtain a combination fertilizer.

5. The method for preparing a microorganism-inorganic combination fertilizer according to claim 4, characterized in that: In the step A, the mass ratio of the microbial liquid, glycerol, biochar and sodium alginate is (1-2): (0.25-0.5): (4-8): (0.1-0.2).

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

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

8. The method for preparing a microorganism-inorganic combination fertilizer according to claim 7, characterized in that: The mass ratio of the combined fertilizer A to the combined fertilizer B in the combined fertilizer is (1-2):(7-11).

9. The method for preparing a microorganism-inorganic combination fertilizer according to claim 8, characterized in that: The granulation particle size in step C is 0.2-0.5 cm.

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